switch to npm ci for GitHub Action CI instead of npm install to save fime

Co-authored-by: Jeffrey Warren <jeff@unterbahn.com>

.github/CODEOWNERS

@@ -0,0 +1,75 @@
+# <-- DOCS FOR THIS FILE -->
+# This is a comment.
+# Each line is a file pattern followed by one or more owners.
+
+# These owners will be the default owners for everything in
+# the repo. Unless a later match takes precedence,
+# @global-owner1 and @global-owner2 will be requested for
+# review when someone opens a pull request.
+# *       @global-owner1 @global-owner2
+
+# Order is important; the last matching pattern takes the most
+# precedence. When someone opens a pull request that only
+# modifies JS files, only @js-owner and not the global
+# owner(s) will be requested for a review.
+# *.js    @js-owner
+
+# You can also use email addresses if you prefer. They'll be
+# used to look up users just like we do for commit author
+# emails.
+# *.go docs@example.com
+
+# In this example, @doctocat owns any files in the build/logs
+# directory at the root of the repository and any of its
+# subdirectories.
+# /build/logs/ @doctocat
+
+# The `docs/*` pattern will match files like
+# `docs/getting-started.md` but not further nested files like
+# `docs/build-app/troubleshooting.md`.
+# docs/*  docs@example.com
+
+# In this example, @octocat owns any file in an apps directory
+# anywhere in your repository.
+# apps/ @octocat
+
+# In this example, @doctocat owns any file in the `/docs`
+# directory in the root of your repository.
+# /docs/ @doctocat
+# <-- /DOCS FOR THIS FILE -->
+
+# <-- COMMON TO ALL MAINTAINERS -->
+/*.json @publiclab/is-maintainers
+/*.md @publiclab/is-maintainers
+/*.lock @ubliclab/is-maintainers
+/Gruntfile.js @publiclab/is-maintainers
+/.github/ @publiclab/is-maintainers
+/scripts/ @publiclab/is-maintainers
+# <-- /COMMON TO ALL MAINTAINERS -->
+
+# <-- SPECIFIC MAINTAINERS -->
+/index.js @publiclab/is-cli-maintainers
+/src/cli/ @publiclab/is-cli-maintainers
+/src/CliUtils.js @publiclab/is-cli-maintainers
+
+/src/*.js @publiclab/is-core-maintainers
+/src/*.json @publiclab/is-core-maintainers
+/src/util/ @publiclab/is-core-maintainers
+/test/core/* @publiclab/is-core-maintainers
+
+/src/modules/ @publiclab/is-module-maintainers
+/docs/ @publiclab/is-module-maintainers
+
+/test/ @publiclab/is-tests-maintainers
+/jest* @publiclab/is-tests-maintainers
+/eslint* @publiclab/is-tests-maintainers
+/travis* @publiclab/is-tests-maintainers
+.travis.yml @publiclab/is-tests-maintainers
+.gitpod* @publiclab/is-tests-maintainers
+/gitpod* @publiclab/is-tests-maintainers
+
+/examples/ @publiclab/is-ui-maintainers
+/icons/ @publiclab/is-ui-maintainers
+/test/ui-2/test/* @publiclab/is-ui-maintainers
+/test/ui/spec/* @publiclab/is-ui-maintainers
+# <-- /SPECIFIC MAINTAINERS -->

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,3 +1,10 @@
+---
+name: Bug report 🐞
+about: Help us identify and fix a bug!
+title: ''
+labels: bug
+---
+
 ### Please describe the problem (or idea)
 
 > What happened just before the problem occurred? Or what problem could this idea solve?
@@ -10,13 +17,13 @@
 
 ### Please show us where to look
 
-https://beta.sequencer.publiclab.org
+Paste in a full URL, starting with:
 
+> https://beta.sequencer.publiclab.org/
 
-### What's your PublicLab.org username?
-
-> This can help us diagnose the issue:
+If you can share a screenshot or a GIF that is EXTRA helpful! 💖
 
+If you can see a version number in the upper right, please note that!
 
 
 ### Browser, version, and operating system

.github/ISSUE_TEMPLATE/release_workflow.md

@@ -0,0 +1,39 @@
+---
+name: New release checklist ✅
+about: Coordinate steps to publish a new release
+title: 'Checklist and coordination for v0.0.0 major/minor/patch release'
+labels: release
+assignees: '@publiclab/is-maintainers'
+---
+
+This template guides us through the steps of creating a new release, based on conversation and testing in [#1692](https://github.com/publiclab/image-sequencer/issues/1692).
+
+Discuss with @publiclab/is-maintainers if anything is ambiguous!
+
+<!-- NOTE: Change v0.0.0 to the appropriate release version -->
+
+* [x] open an issue using the "release" template with this checklist with title `Checklist and coordination for v0.0.0 major/minor/patch release` (see [semantic versioning](https://docs.npmjs.com/about-semantic-versioning/))
+* [ ] create a release [project](https://github.com/publiclab/image-sequencer/projects) from [this template](https://github.com/publiclab/image-sequencer/projects/5). You can copy a project from its menu.
+* [ ] compile release notes below from corresponding [release project](https://github.com/publiclab/image-sequencer/projects).
+* [ ] update version number in `examples/sw.js` (ex #1734) and `package.json` (ex #1695)
+* [ ] finalize and merge to `main` branch (freeze merges to `main` branch until next step)
+* [ ] merge, build and publish `/dist/` files to `stable` (merges to `main` branch can resume for next release)
+* [ ] create a release on GitHub and use features description + release notes from below
+* [ ] tag version number branch (i.e. `v0.0.0`)
+* [ ] publish tagged branch to `npm`
+* [ ] publish to live Github pages [demo](https://sequencer.publiclab.org) (with [bash script](https://github.com/publiclab/image-sequencer/pull/1703) from `/scripts/update-demo`) (from within GitPod works well)
+* [ ] move anything necessary to next release project, i.e. <!-- Update this link -->https://github.com/publiclab/image-sequencer/projects/[insert project number]
+* [ ] close this issue!
+
+Noting we're now in this process in https://github.com/publiclab/image-sequencer/pull/1695 for `v3.6.0`.
+
+****
+
+### Release notes
+Compile and edit release notes below, to be copied into the release description.
+
+#### Added
+
+#### Fixed
+
+#### Changed

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,7 +2,7 @@ Fixes #0000  (<=== Replace `0000` with the Issue Number)
 
 Make sure these boxes are checked before your pull request (PR) is ready to be reviewed and merged. Thanks!
 
-* [ ] tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR -- or run tests locally with `npm test`
+* [ ] tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR -- or run tests locally with `npm run test-all`
 * [ ] code is in uniquely-named feature branch and has no merge conflicts
 * [ ] PR is descriptively titled
 * [ ] ask `@publiclab/is-reviewers` for help, in a comment below

.github/config.yml

@@ -4,22 +4,27 @@
 
 # Comment to be posted to on first time issues
 newIssueWelcomeComment: |
-  Thanks for opening your first issue here! Please follow the issue template to help us help you 👍🎉😄
-  If you have screenshots to share demonstrating the issue, that's really helpful! 📸 You can [make a gif](https://www.cockos.com/licecap/) too!
+ Thanks for opening your first issue here! This space is [protected by our Code of Conduct](https://publiclab.org/conduct) - and we're here to help.
+ Please follow the issue template to help us help you 👍🎉😄
+ If you have screenshots to share demonstrating the issue, that's really helpful! 📸 You can [make a gif](https://www.cockos.com/licecap/) too!
+ Don't forget to join our [PublicLab Gitter channel](https://gitter.im/publiclab/publiclab) and our [ImageSequencer Gitter Channel](https://gitter.im/publiclab/image-sequencer) for some brainstorming discussions. 
 # Configuration for new-pr-welcome - https://github.com/behaviorbot/new-pr-welcome
 
 # Comment to be posted to on PRs from first time contributors in your repository
 newPRWelcomeComment: |
- Thanks for opening this pull request!
+ Thanks for opening this pull request! This space is [protected by our Code of Conduct](https://publiclab.org/conduct).
  There may be some errors, **but don't worry!** We're here to help! 👍🎉😄
+ Also please refer (https://github.com/publiclab/image-sequencer/blob/main/README.md) for installation help.
 # Configuration for first-pr-merge - https://github.com/behaviorbot/first-pr-merge
 
 # Comment to be posted to on pull requests merged by a first time user
 firstPRMergeComment: |
  Congrats on merging your first pull request! 🙌🎉⚡️ 
- Your code will be published to https://beta.sequencer.publiclab.org in a day or two. 
- In the meantime, can you tell us your Twitter handle so we can thank you properly?
- Now that you've completed this, you can help someone else take their first step!
+ Your code will be published to https://beta.sequencer.publiclab.org in a day or two. Please test out your work on this testing server and report back with a comment that all has gone well!
+ In the meantime, can you tell us your Twitter handle so we can thank you properly also do join our weekly check-in to share your this week goal and the awesome work you did 😃. 
+ Please find the link **pinned in the issue section**
+ Now that you've completed this, you can help someone else take their first step! Try looking at this list of `first-timers-only` issues, and see if someone else is waiting for feedback, or even stuck! 😕
+ People often get stuck at the same steps, so you might be able to help someone get unstuck, or help lead them to some documentation that'd help. Reach out and be encouraging and friendly! 😄 🎉  
  See: [Public Lab's coding community!](https://code.publiclab.org)
 
 # It is recommended to include as many gifs and emojis as possible

.github/workflows/tests.yml

@@ -0,0 +1,209 @@
+name: tests
+on: [pull_request]
+jobs:
+  base-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm ci
+    - name: "Base istanbul/tape node tests"
+      run: npm test
+
+  benchmark-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "Benchmark tests"
+      run: npm run benchmark
+
+  gif-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "Gif tests"
+      run: npm run gif-test
+
+  browserify-core-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - run: sudo apt-get install xvfb
+    - name: "Browserify core tests and run"
+      run: grunt tests && xvfb-run --auto-servernum npm run core-tests
+
+  jsmine-ui-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "Jasmine UI tests (mocked browser env)"
+      run: npm run test-ui
+
+  jest-ui-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "jest-puppeteer UI tests (full browser env)"
+      run: npm run test-ui-2    
+
+  cli-tests:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "CLI tests"
+      run: npm run test-cli
+
+  grunt-build-test:
+    runs-on: ubuntu-18.04
+    steps:
+    - uses: actions/checkout@v2
+    - name: Setup node
+      uses: actions/setup-node@v2
+      with:
+        node-version: '12'
+        check-latest: true
+    - name: Cache node modules
+      uses: actions/cache@v2
+      env:
+        cache-name: cache-node-modules
+      with:
+        path: ~/.npm
+        key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/package-lock.json') }}
+        restore-keys: |
+          ${{ runner.os }}-build-${{ env.cache-name }}-
+          ${{ runner.os }}-build-
+          ${{ runner.os }}-
+    - name: Install Dependencies
+      run: npm install
+    - name: "Grunt build test of dev environment"
+      run: grunt build
+
+## Cache NPM folder
+# cache:
+#   directories:
+#     - ~/.npm
+#     - ~/.cache

.gitpod.dockerfile

@@ -0,0 +1,63 @@
+FROM gitpod/workspace-full
+
+USER root
+RUN sudo apt-get update && apt-get install -y apt-transport-https \
+ && sudo apt-get install -y \
+    xserver-xorg-dev \
+    libxext-dev \
+    build-essential \
+    libxi-dev \
+    libglew-dev \
+    pkg-config \
+    libglu1-mesa-dev \
+    freeglut3-dev \
+    mesa-common-dev \
+    x11-apps \
+    libice6 \
+    libsm6 \
+    libxaw7 \
+    libxft2 \
+    libxmu6 \
+    libxpm4 \
+    libxt6 \
+    x11-apps \
+    xbitmaps \
+    ca-certificates \
+    fonts-liberation \
+    libappindicator3-1 \
+    libasound2 \
+    libatk-bridge2.0-0 \
+    libatk1.0-0 \
+    libc6 \
+    libcairo2 \
+    libcups2 \
+    libdbus-1-3 \
+    libexpat1 \
+    libfontconfig1 \
+    libgbm1 \
+    libgcc1 \
+    libglib2.0-0 \
+    libgtk-3-0 \
+    libnspr4 \
+    libnss3 \
+    libpango-1.0-0 \
+    libpangocairo-1.0-0 \
+    libstdc++6 \
+    libx11-6 \
+    libx11-xcb1 \
+    libxcb1 \
+    libxcomposite1 \
+    libxcursor1 \
+    libxdamage1 \
+    libxext6 \
+    libxfixes3 \
+    libxi6 \
+    libxrandr2 \
+    libxrender1 \
+    libxss1 \
+    libxtst6 \
+    lsb-release \
+    wget \
+    xdg-utils \
+    xvfb \
+ && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/*

.gitpod.yml

@@ -0,0 +1,18 @@
+image:
+  file: .gitpod.dockerfile
+tasks:
+  - init: npm run setup
+    command: npm start
+ports:
+  - port: 3000
+    onOpen: open-preview
+
+github:
+  prebuilds:
+    branches: true
+    pullRequests: true
+    pullRequestsFromForks: true
+    addCheck: true
+    addComment: true
+    addBadge: false
+    addLabel: false

.travis.yml

@@ -1,8 +1,8 @@
 sudo: required
 language: node_js
 node_js:
-  - '8'
   - '10'
+  - '12'
 env:
   - CXX=g++-4.8
 before_script:
@@ -10,10 +10,24 @@ before_script:
   - curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
   - chmod +x ./cc-test-reporter
   - ./cc-test-reporter before-build
-script:
-  - npm test
-  - npm run test-ui
-  - grunt build
+jobs:
+  include:
+    - name: "Base istanbul/tape node tests"
+      script: npm test
+    - name: "Benchmark tests"
+      script: npm run benchmark
+    - name: "Gif tests"
+      script: npm run gif-test
+    - name: "Browserify core tests and run"
+      script: grunt tests && npm run core-tests
+    - name: "Jasmine UI tests (mocked browser env)"
+      script: npm run test-ui
+    - name: "jest-puppeteer UI tests (full browser env)"
+      script: npm run test-ui-2    
+    - name: "CLI tests"
+      script: npm run test-cli
+    - name: "Grunt build test of dev environment"
+      script: grunt build
 after_success:
   - bash <(curl -s https://codecov.io/bash)
 after_script:

CONTRIBUTING.md

@@ -17,6 +17,7 @@ Most contribution (we imagine) would be in the form of API-compatible modules, w
 * [Ideas](#Contribution-ideas)
 * [Grunt Tasks](#grunt-tasks)
 * [UI Helper Methods](#ui-helper-methods)
+* [Scripts](#scripts)
 
 ****
 
@@ -374,7 +375,7 @@ module.exports =
 We are now using `eslint` and `husky` to help lint and format our code each time we commit. Eslint defines coding standards and helps in cleaning up the code. To run eslint for checking errors globally or within a specific file run:
 
 ```
-npx eslint . 
+npx eslint .
 
 npx eslint <file path>
 ```
@@ -412,15 +413,15 @@ The following command is used for running the tasks: `grunt [task-name]`. Here `
 
 The method returns a scoped `jQuery` object which only searches for elements inside a given scope (a DOM element).
 
-To use the method, 
+To use the method,
 * import the `scopeSelector` and `scopeSelectorAll` methods from `lib/scopeQuery.js`
 * call the methods with scope as a parameter
-	
+
 ```js
 var scopeQuery = require('./scopeQuery');
 
 var $step = scopeQuery.scopeSelector(scope),
-    $stepAll = scopeQuery.scopeSelectorAll(scope);	
+    $stepAll = scopeQuery.scopeSelectorAll(scope);
 ```
 This will return an object with a constructor which returns a `jQuery` object (from inside the scope) but with new `elem` and `elemAll` methods.
 
@@ -433,7 +434,7 @@ This will return an object with a constructor which returns a `jQuery` object (f
 #### Example
 
 ```js
-//The scope is a div element with id=“container“ and there are three divs in it 
+//The scope is a div element with id=“container“ and there are three divs in it
 //with ids „1“, „2“, and „3“, and all of them have a „child“ class attribute
 
 var $step = require('./scopeQuery').scopeSelector(document.getElementById('container'));
@@ -458,3 +459,23 @@ The following code can be used
 $step('query').show().hide();
 $stepAll('q2').show().hide();
 ```
+
+## Scripts
+The following shell scripts are present in the `scripts/` directory.
+
+- `update-gh-pages`: This script can be used to update the `gh-pages` branch of this repo or a fork.
+ This script is not meant to be used directly as it runs in the current working directory.
+ If you run it on your primary local clone, it can **delete** the local changes. This script is made to be used in a github action
+ or in a temporary directory via another script, such as `update-demo`.
+
+  Arguments:
+  1. Repo(to use as upstream) url in the form username/repo (default: publiclab/image-sequencer) NOTE: Github only
+  2. Branch to pull from eg: main or stable (default: stable)
+  3. CNAME URL (default: none)
+  4. Set the fourth argument to anything to bypass the warning. You will have to set this argument if you want to run this script in another script without needing
+  user interaction, such as in a github action.
+
+- `update-demo`: A safe, interactive script that can be used to update the `gh-pages` branch of any image-sequencer fork.
+ This script is safe to use directly because it separately clones the repo in a temporary directory.
+
+  Arguments: None since it is a an *interactive* script, ie it asks the user for input.

Gruntfile.js

@@ -2,6 +2,7 @@ module.exports = function(grunt) {
   grunt.loadNpmTasks('grunt-browserify');
   grunt.loadNpmTasks('grunt-contrib-uglify-es');
   grunt.loadNpmTasks('grunt-browser-sync');
+  grunt.loadNpmTasks('grunt-text-replace');
 
   require('matchdep')
     .filterDev('grunt-*')
@@ -21,6 +22,11 @@ module.exports = function(grunt) {
     },
 
     browserify: {
+      options: {
+        alias: {
+          'gpu.js': './node_modules/gpu.js/src/index.js'
+        }
+      },
       core: {
         src: ['src/ImageSequencer.js'],
         dest: 'dist/image-sequencer.js'
@@ -36,6 +42,28 @@ module.exports = function(grunt) {
       produi: {
         src: ['examples/demo.js'],
         dest: 'dist/image-sequencer-ui.brow.js'
+      },
+      tests: {
+        src: ['test/core/sequencer/meta-modules.js',
+              'test/core/sequencer/image-sequencer.js',
+              'test/core/sequencer/chain.js',
+              'test/core/sequencer/replace.js',
+              'test/core/sequencer/import-export.js',
+              'test/core/sequencer/run.js',
+              'test/core/sequencer/dynamic-imports.js',
+              'test/core/util/*.js'],
+        dest: './output/core-tests.js'
+      }
+    },
+
+    replace: {
+      version: {
+        src: ['examples/sw.js'],
+        overwrite: true,
+        replacements: [{
+          from: /image-sequencer-static-v.*/g,
+          to: "image-sequencer-static-v<%= pkg.version %>';"
+        }]
       }
     },
 
@@ -69,8 +97,10 @@ module.exports = function(grunt) {
 
   /* Default (development): Watch files and build on change. */
   grunt.registerTask('default', ['watch']);
-  grunt.registerTask('build', ['browserify:core', 'browserify:ui', 'uglify:core', 'uglify:ui']);
-  grunt.registerTask('serve', ['browserify:core', 'browserify:ui', 'browserSync', 'watch']);
+  grunt.registerTask('build', ['browserify:core', 'browserify:ui', 'replace:version', 'uglify:core', 'uglify:ui']);
+  grunt.registerTask('serve', ['browserify:core', 'browserify:ui', 'replace:version', 'browserSync', 'watch']);
   grunt.registerTask('compile', ['browserify:core', 'browserify:ui']);
-  grunt.registerTask('production', ['browserify:prodcore', 'browserify:produi', 'uglify:prodcore', 'uglify:produi']);
+  grunt.registerTask('production', ['browserify:prodcore', 'browserify:produi', 'replace:version', 'uglify:prodcore', 'uglify:produi']);
+
+  grunt.registerTask('tests', ['browserify:tests']);
 };

README.md

@@ -1,13 +1,19 @@
 Image Sequencer
 ====
 
-
+[![Code of Conduct](https://img.shields.io/badge/code-of%20conduct-green.svg)](https://publiclab.org/conduct)
+[![npm version](https://badge.fury.io/js/image-sequencer.svg)](https://badge.fury.io/js/image-sequencer)
 [![Build Status](https://travis-ci.org/publiclab/image-sequencer.svg?branch=master)](https://travis-ci.org/publiclab/image-sequencer) [![Maintainability](https://api.codeclimate.com/v1/badges/5906996dd2e90aca6398/maintainability)](https://codeclimate.com/github/publiclab/image-sequencer/maintainability) [![Codecov](https://img.shields.io/codecov/c/github/publiclab/image-sequencer.svg?logo=codecov)](https://codecov.io/gh/publiclab/image-sequencer)
+[![Gitpod Ready-to-Code](https://img.shields.io/badge/Gitpod-ready--to--code-blue?logo=gitpod)](https://gitpod.io/#https://github.com/publiclab/image-sequencer/)
 
 - **Latest Stable Demo**: https://sequencer.publiclab.org
 - **Latest Beta Demo**: https://beta.sequencer.publiclab.org
 - **Stable Branch**: https://github.com/publiclab/image-sequencer/tree/stable/
 
+Begin running (and contributing to) this codebase immediately with [GitPod](https://gitpod.io) (this also opens the latest `main` branch code):
+
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/#https://github.com/publiclab/image-sequencer)
+
 ## Why
 
