Rest of kraken benchmark example

examples/kraken.js

@@ -17,6 +17,79 @@ img.onload = function(){
 
 img.src = __dirname + '/squid.png';
 
+
+var sigma = 10; // radius
+var kernel, kernelSize, kernelSum;
+buildKernel();
+
+function buildKernel() {
+ var ss = sigma * sigma;
+ var factor = 2 * Math.PI * ss;
+ kernel = [];
+ kernel.push([]);
+ var i = 0, j;
+ do {
+     var g = Math.exp(-(i * i) / (2 * ss)) / factor;
+     if (g < 1e-3) break;
+     kernel[0].push(g);
+     ++i;
+ } while (i < 7);
+ kernelSize = i;
+ for (j = 1; j < kernelSize; ++j) {
+     kernel.push([]);
+     for (i = 0; i < kernelSize; ++i) {
+         var g = Math.exp(-(i * i + j * j) / (2 * ss)) / factor;
+         kernel[j].push(g);
+     }
+ }
+ kernelSum = 0;
+ for (j = 1 - kernelSize; j < kernelSize; ++j) {
+     for (i = 1 - kernelSize; i < kernelSize; ++i) {
+         kernelSum += kernel[Math.abs(j)][Math.abs(i)];
+     }
+ }
+}
+
+function blurTest() {
+ console.log('... running');
+
+ var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
+ var width = imgData.width, height = imgData.height;
+ var data = imgData.data;
+
+ var len = data.length;
+ var startTime = (new Date()).getTime();
+
+ for (var y = 0; y < height; ++y) {
+   for (var x = 0; x < width; ++x) {
+     var r = 0, g = 0, b = 0, a = 0;
+     for (j = 1 - kernelSize; j < kernelSize; ++j) {
+       if (y + j < 0 || y + j >= height) continue;
+       for (i = 1 - kernelSize; i < kernelSize; ++i) {
+         if (x + i < 0 || x + i >= width) continue;
+         r += data[4 * ((y + j) * width + (x + i)) + 0] * kernel[Math.abs(j)][Math.abs(i)];
+         g += data[4 * ((y + j) * width + (x + i)) + 1] * kernel[Math.abs(j)][Math.abs(i)];
+         b += data[4 * ((y + j) * width + (x + i)) + 2] * kernel[Math.abs(j)][Math.abs(i)];
+         a += data[4 * ((y + j) * width + (x + i)) + 3] * kernel[Math.abs(j)][Math.abs(i)];
+       }
+     }
+     data[4 * (y * width + x) + 0] = r / kernelSum;
+     data[4 * (y * width + x) + 1] = g / kernelSum;
+     data[4 * (y * width + x) + 2] = b / kernelSum;
+     data[4 * (y * width + x) + 3] = a / kernelSum;
+   }
+ }
+ var finishTime = Date.now() - startTime;
+ for (var i = 0; i < data.length; i++) {
+     imgData.data[i] = data[i];
+ }
+ //imgData.data = data;
+ ctx.putImageData(imgData, 0, 0);
+ console.log('... finished in %dms', finishTime);
+}
+ 
+blurTest();
+
 var out = fs.createWriteStream(__dirname + '/kraken.png')
   , stream = canvas.createPNGStream();