Added Crop Module

index.html

@@ -69,6 +69,7 @@
 
         sequencer.addStep('ndvi-red');
         sequencer.addStep('image-threshold');
+        sequencer.addStep('crop');
         //sequencer.addStep('plot');
 
         $('.add-step').click(function(e) {

src/Modules.js

@@ -7,6 +7,6 @@ module.exports = {
   'green-channel': require('./modules/GreenChannel'),
   'ndvi-red': require('./modules/NdviRed'),
   'plot': require('./modules/Plot'),
-  'image-threshold': require('./modules/ImageThreshold')
-
+  'image-threshold': require('./modules/ImageThreshold'),
+  'crop': require('./modules/Crop')
 }

src/modules/Crop.js

@@ -0,0 +1,49 @@
+/*
+ * Image Cropping module
+ */
+ module.exports = function Crop(options){
+
+   options = options || {};
+   options.title = "Crop Image";
+   options.format = options.format || "png";
+
+   function draw(image) {
+     var getPixels = require("get-pixels"),
+         savePixels = require("save-pixels"),
+         base64 = require('base64-stream');
+
+     getPixels(image.src,function(err,pixels){
+       var newdata = [];
+       var ox = options.cropX || 0; //Where to begin the crop on X axis
+       var oy = options.cropY || 0; //Where to begin the crop on Y axis
+       var w = options.cropL || Math.floor(0.5*pixels.shape[0]); //Length of crop
+       var h = options.cropH || Math.floor(0.5*pixels.shape[1]); //Height of crop
+       var iw = pixels.shape[0]; //Width of Original Image
+       newarray = new Uint8Array(4*w*h);
+       for (var n = oy; n < oy + h; n++) {
+         newarray.set(pixels.data.slice(n*4*iw + ox, n*4*iw + ox + 4*w),4*w*(n-oy));
+       }
+       pixels.data = newarray;
+       pixels.shape = [w,h,4];
+       pixels.stride[1] = 4*w;
+
+       var buffer = base64.encode();
+       savePixels(pixels, options.format)
+         .on('end', function() {
+
+         var img = new Image();
+
+         img.src = 'data:image/' + options.format + ';base64,' + buffer.read().toString();
+
+         if (options.output) options.output(img);
+
+       }).pipe(buffer);
+
+     });
+   }
+
+   return {
+     options: options,
+     draw: draw
+   }
+ }

src/modules/ImageThreshold.js

@@ -2,7 +2,6 @@
  * Image thresholding with 'image-filter-threshold'
  */
 module.exports = function ImageThreshold(options) {
-
   options = options || {};
   options.title = "Threshold image";
   options.threshold = options.threshold || 30;