 Image Sequencer is different from other image processing systems because it's _non-destructive_: instead of modifying the original image, it **creates a new image at each step in a sequence**. This is because it:
@@ -71,6 +77,12 @@ In case of a port conflict please run the following
 npm i -g http-server ; http-server -p 3000
 ```
 
+### Online one-click setup for contributing
+
+Contribute to ImageSequencer using a fully featured online development environment that will automatically: clone the repo, install the dependencies and start the webserver.
+
+[![Open in Gitpod](https://gitpod.io/button/open-in-gitpod.svg)](https://gitpod.io/from-referrer/)
+
 ### Browser
 
 Just include [image-sequencer.min.js](https://github.com/publiclab/image-sequencer/blob/stable/dist/image-sequencer.min.js) in the Head section of your web page. See the [demo here](https://sequencer.publiclab.org)!
@@ -598,4 +610,17 @@ let sequencer = ImageSequencer() // also for wasm mode i.e. default mode
 
 let sequencer = ImageSequencer({useWasm:false}) //for non-wasm mode 
 
-```
+```
+
+## Experimental GIF processing support
+
+ImageSequencer currently can process GIFs but only for most of the modules. Every frame of the GIF is manipulated sequentially (parallel processing would be preferable in the future).
+The final frames are then converted back to a GIF but in the process, the time duration of each frame is lost and defaults to `0.1s`.
+
+Modules that do not work:
+1. ColorBar (Will get fixed upon fixing overlay as this is a meta module which uses overlay)
+2. FisheyeGL
+3. Overlay
+4. Blend
+5. Histogram
+6. WebGL Distort

docs/MODULES.md

@@ -8,40 +8,44 @@ List of Module Documentations
 3.  [Blend](#blend-module)
 4.  [Blur](#blur-module)
 5.  [Brightness](#brightness-module)
-6.  [Channel](#channel-module)
-7.  [Colorbar](#colorbar-module)
-8.  [Colormap](#colormap-module)
-9.  [ColorTemperature](#color-temperature)
-10. [Contrast](#contrast-module)
-11. [Convolution](#convolution-module)
-12. [Crop](#crop-module)
-13. [DecodeQr](#decodeQr-module)
-14. [Dither](#dither-module)
-15. [DrawRectangle](#draw-rectangle-module)
-16. [Dynamic](#dynamic-module)
-17. [Edge-Detect](#edge-detect-module)
-18. [FisheyeGl](#fisheyeGl-module)
-19. [FlipImage](#flipimage-module)
-20. [Gamma-Correction](#gamma-correction-module)
-21. [Gradient](#gradient-module)
-22. [Grid-Overlay](#grid-overlay)
-23. [Histogram](#histogram-module)
-24. [Import-image](#import-image-module)
-25. [Invert](#invert-module)
-26. [MinifyImage](#minify-image)
-27. [Ndvi](#ndvi-module)
-28. [Ndvi-Colormap](#ndvi-colormap-module)
-29. [NoiseReduction](#noise-reduction)
-30. [Overlay](#overlay-module)
-31. [PaintBucket](#paint-bucket-module)
-32. [ReplaceColor](#replacecolor-module)
-33. [Resize](#resize-module)
-34. [Rotate](#rotate-module)
-35. [Saturation](#saturation-module)
-36. [Segmented-Colormap](#segmented-colormap-module)
-37. [Text-Overlay](#text-overlay)
-38. [Threshold](#threshold)
-39. [Tint](#tint)
+6.  [Canvas-Resize](#canvas-resize-module)
+7.  [Channel](#channel-module)
+8.  [Colorbar](#colorbar-module)
+9.  [Colormap](#colormap-module)
+10. [ColorTemperature](#color-temperature)
+11. [Contrast](#contrast-module)
+12. [Convolution](#convolution-module)
+13. [Crop](#crop-module)
+14. [DecodeQr](#decodeQr-module)
+15. [Dither](#dither-module)
+16. [DrawRectangle](#draw-rectangle-module)
+17. [Dynamic](#dynamic-module)
+18. [Edge-Detect](#edge-detect-module)
+19. [Exposure](#exposure-module)
+20. [FisheyeGl](#fisheyeGl-module)
+21. [FlipImage](#flipimage-module)
+22. [Gamma-Correction](#gamma-correction-module)
+23. [Gradient](#gradient-module)
+24. [Grid-Overlay](#grid-overlay)
+25. [Histogram](#histogram-module)
+26. [Import-image](#import-image-module)
+27. [Invert](#invert-module)
+28. [MinifyImage](#minify-image)
+29. [Ndvi](#ndvi-module)
+30. [Ndvi-Colormap](#ndvi-colormap-module)
+31. [NoiseReduction](#noise-reduction)
+32. [Overlay](#overlay-module)
+33. [PaintBucket](#paint-bucket-module)
+34. [ReplaceColor](#replacecolor-module)
+35. [Resize](#resize-module)
+36. [Rotate](#rotate-module)
+37. [Saturation](#saturation-module)
+38. [Segmented-Colormap](#segmented-colormap-module)
+39. [Text-Overlay](#text-overlay)
+40. [Threshold](#threshold)
+41. [Tint](#tint)
+42. [WebGL-Distort](#webgl-distort-module)
+43. [White-Balance](#white-balance-module)
 
 
 ## add-qr-module
@@ -74,7 +78,8 @@ This module is used for averaging all the pixels of the image.
 
 ## blend-module
 
-This module is used for blending two images .
+This module is used for blending two images. For More info read:  _[wiki](https://en.wikipedia.org/wiki/Blend_modes)_
+
 #### Usage
 
