White balance module (#585)

* white baalance module

* improved algorithm

* limit check

src/Modules.js

@@ -27,5 +27,6 @@ module.exports = {
   'overlay': require('./modules/Overlay'),
   'resize': require('./modules/Resize'),
   'rotate': require('./modules/Rotate'),
-  'saturation': require('./modules/Saturation')
+  'saturation': require('./modules/Saturation'),
+  'white-balance': require('./modules/WhiteBalance')
 }

src/modules/WhiteBalance/Module.js

@@ -0,0 +1,86 @@
+module.exports = function Balance(options, UI) {
+
+    var output;
+
+    function draw (input, callback, progressObj) {
+
+      options.temperature = (options.temperature > "40000") ? "40000" : options.temperature
+
+        progressObj.stop(true);
+        progressObj.overrideFlag = true;
+
+        var step = this;
+
+        function changePixel(r, g, b, a) {
+            return [r, g, b ,a]
+        }
+
+        function extraManipulation(pixels) {
+
+            let temp = parseInt(options.temperature)
+            temp /= 100
+
+            let r, g, b;
+
+            if (temp <= 66) {
+                r = 255;
+                g = Math.min(Math.max(99.4708025861 * Math.log(temp) - 161.1195681661, 0), 255);
+            } else {
+                r = Math.min(Math.max(329.698727446 * Math.pow(temp - 60, -0.1332047592), 0), 255);
+                g = Math.min(Math.max(288.1221695283 * Math.pow(temp - 60, -0.0755148492), 0), 255);
+            }
+
+            if (temp >= 66) {
+                b = 255;
+            } else if (temp <= 19) {
+                b = 0;
+            } else {
+                b = temp - 10;
+                b = Math.min(Math.max(138.5177312231 * Math.log(b) - 305.0447927307, 0), 255);
+            }
+
+            for(let i=0; i<pixels.shape[0]; i++) {
+              for (let j=0; j<pixels.shape[1]; j++) {
+
+                  r_data = pixels.get(i,j,0)
+                  r_new_data = (255/r) * r_data
+                  pixels.set(i,j,0,r_new_data)
+
+                  g_data = pixels.get(i,j,1)
+                  g_new_data = (255/g) * g_data
+                  pixels.set(i,j,1,g_new_data)
+
+                  b_data = pixels.get(i,j,2)
+                  b_new_data = (255/b) * b_data
+                  pixels.set(i,j,2,b_new_data)
+              }
+            }
+
+          return pixels
+        }
+
+        function output (image, datauri, mimetype){
+
+            step.output = {src:datauri,format:mimetype};
+
+        }
+
+        return require('../_nomodule/PixelManipulation.js')(input, {
+            output: output,
+            changePixel: changePixel,
+            extraManipulation: extraManipulation,
+            format: input.format,
+            image: options.image,
+            inBrowser: options.inBrowser,
+            callback: callback
+        });
+    }
+
+    return {
+        options: options,
+        draw: draw,
+        output: output,
+        UI: UI
+    }
+
+}

src/modules/WhiteBalance/index.js

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

src/modules/WhiteBalance/info.json

@@ -0,0 +1,12 @@
+{
+    "name": "White Balance",
+    "description": "Change the colour balance of the image by adjusting the colour temperature.",
+    "inputs": {
+      "temperature": {
+        "type": "string",
+        "desc": "Temperature between 0 - 40,000 Kelvin",
+        "default": "6000"
+      }
+    },
+    "docs-link":"https://github.com/publiclab/image-sequencer/blob/main/docs/MODULES.md"
+}