rotate module (#1218)

* this PR solves the problem of clipping of the image while rotating

* a little clipping was still present .so made the changes

* Splitted into two files

* ommitted extra declared variables

* Update Module.js

* Update Rotate.js

* Update Rotate.js

src/modules/Rotate/Module.js

@@ -23,21 +23,18 @@ module.exports = function Rotate(options, UI) {
 
     function extraManipulation(pixels) {
       var rotate_value = (options.rotate) % 360;
-
+      var radians = (Math.PI) * rotate_value / 180;
-      if (rotate_value % 360 == 0)
+      var width = pixels.shape[0];
-        return pixels;
+      var height = pixels.shape[1];
-
+      var cos = Math.cos(radians);
-      var bitmap = new imagejs.Bitmap({ width: pixels.shape[0], height: pixels.shape[1] });
+      var sin = Math.sin(radians);
-      bitmap._data.data = pixels.data;
+      //final dimensions after rotation
-
+      var pixels2 = require('ndarray')(new Uint8Array(4 * (Math.floor(Math.abs(width * cos) + Math.abs(height * sin) + 5) * (Math.floor(Math.abs(width * sin) + Math.abs(height * cos)) + 5))).fill(0), [Math.floor(Math.abs(width * cos) + Math.abs(height * sin)) + 5, Math.floor(Math.abs(width * sin) + Math.abs(height * cos)) + 4, 4]);
-      var rotated = bitmap.rotate({
+      pixels = require('./Rotate')(pixels, pixels2, options, rotate_value, width, height, cos, sin);
-        degrees: rotate_value,
-      });
-      pixels.data = rotated._data.data;
-
       return pixels;
     }
       
+
     function output(image, datauri, mimetype) {
       // This output is accesible by Image Sequencer
       step.output = { src: datauri, format: mimetype };

src/modules/Rotate/Rotate.js

@@ -0,0 +1,38 @@
+module.exports = function Rotate(pixels, pixels2, options, rotate_value, width, height, cos, sin){
+  var imagejs = require('imagejs');
+  var height_half = Math.floor(height / 2);
+  var width_half = Math.floor(width / 2);
+  var dimension = width + height;
+
+  if (rotate_value % 360 == 0)
+    return pixels;
+  function copyPixel(x1, y1, x2, y2,pixel_set,pixel_get){
+    pixel_set.set(x1, y1, 0, pixel_get.get(x2, y2, 0));
+    pixel_set.set(x1, y1, 1, pixel_get.get(x2, y2, 1));
+    pixel_set.set(x1, y1, 2, pixel_get.get(x2, y2, 2));
+    pixel_set.set(x1, y1, 3, pixel_get.get(x2, y2, 3));
+  }
+
+  pixels1 = require('ndarray')(new Uint8Array(4 * dimension * dimension).fill(0), [dimension, dimension, 4]);
+  //copying all the pixels from image to pixels1
+  for (var n = 0; n < pixels.shape[0]; n++){
+    for (var m = 0; m < pixels.shape[1]; m++){
+      copyPixel(n + height_half, m + width_half, n, m,pixels1,pixels);
+    }
+  }
+  //rotating pixels1
+  var bitmap = new imagejs.Bitmap({ width: pixels1.shape[0], height: pixels1.shape[1] });
+  bitmap._data.data = pixels1.data;
+
+  var rotated = bitmap.rotate({
+    degrees: rotate_value,
+  });
+  pixels1.data = rotated._data.data;
+  //cropping extra whitespace
+  for (var n = 0; n < pixels2.shape[0]; n++){
+    for (var m = 0; m < pixels2.shape[1]; m++){
+      copyPixel(n, m, n + Math.floor(dimension / 2 -  Math.abs(width * cos / 2) - Math.abs(height * sin / 2)) - 1, m + Math.floor(dimension / 2 - Math.abs(height * cos / 2) - Math.abs(width * sin / 2)) - 1,pixels2,pixels1);
+    }
+  }
+  return pixels2;
+};