 ```js
@@ -84,8 +89,12 @@ This module is used for blending two images .
 ```
 
 where `options` is an object with the following properties:
-* offset: step of image with which current image is to be blended(Two steps back is -2, three                steps back is -3 etc; default -2) 
-* func: function used to blend two images (default : function(r1, g1, b1, a1, r2, g2, b2, a2) {            return [ r1, g2, b2, a2 ] })
+* offset: step of image with which current image is to be blended(Two steps back is -2, three steps back is -3 etc; default -2) 
+* blendMode: Blending mode to use for blending two images by default it uses the given function
+* func: function used to blend two images (default : function(r1, g1, b1, a1, r2, g2, b2, a2) { return [ r1, g2, b2, a2 ] })
+
+[More info for different blend modes can be found here](http://docs.gimp.org/en/gimp-concepts-layer-modes.html)
+
 
 ## Blob Analysis
 
@@ -131,6 +140,24 @@ where `options` is an object with the following property:
 * brightness : brightness of the image in percentage (0 to 100; default 100)
 
 
+## canvas-resize-module
+
+This module is used for resizing the canvas of the image.
+#### Usage
+
+```js
+  sequencer.loadImage('PATH')
+           .addSteps('canvas-resize',options)
+           .run()
+```
+
+where `options` is an object with the following property:
+* width: final width of the canvas (default 1000)
+* height: final height of the canvas (default 1000)
+* x: x-coordinate of the top left of the image on the canvas (default 500)
+* y: y-coordinate of the top left of the image on the canvas (default 500)
+
+
 ## channel-module
 
 This module is used for forming a grayscale image by applying one of the three primary colors.
@@ -327,6 +354,21 @@ where `options` is an object with the following properties:
 * lowThresholdratio : Lower Threshold Ratio ( default : 0.2)
 
 
+## exposure-module
+
+This module is used for changing the exposure of the image.
+#### Usage
+
+```js
+  sequencer.loadImage('PATH')
+           .addSteps('exposure',options)
+           .run()
+```
+
+where `options` is an object with the following property:
+* exposure: exposure value for the new image (-3 to 4; default 1)
+
+
 ## fisheyeGl-module
 
 This module is used for correcting Fisheye or Lens Distortion
@@ -667,3 +709,38 @@ It adds color tint to an image
 where `options` is an object with the following property:
 * color : RGB values seperated by a space (default "0 0 255")
 * factor : amount of tint (default 0.5)
+
+
+## webgl-distort-module
+
+This module is used for transforming the perspective of images based on corner coordinates.
+#### Usage
+
+```js
+  sequencer.loadImage('PATH')
+           .addSteps('webgl-distort',options)
+           .run()
+```
+
+where `options` is an object with the following property:
+* nw: top-left corner x and y coordinates separated by a comma (default "0,100")
+* ne: top-right corner x and y coordinates separated by a comma (default "1023,-50")
+* se: bottom-right corner x and y coordinates separated by a comma (default "1223,867")
+* sw: bottom-left corner x and y coordinates separated by a comma (default "100,767")
+
+
+## white-balance-module
+
+This module is used for rendering neutral colors of an image correctly based on the whitest pixel in the image.
+#### Usage
+
+```js
+  sequencer.loadImage('PATH')
+           .addSteps('white-balance',options)
+           .run()
+```
+
+where `options` is an object with the following property:
+* red: red component of the whitest pixel (default 255)
+* green: green component of the whitest pixel (default 255)
+* blue: blue component of the whitest pixel (default 255)

examples/demo.css

@@ -1,12 +1,8 @@
 /* https://github.com/theleagueof/league-spartan */
 @font-face {
   font-family: 'League Spartan';
-  src: url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.eot');
-  src: url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.eot?#iefix') format('embedded-opentype'),
-       url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.woff2') format('woff2'),
-       url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.woff') format('woff'),
-       url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.ttf') format('truetype'),
-       url('https://raw.githubusercontent.com/theleagueof/league-spartan/master/_webfonts/leaguespartan-bold.svg#league_spartanbold') format('svg');
+  src: url('https://cdn.jsdelivr.net/npm/fontsource-league-spartan@3/files/league-spartan-latin-600-normal.woff2') format('woff2'),
+       url('https://cdn.jsdelivr.net/npm/fontsource-league-spartan@3/files/league-spartan-latin-600-normal.woff') format('woff');
   font-weight: bold;
   font-style: normal;
 }
@@ -33,7 +29,7 @@ body > .container-fluid {
 
 .center-align {
   display: flex;
-  justify-content: center;
+  justify-content: left;
   text-align:center;
 }
 
@@ -44,7 +40,6 @@ body > .container-fluid {
 .panel {
   margin-left: 20px;
   margin-right: 20px;
-  min-width:400px;
 }
 
 .mouse {
@@ -66,17 +61,26 @@ body > .container-fluid {
   border-radius: 8px;
   text-align: center;
   color: #444;
-  min-width:300px;
-}
-
-.hover {
-  background: #eee;
 }
 
 .dropzone input {
   max-width: 100%;
 }
 
+.import-image-zone {
+  margin: 10px auto 30px auto;
+  max-width: 250px;
+  min-width: 230px;
+}
+
+.import-image-zone input {
+  max-width: 100%;
+}
+
+.hover {
+  background: #eee;
+}
+
 .step {
   margin-bottom: 20px;
 }
@@ -146,6 +150,13 @@ body > .container-fluid {
   margin: 0px 0px 0px 10px;
   width: 250px;
 }
+
+@media(max-width: 768px) {
+    #dropzone {
+      margin: 0 0% 30px;
+    }
+}
+
 #dwnld {
   max-width: 500px;
   margin: 20px auto;
@@ -252,7 +263,7 @@ a.name-header{
 }
 
 .step-column{
-  display:flex; 
+  display:flex;
   align-content: center;
   justify-content: center;
 }
@@ -276,9 +287,9 @@ a.name-header{
   width:100%;
 }
 .save-button{
-  margin-top:20px; 
+  margin-top:20px;
   margin-bottom:0px;
-  align:center; 
+  align:center;
   width:100%;
 }
 
@@ -286,21 +297,74 @@ a.name-header{
   cursor: default;
 }
 
-.dimension-tooltip:hover{
-  text-decoration: none;  
+.general-tooltip:hover{
+  text-decoration: none;
 }
 
-.dimension-tooltip:focus{
+.general-tooltip:focus{
   outline: none;
 }
 
-.dimension-tooltip:focus-within{
+.general-tooltip:focus-within{
   outline: none;
 }
 
-.dimension-tooltip{
+.general-tooltip{
   position: relative;
   bottom: 7px;
   font-size: 16px;
   color: #444;
-}
+}
+
+#version-number-text {
+  text-align: center;
+  padding-top: 100px;
+  color: gray;
+}
+#version-number-top-right {
+  position: fixed;
+  right: 2%;
+  top: 5%;
+  color: gray;
+}
+/* Non float rightward alignment*/
+.right {
+  margin-left: auto;
+  display: block;
+}
+
+#update-prompt-modal {
+ visibility: hidden;
+ min-width: 250px;
+ margin-left: -125px;
+ background-color: #333;
+ color: #fff;
+ text-align: center;
+ border-radius: 2px;
+ padding: 16px;
+ position: fixed;
+ z-index: 1000;
+ left: 10%;
+ top: 30px;
+}
+#update-prompt-modal.show {
+ visibility: visible;
+ -webkit-animation: fadein 0.5s;
+ animation: fadein 0.5s;
+}
+@-webkit-keyframes fadein {
+ from {
+   opacity: 0;
+ }
+ to {
+   opacity: 1;
+ }
+}
+@keyframes fadein {
+ from {
+   opacity: 0;
+ }
+ to {
+   opacity: 1;
+ }
+}

examples/demo.js

@@ -3,12 +3,48 @@ var defaultHtmlSequencerUi = require('./lib/defaultHtmlSequencerUi.js'),
   intermediateHtmlStepUi = require('./lib/intermediateHtmlStepUi.js'),
   DefaultHtmlStepUi = require('./lib/defaultHtmlStepUi.js'),
   urlHash = require('./lib/urlHash.js'),
-  insertPreview = require('./lib/insertPreview.js');
+  insertPreview = require('./lib/insertPreview.js'),
+  versionManagement = require('./lib/versionManagement.js'),
+  isGIF = require('../src/util/isGif');
+
 
 window.onload = function () {
-  sequencer = ImageSequencer();
+  sequencer = ImageSequencer(); // Set the global sequencer variable
+  
+  options = {
+    sortField: 'text',
+    openOnFocus: false,
+    onInitialize: function () {
+      this.$control.on('click', () => {
+        this.ignoreFocusOpen = true;
+        setTimeout(() => {
+          // Trigger onFocus and open dropdown.
+          this.ignoreFocusOpen = false;
+        }, 50);
+      });
+    },
+    // Open dropdown after timeout of onClick.
+    onFocus: function () {
+      if (!this.ignoreFocusOpen) {
+        this.open();
+      }
+    }
+  };
 
-  function refreshOptions() {
+  versionManagement.getLatestVersionNumber(function(versionNumber) {
+    console.log('The latest NPM version number for Image Sequencer (from GitHub) is v' + versionNumber);
+  });
+  console.log('The local version number for Image Sequencer is v' + versionManagement.getLocalVersionNumber());
+
+  function displayVersionNumber() {
+    $('#version-number-text').text('Image Sequencer v' + versionManagement.getLocalVersionNumber());
+    $('#version-number-top-right').text('v' + versionManagement.getLocalVersionNumber());
+  }
+  displayVersionNumber();
+
+  function refreshOptions(options) {
+    // Default options if parameter is empty.
+    if (options == undefined) options = { sortField: 'text' };
     // Load information of all modules (Name, Inputs, Outputs)
     var modulesInfo = sequencer.modulesInfo();
 
@@ -24,15 +60,16 @@ window.onload = function () {
     }
     // Null option
     addStepSelect.append('<option value="" disabled selected>Select a Module</option>');
-    addStepSelect.selectize({
-      sortField: 'text'
-    });
+    addStepSelect.selectize(options);
   }
-  refreshOptions();
+  refreshOptions(options);
 
   $(window).on('scroll', scrollFunction);
 
-  function scrollFunction() {
+  /**
+   * @description Method to toggle the scroll-up arrow.
+   */
+  function scrollFunction(A, B) {
     var shouldDisplay = $('body').scrollTop() > 20 || $(':root').scrollTop() > 20;
 
     $('#move-up').css({
@@ -40,7 +77,9 @@ window.onload = function () {
     });
   }
 
-
+  /**
+   * @description Method to scroll to the top of the page.
+   */
   function topFunction() {
     $('body').animate({scrollTop: 0});
     $(':root').animate({scrollTop: 0});
@@ -55,7 +94,7 @@ window.onload = function () {
   // UI for the overall demo:
   var ui = defaultHtmlSequencerUi(sequencer);
 
-  // find any `src` parameters in URL hash and attempt to source image from them and run the sequencer
+  // Load image data from URL `src` parameter.
   if (urlHash.getUrlHashParameter('src')) {
     sequencer.loadImage(urlHash.getUrlHashParameter('src'), ui.onLoad);
   } else {
@@ -65,25 +104,33 @@ window.onload = function () {
   var resetSequence = function () {
     var r = confirm('Do you want to reset the sequence?');
     if (r)
-      window.location = '/';
+    {
+      window.location.hash = '';
+      location.reload();
+    }
   };
 
   $('#addStep select').on('change', ui.selectNewStepUi);
   $('#addStep #add-step-btn').on('click', ui.addStepUi);
   $('#resetButton').on('click', resetSequence);
 
-  //Module button radio selection
+  // Module Selector quick buttons click handler.
   $('.radio-group .radio').on('click', function () {
     $(this).parent().find('.radio').removeClass('selected');
     $(this).addClass('selected');
     newStep = $(this).attr('data-value');
-    //$("#addStep option[value=" + newStep + "]").attr('selected', 'selected');
+
     $('#addStep select').val(newStep);
     ui.selectNewStepUi(newStep);
     ui.addStepUi(newStep);
     $(this).removeClass('selected');
   });
 
+  /**
+   * @method displayMessageOnSaveSequence
+   * @description When a sequence is saved to a browser, notification is displayed.
+   * @returns {Null}
+   */
   function displayMessageOnSaveSequence() {
     $('.savesequencemsg').fadeIn();
     setTimeout(function () {
@@ -103,7 +150,7 @@ window.onload = function () {
     }
   }
   $('#saveButton').on('click', function () {
-    // different handlers triggered for different dropdown options
+    // Different handlers triggered for different dropdown options.
 
     let dropDownValue = $('#selectSaveOption option:selected').val();
 
@@ -115,14 +162,18 @@ window.onload = function () {
     }
     else if (dropDownValue == 'save-seq') {
       saveSequence();
+    } else if(dropDownValue == 'save-pdf') {
+      savePDF(getLastImage());
+    }
+    else if (dropDownValue == 'save-to-publiclab.org' ){
+      SaveToPubliclab();
     }
   });
 
   let isWorkingOnGifGeneration = false;
 
-  $('.js-view-as-gif').on('click', function (event) {
-    /* Prevent user from triggering generation multiple times*/
-    if (isWorkingOnGifGeneration) return;
+  $('.js-view-as-gif').on('click', function (event) { // GIF generation and display
+    if (isWorkingOnGifGeneration) return; // Prevent multiple button clicks
 
     isWorkingOnGifGeneration = true;
 
@@ -131,12 +182,12 @@ window.onload = function () {
     button.innerHTML = '<i class="fa fa-circle-o-notch fa-spin"></i>';
 
     try {
-      /* Get gif resources of previous steps  */
+      // Get GIF resources from previous steps
       let options = getGifResources();
 
-      gifshot.createGIF(options, function (obj) { // gif generation
+      gifshot.createGIF(options, function (obj) { // GIF generation
         if (!obj.error) {
-          // Final gif encoded with base64 format
+          // Final GIF encoded with base64 format
           var image = obj.image;
           var animatedImage = document.createElement('img');
 
@@ -146,9 +197,7 @@ window.onload = function () {
           let modal = $('#js-download-gif-modal');
 
           $('#js-download-as-gif-button').one('click', function () {
-            // Trigger download
-            downloadGif(image);
-            // Close modal
+            downloadGif(image); // Trigger GIF download
             modal.modal('hide');
           });
 
@@ -160,7 +209,6 @@ window.onload = function () {
           // Insert image
           gifContainer.appendChild(animatedImage);
 
-
           // Open modal
           modal.modal();
 
@@ -179,16 +227,16 @@ window.onload = function () {
   });
 
   function getGifResources() {
-    /* Returns an object with specific gif options */
+    // Returns an object with specific gif options
     let imgs = document.getElementsByClassName('step-thumbnail');
     var imgSrcs = [];
 
-    // Pushes image sources of all the modules in dom
+    // Pushes image sources of all the modules in the DOM
     for (var i = 0; i < imgs.length; i++) {
       imgSrcs.push(imgs[i].src);
     }
 
-    var options = { // gif frame options
+    var options = { // GIF frame options
       'gifWidth': imgs[0].width,
       'gifHeight': imgs[0].height,
       'images': imgSrcs,
@@ -207,11 +255,64 @@ window.onload = function () {
     });
   }
 
-  function downloadGif(image) {
-    download(image, 'index.gif', 'image/gif');// downloadjs library function
+  /**
+  * Get the data URL for the last image in the sequence.
+  * @return {string} The data URL for the last image in the sequence.
+  */
+  function getLastImage() {
+    // Get the image from the last step.
+    let imgs = document.getElementsByClassName('step-thumbnail');
+    let lastStepImage = imgs[imgs.length - 1];
+    return lastStepImage.getAttribute('src');
   }
 
-  // image selection and drag/drop handling from examples/lib/imageSelection.js
+  /**
+  * Download the given image URL as a PDF file.
+  * @param {string} imageDataURL - The data URL for the image.
+  */
+  function savePDF(imageDataURL) {
+    sequencer.getImageDimensions(imageDataURL, function(dimensions) {
+      if (isGIF(imageDataURL)) {
+        // Get the dimensions of the image.
+        let pageWidth = dimensions.width;
+        let pageHeight = dimensions.height;
+
+        // Create a new pdf with the same dimensions as the image.
+        const pdf = new jsPDF({
+          orientation: pageHeight > pageWidth ? 'portrait' : 'landscape',
+          unit: 'px',
+          format: [pageHeight, pageWidth]
+        });
+
+        // Add the image to the pdf with dimensions equal to the internal dimensions of the page.
+        pdf.addImage(imageDataURL, 0, 0, pdf.internal.pageSize.getWidth(), pdf.internal.pageSize.getHeight());
+
+        // Save the pdf with the filename specified here:
+        pdf.save('index.pdf');
+      }
+      else console.log('GIFs cannot be converted to PDF');
+    });
+  }
+
+
+
+  function downloadGif(image) {
+    download(image, 'index.gif', 'image/gif'); // Downloadjs library function
+  }
+
+  function SaveToPubliclab() {
+    function postToPL(imgSrc) {
+      var uniq = Date.now();
+      $('body').append('<form method="post" id="postToPL' + uniq + '" action="https://publiclab.org/post" target="postToPLWindow"><input type="hidden" name="datauri_main_image" /></form>');
+      f = $('#postToPL' + uniq)[0];
+      f.datauri_main_image.value = imgSrc;
+      window.open('', 'postToPLWindow');
+      f.submit();
+    }
+    postToPL($('img')[sequencer.steps.length - 1].src);
+  }
+
+  // Image selection and drag/drop handling from examples/lib/imageSelection.js
   sequencer.setInputStep({
     dropZoneSelector: '#dropzone',
     fileInputSelector: '#fileInput',
@@ -226,8 +327,9 @@ window.onload = function () {
         step.options.step.imgElement.src = reader.result;
       else
         step.imgElement.src = reader.result;
-      insertPreview.updatePreviews(reader.result, '#addStep');
-      insertPreview.updatePreviews(sequencer.steps[0].imgElement.src, '.insertDiv');
+
+      insertPreview.updatePreviews(reader.result, document.querySelector('#addStep'));
+      DefaultHtmlStepUi(sequencer).updateDimensions(step);
     },
     onTakePhoto: function (url) {
       var step = sequencer.steps[0];
@@ -237,16 +339,16 @@ window.onload = function () {
         step.options.step.imgElement.src = url;
       else
         step.imgElement.src = url;
-      insertPreview.updatePreviews(url, '#addStep');
-      insertPreview.updatePreviews(sequencer.steps[0].imgElement.src, '.insertDiv');
+      insertPreview.updatePreviews(url, document.querySelector('#addStep'));
+      DefaultHtmlStepUi(sequencer).updateDimensions(step);
     }
   });
 
   setupCache();
 
-  if (urlHash.getUrlHashParameter('src')) {
-    insertPreview.updatePreviews(urlHash.getUrlHashParameter('src'), '#addStep');
+  if (urlHash.getUrlHashParameter('src')) {  // Gets the sequence from the URL
+    insertPreview.updatePreviews(urlHash.getUrlHashParameter('src'), document.querySelector('#addStep'));
   } else {
-    insertPreview.updatePreviews('images/tulips.png', '#addStep');
+    insertPreview.updatePreviews('images/tulips.png', document.querySelector('#addStep'));
   }
-};
+};

examples/index.html

@@ -33,9 +33,12 @@
   <script src="../node_modules/gifshot/dist/gifshot.min.js" type="text/javascript"></script>
 
   <!-- Download.js for large files -->
-  <script src="../node_modules/downloadjs/download.min.js" type="text/javascript" />
+  <script src="../node_modules/downloadjs/download.min.js" type="text/javascript" ></script>
 
-  <script src="lib/scrollToTop.js"></script>
+  <!-- jspdf to enable save image as pdf -->
+  <script src="../node_modules/jspdf/dist/jspdf.min.js" type="text/javascript" ></script>
+
+  <!-- <script src="lib/scrollToTop.js"></script> -->
   <script src="../node_modules/selectize/dist/js/standalone/selectize.min.js"></script>
 </head>
 
@@ -53,9 +56,11 @@
   <link href="./selectize.default.css" rel="stylesheet">
   <link rel="stylesheet" href="demo.css">
 
+  <div id="update-prompt-modal">A new version of image sequencer is available. Click <a href="#" id="reload">here</a> to update.</div>
+
   <div class="container-fluid">
 
-    <header class="text-center" style="min-width: 450px">
+    <header class="text-center">
       <h1><a href="/" target='_blank' class="name-header">Image Sequencer</a></h1>
       <p>
         A pure JavaScript sequential image processing system, inspired by storyboards. Instead of modifying the original
@@ -70,10 +75,11 @@
         </a>
         by <a href="https://publiclab.org" title="Publiclab Website"><i class="fa fa-globe"></i> Publiclab</a>
       </p>
+      <span id="version-number-top-right"></span>
     </header>
 
     <div id="dropzone" class="dropzone">
-      <p>
+      <p id="dropzone-text">
         <i>Select or drag in an image to start!</i>
       </p>
       <center>
@@ -148,7 +154,7 @@
                   </select>
                 </div>
                 <div class="col-lg-4">
-                  <button class="btn btn-success btn-lg" name="add" id="add-step-btn">Add Step</button></div>
+                  <button class="btn btn-primary btn-lg" name="add" id="add-step-btn">Add Step</button></div>
               </div>
               <div class="row center-align">
                 <button id="resetButton" class="btn btn-default btn-lg"
@@ -190,8 +196,10 @@
                 <select class="form-control input-md mouse" id="selectSaveOption" style="margin-top:20px">
                   <option value="save-image">Save as PNG</option>
                   <option value="save-gif">Save as GIF (all steps)</option>
+                  <option value="save-pdf">Save as PDF</option>
                   <option value="save-seq">Save sequence</option>
                   <option value="save-seq-string">Save sequence string</option>
+                  <option value="save-to-publiclab.org">Save to PublicLab.org</option>>
                 </select>
                 <p><button id="saveButton" class="btn btn-primary btn-lg save-button">Save</button></p>
                 <p><button class="btn btn-default btn-lg js-view-as-gif" id="gif">Preview GIF</button></p>
@@ -210,7 +218,7 @@
           <h2>Need Help?</h2>
           <p>
             <a class="btn btn-default" href="https://github.com/publiclab/image-sequencer/issues">Ask a question</a>
-            <a class="btn btn-default" href="https://publiclab.org/chat">Ask in our chatroom</a>
+            <a class="btn btn-default" href="https://gitter.im/publiclab/image-sequencer"  target="_blank">Ask in our chatroom </a>
           </p>
         </div>
         <div class="col-md-6">
@@ -223,6 +231,9 @@
           </p>
         </div>
       </div>
+      <div class="row">
+        <p id="version-number-text">Loading Version Number</p>
+      </div>
     </footer>
 
     <button id="move-up"><i class="fa fa-arrow-circle-o-up"></i></button>

examples/lib/cache.js

@@ -1,7 +1,41 @@
 var setupCache = function() {
+  let newWorker; // When sw.js is changed, this is the new service worker generated.
+
+  // Toggle a CSS class to display a popup prompting the user to fetch a new version.
+  function showUpdateModal() {
+    $('#update-prompt-modal').addClass('show');
+  }
+
+  /**
+  * When a new service worker has been loaded, the button in the update prompt
+  * modal should trigger the skipWaiting event to replace the current
+  * service worker with the new one.
+  */
+  $('#reload').on('click', function() {
+    newWorker.postMessage({ action: 'skipWaiting' });
+  });
+
   if ('serviceWorker' in navigator) {
+    // Register the service worker.
     navigator.serviceWorker.register('sw.js', { scope: '/examples/' })
       .then(function(registration) {
+        registration.addEventListener('updatefound', () => {
+          // When sw.js has been changed, get a reference to the new service worker.
+          newWorker = registration.installing;
+          newWorker.addEventListener('statechange', () => {
+            // Check if service worker state has changed.
+            switch(newWorker.state) {
+              case 'installed':
+                if(navigator.serviceWorker.controller) {
+                  // New service worker available; prompt the user to update.
+                  showUpdateModal();
+                }
+                // No updates available; do nothing.
+                break;
+            }
+          });
+        });
+
         const installingWorker = registration.installing;
         installingWorker.onstatechange = () => {
           console.log(installingWorker);
@@ -14,6 +48,17 @@ var setupCache = function() {
       .catch(function(error) {
         console.log('Service worker registration failed, error:', error);
       });
+
+      /**
+      * This is the event listener for when the service worker updates.
+      * When the service worker updates, reload the page.
+      */
+      let refreshing;
+      navigator.serviceWorker.addEventListener('controllerchange', function() {
+        if(refreshing) return;
+        window.location.reload();
+        refreshing = true;
+      });
   }
 
   if ('serviceWorker' in navigator) {
@@ -34,6 +79,11 @@ var setupCache = function() {
     }
     location.reload();
   });
+
+
+
+
+
 };
 
 module.exports = setupCache;

examples/lib/defaultHtmlSequencerUi.js

@@ -1,4 +1,5 @@
 var urlHash = require('./urlHash.js');
+   insertPreview = require('./insertPreview.js');
 function DefaultHtmlSequencerUi(_sequencer, options) {
 
   options = options || {};
@@ -27,12 +28,17 @@ function DefaultHtmlSequencerUi(_sequencer, options) {
   function selectNewStepUi() {
     var m = $(addStepSel + ' select').val();
     if(!m) m = arguments[0];
-    $(addStepSel + ' .info').html(_sequencer.modulesInfo(m).description);
+    else $(addStepSel + ' .info').html(_sequencer.modulesInfo(m).description);
     $(addStepSel + ' #add-step-btn').prop('disabled', false);
   }
 
   function removeStepUi() {
     var index = $(removeStepSel).index(this) + 1;
+    // If last step is removed.
+    if(sequencer.steps.length==index+1){
+      console.log("inside")
+      insertPreview.updatePreviews(sequencer.steps[index-1].output.src, document.querySelector('#addStep'));
+    }
