Question

我可以通过以下方式测量画布中加载的两个图像之间的差异：

<canvas id="canvas1" width="255" height="255"></canvas>
<canvas id="canvas2" width="255" height="255"></canvas>

<script>

// THIS FUNCTION IS THE MOST RELEVANT BIT:
function getSumSq (ctx1, ctx2) {
  var
    i,
    sumSq = 0,
    w = 255, h= 255,
    numPixelComponents = w * h * 4,
    data1 = ctx1.getImageData(0, 0, w, h).data,
    data2 = ctx2.getImageData(0, 0, w, h).data;

  for (i = 0; i < numPixelComponents - 3; i += 4) {
    sumSq += Math.pow(data1[i] - data2[i], 2) +
      Math.pow(data1[i + 1] - data2[i + 1], 2) +
      Math.pow(data1[i + 2] - data2[i + 2], 2);
    // no transparency so ignore i + 3, the alpha channel.
  }

  return sumSq;
}

var c1 = document.getElementById('canvas1');
var ctx1 = c1.getContext('2d');
var img1 = new Image();
img1.src = 'img1.png';
img1.onload = function() {
  ctx1.drawImage(img1, 0, 0);
  var c2 = document.getElementById('canvas2');
  var ctx2 = c2.getContext('2d');
  var img2 = new Image();
  img2.src = 'img2.png';
  img2.onload = function() {
    ctx2.drawImage(img2, 0, 0);
    console.log(getSumSq(ctx1, ctx2));
  };
};

</script>

我想使用画布为大量图像执行此操作。是否有任何浏览器支持以硬件加速的方式测量画布中加载的两个图像之间的差异？

Answer 1

我找不到办法做到这一点 - 猜测答案是否定的。

JS硬件加速图像比较

1 个答案: