Add: Exposure Module (#721)

* exposure module

* requested changes

* update module

src/Modules.js

@@ -18,6 +18,7 @@ module.exports = {
   'draw-rectangle': require('./modules/DrawRectangle'),
   'dynamic': require('./modules/Dynamic'),
   'edge-detect': require('./modules/EdgeDetect'),
+  'exposure': require('./modules/Exposure'),
   'flip-image': require('./modules/FlipImage'),
   'fisheye-gl': require('./modules/FisheyeGl'),
   'histogram': require('./modules/Histogram'),

src/modules/Exposure/Module.js

@@ -0,0 +1,50 @@
+/*
+* Changes the Image Exposure
+*/
+
+module.exports = function Exposure(options,UI){
+
+    var defaults = require('./../../util/getDefaults.js')(require('./info.json'));
+    var output;
+
+    function draw(input,callback,progressObj){
+
+        options.exposure = options.exposure || defaults.exposure
+        var exposure = Math.pow(2, options.exposure);
+        progressObj.stop(true);
+        progressObj.overrideFlag = true;
+
+        var step = this;
+
+        function changePixel(r, g, b, a){
+
+            r = Math.min(255, r*exposure)
+            g = Math.min(255, g*exposure)
+            b = Math.min(255, b*exposure)
+            return [r, g, b, a]
+        }
+
+        function output(image,datauri,mimetype){
+
+            // This output is accessible by Image Sequencer
+            step.output = {src:datauri,format:mimetype};
+
+        }
+
+        return require('../_nomodule/PixelManipulation.js')(input, {
+            output: output,
+            changePixel: changePixel,
+            format: input.format,
+            image: options.image,
+            inBrowser: options.inBrowser,
+            callback: callback
+        });
+
+    }
+    return {
+        options: options,
+        draw:  draw,
+        output: output,
+        UI: UI
+    }
+}

src/modules/Exposure/index.js

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

src/modules/Exposure/info.json

@@ -0,0 +1,15 @@
+{
+  "name": "Exposure",
+  "description": "Change the exposure of the image by given exposure value",
+  "inputs": {
+      "exposure": {
+          "type": "float",
+          "desc": "exposure value for the new image",
+          "default": 1,
+          "min": -3,
+          "max": 4,
+          "step": 0.05
+      }
+  },
+  "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md"
+}