     sequencer.removeSteps(index).run({ index: index - 1 });
     // remove from URL hash too
     urlHash.setUrlHashParameter('steps', sequencer.toString());

examples/lib/defaultHtmlStepUi.js

@@ -11,27 +11,33 @@
 const intermediateHtmlStepUi = require('./intermediateHtmlStepUi.js'),
   urlHash = require('./urlHash.js'),
   _ = require('lodash'),
+  insertPreview = require('./insertPreview.js');
   mapHtmlTypes = require('./mapHtmltypes'),
-  scopeQuery = require('./scopeQuery');
+  scopeQuery = require('./scopeQuery'),
+  isGIF = require('../../src/util/isGif');
 
 function DefaultHtmlStepUi(_sequencer, options) {
-  let $step, $stepAll;
-
   options = options || {};
   var stepsEl = options.stepsEl || document.querySelector('#steps');
   var selectStepSel = options.selectStepSel = options.selectStepSel || '#selectStep';
 
   function onSetup(step, stepOptions) {
-
     if (step.options && step.options.description)
       step.description = step.options.description;
 
-    step.ui =
+    step.ui = // Basic UI markup for the step
       '\
       <div class="container-fluid step-container">\
           <div class="panel panel-default">\
             <div class="panel-heading">\
-              <div class="trash-container pull-right"><button type="button" class="btn btn-link ' + step.name + ' dimension-tooltip" data-toggle="tooltip" data-html="true" title="" data-original-title=""><i class="fa fa-info-circle"></i></button></div>\
+              <div class="trash-container pull-right">\
+                <a type="button" target="_blank" href="https://developer.mozilla.org/en-US/docs/WebAssembly" style="display: none;" class="btn btn-link general-tooltip wasm-tooltip" data-toggle="tooltip" data-html="true" data-original-title="<div style=\'text-align: center\'><p>This step is Web Assembly accelerated. Click to Read More</div>">\
+                  <i class="fa fa-bolt"></i>\
+                </a>\
+                <button type="button" class="btn btn-link ' + step.name + ' general-tooltip dimension-tooltip" data-toggle="tooltip" data-html="true" data-original-title="">\
+                  <i class="fa fa-info-circle"></i>\
+                </button>\
+              </div>\
               <h3 class="panel-title">' +
                 '<span class="toggle mouse">' + step.name + ' <span class="caret toggleIcon rotated"></span>\
                  <span class="load-spin pull-right" style="display:none;padding:1px 8px;"><i class="fa fa-circle-o-notch fa-spin"></i></span>\
@@ -42,7 +48,7 @@ function DefaultHtmlStepUi(_sequencer, options) {
               <div class="row step">\
                 <div class="col-md-4 details container-fluid">\
                   <div class="cal collapse in"><p>' +
-                    '<i>' + (step.description || '') + '</i>' +
+                    '<a href="https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#' + step.name + '-module">' + (step.description || '') + '</a>' +
                  '</p></div>\
                 </div>\
                 <div class="col-md-8 cal collapse in step-column">\
@@ -68,21 +74,20 @@ function DefaultHtmlStepUi(_sequencer, options) {
     var util = intermediateHtmlStepUi(_sequencer, step);
 
     var parser = new DOMParser();
-    step.ui = parser.parseFromString(step.ui, 'text/html');
+    step.ui = parser.parseFromString(step.ui, 'text/html'); // Convert the markup string to a DOM node.
     step.ui = step.ui.querySelector('div.container-fluid');
 
-    $step = scopeQuery.scopeSelector(step.ui);
-    $stepAll = scopeQuery.scopeSelectorAll(step.ui);
-    step.ui.$step = $step;
-    step.ui.$stepAll = $stepAll;
+    step.$step = scopeQuery.scopeSelector(step.ui); // Shorthand methods for scoped DOM queries. Read the docs [CONTRIBUTING.md](https://github.com/publiclab/image-sequencer/blob/main/CONTRIBUTING.md) for more info.
+    step.$stepAll = scopeQuery.scopeSelectorAll(step.ui);
+    let {$step, $stepAll} = step;
 
-    step.linkElements = step.ui.querySelectorAll('a');
-    step.imgElement = $step('a img.img-thumbnail')[0];
+    step.linkElements = step.ui.querySelectorAll('a'); // All the anchor tags in the step UI
+    step.imgElement = $step('a img.img-thumbnail')[0]; // The output image
 
     if (_sequencer.modulesInfo().hasOwnProperty(step.name)) {
       var inputs = _sequencer.modulesInfo(step.name).inputs;
       var outputs = _sequencer.modulesInfo(step.name).outputs;
-      var merged = Object.assign(inputs, outputs); // combine outputs w inputs
+      var merged = Object.assign(inputs, outputs); // Combine outputs with inputs
 
       for (var paramName in merged) {
         var isInput = inputs.hasOwnProperty(paramName);
@@ -102,10 +107,10 @@ function DefaultHtmlStepUi(_sequencer, options) {
         else {
           let paramVal = step.options[paramName] || inputDesc.default;
 
-          if (inputDesc.id == 'color-picker') { // separate input field for color-picker
+          if (inputDesc.id == 'color-picker') { // Separate input field for color-picker
             html +=
               '<div id="color-picker" class="input-group colorpicker-component">' +
-              '<input class="form-control target" type="' +
+              '<input class="form-control color-picker-target" type="' +
               inputDesc.type +
               '" name="' +
               paramName +
@@ -113,7 +118,7 @@ function DefaultHtmlStepUi(_sequencer, options) {
               paramVal + '">' + '<span class="input-group-addon"><i></i></span>' +
               '</div>';
           }
-          else { // use this if the the field isn't color-picker
+          else { // Non color-picker input types
             html =
               '<input class="form-control target" type="' +
               inputDesc.type +
@@ -123,7 +128,7 @@ function DefaultHtmlStepUi(_sequencer, options) {
               paramVal +
               '" placeholder ="' +
               (inputDesc.placeholder || '');
-              
+
             if (inputDesc.type.toLowerCase() == 'range') {
               html +=
                 '"min="' +
@@ -131,7 +136,7 @@ function DefaultHtmlStepUi(_sequencer, options) {
                 '"max="' +
                 inputDesc.max +
                 '"step="' +
-                (inputDesc.step ? inputDesc.step : 1) + '">' + '<span>' + paramVal + '</span>';
+                inputDesc.step + '">' + '<span>' + paramVal + '</span>';
 
             }
             else html += '">';
@@ -155,10 +160,10 @@ function DefaultHtmlStepUi(_sequencer, options) {
                          </div>';
         $step('div.details').append(div);
       }
-      $step('div.panel-footer').append(
+      $step('div.panel-footer').append( // Save button
         '<div class="cal collapse in"><button type="submit" class="btn btn-sm btn-default btn-save" disabled = "true" >Apply</button> <small style="padding-top:2px;">Press apply to see changes</small></div>'
       );
-      $step('div.panel-footer').prepend(
+      $step('div.panel-footer').prepend( // Markup for tools: download and insert step buttons
         '<button class="pull-right btn btn-default btn-sm insert-step" >\
         <span class="insert-text"><i class="fa fa-plus"></i> Insert Step</span><span class="no-insert-text" style="display:none">Close</span></button>\
         <button class="pull-right btn btn-default btn-sm download-btn" style="margin-right:2px" >\
@@ -173,9 +178,10 @@ function DefaultHtmlStepUi(_sequencer, options) {
           parser.parseFromString(tools, 'text/html').querySelector('div')
         );
 
-      $stepAll('.remove').on('click', function() {notify('Step Removed', 'remove-notification');});
-      $stepAll('.insert-step').on('click', function() { util.insertStep(step.ID); });
+      $stepAll('.remove').on('click', function() {notify('Step Removed', 'remove-notification');}); // Notification on removal of a step
+      $step('.insert-step').on('click', function() { util.insertStep(step.ID); }); // Insert a step in between the sequence
       // Insert the step's UI in the right place
+
       if (stepOptions.index == _sequencer.steps.length) {
         stepsEl.appendChild(step.ui);
         $('#steps .step-container:nth-last-child(1) .insert-step').prop('disabled', true);
@@ -185,16 +191,30 @@ function DefaultHtmlStepUi(_sequencer, options) {
       else {
         stepsEl.insertBefore(step.ui, $(stepsEl).children()[stepOptions.index]);
       }
+
+      // Enable the load-image insert-step button when there are steps after load-image
+      // The logical operator is `> 0` because the number of steps is found before adding the step, actual logic is `steps.length + 1 > 1` which is later simplified.
+      if (_sequencer.steps.length > 0) $('#load-image .insert-step').prop('disabled', false);
+      else $('#load-image .insert-step').prop('disabled', true);
     }
     else {
-      $('#load-image').append(step.ui);
+      $('#load-image').append(step.ui); // Default UI without extra tools for the first step(load image)
+
+      $step('div.panel-footer').prepend( `
+          <button class="right btn btn-default btn-sm insert-step" disabled="true">
+            <span class="insert-text"><i class="fa fa-plus"></i> Insert Step</span>
+            <span class="no-insert-text" style="display:none">Close</span>
+          </button>`
+      );
+
+      $step('.insert-step').on('click', function() { util.insertStep(step.ID); });
     }
-    $step('.toggle').on('click', () => {
+    $step('.toggle').on('click', () => { // Step container dropdown
       $step('.toggleIcon').toggleClass('rotated');
       $stepAll('.cal').collapse('toggle');
     });
-    
-    $(step.imgElement).on('mousemove', _.debounce(() => imageHover(step), 150));
+
+    $(step.imgElement).on('mousemove', _.debounce(() => imageHover(step), 150)); // Shows the pixel coordinates on hover
     $(step.imgElement).on('click', (e) => {e.preventDefault(); });
     $stepAll('#color-picker').colorpicker();
 
@@ -211,15 +231,23 @@ function DefaultHtmlStepUi(_sequencer, options) {
           });
         _sequencer.run({ index: step.index - 1 });
 
-        // modify the url hash
+        // Modify the URL hash
         urlHash.setUrlHashParameter('steps', _sequencer.toString());
-        // disable the save button
+        // Disable the save button
         $step('.btn-save').prop('disabled', true);
         optionsChanged = false;
         changedInputs = 0;
       }
     }
 
+    /**
+     * @method handleInputValueChange
+     * @description Enables the save button on input change
+     * @param {*} currentValue The current value of the input
+     * @param {*} initValue The initial/old value of the input
+     * @param {Boolean} hasChangedBefore Whether the input was changed before
+     * @returns {Boolean} True if the value has changed
+     */
     function handleInputValueChange(currentValue, initValue, hasChangedBefore) {
       var inputChanged = !(isNaN(initValue) || isNaN(currentValue) ? currentValue === initValue : currentValue - initValue === 0);
       changedInputs += hasChangedBefore ? inputChanged ? 0 : -1 : inputChanged ? 1 : 0;
@@ -250,6 +278,21 @@ function DefaultHtmlStepUi(_sequencer, options) {
         });
     });
 
+    $stepAll('.color-picker-target').each(function(i, input) {
+      $(input)
+        .data('initValue', $(input).val())
+        .data('hasChangedBefore', false)
+        .on('input change', function() {
+          $(this)
+            .data('hasChangedBefore',
+              handleInputValueChange(
+                $(this).val(),
+                $(this).data('initValue'),
+                $(this).data('hasChangedBefore')
+              )
+            );
+        });
+    });
 
 
     $('input[type="range"]').on('input', function() {
@@ -258,17 +301,20 @@ function DefaultHtmlStepUi(_sequencer, options) {
   }
 
 
-  function onDraw() {
+  function onDraw({$step, $stepAll}) {
     $step('.load').show();
     $step('img').hide();
     $stepAll('.load-spin').show();
   }
 
   function onComplete(step) {
+    let {$step, $stepAll} = step;
     $step('img').show();
     $stepAll('.load-spin').hide();
     $step('.load').hide();
 
+    $stepAll('.download-btn').off('click');
+    
     step.imgElement.src = (step.name == 'load-image') ? step.output.src : step.output;
     var imgthumbnail = $step('.img-thumbnail').getDomElem();
     for (let index = 0; index < step.linkElements.length; index++) {
@@ -276,28 +322,23 @@ function DefaultHtmlStepUi(_sequencer, options) {
         step.linkElements[index].href = step.imgElement.src;
     }
 
-    // TODO: use a generalized version of this
+    // TODO: use a generalized version of this.
     function fileExtension(output) {
       return output.split('/')[1].split(';')[0];
     }
 
     $stepAll('.download-btn').on('click', () => {
 
-      for (let index = 0; index < step.linkElements.length; index++){
-        
-        var element = document.createElement('a');
-        element.setAttribute('href', step.linkElements[index].href);
-        element.setAttribute('download', step.name + '.' + fileExtension(step.imgElement.src));
-        element.style.display = 'none';
-        document.body.appendChild(element);
-        
-        element.click();
+      var element = document.createElement('a');
+      element.setAttribute('href', step.output);
+      element.setAttribute('download', step.name + '.' + fileExtension(step.imgElement.src));
+      element.style.display = 'none';
+      document.body.appendChild(element);
 
-        document.body.removeChild(element);
-      }
+      element.click();
     });
 
-    // fill inputs with stored step options
+    // Fill inputs with stored step options
     if (_sequencer.modulesInfo().hasOwnProperty(step.name)) {
       var inputs = _sequencer.modulesInfo(step.name).inputs;
       var outputs = _sequencer.modulesInfo(step.name).outputs;
@@ -309,7 +350,7 @@ function DefaultHtmlStepUi(_sequencer, options) {
               .data('initValue', step.options[i]);
           if (inputs[i].type.toLowerCase() === 'select')
             $step('div[name="' + i + '"] select')
-              .val(step.options[i])
+              .val(String(step.options[i]))
               .data('initValue', step.options[i]);
         }
       }
@@ -322,12 +363,38 @@ function DefaultHtmlStepUi(_sequencer, options) {
 
     $(function () {
       $('[data-toggle="tooltip"]').tooltip();
-      _sequencer.getImageDimensions(step.imgElement.src, function (dim) {
-        step.ui.querySelector('.' + step.name).attributes['data-original-title'].value = `<div style="text-align: center"><p>Image Width: ${dim.width}<br>Image Height: ${dim.height}</br></div>`;
-      });
+      updateDimensions(step);
+    });
+
+    if (step.name === 'load-image') insertPreview.updatePreviews(step.output.src, document.querySelector('#addStep'));
+    else insertPreview.updatePreviews(step.output, document.querySelector('#addStep'));  
+
+    // Handle the wasm bolt display
+
+    if (step.useWasm) {
+      if (step.wasmSuccess) $step('.wasm-tooltip').fadeIn();
+      else $step('.wasm-tooltip').fadeOut();
+    }
+    else $step('.wasm-tooltip').fadeOut();
+  }
+  /**
+   * @description Updates Dimension of the image
+   * @param {Object} step  - Current Step
+   * @returns {void}
+   *
+   */
+  function updateDimensions(step){
+    _sequencer.getImageDimensions(step.imgElement.src, function (dim) {
+      step.ui.querySelector('.' + step.name).attributes['data-original-title'].value = `<div style="text-align: center"><p>Image Width: ${dim.width}<br>Image Height: ${dim.height}</br>${isGIF(step.output) ? `Frames: ${dim.frames}` : ''}</div>`;
     });
   }
 
+  /**
+   * @method imageHover
+   * @description Handler to display image coordinates on hover.
+   * @param {Object} step Current step variable
+   * @returns {Null}
+   */
   function imageHover(step){
 
     var img = $(step.imgElement);
@@ -350,27 +417,42 @@ function DefaultHtmlStepUi(_sequencer, options) {
   function onRemove(step) {
     step.ui.remove();
     $('#steps .step-container:nth-last-child(1) .insert-step').prop('disabled', true);
-    $('div[class*=imgareaselect-]').remove();
+
+    // Enable the load-image insert-step button when there are steps after load-image
+    // The logical operator is `> 2` because the number of steps is found before removing the step, actual logic is `steps.length - 1 > 1` which is later simplified.
+    if (_sequencer.steps.length - 1 > 1) $('#load-image .insert-step').prop('disabled', false);
+    else $('#load-image .insert-step').prop('disabled', true);
+
+    $(step.imgElement).imgAreaSelect({
+      remove: true
+    });
   }
 
   function getPreview() {
     return step.imgElement;
   }
 
+  /**
+   * @method notify
+   * @description General purpose DOM toast notification
+   * @param {String} msg Message to be displayed
+   * @param {String} id A unique identifier for the notification
+   * @returns {Null}
+   */
   function notify(msg, id){
     if ($('#' + id).length == 0) {
       var notification = document.createElement('span');
       notification.innerHTML = ' <i class="fa fa-info-circle" aria-hidden="true"></i> ' + msg ;
       notification.id = id;
       notification.classList.add('notification');
-  
+
       $('body').append(notification);
     }
-  
+
     $('#' + id).fadeIn(500).delay(200).fadeOut(500);
   }
-    
-  
+
+
   return {
     getPreview: getPreview,
     onSetup: onSetup,
@@ -378,7 +460,8 @@ function DefaultHtmlStepUi(_sequencer, options) {
     onRemove: onRemove,
     onDraw: onDraw,
     notify: notify,
-    imageHover: imageHover
+    imageHover: imageHover,
+    updateDimensions: updateDimensions
   };
 }
 

examples/lib/insertPreview.js

@@ -1,5 +1,5 @@
-function generatePreview(previewStepName, customValues, path, selector) {
-
+// Generate downscaled preview images for quick buttons.
+function generatePreview(previewStepName, customValues, path, DomNode) {
   var previewSequencer = ImageSequencer();
   function insertPreview(src) {
     var img = document.createElement('img');
@@ -8,9 +8,10 @@ function generatePreview(previewStepName, customValues, path, selector) {
     img.src = src;
     $(img).css('max-width', '200%');
     $(img).css('transform', 'translateX(-20%)');
-    $(selector + ' .radio-group').find('div').each(function() {
-      if ($(this).find('div').attr('data-value') === previewStepName) {
-        $(this).find('div').append(img);
+    $(DomNode.querySelector('.radio-group')).find('.radio').each(function() {
+      if ($(this).attr('data-value') === previewStepName) {
+        $(this).find('img').remove();
+        $(this).append(img);
       }
     });
   }
@@ -29,8 +30,8 @@ function generatePreview(previewStepName, customValues, path, selector) {
     previewSequencer.loadImage(path, loadPreview);
 }
 
-function updatePreviews(src, selector) {
-  $(selector + ' img').remove();
+function updatePreviews(src, DomNode) {
+  $(DomNode).find('img').remove();
 
   var previewSequencerSteps = {
     'resize': '125%',
@@ -41,19 +42,20 @@ function updatePreviews(src, selector) {
     'crop': {
       'x': 0,
       'y': 0,
-      'w': '(50%)',
-      'h': '(50%)',
+      'w': '50%',
+      'h': '50%',
       'noUI': true
     }
   };
 
   var img = new Image();
+
   img.onload = function(){
     var height = img.height;
     var width = img.width;
 
-    let percentage = (80 / height) * 100; //take the min resize value that fits the preview area => (new-width/orig_ht) - '80 as the preview area has 80*80 dimension
-    percentage = Math.max((80 / width) * 100, percentage); // make sure that one dimension doesn't resize greater, leading distorting preview-area fitting
+    let percentage = (80 / height) * 100; // Take the min resize value that fits the preview area => (new-width/orig_ht) - '80 as the preview area has 80*80 dimension.
+    percentage = Math.max((80 / width) * 100, percentage); // Make sure that one dimension doesn't resize greater, leading distorting preview-area fitting.
     percentage = Math.ceil(percentage);
 
     var sequencer = ImageSequencer();
@@ -62,7 +64,7 @@ function updatePreviews(src, selector) {
       this.addSteps('resize', {['resize']: percentage + '%'});
       this.run((src)=>{
         Object.keys(previewSequencerSteps).forEach(function (step, index) {
-          generatePreview(step, Object.values(previewSequencerSteps)[index], src, selector);
+          generatePreview(step, Object.values(previewSequencerSteps)[index], src, DomNode);
         });
       });
     });
@@ -74,4 +76,4 @@ function updatePreviews(src, selector) {
 module.exports = {
   generatePreview : generatePreview,
   updatePreviews : updatePreviews
-};
+};

examples/lib/intermediateHtmlStepUi.js

@@ -1,8 +1,17 @@
 var urlHash = require('./urlHash.js'),
   insertPreview = require('./insertPreview.js');
 
+/**
+ * @method IntermediateHtmlStepUi
+ * @description Inserts a module selector in between the current sequence
+ * @param {Object} _sequencer Sequencer instance
+ * @param {Object} step Current step variable
+ * @param {Object} options Optional options Object
+ * @returns {Object} Object containing the insertStep function
+ */
 function IntermediateHtmlStepUi(_sequencer, step, options) {
   function stepUI() {
+    // Basic markup for the selector
     return '<div class="row insertDiv collapse">\
           <section class="panel panel-primary .insert-step">\
             <button class="btn btn-default close-insert-box"><i class="fa fa-times" aria-hidden="true"></i> Close</button>\
@@ -55,7 +64,7 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
                     </select>\
                   <div>\
                   <div class="col-md-4">\
-                    <button class="btn btn-success btn-lg insert-save-btn add-step-btn" name="add">Add Step</button>\
+                    <button class="btn btn-primary btn-lg insert-save-btn add-step-btn" name="add">Add Step</button>\
                   <div>\
                 </div>\
               </div>\
@@ -64,6 +73,13 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
         </div>';
   }
 
+  /**
+   * @method toggleDiv
+   * @description Toggles the module selector dropdown.
+   * @param {Object} $step $step util function
+   * @param {Fucntion} callback Optional callback function
+   * @returns {Null}
+   */
   var toggleDiv = function($step, callback = function(){}){
     $step('.insertDiv').collapse('toggle');
     if ($step('.insert-text').css('display') != 'none'){
@@ -74,13 +90,19 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
     }
   };
 
+  /**
+   * @method insertStep
+   * @description Handler to insert selected module in the sequence
+   * @returns {Null}
+   */
   insertStep = function (id) {
-    const $step = step.ui.$step,
-      $stepAll = step.ui.$stepAll;
+    const $step = step.$step,
+      $stepAll = step.$stepAll;
     var modulesInfo = _sequencer.modulesInfo();
     var parser = new DOMParser();
     var addStepUI = stepUI();
     addStepUI = parser.parseFromString(addStepUI, 'text/html').querySelector('div');
+
     if ($step('.insertDiv').length > 0){
       toggleDiv($step);
     }
@@ -91,17 +113,20 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
           addStepUI
         );
       toggleDiv($step, function(){
-        insertPreview.updatePreviews(step.output, '.insertDiv');
+        if (step.name === 'load-image') insertPreview.updatePreviews(step.output.src, $step('.insertDiv').getDomElem());
+        else insertPreview.updatePreviews(step.output, $step('.insertDiv').getDomElem());
       });
     }
 
+
     $step('.insertDiv .close-insert-box').off('click').on('click', function(){
       toggleDiv($step);
       $step('.insertDiv').removeClass('insertDiv');
     });
-    
+
     var insertStepSelect = $step('.insert-step-select');
     insertStepSelect.html('');
+
     // Add modules to the insertStep dropdown
     for (var m in modulesInfo) {
       if (modulesInfo[m] && modulesInfo[m].name)
@@ -109,20 +134,30 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
           '<option value="' + m + '">' + modulesInfo[m].name + '</option>'
         );
     }
+
     insertStepSelect.selectize({
       sortField: 'text'
     });
+
     $('.insertDiv .radio-group .radio').on('click', function () {
-      var newStepName = $(this).attr('data-value');
+      var newStepName = $(this).attr('data-value'); // Get the name of the module to be inserted
       id = $($step('.insertDiv').parents()[3]).prevAll().length;
-      insert(id, $step, newStepName);
+      insert(id, $step, newStepName); // Insert the selected module
     });
+
     $step('.insertDiv .add-step-btn').on('click', function () {
       var newStepName = insertStepSelect.val();
       id = $($step('.insertDiv').parents()[3]).prevAll().length;
       insert(id, $step, newStepName); });
   };
 
+  /**
+   * @method insert
+   * @description Inserts the specified step at the specified index in the sequence
+   * @param {Number} id Index of the step
+   * @param {Function} $step $step util function
+   * @param {String} newStepName Name of the new step
+   */
   function insert(id, $step, newStepName) {
     toggleDiv($step);
     $step('.insertDiv').removeClass('insertDiv');
@@ -134,4 +169,4 @@ function IntermediateHtmlStepUi(_sequencer, step, options) {
     insertStep
   };
 }
-module.exports = IntermediateHtmlStepUi;
+module.exports = IntermediateHtmlStepUi;

examples/lib/mapHtmltypes.js

@@ -1,8 +1,13 @@
+/**
+ * @description Maps module input types to their respective html <input> tag types.
+ * @param {Object} inputInfo Object containing the type and optionally min/max for range type inputs.
