Dynamic fix as fun (#207)

getNeighborPixel(x, y) method for Dynamic module

src/modules/Dynamic/Module.js

@@ -1,22 +1,22 @@
 module.exports = function Dynamic(options,UI) {
-
+  
   options = options || {};
   options.title = "Dynamic";
-
+  
   // Tell the UI that a step has been set up.
   UI.onSetup(options.step);
   var output;
-
+  
   // This function is called on every draw.
   function draw(input,callback) {
-
+    
     // Tell the UI that the step is being drawn
     UI.onDraw(options.step);
     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";
-
+    
     function generator(expression) {
       var func = 'f = function (r, g, b, a) { var R = r, G = g, B = b, A = a;'
       func = func + 'return ';
@@ -25,48 +25,65 @@ module.exports = function Dynamic(options,UI) {
       eval(func);
       return f;
     }
-
+    
     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);
     });
-
+    
     function changePixel(r, g, b, a) {
+
+      /* neighbourpixels can be calculated by
+       this.getNeighbourPixel.fun(x,y)  or this.getNeighborPixel.fun(x,y)
+       */
       var combined = (r + g + b) / 3.000;
       return [
-        options.red_function(  r, g, b, a),
+        options.red_function(r, g, b, a),
         options.green_function(r, g, b, a),
-        options.blue_function( r, g, b, a),
+        options.blue_function(r, g, b, a),
         options.alpha_function(r, g, b, a),
       ];
     }
-
+
+    /* Functions to get the neighbouring pixel by position (x,y) */
+    function getNeighbourPixel(pixels,curX,curY,distX,distY){
+      return [
+         pixels.get(curX+distX,curY+distY,0)
+        ,pixels.get(curX+distX,curY+distY,1)
+        ,pixels.get(curX+distX,curY+distY,2)
+        ,pixels.get(curX+distX,curY+distY,3)
+      ]
+    }
+
+
     function output(image,datauri,mimetype){
-
+      
       // This output is accessible by Image Sequencer
       step.output = { src: datauri, format: mimetype };
-
+      
       // This output is accessible by the UI
       options.step.output = datauri;
-
+      
       // Tell the UI that the draw is complete
       UI.onComplete(options.step);
-
+      
     }
     return require('../_nomodule/PixelManipulation.js')(input, {
       output: output,
       changePixel: changePixel,
+      getNeighbourPixel: getNeighbourPixel,
+      getNeighborPixel: getNeighbourPixel,
       format: input.format,
       image: options.image,
       inBrowser: options.inBrowser,
       callback: callback
     });
-
+    
   }
-
+  
   return {
     options: options,
     draw: draw,

src/modules/_nomodule/PixelManipulation.js

@@ -21,6 +21,12 @@ module.exports = function PixelManipulation(image, options) {
       console.log('Bad image path');
       return;
     }
+
+    if(options.getNeighbourPixel){
+      options.getNeighbourPixel.fun = function (distX,distY) { 
+        return options.getNeighbourPixel(pixels,x,y,distX,distY);
+      };
+    }
 
     // iterate through pixels;
     // this could possibly be more efficient; see
@@ -31,13 +37,13 @@ module.exports = function PixelManipulation(image, options) {
 
     for(var x = 0; x < pixels.shape[0]; x++) {
       for(var y = 0; y < pixels.shape[1]; y++) {
-
+          
         var pixel = options.changePixel(
-          pixels.get(x, y, 0),
-          pixels.get(x, y, 1),
-          pixels.get(x, y, 2),
-          pixels.get(x, y, 3)
-        );
+            pixels.get(x, y, 0),
+            pixels.get(x, y, 1),
+            pixels.get(x, y, 2),
+            pixels.get(x, y, 3)
+          );
 
         pixels.set(x, y, 0, pixel[0]);
         pixels.set(x, y, 1, pixel[1]);
@@ -48,9 +54,9 @@ module.exports = function PixelManipulation(image, options) {
         pace.op()
       }
     }
-
+    
     if(options.extraManipulation)
-      pixels = options.extraManipulation(pixels)
+    pixels = options.extraManipulation(pixels)
 
     // there may be a more efficient means to encode an image object,
     // but node modules and their documentation are essentially arcane on this point