Colorbar added (#316)

* setup

Signed-off-by: tech4GT <varun.gupta1798@gmail.com>

* overlay done

Signed-off-by: tech4GT <varun.gupta1798@gmail.com>

* add colorbar fixes #285

Signed-off-by: tech4GT <varun.gupta1798@gmail.com>

* add inputs to colorbar

Signed-off-by: tech4GT <varun.gupta1798@gmail.com>

src/modules/Gradient/Module.js

@@ -0,0 +1,62 @@
+module.exports = function Invert(options, UI) {
+
+    var output;
+
+    // The function which is called on every draw.
+    function draw(input, callback, progressObj) {
+        var getPixels = require('get-pixels');
+        var savePixels = require('save-pixels');
+
+        var step = this;
+
+        getPixels(input.src, function(err, pixels) {
+
+            if (err) {
+                console.log("Bad Image path");
+                return;
+            }
+            var width = 0;
+
+            for (var i = 0; i < pixels.shape[0]; i++) width++;
+
+            for (var i = 0; i < pixels.shape[0]; i++) {
+                for (var j = 0; j < pixels.shape[1]; j++) {
+                    let val = (i / width) * 255;
+                    pixels.set(i, j, 0, val);
+                    pixels.set(i, j, 1, val);
+                    pixels.set(i, j, 2, val);
+                    pixels.set(i, j, 3, 255);
+                }
+            }
+            var chunks = [];
+            var totalLength = 0;
+            var r = savePixels(pixels, input.format, { quality: 100 });
+
+            r.on("data", function(chunk) {
+                totalLength += chunk.length;
+                chunks.push(chunk);
+            });
+
+            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();
+            });
+        });
+
+        function output(image, datauri, mimetype) {
+
+            // This output is accessible by Image Sequencer
+            step.output = { src: datauri, format: mimetype };
+
+        }
+    }
+
+    return {
+        options: options,
+        draw: draw,
+        output: output,
+        UI: UI
+    }
+}