+ */
 function mapHtmlTypes(inputInfo){
   var htmlType;
   switch(inputInfo.type.toLowerCase()){
   case 'integer':
     htmlType = inputInfo.min != undefined ? 'range' : 'number';
+    if (htmlType === 'range') inputInfo.step = inputInfo.step || 1; // default range step size for integer
     break;
   case 'string':
     htmlType = 'text';
@@ -15,14 +20,15 @@ function mapHtmlTypes(inputInfo){
     break;
   case 'float':
     htmlType = inputInfo.min != undefined ? 'range' : 'text';
+    if (htmlType === 'range') inputInfo.step = inputInfo.step || 0.1; // default range step size for float
     break;
   default:
     htmlType = 'text';
     break;
   }
-  var response = inputInfo;
+  var response = Object.assign({}, inputInfo);
   response.type = htmlType;
   return response;
 }
 
-module.exports = mapHtmlTypes;
+module.exports = mapHtmlTypes;

examples/lib/scopeQuery.js

@@ -1,6 +1,7 @@
 /**
  * @method $scope
  * @param {"DOMNode"} scope A DOM Node as the scope
+ * @returns {Function} Constructor for the scopeSelector Object.
  */
 function $scope(scope) {
   return function(queryString){
@@ -24,6 +25,7 @@ function $scope(scope) {
 /**
  * @method $scopeAll
  * @param {"DOMNode"} scope A DOM Node as the scope
+ * @returns {Function} Constructor for the scopeSelectorAll Object.
  */
 function $scopeAll(scope){
   return function(queryString){
@@ -47,7 +49,8 @@ function $scopeAll(scope){
 /**
  * @method scopeSelector
  * @description A scoped jQuery selector
- * @param {"DOMNode"} scope DOM Node as the scope
+ * @param {"DOMNode"} scope A DOM Node as the scope
+ * @returns {Function}
  */
 function scopeSelector(scope){
   return $scope(scope);
@@ -56,7 +59,8 @@ function scopeSelector(scope){
 /**
  * @method scopeSelectorAll
  * @description A scoped jQuery multiple selector
- * @param {"DOMNode} scope DOM Node as the scope
+ * @param {"DOMNode} scope A DOM Node as the scope
+ * @returns {Function}
  */
 function scopeSelectorAll(scope){
   return $scopeAll(scope);

examples/lib/versionManagement.js

@@ -0,0 +1,43 @@
+/**
+ * Functions for getting version information.
+ * Note: these functions are not used by the service worker to check for updates;
+ * the service worker updates whenever sw.js has changed.
+ * sw.js is changed when grunt replace:version is run. This task is run during
+ * grunt build, serve, and productions tasks.
+ */
+
+const package = require('../../package.json');
+
+/**
+ * Get the current version number from package.json on the homepage.
+ * @param {function} callback The function that uses the version number.
+ */
+function getLatestVersionNumber(callback) {
+  // Get the homepage reference from the local package.json.
+  var homepage = package.homepage;
+  var request = new XMLHttpRequest();
+  request.onreadystatechange = function() {
+    if (request.readyState == 4 && request.status == 200) {
+      var response = JSON.parse(this.responseText);
+      var latestVersionNumber = response.version;
+
+      // Do something with the version number using a callback function.
+      if (callback)
+        callback(latestVersionNumber);
+    }
+  }
+
+  // Get the package.json file from online using a GET request.
+  request.open("GET", homepage + "/package.json", true);
+  request.send();
+}
+
+// Get the version number from the local package.json file.
+function getLocalVersionNumber() {
+  return package.version;
+}
+
+module.exports = {
+  getLatestVersionNumber,
+  getLocalVersionNumber
+}

examples/sw.js

@@ -1,5 +1,4 @@
-const staticCacheName = 'image-sequencer-static-v3';
-
+const staticCacheName = 'image-sequencer-static-v3.6.0';
 self.addEventListener('install', event => {
   console.log('Attempting to install service worker');
 });
@@ -33,3 +32,10 @@ self.addEventListener('fetch', function(event) {
     })
   );
 });
+
+// When the update modal sends a 'skipWaiting' message, call the skipWaiting method.
+self.addEventListener('message', function(event) {
+  if(event.data.action === 'skipWaiting') {
+    self.skipWaiting();
+  }
+});

jest-puppeteer.config.js

@@ -0,0 +1,12 @@
+module.exports = {
+  launch: {
+    args: ['--no-sandbox', '--disable-setuid-sandbox'], // https://github.com/puppeteer/puppeteer/blob/main/docs/troubleshooting.md#setting-up-chrome-linux-sandbox
+    headless: process.env.HEADLESS !== 'false',
+  },
+  server: {
+    command: 'grunt serve',
+    port:3000,
+    launchTimeout: 5000000,
+  },
+  
+};

jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  preset: 'jest-puppeteer',
+  testRegex: './*\\.test\\.js$',
+  verbose: true,
+};
+

package.json

@@ -1,13 +1,19 @@
 {
   "name": "image-sequencer",
-  "version": "3.5.1",
+  "version": "3.6.0",
   "description": "A modular JavaScript image manipulation library modeled on a storyboard.",
   "main": "src/ImageSequencer.js",
   "scripts": {
     "debug": "TEST=true node ./index.js -i ./examples/images/monarch.png -s invert",
-    "test": "TEST=true istanbul cover tape test/core/*.js test/core/ui/user-interface.js test/core/modules/*.js | tap-spec; node test/core/sequencer/benchmark.js;  browserify test/core/sequencer/meta-modules.js test/core/sequencer/image-sequencer.js test/core/sequencer/chain.js  test/core/sequencer/replace.js test/core/sequencer/import-export.js test/core/sequencer/run.js test/core/sequencer/dynamic-imports.js test/core/util/*.js | tape-run --render=\"tap-spec\"",
+    "test": "TEST=true istanbul cover tape test/core/*.js test/core/ui/user-interface.js test/core/modules/*.js | tap-spec;",
+    "benchmark": "node test/core/sequencer/benchmark.js | tap-spec;",
+    "gif-test": "node test/core/gifs/gif-test.js | tap-spec;",
+    "core-tests": "cat ./output/core-tests.js | tape-run --render=\"tap-spec\"",
+    "test-all": "npm run test && npm run benchmark && npm run gif-test && grunt tests && npm run core-tests",
     "test-ui": "node node_modules/jasmine/bin/jasmine test/ui/spec/*.js",
-    "setup": "npm i && npm i -g grunt grunt-cli && grunt build",
+    "test-ui-2": "node ./node_modules/.bin/jest",
+    "test-cli": "node test/cli/*.js | tap-spec",
+    "setup": "npm i && npm i -g grunt grunt-cli && npm rebuild --build-from-source && grunt build",
     "start": "grunt serve"
   },
   "lint-staged": {
@@ -32,12 +38,12 @@
   "dependencies": {
     "atob": "^2.1.2",
     "base64-img": "^1.0.4",
-    "bootstrap": "~3.4.0",
+    "bootstrap": "^3.4.1",
     "bootstrap-colorpicker": "^2.5.3",
-    "buffer": "~5.4.0",
-    "commander": "^3.0.1",
+    "buffer": "~6.0.2",
+    "commander": "^6.2.0",
     "compressorjs": "^1.0.5",
-    "data-uri-to-buffer": "^2.0.0",
+    "data-uri-to-buffer": "^3.0.0",
     "downloadjs": "^1.4.7",
     "eslint": "^6.1.0",
     "fisheyegl": "^0.1.2",
@@ -46,23 +52,26 @@
     "get-pixels": "~3.3.0",
     "gifshot": "^0.4.5",
     "glfx": "0.0.4",
-    "gpu.js": "^2.0.0-rc.12",
+    "gpu.js": "^2.3.1",
     "image-sequencer-invert": "^1.0.0",
     "imagejs": "0.0.9",
-    "imagemin": "^7.0.0",
-    "imagemin-jpegtran": "^6.0.0",
-    "imagemin-pngquant": "^8.0.0",
+    "imagemin": "^7.0.1",
+    "imagemin-jpegtran": "^7.0.0",
+    "imagemin-pngquant": "^9.0.1",
     "imgareaselect": "git://github.com/jywarren/imgareaselect.git#v1.0.0-rc.2",
     "istanbul": "^0.4.5",
     "jasmine": "^3.4.0",
+    "jpegtran-bin": "^5.0.2",
     "jquery": "^3.3.1",
-    "jsdom": "^15.0.0",
+    "jsdom": "^16.3.0",
+    "jspdf": "^2.1.1",
     "jsqr": "^1.1.1",
     "lodash": "^4.17.11",
     "ndarray": "^1.0.18",
     "opencv.js": "^1.2.1",
-    "ora": "^3.0.0",
+    "ora": "^5.1.0",
     "pace": "0.0.4",
+    "pngquant-bin": "^6.0.0",
     "puppeteer": "^1.14.0",
     "qrcode": "^1.3.3",
     "readline-sync": "^1.4.7",
@@ -77,7 +86,7 @@
     "@babel/plugin-proposal-object-rest-spread": "^7.4.3",
     "@babel/plugin-syntax-object-rest-spread": "^7.2.0",
     "babelify": "^10.0.0",
-    "browserify": "16.2.3",
+    "browserify": "17.0.0",
     "eslint": "^6.1.0",
     "grunt": "^1.0.3",
     "grunt-browser-sync": "^2.2.0",
@@ -85,18 +94,22 @@
     "grunt-contrib-concat": "^1.0.1",
     "grunt-contrib-uglify-es": "^3.3.0",
     "grunt-contrib-watch": "^1.1.0",
+    "grunt-text-replace": "^0.4.0",
     "husky": "^3.0.5",
     "image-filter-core": "~2.0.2",
     "image-filter-threshold": "~2.0.1",
     "jasmine-core": "^3.3.0",
     "jasmine-jquery": "^2.1.1",
-    "jasmine-spec-reporter": "^4.2.1",
-    "lint-staged": "^9.1.0",
+    "jasmine-spec-reporter": "^6.0.0",
+    "jest": "^26.1.0",
+    "jest-puppeteer": "^4.3.0",
+    "lint-staged": "^10.0.3",
     "looks-same": "^7.0.0",
     "matchdep": "^2.0.0",
+    "resemblejs": "^3.2.5",
     "tap-spec": "^5.0.0",
     "tape": "^4.9.2",
-    "tape-run": "^6.0.0",
+    "tape-run": "^8.0.0",
     "uglify-es": "^3.3.7"
   },
   "husky": {

scripts/update-demo

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+scriptsDir=$(realpath $(dirname $0))
+
+echo -ne "Enter the repo to push to in the form username/repo (required): "
+read -e pushRepo
+
+echo -ne "Enter repo URL to pull from (upstream) in the form username/repo (default: publiclab/image-sequencer): "
+read -e repoInput
+
+echo -ne "Enter branch name (default: stable): "
+read -e branchInput
+
+echo -ne "Enter CNAME URL(default: none): "
+read -e cnameUrlInput
+
+tempDir=$(mktemp -d)
+pushd $tempDir > /dev/null
+
+git clone https://github.com/$pushRepo
+pushd image-sequencer > /dev/null
+
+$scriptsDir/update-gh-pages "$repoInput" "$branchInput" "$cnameUrlInput" "no warn"
+
+popd > /dev/null
+popd > /dev/null

scripts/update-gh-pages

@@ -0,0 +1,117 @@
+#!/bin/bash
+set -e # So that nothing wrong is published
+
+warn() {
+  echo -e "\033[1;31m
+------IMPORTANT------
+  THIS SCRIPT IS NOT MEANT TO BE USED DIRECTLY, PLEASE NEWLY CLONE THE REPO IN A SEPARATE DIRECTORY AND USE THE SCRIPT THERE.
+  USING THIS SCRIPT IN YOUR MAIN CLONE MAY DELETE YOUR LOCAL CHANGES.
+  This script is made to be reusable: If you want to manually update the demo, \
+  use the interactive script \`update-demo\`. This script can also be used in a github action.
+
+  You can set the 4th argument to anything to bypass this warning. \
+  Setting the 4th argument means that the first 3 arguments are also set which means that you know what you are doing (I assume).
+------IMPORTANT------
+\033[0m"
+
+  echo -ne "Do you still want to continue? [Y/n]: "
+  read -e yN
+
+  case $yN in
+    [yY][eE][sS] | [yY])
+    ;;
+    *)
+      exit 0
+    ;;
+  esac
+}
+
+# --- Constants ---
+deps="jquery bootstrap imgareaselect gifshot downloadjs selectize font-awesome bootstrap-colorpicker jspdf opencv.js/opencv.js" # A list of node_module dependencies to force commit
+# --- Constants ---
+
+# --- Arguments ---
+# $1: Repo(to use as upstream) url in the form username/repo (default: publiclab/image-sequencer) NOTE: Github only
+# $2: Branch to pull from eg: main or stable (default: stable)
+# $3: CNAME URL (default: none)
+# $4: Set the fourth argument to anything to bypass the warning.
+
+if [[ "$1" != "" ]];
+then
+  repo=$1
+else
+  repo="publiclab/image-sequencer"
+fi
+
+if [[ "$2" != "" ]];
+then
+  branch=$2
+else
+  branch="stable"
+fi
+
+if [[ "$3" != "" ]];
+then
+  CNAMEURL=$3
+else
+  CNAMEURL=""
+fi
+# --- Arguments ---
+
+# --- Main Script ---
+if [[ "$4" == "" ]]; # Set a 4th argument to anything to bypass this warning.
+then
+  warn
+fi
+
+git checkout gh-pages
+git remote add upstream https://github.com/$repo
+git fetch upstream
+
+git reset --hard upstream/$branch
+
+echo -e "Running setup script."
+npm run setup
+
+echo -e "Building dist files."
+grunt production
+
+if [ ! -f CNAME ];
+then
+  echo -e "Creating CNAME"
+  touch CNAME
+fi
+
+echo $CNAMEURL > CNAME
+
+echo -e "Removing unnecessary files."
+rm -R docs/
+rm -R test/
+rm CONTRIBUTING.md
+rm index.js
+
+echo -e "Copying important files from src/"
+cp src/ui/prepareDynamic.js prepareDynamic.js
+
+echo "Removing src/"
+rm -R src/
+mkdir -p src/ui/
+mv prepareDynamic.js src/ui/prepareDynamic.js
+
+echo -e "git add dist and node_modules dependencies."
+git add .
+
+for dep in $deps; # Force add node_modules dependencies
+do
+  git add -f node_modules/$dep
+done
+
+git add -f dist/image-sequencer.js
+git add -f dist/image-sequencer-ui.js
+
+echo -e "committing and pusing."
+git commit --no-verify -m "update"
+git push -f
+
+exit 0
+# --- Main Script ---

src/ImageSequencer.js

@@ -2,6 +2,11 @@ if (typeof window !== 'undefined') { isBrowser = true; }
 else { var isBrowser = false; }
 require('./util/getStep.js');
 
+/**
+ * @method ImageSequencer
+ * @param {Object|Float32Array} options Optional options
+ * @returns {Object}
+ */
 ImageSequencer = function ImageSequencer(options) {
 
   var str = require('./Strings.js')(this.steps, modulesInfo, addSteps, copy);
@@ -14,6 +19,12 @@ ImageSequencer = function ImageSequencer(options) {
     return Object.prototype.toString.call(object).split(' ')[1].slice(0, -1);
   }
 
+  /**
+   * @method log
+   * @description Logs colored messages to the console using ASCII color codes
+   * @param {String} color ASCII color code
+   * @param {String} msg Message to be logged to the console
+   */
   function log(color, msg) {
     if (options.ui != 'none') {
       if (arguments.length == 1) console.log(arguments[0]);
@@ -21,6 +32,12 @@ ImageSequencer = function ImageSequencer(options) {
     }
   }
 
+  /**
+   * @method copy
+   * @description Returns a clone of the input object.
+   * @param {Object|Float32Array} a The Object/Array to be cloned
+   * @returns {Object|Float32Array}
+   */
   function copy(a) {
     if (!typeof (a) == 'object') return a;
     if (objTypeOf(a) == 'Array') return a.slice();
@@ -53,10 +70,10 @@ ImageSequencer = function ImageSequencer(options) {
     for (o in sequencer) {
       modules[o] = sequencer[o];
     }
-    sequences = JSON.parse(window.localStorage.getItem('sequences'));
+    sequences = JSON.parse(window.localStorage.getItem('sequences')); // Get saved sequences from localStorage
     if (!sequences) {
       sequences = {};
-      window.localStorage.setItem('sequences', JSON.stringify(sequences));
+      window.localStorage.setItem('sequences', JSON.stringify(sequences)); // Set the localStorage entry as an empty Object by default
     }
   }
 
@@ -64,11 +81,16 @@ ImageSequencer = function ImageSequencer(options) {
   // if (options.imageSelect || options.inBrowser) addStep('image-select');
   // else if (options.imageUrl) loadImage(imageUrl);
 
+  /**
+   * @method addSteps
+   * @description Adds one of more steps to the sequence.
+   * @return {Object}
+   */
   function addSteps() {
     var this_ = (this.name == 'ImageSequencer') ? this : this.sequencer;
     var args = [];
     var json_q = {};
-    for (var arg in arguments) { args.push(copy(arguments[arg])); }
+    for (var arg in arguments) { args.push(copy(arguments[arg])); } // Get all the module names from the arguments
     json_q = formatInput.call(this_, args, '+');
 
     inputlog.push({ method: 'addSteps', json_q: copy(json_q) });
@@ -77,17 +99,28 @@ ImageSequencer = function ImageSequencer(options) {
     return this;
   }
 
+  /**
+   * @method removeStep
+   * @description Removes the step at the specified index from the sequence.
+   * @param {Object} ref ImageSequencer instance
+   * @param {Number} index Index of the step to be removed
+   * @returns {Null}
+   */
   function removeStep(ref, index) {
-    //remove the step from images[image].steps and redraw remaining images
+    // Remove the step from images[image].steps and redraw remaining images
     if (index > 0) {
-      //var this_ = (this.name == "ImageSequencer") ? this : this.sequencer;
+      // var this_ = (this.name == "ImageSequencer") ? this : this.sequencer;
       thisStep = ref.steps[index];
       thisStep.UI.onRemove(thisStep.options.step);
       ref.steps.splice(index, 1);
     }
-    //tell the UI a step has been removed
   }
 
+  /**
+   * @method removeSteps
+   * @description Removes one or more steps from the sequence
+   * @returns {Object}
+   */
   function removeSteps() {
     var   indices;
     var this_ = (this.name == 'ImageSequencer') ? this : this.sequencer;
@@ -103,6 +136,11 @@ ImageSequencer = function ImageSequencer(options) {
     return this;
   }
 
+  /**
+   * @method insertSteps
+   * @description Inserts steps at the specified index
+   * @returns {Object}
+   */
   function insertSteps() {
     var this_ = (this.name == 'ImageSequencer') ? this : this.sequencer;
     var args = [];
@@ -118,8 +156,11 @@ ImageSequencer = function ImageSequencer(options) {
     return this;
   }
 
-  // Config is an object which contains the runtime configuration like progress bar
-  // information and index from which the sequencer should run
+  /**
+   * @method run
+   * @param {Object} config Object which contains the runtime configuration like progress bar information and index from which the sequencer should run.
+   * @returns {Boolean}
+   */
   function run(config) {
     var progressObj, index = 0;
     config = config || { mode: 'no-arg' };
@@ -137,7 +178,7 @@ ImageSequencer = function ImageSequencer(options) {
     var callback = function() { };
     for (var arg in args)
       if (objTypeOf(args[arg]) == 'Function')
-        callback = args.splice(arg, 1)[0]; //callback is formed
+        callback = args.splice(arg, 1)[0]; // Callback is formed
 
     var json_q = formatInput.call(this_, args, 'r');
 
@@ -146,6 +187,11 @@ ImageSequencer = function ImageSequencer(options) {
     return true;
   }
 
+  /**
+   * @method loadImages
+   * @description Loads an image via dataURL or normal URL. Read the docs(https://github.com/publiclab/image-sequencer/blob/main/README.md) for more info.
+   * @returns {Null}
+   */
   function loadImages() {
     var args = [];
     var prevSteps = this.getSteps().slice(1).map(step=>step.options.name);
@@ -182,17 +228,35 @@ ImageSequencer = function ImageSequencer(options) {
 
   }
 
+  /**
+   * @method replaceImage
+   * @description Replaces the current image in the sequencer
+   * @param {String} selector DOM selector string for the image input
+   * @param {*} steps Current steps Object
+   * @param {Object} options
+   * @returns {*}
+   */
   function replaceImage(selector, steps, options) {
     options = options || {};
     options.callback = options.callback || function() { };
     return require('./ReplaceImage')(this, selector, steps, options);
   }
 
-  //returns the steps added
+  /**
+   * @method getSteps
+   * @description Returns the current sequence of steps
+   * @returns {Object}
+   */
   function getSteps(){
     return this.steps;
   }
 
+  /**
+   * @method setUI
+   * @description To set up a UI for ImageSequencer via different callback methods. Read the docs(https://github.com/publiclab/image-sequencer/blob/main/README.md) for more info.
+   * @param {Object} UI Object containing UI callback methods. Read the docs(https://github.com/publiclab/image-sequencer/blob/main/README.md) for more info.
+   * @returns {Null}
+   */
   function setUI(UI) {
     this.events = require('./ui/UserInterface')(UI);
   }
@@ -201,6 +265,12 @@ ImageSequencer = function ImageSequencer(options) {
     return require('./ExportBin')(dir, this, basic, filename);
   };
 
+  /**
+   * @method modulesInfo
+   * @description Returns information about the given module or all the available modules
+   * @param {String} name Module name
+   * @returns {Object}
+   */
   function modulesInfo(name) {
     var modulesdata = {};
     if (name == 'load-image') return {};
@@ -222,23 +292,30 @@ ImageSequencer = function ImageSequencer(options) {
     return modulesdata;
   }
 
+  /**
+   * @method loadNewModule
+   * @description Adds a new local module to sequencer. Read the docs(https://github.com/publiclab/image-sequencer/blob/main/README.md) for mode info.
+   * @param {String} name Name of the new module
+   * @param {Object} options An Object containing path and info about the new module.
+   * @returns {Object}
+   */
   function loadNewModule(name, options) {
 
     if (!options) {
       return this;
 
     } else if (Array.isArray(options)) {
-      // contains the array of module and info
+      // Contains the array of module and info
       this.modules[name] = options;
 
     } else if (options.func && options.info) {
-      // passed in options object
+      // Passed in options object
       this.modules[name] = [
         options.func, options.info
       ];
 
     } else if (options.path && !this.inBrowser) {
-      // load from path(only in node)
+      // Load from path(only in node)
       const module = [
         require(`${options.path}/Module.js`),
         require(`${options.path}/info.json`)
@@ -248,6 +325,13 @@ ImageSequencer = function ImageSequencer(options) {
     return this;
   }
 
+  /**
+   * @method saveNewModule
+   * @description Saves a new local module to ImageSequencer
+   * @param {String} name Name of the new module
+   * @param {String} path Path to the new module
+   * @returns {Null}
+   */
   function saveNewModule(name, path) {
     if (options.inBrowser) {
       // Not for browser context
@@ -258,6 +342,13 @@ ImageSequencer = function ImageSequencer(options) {
     fs.writeFileSync('./src/Modules.js', mods);
   }
 
+  /**
+   * @method saveSequence
+   * @description Saves a sequence on the browser localStorage.
+   * @param {String} name Name for the sequence
+   * @param {String} sequenceString Sequence data as a string
+   * @returns {Null}
+   */
   function saveSequence(name, sequenceString) { // 4. save sequence
     const sequence = str.stringToJSON(sequenceString);
     // Save the given sequence string as a module
@@ -276,7 +367,7 @@ ImageSequencer = function ImageSequencer(options) {
   }
 
   function loadModules() {
-    // This function loads the modules and saved sequences
+    // loadModules function loads the modules and saved sequences.
     this.modules = require('./Modules');
     if (options.inBrowser)
       this.sequences = JSON.parse(window.localStorage.getItem('sequences'));
@@ -286,7 +377,7 @@ ImageSequencer = function ImageSequencer(options) {
 
 
   return {
-    //literals and objects
+    // Literals and objects
     name: 'ImageSequencer',
     options: options,
     inputlog: inputlog,
@@ -296,7 +387,7 @@ ImageSequencer = function ImageSequencer(options) {
     steps: steps,
     image: image,
 
-    //user functions
+    // User functions
     loadImages: loadImages,
     loadImage: loadImages,
     addSteps: addSteps,
@@ -325,7 +416,7 @@ ImageSequencer = function ImageSequencer(options) {
     loadModules: loadModules,
     getSteps:getSteps,
 
-    //other functions
+    // Other functions
     log: log,
     objTypeOf: objTypeOf,
     copy: copy,

src/Modules.js

@@ -11,8 +11,10 @@ module.exports = {
   'canvas-resize': require('./modules/CanvasResize'),
   'channel': require('./modules/Channel'),
   'colorbar': require('./modules/Colorbar'),
+  'color-halftone': require('./modules/ColorHalftone'),
   'color-temperature': require('./modules/ColorTemperature'),
   'colormap': require('./modules/Colormap'),
+  'constrained-crop': require('./modules/ConstrainedCrop'),
   'contrast': require('./modules/Contrast'),
   'convolution': require('./modules/Convolution'),
   'crop': require('./modules/Crop'),
@@ -29,8 +31,10 @@ module.exports = {
   'gradient': require('./modules/Gradient'),
   'grid-overlay': require('./modules/GridOverlay'),
   'import-image': require('./modules/ImportImage'),
+  'mask': require('./modules/Mask'),
   'minify-image': require('./modules/MinifyImage'),
-  'invert': require('image-sequencer-invert'),
+  // 'invert': require('image-sequencer-invert'),
+  'invert': require('./modules/Invert'),
   'ndvi': require('./modules/Ndvi'),
   'ndvi-colormap': require('./modules/NdviColormap'),
   'noise-reduction': require('./modules/NoiseReduction'),
@@ -40,6 +44,7 @@ module.exports = {
   'resize': require('./modules/Resize'),
   'rotate': require('./modules/Rotate'),
   'saturation': require('./modules/Saturation'),
+  'shadow': require('./modules/Shadow'),
   'text-overlay': require('./modules/TextOverlay'),
   'threshold': require('./modules/Threshold'),
   'tint': require('./modules/Tint'),

src/Run.js

@@ -45,6 +45,8 @@ function Run(ref, json_q, callback, ind, progressObj) {
 
           // This output is accessible by UI
           ref.steps[i].options.step.output = ref.steps[i].output.src;
+          ref.steps[i].options.step.wasmSuccess = ref.steps[i].output.wasmSuccess || false;
+          ref.steps[i].options.step.useWasm = ref.steps[i].output.useWasm || false;
 
           // Tell UI that step has been drawn.
           ref.steps[i].UI.onComplete(ref.steps[i].options.step);

src/modules/AddQR/Module.js

@@ -1,46 +1,58 @@
+const _ = require('lodash'),
+  parseCornerCoordinateInputs = require('../../util/ParseInputCoordinates');
 module.exports = function AddQR(options, UI) {
 
   var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
-  options.size = options.size || defaults.size;
-  options.qrCodeString = options.qrCodeString || 'https://github.com/publiclab/image-sequencer';
   var output;
   getPixels = require('get-pixels');
 
   function draw(input, callback, progressObj) {
 
+    options.size = Number(options.size || defaults.size);
+    options.qrCodeString = options.qrCodeString || defaults.qrCodeString;
+    options.startingX = options.startingX || defaults.startingX;
+    options.startingY = options.startingY || defaults.startingY;
     progressObj.stop(true);
     progressObj.overrideFlag = true;
 
     var step = this;
 
-    return getPixels(input.src, function(err, oldPixels) {
-      function changePixel(r, g, b, a) {
-        return [r, g, b, a];
-      }
+    function extraManipulation(pixels, setRenderState, generateOutput) {
+      let iw = pixels.shape[0], // Width of Original Image
+        ih = pixels.shape[1]; // Height of Original Image
+      const oldPixels = _.cloneDeep(pixels);
+      setRenderState(false); // Prevent rendering of final output image until extraManipulation completes.
 
-      function extraManipulation(pixels, generateOutput) {
-        if (err) {
-          console.log(err);
-          return;
-        }
-        require('./QR')(options, pixels, oldPixels, generateOutput);
-      }
-      function output(image, datauri, mimetype) {
-        step.output = { src: datauri, format: mimetype };
-      }
-      return require('../_nomodule/PixelManipulation.js')(input, {
-        output: output,
-        ui: options.step.ui,
-        changePixel: changePixel,
-        extraManipulation: extraManipulation,
-        format: input.format,
-        image: options.image,
-        inBrowser: options.inBrowser,
-        callback: callback,
-        useWasm:options.useWasm
+      // Parse the inputs.
+      parseCornerCoordinateInputs({iw, ih},
+        {
+          startingX: { valInp: options.startingX, type: 'horizontal'},
+          startingY: { valInp: options.startingY, type: 'vertical' },
+        }, function(opt, cord){
+          options.startingX = Math.floor(cord.startingX.valInp);
+          options.startingY = Math.floor(cord.startingY.valInp);
+        });
+
+      require('./QR')(options, pixels, oldPixels, () => {
+        setRenderState(true); // Allow rendering in the callback.
+        generateOutput();
       });
-    });
+    }
 
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
+
+    return require('../_nomodule/PixelManipulation.js')(input, {
+      output: output,
+      ui: options.step.ui,
+      extraManipulation: extraManipulation,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      callback: callback,
+      useWasm:options.useWasm
+    });
   }
 
   return {

src/modules/AddQR/QR.js

@@ -1,44 +1,37 @@
-module.exports = exports = function (options, pixels, oldPixels, callback) {
-  const pixelSetter = require('../../util/pixelSetter.js');
+const pixelSetter = require('../../util/pixelSetter.js'),
+  getPixels = require('get-pixels'),
+  QRCode = require('qrcode');
+module.exports = exports = function (options, pixels, oldPixels, cb) {
 
-  var QRCode = require('qrcode');
-  QRCode.toDataURL(options.qrCodeString, function (err, url) {
-    var getPixels = require('get-pixels');
+  QRCode.toDataURL(options.qrCodeString, {width: options.size, scale: 1}, function (error, url) {
     getPixels(url, function (err, qrPixels) {
       if (err) {
-        console.log('Bad image path', image);
+        console.log('get-pixels error: ', err);
       }
 
-      var imagejs = require('imagejs');
-      var bitmap = new imagejs.Bitmap({ width: qrPixels.shape[0], height: qrPixels.shape[1] });
-      bitmap._data.data = qrPixels.data;
-      var resized = bitmap.resize({
-        width: options.size, height: options.size,
-        algorithm: 'bicubicInterpolation'
-      });
-
-      qrPixels.data = resized._data.data;
-      qrPixels.shape = [options.size, options.size, 4];
-      qrPixels.stride[1] = 4 * options.size;
-
-      var width = oldPixels.shape[0],
+      const width = oldPixels.shape[0],
         height = oldPixels.shape[1];
-      var xe = width - options.size,
-        ye = height - options.size;
-      for (var m = 0; m < width; m++) {
-        for (var n = 0; n < height; n++) {
-          if (m >= xe && n >= ye) {
-            pixelSetter(m, n, [qrPixels.get(m - xe, n - ye, 0), qrPixels.get(m - xe, n - ye, 1), qrPixels.get(m - xe, n - ye, 2), qrPixels.get(m - xe, n - ye, 3)], pixels);
-          }
 
-          else {
-            pixelSetter(m, n, [oldPixels.get(m, n, 0), oldPixels.get(m, n, 1), oldPixels.get(m, n, 2), oldPixels.get(m, n, 3)], pixels);
-          }
+      const xe = Math.min(options.startingX, width - options.size), // Starting pixel coordinates
+        ye = Math.min(options.startingY, height - options.size);
 
+      for (let x = xe; x < Math.min(xe + options.size, width); x++) {
+        for (let y = ye; y < Math.min(ye + options.size, height); y++) {
+          pixelSetter(
+            x,
+            y,
+            [
+              qrPixels.get(x - xe, y - ye, 0),
+              qrPixels.get(x - xe, y - ye, 1),
+              qrPixels.get(x - xe, y - ye, 2),
+              qrPixels.get(x - xe, y - ye, 3)
+            ],
+            pixels
+          );
         }
       }
-      callback();
 
+      if(cb) cb();
     });
   });
 };

src/modules/AddQR/info.json

@@ -12,6 +12,16 @@
         "type": "string",
         "desc": "input string to generate QR code",
         "default": "https://github.com/publiclab/image-sequencer"
+      },
+      "startingX": {
+        "type": "string",
+        "desc": "X-position (measured from left) from where QR starts",
+        "default": "0"
+      },
+      "startingY": {
+        "type": "string",
+        "desc": "Y-position (measured from top) from where QR starts",
+        "default": "0"
       }
     },
     "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#add-qr-module"

src/modules/Average/Module.js

@@ -16,7 +16,6 @@ module.exports = function Average(options, UI) {
 
     // do the averaging
     function extraManipulation(pixels) {
-      const $ = window.$;
       var i = 0, sum = [0, 0, 0, 0];
       while (i < pixels.data.length) {
         sum[0] += pixels.data[i++];
@@ -43,23 +42,19 @@ module.exports = function Average(options, UI) {
       // report back and store average in metadata:
       options.step.metadata.averages = sum;
 
-      // TODO: refactor into a new "display()" method as per https://github.com/publiclab/image-sequencer/issues/242
-      if (options.step.inBrowser && options.step.ui) $(options.step.ui).find('.details').append('<p><b>Averages</b> (r, g, b, a): ' + sum.join(', ') + '</p>');
+      if (options.step.average === undefined) options.step.average = '';
+      options.step.average += 'rgba(' + sum.join(', ') + ')';
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = {
-        src: datauri,
-        format: mimetype
-      };
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,
+      inBrowser: options.inBrowser,
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,

src/modules/Average/info.json

@@ -3,5 +3,11 @@
     "description": "Average all pixel color",
     "inputs": {
     },
+    "outputs": {
+        "average": {
+            "type": "string",
+            "desc": "The average value of all the pixels."
+        }
+    },
     "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#average-module"
 }

src/modules/Blend/Module.js

@@ -1,9 +1,10 @@
-module.exports = function Dynamic(options, UI, util) {
+module.exports = function Blend(options, UI, util) {
 
   var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
 
-  options.func = options.func || defaults.blend;
+  options.func = options.blend || defaults.blend;
   options.offset = options.offset || defaults.offset;
+  options.blendMode = options.blendMode || defaults.blendMode;
 
   var output;
 
@@ -15,9 +16,6 @@ module.exports = function Dynamic(options, UI, util) {
 
     var step = this;
 
-    // convert to runnable code:
-    if (typeof options.func === 'string') eval('options.func = ' + options.func);
-
     var getPixels = require('get-pixels');
 
     // convert offset as string to int
@@ -32,26 +30,83 @@ module.exports = function Dynamic(options, UI, util) {
       callback();
     }
 
+    // see http://docs.gimp.org/en/gimp-concepts-layer-modes.html for other blend modes
+
+    const multiply_mode = function (i, m) {
+      return ~~( (i * m) / 255 );
+    };
+    const divide_mode = function (i, m) {
+      return ~~( (256 * i) / (m + 1) );
+    };
+
+    const overlay_mode = function (i, m) {
+      return ~~( (i / 255) * (i + ((2 * m) / 255) * (255 - i)) );
+    };
+    
+    const screen_mode = function (i, m) {
+      return ~~( 255 - ((255 - m) * (255 - i)) / 255 );
+    };
+    
+    const sof_light_mode = function (i, m) {
+      var Rs = screen_mode(i, m);
+      return ~~( ((((255 - i) * m) + Rs) * i) / 255 );
+    };
+    
+    const color_dodge = function (i, m) {
+      return ~~( (256 * i) / (255 - m + 1) );
+    };
+
+    const burn_mode = function (i, m) {
+      return ~~( 255 - (256 * (255 - i)) / (m + 1));
+    };
+
+    const grain_extract_mode = function (i, m) {
+      return ~~( i - m + 128 );
+    };
+
+    const grain_merge_mode = function (i, m) {
+      return ~~( i + m - 128 );
+    };
+
+    
     getPixels(priorStep.output.src, function(err, pixels) {
       options.firstImagePixels = pixels;
 
+      // Convert to runnable code.
+      if (typeof options.func === 'string') eval('options.func = ' + options.func);
+      
       function changePixel(r2, g2, b2, a2, x, y) {
         // blend!
         let p = options.firstImagePixels;
-        return options.func(
-          r2, g2, b2, a2,
-          p.get(x, y, 0),
-          p.get(x, y, 1),
-          p.get(x, y, 2),
-          p.get(x, y, 3)
-        );
+        let r1 = p.get(x, y, 0),
+          g1 = p.get(x, y, 1),
+          b1 = p.get(x, y, 2),
+          a1 = p.get(x, y, 3);
+
+        const blends = {
+          'Color Dodge': () => [color_dodge(r2, r1), color_dodge(g2, g1), color_dodge(b2, b1), 255],
+          'Multiply': () => [multiply_mode(r2, r1), multiply_mode(g2, g1), multiply_mode(b2, b1), multiply_mode(a2, a1)],
+          'Divide': () => [divide_mode(r2, r1), divide_mode(g2, g1), divide_mode(b2, b1), 255],
+          'Overlay': () => [overlay_mode(r2, r1), overlay_mode(g2, g1), overlay_mode(b2, b1), 255],
+          'Screen': () => [screen_mode(r2, r1), screen_mode(g2, g1), screen_mode(b2, b1), 255],
+          'Soft Light': () => [sof_light_mode(r2, r1), sof_light_mode(g2, g1), sof_light_mode(b2, b1), 255],
+          'Color Burn': () => [burn_mode(r2, r1), burn_mode(g2, g1), burn_mode(b2, b1), 255],
+          'Grain Extract': () => [grain_extract_mode(r2, r1), grain_extract_mode(g2, g1), grain_extract_mode(b2, b1), 255],
+          'Grain Merge': () => [grain_merge_mode(r2, r1), grain_merge_mode(g2, g1), grain_merge_mode(b2, b1), 255]
+        };
+        
+        if(options.blendMode == 'custom')
+          return options.func(
+            r2, g2, b2, a2, r1, g1, b1, a1
+          );
+        else {
+          return blends[options.blendMode]();
+        }
+
       }
 
-      function output(image, datauri, mimetype) {
-
-        // This output is accessible by Image Sequencer
-        step.output = { src: datauri, format: mimetype };
-
+      function output(image, datauri, mimetype, wasmSuccess) {
+        step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
       }
 
       // run PixelManipulatin on second image's pixels

src/modules/Blend/info.json

@@ -1,17 +1,34 @@
 {
   "name": "blend",
-  "description": "Blend two chosen image steps with the given function. Defaults to using the red channel from image 1 and the green and blue and alpha channels of image 2. Easier to use interfaces coming soon!",
+  "description": "Blend two chosen image steps with the given function. Defaults to using the red channel from image 1 and the green and blue and alpha channels of image 2.",
   "inputs": {
     "offset": {
       "type": "integer",
       "desc": "Choose which image to blend the current image with. Two steps back is -2, three steps back is -3 etc.",
       "default": -2
     },
+    "blendMode": {
+      "type": "select",
+      "desc": "Name of the Blend Mode to use",
+      "default": "custom",
+      "values": [
+        "custom",
+        "Multiply",
+        "Divide",
+        "Overlay",
+        "Screen",
+        "Soft Light",
+        "Color Burn",
+        "Color Dodge",
+        "Grain Extract",
+        "Grain Merge"
+      ]
+    },
     "blend": {
       "type": "string",
       "desc": "Function to use to blend the two images.",
-      "default": "function(r1, g1, b1, a1, r2, g2, b2, a2) { return [ r1, g2, b2, a2 ] }"
+      "default": "function(r1, g1, b1, a1, r2, g2, b2, a2, x, y) { return [ r2, g2, b2, a2 ] }"
     }
   },
-  "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#blend-module"
+  "docs-link": "https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#blend-module"
 }

src/modules/BlobAnalysis/BlobAnalysis.js

@@ -1,17 +1,10 @@
-module.exports = function(pixels, options, priorStep){
-
-  var $ = require('jquery'); // to make Blob-analysis work for node.js
-  
-  var img = $(priorStep.imgElement);
-  if(Object.keys(img).length === 0){
-    img = $(priorStep.options.step.imgElement);
-  }
-
+module.exports = function(pixels){
   var canvas = document.createElement('canvas');
   canvas.width = pixels.shape[0];
   canvas.height = pixels.shape[1];
   var ctx = canvas.getContext('2d');
-  ctx.drawImage(img[0], 0, 0);
+  ctx.putImageData(new ImageData(new Uint8ClampedArray(pixels.data), pixels.shape[0], pixels.shape[1]), 0, 0);
+  
   let imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
 
 
@@ -25,26 +18,26 @@ module.exports = function(pixels, options, priorStep){
   let unknown = new cv.Mat();
   let markers = new cv.Mat();
  
-  // gray and threshold image
+  // Gray and Threshold the image
   cv.cvtColor(src, gray, cv.COLOR_RGBA2GRAY, 0);
   cv.threshold(gray, gray, 0, 255, cv.THRESH_BINARY_INV + cv.THRESH_OTSU);
  
-  // get background
+  // Get background
   let M = cv.Mat.ones(3, 3, cv.CV_8U);
   cv.erode(gray, gray, M);
   cv.dilate(gray, opening, M);
   cv.dilate(opening, imageBg, M, new cv.Point(-1, -1), 3);
  
-  // distance transform
+  // Distance transform
   cv.distanceTransform(opening, distTrans, cv.DIST_L2, 5);
   cv.normalize(distTrans, distTrans, 1, 0, cv.NORM_INF);
  
-  // get foreground
+  // Get foreground
   cv.threshold(distTrans, imageFg, 0.7 * 1, 255, cv.THRESH_BINARY);
   imageFg.convertTo(imageFg, cv.CV_8U, 1, 0);
   cv.subtract(imageBg, imageFg, unknown);
  
-  // get connected components markers
+  // Get connected components markers
   cv.connectedComponents(imageFg, markers);
   for (let i = 0; i < markers.rows; i++) {
     for (let j = 0; j < markers.cols; j++) {
@@ -58,13 +51,13 @@ module.exports = function(pixels, options, priorStep){
   cv.cvtColor(src, src, cv.COLOR_RGBA2RGB, 0);
   cv.watershed(src, markers);
  
-  // draw barriers
+  // Grow barriers
   for (let i = 0; i < markers.rows; i++) {
     for (let j = 0; j < markers.cols; j++) {
       if (markers.intPtr(i, j)[0] == -1) {
-        src.ucharPtr(i, j)[0] = 255; // R
-        src.ucharPtr(i, j)[1] = 0; // G
-        src.ucharPtr(i, j)[2] = 0; // B
+        src.ucharPtr(i, j)[0] = 255; // Red
+        src.ucharPtr(i, j)[1] = 0; // Green
+        src.ucharPtr(i, j)[2] = 0; // Blue
       }
     }
   }
@@ -78,4 +71,4 @@ module.exports = function(pixels, options, priorStep){
   pixels.data = myImageData.data;
  
   return pixels;
-};
+};

src/modules/BlobAnalysis/Module.js

@@ -10,17 +10,14 @@ module.exports = function BlobAnalysis(options, UI){
   
     var step = this;
 
-    var priorStep = this.getStep(-1); // get the previous step to process it
-
     function extraManipulation(pixels){
   
-      pixels = require('./BlobAnalysis')(pixels, options, priorStep);
+      pixels = require('./BlobAnalysis')(pixels);
       return pixels;
     }
   
-    function output(image, datauri, mimetype){
-  
-      step.output = { src: datauri, format: mimetype};
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
   
     return require('../_nomodule/PixelManipulation.js')(input, {
@@ -40,4 +37,4 @@ module.exports = function BlobAnalysis(options, UI){
     output: output,
     UI: UI
   };
-};
+};

src/modules/BlobAnalysis/info.json

@@ -2,5 +2,6 @@
     "name": "Blob Analysis",
     "description": "Blob/Region identification for microscopic images.",
     "inputs": {},
+    "requires": ["webgl", "browser"],
     "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#blob-analysis"
 }

src/modules/Blur/Blur.js

@@ -1,8 +1,36 @@
+// Generates a 5x5 Gaussian kernel
+function kernelGenerator(sigma = 1) {
+
+  let kernel = [],
+    sum = 0;
+
+  if (sigma == 0) sigma += 0.05;
+
+  const s = 2 * Math.pow(sigma, 2);
+
+  for (let y = -2; y <= 2; y++) {
+    kernel.push([]);
+    for (let x = -2; x <= 2; x++) {
+      let r = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
+      kernel[y + 2].push(Math.exp(-(r / s)));
+      sum += kernel[y + 2][x + 2];
+    }
+  }
+
+  for (let x = 0; x < 5; x++){
+    for (let y = 0; y < 5; y++){
+      kernel[y][x] = (kernel[y][x] / sum);
+    }
+  }
+
+  return kernel;
+}
+
 module.exports = exports = function(pixels, blur) {
   const pixelSetter = require('../../util/pixelSetter.js');
 
-  let kernel = kernelGenerator(blur),
-    pixs = {
+  let kernel = kernelGenerator(blur), // Generate the Gaussian kernel based on the sigma input.
+    pixs = { // Separates the rgb channel pixels to convolve on the GPU.
       r: [],
       g: [],
       b: [],
@@ -20,46 +48,18 @@ module.exports = exports = function(pixels, blur) {
     }
   }
 
-  const convolve = require('../_nomodule/gpuUtils').convolve;
+  const convolve = require('../_nomodule/gpuUtils').convolve; // GPU convolution function.
 
-  const conPix = convolve([pixs.r, pixs.g, pixs.b], kernel);
+  const conPix = convolve([pixs.r, pixs.g, pixs.b], kernel); // Convolves the pixels (all channels separately) on the GPU.
 
   for (let y = 0; y < pixels.shape[1]; y++){
     for (let x = 0; x < pixels.shape[0]; x++){
       var pixelvalue = [Math.max(0, Math.min(conPix[0][y][x], 255)),
         Math.max(0, Math.min(conPix[1][y][x], 255)),
         Math.max(0, Math.min(conPix[2][y][x], 255))];
-      pixelSetter(x, y, pixelvalue, pixels);
+      pixelSetter(x, y, pixelvalue, pixels); // Sets the image pixels according to the blurred values.
     }
   }
 
   return pixels;
-
-  //Generates a 5x5 Gaussian kernel
-  function kernelGenerator(sigma = 1) {
-
-    let kernel = [],
-      sum = 0;
-
-    if (sigma == 0) sigma += 0.05;
-
-    const s = 2 * Math.pow(sigma, 2);
-
-    for (let y = -2; y <= 2; y++) {
-      kernel.push([]);
-      for (let x = -2; x <= 2; x++) {
-        let r = Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
-        kernel[y + 2].push(Math.exp(-(r / s)));
-        sum += kernel[y + 2][x + 2];
-      }
-    }
-
-    for (let x = 0; x < 5; x++){
-      for (let y = 0; y < 5; y++){
-        kernel[y][x] = (kernel[y][x] / sum);
-      }
-    }
-
-    return kernel;
-  }
-};
+};

src/modules/Blur/Module.js

@@ -20,16 +20,14 @@ module.exports = function Blur(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,
+      inBrowser: options.inBrowser,
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,

src/modules/Brightness/Module.js

@@ -31,11 +31,8 @@ module.exports = function Brightness(options, UI) {
       return [r, g, b, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/CanvasResize/Module.js

@@ -35,11 +35,8 @@ module.exports = function canvasResize(options, UI) {
       return newPixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/CanvasResize/info.json

@@ -22,5 +22,6 @@
             "desc": "Y-cord of the top left corner of the image on the canvas",
             "default": 500
         }
-    }
+    },
+    "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#canvas-resize-module"
 }

src/modules/Channel/Module.js

@@ -22,11 +22,8 @@ module.exports = function Channel(options, UI) {
       if (options.channel === 'blue') return [0, 0, b, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accesible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/ColorHalftone/Module.js

@@ -0,0 +1,135 @@
+/*
+* Generate halftone versions of CMYK channels and blend them with varying rotations as in analog print color separation processes.
+* Simulates a CMYK halftone rendering of the image by multiplying pixel values with a four rotated 2D sine wave patterns, one each for cyan, magenta, yellow, and black.
+* http://evanw.github.io/glfx.js/docs/#colorHalftone
+*/
+module.exports = function ColorHalftone(options, UI) {
+
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+
+  var output;
+  var fx = require('glfx');
+
+  var dataURItoBlob = function dataURItoBlob(dataURI) {
+    // convert base64/URLEncoded data component to raw binary data held in a string
+    var byteString;
+    if (dataURI.split(',')[0].indexOf('base64') >= 0)
+      byteString = atob(dataURI.split(',')[1]);
+    else
+      byteString = unescape(dataURI.split(',')[1]);
+
+    // separate out the mime component
+    var mimeString = dataURI.split(',')[0].split(':')[1].split(';')[0];
+
+    // write the bytes of the string to a typed array
+    var ia = new Uint8Array(byteString.length);
+    for (var i = 0; i < byteString.length; i++) {
+      ia[i] = byteString.charCodeAt(i);
+    }
+
+    return new Blob([ia], { type: mimeString });
+  };
+
+  var canvasToBlobUrl = function canvasToBlobUrl(canvas) {
+
+    var blob = dataURItoBlob(canvas.toDataURL('image/png'));
+    return window.URL.createObjectURL(blob);
+
+  };
+
+  var colorHalftone = function colorHalftone(id, options, download) {
+
+    // try to create a WebGL canvas (will fail if WebGL isn't supported)
+    try {
+      var canvas = fx.canvas(1500, 1500);
+    } catch (e) {
+      alert(e);
+      return;
+    }
+
+    // convert the image to a texture
+    var imageEl = document.getElementById(id);
+
+    var image = new Image();
+
+    image.onload = function() {
+
+      var texture = canvas.texture(image);
+
+      canvas.draw(texture,
+        image.width, //  * ratio,
+        image.height// * ratio
+      );
+
+      canvas.colorHalftone(
+        image.width / 2,
+        image.height / 2,
+        parseFloat(options.angle),
+        parseFloat(options.size)
+      ).update();
+
+      var burl = canvasToBlobUrl(canvas);
+
+      if (download) {
+
+        window.open(burl);
+
+      } else { // replace the image
+
+        // keep non-blob version in case we have to fall back:
+        // image.src = canvas.toDataURL('image/png');
+        // window.location = canvas.toDataURL('image/png');
+        imageEl.src = burl;
+
+      }
+
+    };
+
+    $(image).hide();
+    image.src = imageEl.src;
+
+  };
+
+  function draw(input, callback) {
+
+    var step = this;
+
+    options.angle = options.angle || defaults.angle;
+    options.size = options.size || defaults.size;
+
+    if (!options.inBrowser) {
+      // this.output = input;
+      // callback();
+      require('../_nomodule/gl-context')(input, callback, step, options);
+    }
+    else {
+      var image = document.createElement('img');
+      image.onload = () => {
+        colorHalftone(
+          'img',
+          options
+        );
+        image.onload = () => {
+          var canvas = document.createElement('canvas');
+          canvas.width = image.naturalWidth; // or 'width' if you want a special/scaled size
+          canvas.height = image.naturalHeight; // or 'height' if you want a special/scaled size
+          canvas.getContext('2d').drawImage(image, 0, 0);
+
+          step.output = { src: canvas.toDataURL('image/png'), format: 'png' };
+          image.remove();
+          callback();
+        };
+      };
+      image.src = input.src;
+      image.id = 'img';
+      document.body.appendChild(image);
+    }
+  }
+
+  return {
+    options: options,
+    draw: draw,
+    output: output,
+    UI: UI
+  };
+};

src/modules/ColorHalftone/index.js

@@ -0,0 +1,4 @@
+module.exports = [
+  require('./Module'),
+  require('./info.json')
+];

src/modules/ColorHalftone/info.json

@@ -0,0 +1,23 @@
+{
+    "name": "color-halftone",
+    "requires": ["webgl"],
+    "description": "Generate halftone versions of CMYK channels and blend them with varying rotations as in analog print color separation processes.",
+    "inputs": {
+        "angle": {
+            "type": "float",
+            "desc": "angle of rotation of the halftone patterns in radians",
+            "default": "0.25",
+            "min": "0",
+            "max": "1.57",
+            "step": "0.05"
+        },
+        "size": {
+            "type": "integer",
+            "desc": "the diameter of a dot in pixels",
+            "default": "4",
+            "min": "3",
+            "max": "20"
+        }
+    },
+    "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#color-halftone-module"
+}

src/modules/ColorTemperature/Module.js

@@ -1,12 +1,15 @@
 module.exports = function ColorTemperature(options, UI) {
   
   const pixelSetter = require('../../util/pixelSetter.js');
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
 
   var output;
 
   function draw(input, callback, progressObj) {
 
-    options.temperature = (options.temperature > '40000') ? '40000' : options.temperature;
+    options.temperature = options.temperature || defaults.temperature;
+    options.temperature = (options.temperature > 40000) ? 40000 : options.temperature;
+    options.temperature = (options.temperature < 0) ? 0 : options.temperature;
 
     progressObj.stop(true);
     progressObj.overrideFlag = true;
@@ -52,10 +55,8 @@ module.exports = function ColorTemperature(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/Colorbar/Module.js

@@ -1,12 +1,12 @@
 module.exports = require('../../util/createMetaModule.js')(
   function mapFunction(options) {
-
+    var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
     // return steps with options:
     return [
       { 'name': 'gradient', 'options': {} },
-      { 'name': 'colormap', 'options': { colormap: options.colormap } },
-      { 'name': 'crop', 'options': { 'y': 0, 'h': options.h } },
-      { 'name': 'overlay', 'options': { 'x': options.x, 'y': options.y, 'offset': -4 } }
+      { 'name': 'colormap', 'options': { colormap: options.colormap || defaults.colormap } },
+      { 'name': 'crop', 'options': { 'y': 0, 'w': '100%', 'h': options.h || defaults.h } },
+      { 'name': 'overlay', 'options': { 'x': options.x || defaults.x, 'y': options.y || defaults.y, 'offset': -4 }  }
     ];
   }, {
     infoJson: require('./info.json')

src/modules/Colormap/Colormap.js

@@ -12,7 +12,8 @@
  */
 
 module.exports = function Colormap(value, options) {
-  options.colormap = options.colormap || colormaps.default;
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  options.colormap = options.colormap || defaults.colormap;
   // if a lookup table is provided as an array:
   if(typeof(options.colormap) == 'object')
     colormapFunction = colormap(options.colormap);

src/modules/Colormap/Module.js

@@ -16,12 +16,10 @@ module.exports = function Colormap(options, UI) {
       return [res[0], res[1], res[2], 255];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
+    
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,

src/modules/ConstrainedCrop/Module.js

@@ -0,0 +1,56 @@
+/*
+* Crops an Image on the basis of the ratio provided
+*/
+module.exports = function ConstrainedCrop(options, UI) {
+
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  var output;
+
+  function draw(input, callback) {
+
+    var step = this,
+      startingX = Number(options.startingX || defaults.startingX),
+      startingY = Number(options.startingY || defaults.startingY),
+      aspectRatio = (options.aspectRatio || defaults.aspectRatio).split(':'),
+      widthRatio = Number(aspectRatio[0]),
+      heightRatio = Number(aspectRatio[1]);
+
+    function extraManipulation(pixels) {
+      var width = pixels.shape[0],
+        height = pixels.shape[1];
+      var endX, endY;
+      if(((width - startingX) / widthRatio) * heightRatio <= (height - startingY)) {
+        endX = width;
+        endY = (((width - startingX) / widthRatio) * heightRatio) + startingY;
+      }
+      else {
+        endX = (((height - startingY) / heightRatio) * widthRatio) + startingX;
+        endY = height;
+      }
+      const newPixels = require('../Crop/Crop')(pixels, {'x': startingX, 'y': startingY, 'w': endX - startingX, 'h': endY - startingY}, function() {
+      });
+      return newPixels;
+    }
+
+
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
+    return require('../_nomodule/PixelManipulation')(input, {
+      output: output,
+      ui: options.step.ui,
+      extraManipulation: extraManipulation,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      callback: callback,
+      useWasm:options.useWasm
+    });
+  }
+  return {
+    options: options,
+    draw: draw,
+    output: output,
+    UI: UI
+  };
+};

src/modules/ConstrainedCrop/index.js

@@ -0,0 +1,4 @@
+module.exports = [
+  require('./Module'),
+  require('./info.json')
+];

src/modules/ConstrainedCrop/info.json

@@ -0,0 +1,23 @@
+{
+    "name": "constrained-crop",
+    "description": "Crops an image in a particular aspect-ratio",
+    "inputs": {
+      "startingX": {
+        "type": "integer",
+        "desc": "X-position (measured from left) from where cropping starts",
+        "default": 0
+      },
+      "startingY": {
+        "type": "integer",
+        "desc": "Y-position (measured from top) from where cropping starts",
+        "default": 0
+      },
+      "aspectRatio":{
+        "type": "string",
+        "desc": "Enter aspect ratio in following format width:height",
+        "default": "1:1"
+      }
+    },
+   "docs-link":""
+  }
+  

src/modules/Contrast/Contrast.js

@@ -1,30 +0,0 @@
-var _ = require('lodash');
-const pixelSetter = require('../../util/pixelSetter.js');
-
-module.exports = exports = function(pixels, contrast) {
-  let oldpix = _.cloneDeep(pixels);
-  contrast = Number(contrast);
-  if (contrast < -100) contrast = -100;
-  if (contrast > 100) contrast = 100;
-  contrast = (100.0 + contrast) / 100.0;
-  contrast *= contrast;
-
-  for (let i = 0; i < pixels.shape[0]; i++) {
-    for (let j = 0; j < pixels.shape[1]; j++) {
-            
-      var rgbarray = [oldpix.get(i, j, 0) / 255.0, oldpix.get(i, j, 1) / 255.0, oldpix.get(i, j, 2) / 255.0];
-      for(var idx = 0;idx < 3;idx++){
-        rgbarray[idx] -= 0.5;
-        rgbarray[idx] *= contrast;
-        rgbarray[idx] += 0.5;
-        rgbarray[idx] *= 255;
-        if (rgbarray[idx] < 0) rgbarray[idx] = 0;
-        if (rgbarray[idx] > 255) rgbarray[idx] = 255;
-      }
-            
-      pixelSetter(i, j, rgbarray, pixels);
-            
-    }
-  }
-  return pixels;
-};

src/modules/Contrast/Module.js

@@ -15,25 +15,41 @@ module.exports = function Contrast(options, UI) {
 
     var step = this;
 
-    function extraManipulation(pixels) {
-      pixels = require('./Contrast')(pixels, options.contrast);
-      return pixels;
+    let contrast = options.contrast;
+
+    contrast = Number(contrast);
+    if (contrast < -100) contrast = -100;
+    if (contrast > 100) contrast = 100;
+    contrast = (100.0 + contrast) / 100.0;
+    contrast *= contrast;
+
+    function changeContrast(p){
+      p -= 0.5;
+      p *= contrast;
+      p += 0.5;
+      p *= 255;
+      p = Math.max(0, p);
+      p = Math.min(p, 255);
+      return p;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
+    function changePixel(r, g, b, a) {
+      
+      return [changeContrast(r / 255), changeContrast(g / 255), changeContrast(b / 255), a];
+    }
 
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,
-      extraManipulation: extraManipulation,
+      changePixel: changePixel,
       format: input.format,
       image: options.image,
       callback: callback,
+      inBrowser: options.inBrowser,
       useWasm:options.useWasm
     });
 

src/modules/Convolution/Module.js

@@ -19,10 +19,8 @@ module.exports = function Convolution(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
@@ -31,6 +29,7 @@ module.exports = function Convolution(options, UI) {
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,
+      inBrowser: options.inBrowser,
       callback: callback,
       useWasm:options.useWasm
     });

src/modules/Crop/Crop.js

@@ -1,61 +1,71 @@
-module.exports = function Crop(input, options, callback) {
+const ndarray = require('ndarray'),
+  pixelSetter = require('../../util/pixelSetter'),
+  parseCornerCoordinateInputs = require('../../util/ParseInputCoordinates');
+
+module.exports = function Crop(pixels, options, cb) {
   var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
-  var getPixels = require('get-pixels'),
-    savePixels = require('save-pixels');
+  options.x = options.x || defaults.x;
+  options.y = options.y || defaults.y;
 
-  options.x = parseInt(options.x) || defaults.x;
-  options.y = parseInt(options.y) || defaults.y;
+  options.w = options.w || defaults.w;
+  options.h = options.h || defaults.h;
 
-  getPixels(input.src, function(err, pixels){
-    options.w = parseInt(options.w) || Math.floor(pixels.shape[0]);
-    options.h = parseInt(options.h) || Math.floor(pixels.shape[1]);
-    options.backgroundColor = options.backgroundColor || defaults.backgroundColor;
-    var ox = options.x;
-    var oy = options.y;
-    var w = options.w;
-    var h = options.h;
-    var iw = pixels.shape[0]; //Width of Original Image
-    var ih = pixels.shape[1]; //Height of Original Image
-    var backgroundArray = [];
-    backgroundColor = options.backgroundColor.substring(options.backgroundColor.indexOf('(') + 1, options.backgroundColor.length - 1); // extract only the values from rgba(_,_,_,_)
-    backgroundColor = backgroundColor.split(',');
-    for(var i = 0; i < w ; i++){
-      backgroundArray = backgroundArray.concat([backgroundColor[0], backgroundColor[1], backgroundColor[2], backgroundColor[3]]);
-    }
-    // var newarray = new Uint8Array(4*w*h);
-    var array = [];
-    for (var n = oy; n < oy + h; n++) {
-      var offsetValue = 4 * w * n;
-      if(n < ih){
-        var start = n * 4 * iw + ox * 4;
-        var end = n * 4 * iw + ox * 4 + 4 * w;
-        var pushArray = Array.from(pixels.data.slice(start, end ));
-        array.push.apply(array, pushArray);
-      } else {
-        array.push.apply(array, backgroundArray);
-      }
-    }
-    
-    var newarray = Uint8Array.from(array);
-    pixels.data = newarray;
-    pixels.shape = [w, h, 4];
-    pixels.stride[1] = 4 * w;
+  options.backgroundColor = options.backgroundColor || defaults.backgroundColor;
 
-    options.format = input.format;
+  const bg = options.backgroundColor.replace('rgba', '').replace('(', '').replace(')', '').split(',');
 
-    var chunks = [];
-    var totalLength = 0;
-    var r = savePixels(pixels, options.format);
+  let iw = pixels.shape[0], // Width of Original Image
+    ih = pixels.shape[1], // Height of Original Image
+    offsetX,
+    offsetY,
+    w,
+    h;
 
-    r.on('data', function(chunk){
-      totalLength += chunk.length;
-      chunks.push(chunk);
+  // Parse the inputs
+  parseCornerCoordinateInputs({iw, ih},
+    {
+      x: { valInp: options.x, type: 'horizontal' },
+      y: { valInp: options.y, type: 'vertical' },
+      w: { valInp: options.w, type: 'horizontal' },
+      h: { valInp: options.h, type: 'vertical' },
+    }, function (opt, coord) {
+      offsetX = Math.floor(coord.x.valInp);
+      offsetY = Math.floor(coord.y.valInp);
+      w = Math.floor(coord.w.valInp);
+      h = Math.floor(coord.h.valInp);
     });
 
-    r.on('end', function(){
-      var data = Buffer.concat(chunks, totalLength).toString('base64');
-      var datauri = 'data:image/' + options.format + ';base64,' + data;
-      callback(datauri, options.format);
-    });
-  });
+  const newPixels = new ndarray([], [w, h, 4]);
+
+  for (let x = 0; x < w; x++) {
+    for (let y = 0; y < h; y++) {
+      pixelSetter(x, y, bg, newPixels); // Set the background color
+    }
+  }
+
+  for (
+    let x = 0;
+    x < Math.min(w - 1, offsetX + iw - 1);
+    x++
+  ) {
+    for (
+      let y = 0;
+      y < Math.min(h - 1, offsetY + ih - 1);
+      y++
+    ) {
+      const inputImgX = x + offsetX,
+        inputImgY = y + offsetY;
+      
+      pixelSetter(x, y, [
+        pixels.get(inputImgX, inputImgY, 0),
+        pixels.get(inputImgX, inputImgY, 1),
+        pixels.get(inputImgX, inputImgY, 2),
+        pixels.get(inputImgX, inputImgY, 3)
+      ], newPixels); // Set the background color
+    }
+  }
+
+  if (cb) cb();
+
+  return newPixels;
 };

src/modules/Crop/Module.js

@@ -1,3 +1,4 @@
+const pixelManipulation = require('../_nomodule/PixelManipulation');
 /*
  * Image Cropping module
  * Usage:
@@ -26,54 +27,39 @@ module.exports = function CropModule(options, UI) {
 
     var step = this;
 
-    // save the input image;
-    // TODO: this should be moved to module API to persist the input image
     options.step.input = input.src;
-    var parseCornerCoordinateInputs = require('../../util/ParseInputCoordinates');
 
-    //parse the inputs
-    parseCornerCoordinateInputs(options, {
-      src: input.src,
-      x: { valInp: options.x, type: 'horizontal' },
-      y: { valInp: options.y, type: 'vertical' },
-      w: { valInp: options.w, type: 'horizontal' },
-      h: { valInp: options.h, type: 'vertical' },
-    }, function (options, coord) {
-      options.x = parseInt(coord.x.valInp);
-      options.y = parseInt(coord.y.valInp);
-      options.w = coord.w.valInp;
-      options.h = coord.h.valInp;
+    // We should do this via event/listener:
+    if (ui && ui.hide) ui.hide();
+
+
+    function extraManipulation(pixels) {
+      const newPixels = require('./Crop')(pixels, options, function() {
+        
+        // Start custom UI setup (draggable UI)
+        // Only once we have an input image
+        if (setupComplete === false && options.step.inBrowser && !options.noUI) {
+          setupComplete = true;
+          ui.setup();
+        }
+      });
+      return newPixels;
+    }
+
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
+
+    return pixelManipulation(input, {
+      output: output,
+      ui: options.step.ui,
+      extraManipulation: extraManipulation,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      callback: callback,
+      useWasm:options.useWasm
     });
-
-    require('./Crop')(input, options, function (out, format) {
-
-      // This output is accessible to Image Sequencer
-      step.output = {
-        src: out,
-        format: format
-      };
-
-      // This output is accessible to the UI
-      options.step.output = out;
-
-      // Tell the UI that the step has been drawn
-      UI.onComplete(options.step);
-
-      // we should do this via event/listener:
-      if (ui && ui.hide) ui.hide();
-
-      // start custom UI setup (draggable UI)
-      // only once we have an input image
-      if (setupComplete === false && options.step.inBrowser && !options.noUI) {
-        setupComplete = true;
-        ui.setup();
-      }
-
-      // Tell Image Sequencer that step has been drawn
-      callback();
-
-    });
-
   }
 
   return {

src/modules/Crop/Ui.js

@@ -59,12 +59,6 @@ module.exports = function CropModuleUi(step, ui) {
     ];
   }
 
-  function remove() {
-    $(imgEl()).imgAreaSelect({
-      remove: true
-    });
-  }
-
   function hide() {
     // then hide the draggable UI
     $(imgEl()).imgAreaSelect({
@@ -92,7 +86,6 @@ module.exports = function CropModuleUi(step, ui) {
 
   return {
     setup: setup,
-    remove: remove,
     hide: hide
   };
 };

src/modules/Crop/info.json

@@ -16,12 +16,12 @@
     "w": {
       "type": "string",
       "desc": "Width of crop",
-      "default": "(50%)"
+      "default": "100%"
     },
     "h": {
       "type": "string",
       "desc": "Height of crop",
-      "default": "(50%)"
+      "default": "100%"
     },
     "backgroundColor": {
       "type": "text",

src/modules/DecodeQr/Module.js

@@ -28,18 +28,16 @@ module.exports = function DoNothing(options, UI) {
       options.step.qrval = (decoded) ? decoded.data : 'undefined';
     });
 
-    function output(image, datauri, mimetype) {
-      // This output is accessible by Image Sequencer
-      step.output = {
-        src: datauri,
-        format: mimetype
-      };
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
+    
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,
       format: input.format,
       image: options.image,
+      inBrowser: options.inBrowser,
       callback: callback,
       useWasm:options.useWasm
     });

src/modules/Dither/Module.js

@@ -15,10 +15,8 @@ module.exports = function Dither(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
@@ -27,6 +25,7 @@ module.exports = function Dither(options, UI) {
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,
+      inBrowser: options.inBrowser,
       callback: callback,
       useWasm:options.useWasm
     });

src/modules/DrawRectangle/DrawRectangle.js

@@ -4,22 +4,24 @@ module.exports = exports = function(pixels, options){
 
   options.startingX = options.startingX || defaults.startingX;
   options.startingY = options.startingY || defaults.startingY;
+
   var ox = Number(options.startingX),
 	  oy = Number(options.startingY),
 	  iw = pixels.shape[0],
 	  ih = pixels.shape[1],
     thickness = Number(options.thickness) || defaults.thickness,
-	  ex =  options.endX = Number(options.endX) - thickness || iw - 1,
-	  ey = options.endY = Number(options.endY) - thickness || ih - 1,
+	  ex = Number(options.endX || defaults.endX) - thickness || iw - 1,
+	  ey = Number(options.endY || defaults.endY) - thickness || ih - 1,
     color = options.color || defaults.color;
-  color = color.substring(color.indexOf('(') + 1, color.length - 1); // extract only the values from rgba(_,_,_,_)
+  
+  color = color.substring(color.indexOf('(') + 1, color.length - 1); // Extract only the values from rgba(_,_,_,_)
   color = color.split(',');
 
   var drawSide = function(startX, startY, endX, endY){
     for (var n = startX; n <= endX + thickness; n++){
       for (var k = startY; k <= endY + thickness; k++){
 
-        pixelSetter(n, k, [color[0], color[1], color[2]], pixels); //to remove 4th channel - pixels.set(n, k, 3, color[3]);
+        pixelSetter(n, k, [color[0], color[1], color[2]], pixels); // To remove 4th channel - pixels.set(n, k, 3, color[3]);
       }
     }
   };

src/modules/DrawRectangle/Module.js

@@ -19,10 +19,8 @@ module.exports = function DrawRectangle(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
@@ -32,6 +30,7 @@ module.exports = function DrawRectangle(options, UI) {
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,
+      inBrowser: options.inBrowser,
       callback: callback,
       useWasm:options.useWasm
     });

src/modules/DrawRectangle/info.json

@@ -17,13 +17,13 @@
       "endX":{
         "type": "integer",
         "desc": "last x position of the rectangle",
-        "default": "width"
+        "default": 10
       },
 
       "endY":{
         "type": "integer",
         "desc": "last y position of the rectangle",
-        "default": "height"
+        "default": 10
       },
 
       "thickness":{

src/modules/Dynamic/Module.js

@@ -1,5 +1,5 @@
 module.exports = function Dynamic(options, UI) {
-
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
   var output;
 
   // This function is called on every draw.
@@ -10,13 +10,12 @@ module.exports = function Dynamic(options, UI) {
 
     var step = this;
 
-    // start with monochrome, but if options.red, options.green, and options.blue are set, accept them too
-    options.monochrome = options.monochrome || '(R+G+B)/3';
+    options.red = options.red || defaults.red;
+    options.blue = options.blue || defaults.blue;
+    options.green = options.green || defaults.green;
 
     function generator(expression) {
-      var func = 'f = function (r, g, b, a) { var R = r, G = g, B = b, A = a;';
-      func = func + 'return ';
-      func = func + expression + '}';
+      var func = 'f = function (r, g, b, a) { var R = r, G = g, B = b, A = a; return ' + expression + ';}';
       var f;
       eval(func);
       return f;
@@ -25,9 +24,12 @@ module.exports = function Dynamic(options, UI) {
     var channels = ['red', 'green', 'blue', 'alpha'];
 
     channels.forEach(function(channel) {
-      if (options.hasOwnProperty(channel)) options[channel + '_function'] = generator(options[channel]);
-      else if (channel === 'alpha') options['alpha_function'] = function() { return 255; };
-      else options[channel + '_function'] = generator(options.monochrome);
+      if (channel === 'alpha'){
+        options['alpha_function'] = function() { return 255; };
+      }
+      else{
+        options[channel + '_function'] = generator(options[channel]);
+      }
     });
 
     function changePixel(r, g, b, a) {
@@ -71,12 +73,10 @@ module.exports = function Dynamic(options, UI) {
       }
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
+    
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       ui: options.step.ui,

src/modules/Dynamic/info.json

@@ -16,11 +16,6 @@
       "type": "string",
       "desc": "Expression to return for blue channel with R, G, B, and A inputs",
       "default": "b"
-    },
-    "monochrome (fallback)": {
-      "type": "string",
-      "desc": "Expression to return with R, G, B, and A inputs; fallback for other channels if none provided",
-      "default": "r + g + b"
     }
   },
   "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#dynamic-module"

src/modules/EdgeDetect/EdgeUtils.js

@@ -1,6 +1,8 @@
-// Define kernels for the sobel filter
+// Read More: https://en.wikipedia.org/wiki/Canny_edge_detector
 
 const pixelSetter = require('../../util/pixelSetter.js');
+
+// Define kernels for the sobel filter.
 const kernelx = [
     [-1, 0, 1],
     [-2, 0, 2],
@@ -12,16 +14,14 @@ const kernelx = [
     [ 1, 2, 1]
   ];
 
-let pixelsToBeSupressed = [];
-
 module.exports = function(pixels, highThresholdRatio, lowThresholdRatio, useHysteresis) {
-  let angles = [], grads = [], strongEdgePixels = [], weakEdgePixels = [];
-  
+  let angles = [], grads = [], strongEdgePixels = [], weakEdgePixels = [], pixelsToBeSupressed = [];
+
   for (var x = 0; x < pixels.shape[0]; x++) {
     grads.push([]);
     angles.push([]);
     for (var y = 0; y < pixels.shape[1]; y++) {
-      var result = sobelFilter(
+      var result = sobelFilter( // Convolves the sobel filter on every pixel
         pixels,
         x,
         y
@@ -32,28 +32,47 @@ module.exports = function(pixels, highThresholdRatio, lowThresholdRatio, useHyst
       angles.slice(-1)[0].push(result.angle);
     }
   }
-  nonMaxSupress(pixels, grads, angles);
-  doubleThreshold(pixels, highThresholdRatio, lowThresholdRatio, grads, strongEdgePixels, weakEdgePixels);
-  if(useHysteresis.toLowerCase() == 'true') hysteresis(strongEdgePixels, weakEdgePixels);
+  nonMaxSupress(pixels, grads, angles, pixelsToBeSupressed); // Non Maximum Suppression: Filter fine edges.
+  doubleThreshold(pixels, highThresholdRatio, lowThresholdRatio, grads, strongEdgePixels, weakEdgePixels, pixelsToBeSupressed); // Double Threshold: Categorizes edges into strong and weak edges based on two thresholds.
+  if(useHysteresis.toLowerCase() == 'true') hysteresis(strongEdgePixels, weakEdgePixels); // Optional Hysteresis (very slow) to minimize edges generated due to noise.
 
-  strongEdgePixels.forEach(pixel => preserve(pixels, pixel));
-  weakEdgePixels.forEach(pixel => supress(pixels, pixel));
-  pixelsToBeSupressed.forEach(pixel => supress(pixels, pixel));
+  strongEdgePixels.forEach(pixel => preserve(pixels, pixel)); // Makes the strong edges White.
+  weakEdgePixels.forEach(pixel => supress(pixels, pixel)); // Makes the weak edges black(bg color) after filtering.
+  pixelsToBeSupressed.forEach(pixel => supress(pixels, pixel)); // Makes the rest of the image black.
 
   return pixels;
 };
 
+/**
+ * @method supress
+ * @description Supresses (fills with background color) the specified (non-edge)pixel.
+ * @param {Object} pixels ndarry of pixels
+ * @param {Float32Array} pixel Pixel coordinates
+ * @returns {Null}
+ */
 function supress(pixels, pixel) {
   pixelSetter(pixel[0], pixel[1], [0, 0, 0, 255], pixels);
-
 }
 
+/**
+ * @method preserve
+ * @description Preserve the specified pixel(of an edge).
+ * @param {Object} pixels ndarray of pixels
+ * @param {*} pixel Pixel coordinates
+ * @returns {Null}
+ */
 function preserve(pixels, pixel) {
   pixelSetter(pixel[0], pixel[1], [255, 255, 255, 255], pixels);
-
 }
 
-// sobelFilter function that convolves sobel kernel over every pixel
+/**
+ * @method sobelFiler
+ * @description Runs the sobel filter on the specified and neighbouring pixels.
+ * @param {Object} pixels ndarray of pixels
+ * @param {Number} x x-coordinate of the pixel
+ * @param {Number} y y-coordinate of the pixel
+ * @returns {Object} Object containing the gradient and angle.
+ */
 function sobelFilter(pixels, x, y) {
   let val = pixels.get(x, y, 0),
     gradX = 0.0,
@@ -65,8 +84,8 @@ function sobelFilter(pixels, x, y) {
       let xn = x + a - 1,
         yn = y + b - 1;
 
-      if (isOutOfBounds(pixels, xn, yn)) {
-        gradX += pixels.get(xn + 1, yn + 1, 0) * kernelx[a][b];
+      if (isOutOfBounds(pixels, xn, yn)) { // Fallback for coordinates which lie outside the image.
+        gradX += pixels.get(xn + 1, yn + 1, 0) * kernelx[a][b]; // Fallback to nearest pixel
         gradY += pixels.get(xn + 1, yn + 1, 0) * kernely[a][b];
       }
       else {
@@ -84,11 +103,20 @@ function sobelFilter(pixels, x, y) {
   };
 }
 
+/**
+ * @method categorizeAngle
+ * @description Categorizes the given angle into 4 catagories according to the Category Map given below.
+ * @param {Number} angle Angle in degrees
+ * @returns {Number} Category number of the given angle
+ */
 function categorizeAngle(angle){
-  if ((angle >= -22.5 && angle <= 22.5) || (angle < -157.5 && angle >= -180)) return 1;
-  else if ((angle >= 22.5 && angle <= 67.5) || (angle < -112.5 && angle >= -157.5)) return 2;
-  else if ((angle >= 67.5 && angle <= 112.5) || (angle < -67.5 && angle >= -112.5)) return 3;
-  else if ((angle >= 112.5 && angle <= 157.5) || (angle < -22.5 && angle >= -67.5)) return 4;
+  const pi = Math.PI;
+  angle = angle > 0 ? angle : pi - Math.abs(angle); // Diagonally flip the angle if it is negative (since edge remains the same)
+
+  if (angle <= pi / 8 || angle > 7 * pi / 8) return 1;
+  else if (angle > pi / 8 && angle <= 3 * pi / 8) return 2;
+  else if (angle > 3 * pi / 8 && angle <= 5 * pi / 8) return 3;
+  else if (angle > 5 * pi / 8 && angle <= 7 * pi / 8) return 4;
 
   /* Category Map
   * 1 => E-W
@@ -98,33 +126,39 @@ function categorizeAngle(angle){
   */
 }
 
+/**
+ * @method isOutOfBounds
+ * @description Checks whether the given coordinates lie outside the bounds of the image. Used for error handling in convolution.
+ * @param {Object} pixels ndarray of pixels
+ * @param {*} x x-coordinate of the pixel
+ * @param {*} y y-coordinate of the pixel
+ * @returns {Boolean} True if the given coordinates are out of bounds.
+ */
 function isOutOfBounds(pixels, x, y){
   return ((x < 0) || (y < 0) || (x >= pixels.shape[0]) || (y >= pixels.shape[1]));
 }
 
-const removeElem = (arr = [], elem) => {
+const removeElem = (arr = [], elem) => { // Removes the specified element from the given array.
   return arr = arr.filter((arrelem) => {
     return arrelem !== elem;
   });
 };
 
-// Non Maximum Supression without interpolation
-function nonMaxSupress(pixels, grads, angles) {
-  angles = angles.map((arr) => arr.map(convertToDegrees));
-
+// Non Maximum Supression without interpolation.
+function nonMaxSupress(pixels, grads, angles, pixelsToBeSupressed) {
   for (let x = 0; x < pixels.shape[0]; x++) {
     for (let y = 0; y < pixels.shape[1]; y++) {
 
       let angleCategory = categorizeAngle(angles[x][y]);
 
       if (!isOutOfBounds(pixels, x - 1, y - 1) && !isOutOfBounds(pixels, x + 1, y + 1)){
-        switch (angleCategory){
+        switch (angleCategory){ // Non maximum suppression according to angle category
         case 1:
           if (!((grads[x][y] >= grads[x][y + 1]) && (grads[x][y] >= grads[x][y - 1]))) {
             pixelsToBeSupressed.push([x, y]);
           }
           break;
-          
+
         case 2:
           if (!((grads[x][y] >= grads[x + 1][y + 1]) && (grads[x][y] >= grads[x - 1][y - 1]))){
             pixelsToBeSupressed.push([x, y]);
@@ -147,17 +181,15 @@ function nonMaxSupress(pixels, grads, angles) {
     }
   }
 }
-// Converts radians to degrees
-var convertToDegrees = radians => (radians * 180) / Math.PI;
 
-// Finds the max value in a 2d array like grads
+// Finds the max value in a 2d array like grads.
 var findMaxInMatrix = arr => Math.max(...arr.map(el => el.map(val => val ? val : 0)).map(el => Math.max(...el)));
 
-// Applies the double threshold to the image
-function doubleThreshold(pixels, highThresholdRatio, lowThresholdRatio, grads, strongEdgePixels, weakEdgePixels) {
+// Applies the double threshold to the image.
+function doubleThreshold(pixels, highThresholdRatio, lowThresholdRatio, grads, strongEdgePixels, weakEdgePixels, pixelsToBeSupressed) {
 
-  const highThreshold = findMaxInMatrix(grads) * highThresholdRatio,
-    lowThreshold = highThreshold * lowThresholdRatio;
+  const highThreshold = findMaxInMatrix(grads) * highThresholdRatio, // High Threshold relative to the strongest edge
+    lowThreshold = highThreshold * lowThresholdRatio; // Low threshold relative to high threshold
 
   for (let x = 0; x < pixels.shape[0]; x++) {
     for (let y = 0; y < pixels.shape[1]; y++) {
@@ -178,6 +210,12 @@ function doubleThreshold(pixels, highThresholdRatio, lowThresholdRatio, grads, s
   }
 }
 
+/**
+ * @method hysteresis
+ * @description Filters weak edge pixels that are not connected to a strong edge pixel.
+ * @param {Float32array} strongEdgePixels 2D array of strong edge pixel coordinates
+ * @param {*} weakEdgePixels 2D array of weak edge pixel coordinated
+ */
 function hysteresis(strongEdgePixels, weakEdgePixels){
   strongEdgePixels.forEach(pixel => {
     let x = pixel[0],

src/modules/EdgeDetect/Module.js

@@ -1,5 +1,8 @@
+const Blur = require('../Blur/Blur');
 /*
 * Detect Edges in an Image
+* Uses Canny method for the same
+* Read more: https://en.wikipedia.org/wiki/Canny_edge_detector
 */
 module.exports = function edgeDetect(options, UI) {
 
@@ -13,48 +16,36 @@ module.exports = function edgeDetect(options, UI) {
 
   // The function which is called on every draw.
   function draw(input, callback, progressObj) {
-
     progressObj.stop(true);
     progressObj.overrideFlag = true;
 
     var step = this;
 
-    // Blur the image
-    const internalSequencer = ImageSequencer({ inBrowser: false, ui: false });
-    return internalSequencer.loadImage(input.src, function() {
-      internalSequencer.importJSON([{ 'name': 'blur', 'options': { blur: options.blur } }]);
-      return internalSequencer.run(function onCallback(internalOutput) {
-        require('get-pixels')(internalOutput, function(err, blurPixels) {
-          if (err) {
-            return;
-          }
+    // Makes the image greyscale
+    function changePixel(r, g, b, a) {
+      return [(r + g + b) / 3, (r + g + b) / 3, (r + g + b) / 3, a];
+    }
 
-          // Extra Manipulation function used as an enveloper for applying gaussian blur and Convolution
-          function changePixel(r, g, b, a) {
-            return [(r + g + b) / 3, (r + g + b) / 3, (r + g + b) / 3, a];
-          }
+    // Extra Manipulation function used as an enveloper for applying gaussian blur and Convolution
+    function extraManipulation(pixels) {
+      const blurPixels = Blur(pixels, options.blur);
+      return require('./EdgeUtils')(blurPixels, options.highThresholdRatio, options.lowThresholdRatio, options.hysteresis);
+    }
 
-          function extraManipulation() {
-            return require('./EdgeUtils')(blurPixels, options.highThresholdRatio, options.lowThresholdRatio, options.hysteresis);
-          }
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
 
-          function output(image, datauri, mimetype) {
-            step.output = { src: datauri, format: mimetype };
-          }
-
-          return require('../_nomodule/PixelManipulation.js')(input, {
-            output: output,
-            ui: options.step.ui,
-            changePixel: changePixel,
-            extraManipulation: extraManipulation,
-            format: input.format,
-            image: options.image,
-            inBrowser: options.inBrowser,
-            callback: callback,
-            useWasm: options.useWasm
-          });
-        });
-      });
+    return require('../_nomodule/PixelManipulation.js')(input, {
+      output: output,
+      ui: options.step.ui,
+      changePixel: changePixel,
+      extraManipulation: extraManipulation,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      callback: callback,
+      useWasm: options.useWasm
     });
   }
 
@@ -64,4 +55,4 @@ module.exports = function edgeDetect(options, UI) {
     output: output,
     UI: UI
   };
-};
+};

src/modules/EdgeDetect/info.json

@@ -1,6 +1,6 @@
 {
     "name": "edge-detect",
-    "description": "This module detects edges using the Canny method, which first Gaussian blurs the image to reduce noise (amount of blur configurable in settings as `options.blur`), then applies a number of steps to highlight edges, resulting in a greyscale image where the brighter the pixel, the stronger the detected edge.<a href='https://en.wikipedia.org/wiki/Canny_edge_detector'> Read more. </a>",
+    "description": "Edge Detect module detects edges using the Canny method, which first blurs the image to reduce noise (amount of blur configurable in settings as `options.blur`), then applies a number of steps to highlight edges, resulting in a greyscale image where the brighter the pixel, the stronger the detected edge. [Read more](https://en.wikipedia.org/wiki/Canny_edge_detector)",
     "inputs": {
         "blur": {
             "type": "float",

src/modules/Exposure/Module.js

@@ -24,11 +24,8 @@ module.exports = function Exposure(options, UI) {
       return [r, g, b, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/Exposure/info.json

@@ -11,5 +11,5 @@
           "step": 0.05
       }
   },
-  "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md"
+  "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#exposure-module"
 }

src/modules/FlipImage/Module.js

@@ -1,11 +1,12 @@
+const _ = require('lodash');
 /*
  * Flip the image on vertical/horizontal axis.
  */
 module.exports = function FlipImage(options, UI) {
-  options.Axis = options.Axis || require('./info.json').inputs.Axis.default;
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  options.Axis = options.Axis || defaults.Axis;
 
-  var output,
-    getPixels = require('get-pixels');
+  let output;
 
   function draw(input, callback, progressObj) {
 
@@ -14,34 +15,30 @@ module.exports = function FlipImage(options, UI) {
 
     var step = this;
 
-    return getPixels(input.src, function(err, oldPixels) {
-      function changePixel(r, g, b, a) {
-        return [r, g, b, a];
-      }
-      function extraManipulation(pixels) {
-        if (err) {
-          console.log(err);
-          return;
-        }
-        return require('./flipImage')(oldPixels, pixels, options.Axis);
-      }
-      function output(image, datauri, mimetype) {
-        step.output = { src: datauri, format: mimetype };
-      }
+    function changePixel(r, g, b, a) {
+      return [r, g, b, a];
+    }
+    function extraManipulation(pixels) {
+      const oldPixels = _.cloneDeep(pixels);
 
-      return require('../_nomodule/PixelManipulation.js')(input, {
-        output: output,
-        ui: options.step.ui,
-        changePixel: changePixel,
-        extraManipulation: extraManipulation,
-        format: input.format,
-        image: options.image,
-        inBrowser: options.inBrowser,
-        callback: callback,
-        useWasm:options.useWasm
-      });
+      return require('./flipImage')(oldPixels, pixels, options.Axis);
+    }
+    
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
+
+    return require('../_nomodule/PixelManipulation.js')(input, {
+      output: output,
+      ui: options.step.ui,
+      changePixel: changePixel,
+      extraManipulation: extraManipulation,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      callback: callback,
+      useWasm:options.useWasm
     });
-
   }
 
   return {

src/modules/GammaCorrection/Module.js

@@ -21,10 +21,8 @@ module.exports = function Gamma(options, UI) {
       return [r, g, b, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/Gradient/Module.js

@@ -1,55 +1,57 @@
-module.exports = function Invert(options, UI) {
-  const pixelSetter = require('../../util/pixelSetter.js');
+const pixelSetter = require('../../util/pixelSetter.js'),
+  pixelManipulation = require('../_nomodule/PixelManipulation');
+
+module.exports = function Gradient(options, UI) {
+
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  options.gradientType = options.gradientType || defaults.gradientType;
 
   var output;
 
   // The function which is called on every draw.
   function draw(input, callback) {
-
-    var getPixels = require('get-pixels');
-    var savePixels = require('save-pixels');
-
     var step = this;
 
-    getPixels(input.src, function(err, pixels) {
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+    }
 
-      if (err) {
-        console.log('Bad Image path');
-        return;
-      }
-
-      var width = pixels.shape[0];
-
-      for (var i = 0; i < pixels.shape[0]; i++) {
-        for (var j = 0; j < pixels.shape[1]; j++) {
-          let val = (i / width) * 255;
-          pixelSetter(i, j, [val, val, val, 255], pixels);
-                
+    function extraManipulation(pixels) {
+      const [w, h] = pixels.shape;
+      if (options.gradientType === 'linear') {
+        for (var i = 0; i < w; i++) {
+          for (var j = 0; j < h; j++) {
+            let val = (i / w) * 255;
+            
+            pixelSetter(i, j, [val, val, val, 255], pixels);
+          }
+        }
+      }
+      else {
+        for (var i = 0; i < w; i++) {
+          for (var j = 0; j < h; j++) {
+            var distX = Math.abs(w / 2 - i);
+            var distY = Math.abs(h / 2 - j);
+            var distance = Math.sqrt(Math.pow(distX, 2) + Math.pow(distY, 2));
+            val = 255 * (distance / pixels.shape[0]);
+            pixelSetter(i, j, [val, val, val, 255], pixels);
+          }
         }
       }
-      var chunks = [];
-      var totalLength = 0;
-      var r = savePixels(pixels, input.format, { quality: 100 });
 
-      r.on('data', function(chunk) {
-        totalLength += chunk.length;
-        chunks.push(chunk);
-      });
+      return pixels;
+    }
 
-      r.on('end', function() {
-        var data = Buffer.concat(chunks, totalLength).toString('base64');
-        var datauri = 'data:image/' + input.format + ';base64,' + data;
-        output(input.image, datauri, input.format);
-        callback();
-      });
+    return pixelManipulation(input, {
+      output,
+      extraManipulation,
+      callback,
+      format: input.format,
+      image: options.image,
+      inBrowser: options.inBrowser,
+      useWasm:options.useWasm
     });
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
-    }
   }
 
   return {

src/modules/Gradient/info.json

@@ -1,6 +1,13 @@
 {
     "name": "gradient",
     "description": "Gives a gradient of the image",
-    "inputs": {},
+    "inputs": {
+      "gradientType": {
+        "type": "select",
+        "desc": "Choose between linear or circular gradient",
+        "default": "linear",
+        "values": ["linear", "circular"]
+      }
+    },
     "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#gradient-module"
 }

src/modules/GridOverlay/Module.js

@@ -15,11 +15,8 @@ module.exports = function GridOverlay(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accesible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/Histogram/Module.js

@@ -11,7 +11,7 @@ module.exports = function Channel(options, UI) {
     const pixelSetter = require('../../util/pixelSetter.js');
 
     options.gradient = options.gradient || defaults.gradient;
-    options.gradient = JSON.parse(options.gradient);
+    options.gradient = String(JSON.parse(options.gradient));
 
     progressObj.stop(true);
     progressObj.overrideFlag = true;
@@ -63,11 +63,8 @@ module.exports = function Channel(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accesible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {

src/modules/ImportImage/Ui.js

@@ -8,7 +8,7 @@ module.exports = function ImportImageModuleUi(step, ui) {
 
     // add a file input listener
     var dropZone = '\
-    <div class="dropzone" style="padding: 30px;margin: 10px 20% 30px;border: 4px dashed #ccc;border-radius: 8px;text-align: center;color: #444;" id="' + dropzoneId + '">\
+    <div class="dropzone import-image-zone" id="' + dropzoneId + '">\
           <p>\
         <i>Select or drag in an image to overlay.</i>\
       </p>\

src/modules/Invert/Module.js

@@ -1,3 +1,4 @@
+const pixelManipulation = require('../_nomodule/PixelManipulation');
 /*
  * Invert the image
  */
@@ -17,14 +18,11 @@ function Invert(options, UI) {
       return [255 - r, 255 - g, 255 - b, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
-    return input.pixelManipulation({
+    return pixelManipulation(input, {
       output: output,
       changePixel: changePixel,
       format: input.format,
@@ -43,10 +41,4 @@ function Invert(options, UI) {
     UI: UI
   };
 }
-var info = {
-  'name': 'invert',
-  'description': 'Inverts the image.',
-  'inputs': {
-  }
-};
-module.exports = [Invert, info];
+module.exports = Invert;

src/modules/Invert/index.js

@@ -0,0 +1,4 @@
+module.exports = [
+  require('./Module'),
+  require('./info.json')
+];

src/modules/Mask/Module.js

@@ -0,0 +1,82 @@
+module.exports = function Mask(options, UI, util) {
+  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  options.offset = options.offset || defaults.offset;
+  options.resize = options.resize || defaults.resize;
+
+  var output;
+
+  // This function is called on every draw.
+  function draw(input, callback, progressObj) {
+    progressObj.stop(true);
+    progressObj.overrideFlag = true;
+
+    var step = this;
+
+    var getPixels = require('get-pixels');
+
+    // convert offset as string to int
+    if (typeof options.offset === 'string')
+      options.offset = parseInt(options.offset);
+
+    // save first image's pixels
+    var priorStep = this.getStep(options.offset);
+
+    if (priorStep.output === undefined) {
+      this.output = input;
+      UI.notify('Offset Unavailable', 'offset-notification');
+      callback();
+    }
+
+    const alpha_masking = function(c, a) {
+      return (a * c + (255 - a) * c) / 255;
+    };
+    const internalSequencer = ImageSequencer({ inBrowser: false, ui: false });
+    internalSequencer.loadImage(priorStep.output.src, function() {
+      internalSequencer.importJSON([{ 'name': 'resize', 'options': { resize: options.resize } }]);
+      internalSequencer.run(function onCallback(internalOutput) {
+
+        getPixels(internalOutput, function(err, pixels) {
+          options.firstImagePixels = pixels;
+
+          function changePixel(r2, g2, b2, a2, x, y) {
+            let p = options.firstImagePixels;
+            let r1 = p.get(x, y, 0),
+              g1 = p.get(x, y, 1),
+              b1 = p.get(x, y, 2),
+              a1 = p.get(x, y, 3);
+
+            return [alpha_masking(r1, a2), alpha_masking(g1, a2), alpha_masking(b1, a2)];
+          }
+
+          function output(image, datauri, mimetype, wasmSuccess) {
+            step.output = {
+              src: datauri,
+              format: mimetype,
+              wasmSuccess,
+              useWasm: options.useWasm
+            };
+          }
+
+          // run PixelManipulatin on second image's pixels
+          return require('../_nomodule/PixelManipulation.js')(input, {
+            output: output,
+            ui: options.step.ui,
+            changePixel: changePixel,
+            format: input.format,
+            image: options.image,
+            inBrowser: options.inBrowser,
+            callback: callback,
+            useWasm: options.useWasm
+          });
+        });
+      });
+    });
+  }
+
+  return {
+    options: options,
+    draw: draw,
+    output: output,
+    UI: UI
+  };
+};

src/modules/Mask/index.js

@@ -0,0 +1,4 @@
+module.exports = [
+  require('./Module'),
+  require('./info.json')
+];

src/modules/Mask/info.json

@@ -0,0 +1,18 @@
+{
+    "name": "mask",
+    "description": "Masks two images according to their Alpha values",
+    "inputs": {
+      "offset": {
+        "type": "integer",
+        "desc": "Choose which image to mask the current image with. Two steps back is -2, three steps back is -3 etc.",
+        "default": -2
+      },
+      "resize": {
+        "type": "string",
+        "desc": "Percentage value by which first image is to be resized",
+        "default": "125%"
+      }
+    },
+    "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md"
+  }
+  

src/modules/MinifyImage/Module.js

@@ -49,7 +49,7 @@ module.exports = function MinifyImage(options, UI) {
           reader.readAsDataURL(result);
           reader.onloadend = function () {
             base64data = reader.result;
-            output(base64data, input.format);
+            output(null, base64data, input.format, false);
             if (callback) callback();
             return;
           };
@@ -76,19 +76,14 @@ module.exports = function MinifyImage(options, UI) {
         });
         var destPath = __dirname + '/results/test.' + input.format;
         var data = base64Img.base64Sync(destPath);
-        output(data, input.format);
+        output(null, data, input.format, false);
         if (callback) callback();
-      })();
+      })().catch(e => console.log(e));
     }
 
 
-    function output(datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = {
-        src: datauri,
-        format: mimetype
-      };
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
   }
   return {

src/modules/Ndvi/Module.js

@@ -25,11 +25,8 @@ module.exports = function Ndvi(options, UI) {
       return [x, x, x, a];
     }
 
-    function output(image, datauri, mimetype) {
-
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     function modifiedCallback() {

src/modules/NdviColormap/info.json

@@ -1,6 +1,24 @@
 {
     "name": "ndvi-colormap",
     "description": "Sequentially Applies NDVI and Colormap steps",
-    "inputs": {},
+    "inputs": {
+        "filter": {
+            "type": "select",
+            "desc": "Filter color",
+            "default": "red",
+            "values": ["red", "blue"]
+          },
+        "colormap": {
+            "type": "select",
+            "desc": "Name of the Colormap",
+            "default": "default",
+            "values": [
+                "default",
+                "greyscale",
+                "stretched",
+                "fastie"
+            ]
+        }
+    },
     "docs-link": "https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#ndvi-colormap-module"
 }

src/modules/NoiseReduction/Module.js

@@ -15,10 +15,8 @@ module.exports = function NoiseReduction(options, UI) {
       return pixels;
     }
 
-    function output(image, datauri, mimetype) {
-      // This output is accessible by Image Sequencer
-      step.output = { src: datauri, format: mimetype };
-
+    function output(image, datauri, mimetype, wasmSuccess) {
+      step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
     }
 
     return require('../_nomodule/PixelManipulation.js')(input, {
@@ -27,6 +25,7 @@ module.exports = function NoiseReduction(options, UI) {
       extraManipulation: extraManipulation,
       format: input.format,
       image: options.image,
+      inBrowser: options.inBrowser,
       callback: callback,
       useWasm:options.useWasm
     });

src/modules/Overlay/Module.js

@@ -1,65 +1,88 @@
 module.exports = function Dynamic(options, UI, util) {
 
-  var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+  const defaults = require('./../../util/getDefaults.js')(require('./info.json'));
   options.x = options.x || defaults.x;
   options.y = options.y || defaults.y;
 
-  var output;
+  if(options.step.inBrowser && !options.noUI && sequencer.getSteps().length < 2)
+    options.offset = -1;
+
+  let ui;
+
+  if (options.step.inBrowser && !options.noUI)  ui = require('./Ui.js')(options.step, UI);
+
+  let output;
 
   // This function is called on every draw.
   function draw(input, callback, progressObj) {
 
-    options.offset = parseInt(options.offset) || -2;
+    options.offset = parseInt(options.offset || defaults.offset);
 
     progressObj.stop(true);
     progressObj.overrideFlag = true;
 
-    var step = this;
+    const step = this;
 
-    var parseCornerCoordinateInputs = require('../../util/ParseInputCoordinates');
-
-    //parse the inputs
-    parseCornerCoordinateInputs(options, {
-      src: input.src,
-      x: { valInp: options.x, type: 'horizontal' },
-      y: { valInp: options.y, type: 'vertical' },
-    }, function(options, input) {
-      options.x = parseInt(input.x.valInp);
-      options.y = parseInt(input.y.valInp);
-    });
+    const parseCornerCoordinateInputs = require('../../util/ParseInputCoordinates');
 
     // save the pixels of the base image
-    var baseStepImage = this.getStep(options.offset).image;
-    var baseStepOutput = this.getOutput(options.offset);
+    const baseStepImage = this.getStep(options.offset).image;
+    const baseStepOutput = this.getOutput(options.offset);
 
-    var getPixels = require('get-pixels');
+    const getPixels = require('get-pixels');
 
     getPixels(input.src, function(err, pixels) {
+      // parse the inputs
+      parseCornerCoordinateInputs({
+        iw: pixels.shape[0],
+        ih: pixels.shape[1]
+      },
+      {
+        x: { valInp: options.x, type: 'horizontal' },
+        y: { valInp: options.y, type: 'vertical' },
+      }, function(opt, input) {
+        options.x = parseInt(input.x.valInp);
+        options.y = parseInt(input.y.valInp);
+      });
+
       options.secondImagePixels = pixels;
 
       function changePixel(r1, g1, b1, a1, x, y) {
 
+        const firstImagePixels = [r1, g1, b1, a1];
+
         // overlay
-        var p = options.secondImagePixels;
+        const p = options.secondImagePixels;
         if (x >= options.x
           && x - options.x < p.shape[0]
           && y >= options.y
-          && y - options.y < p.shape[1])
-          return [
+          && y - options.y < p.shape[1]){
+
+          const secondImagePixels = [
             p.get(x - options.x, y - options.y, 0),
             p.get(x - options.x, y - options.y, 1),
             p.get(x - options.x, y - options.y, 2),
             p.get(x - options.x, y - options.y, 3)
           ];
+          
+          if(secondImagePixels[3] === 0)
+            return firstImagePixels;
+          else
+            return secondImagePixels;
+        }
         else
-          return [r1, g1, b1, a1];
+          return firstImagePixels;
       }
 
-      function output(image, datauri, mimetype) {
-
-        // This output is accessible by Image Sequencer
-        step.output = { src: datauri, format: mimetype };
+      function output(image, datauri, mimetype, wasmSuccess) {
+        step.output = { src: datauri, format: mimetype, wasmSuccess, useWasm: options.useWasm };
+      }
 
+      function modifiedCallback() {
+        if (options.step.inBrowser && !options.noUI) {
+          ui.setup();
+        }
+        callback();
       }
 
       // run PixelManipulation on first Image pixels
@@ -70,7 +93,7 @@ module.exports = function Dynamic(options, UI, util) {
         format: baseStepOutput.format,
         image: baseStepImage,
         inBrowser: options.inBrowser,
-        callback: callback,
+        callback: modifiedCallback,
         useWasm:options.useWasm
       });
     });

src/modules/Overlay/Ui.js

@@ -0,0 +1,19 @@
+module.exports = function OverlayModuleUi(step, ui) {
+
+  function setup() {
+    var steps = sequencer.getSteps();
+    steps.forEach(function (_step, index) {
+      if(_step.options && step.options.number === _step.options.number) {
+        if(index === 1){
+          step.ui.querySelector('input[type=range]').value = -1;
+          step.ui.querySelector('input[type=range]').min = -1;
+        }else
+          step.ui.querySelector('input[type=range]').min = -index;
+      }
+    });
+  }
+
+  return {
+    setup: setup
+  };
+};

src/modules/Overlay/info.json

@@ -15,7 +15,10 @@
         "offset": {
             "type": "integer",
             "desc": "offset to the output of the step on which the output of the last step is overlayed",
-            "default": -2
+            "default": -2,
+            "min": -2,
+            "max": -1,
+            "step": 1
         }
     },
     "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md#overlay-module"