js代码:
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');
var img = new Image();
img.crossOrigin = ''; //图片转canvas
img.onload = function () {
context.drawImage(this, 0, 0);
context.getImageData(0, 0, this.width, this.height);
document.body.appendChild(canvas);
};
img.src = "https://pic4.zhimg.com/869cf812c5a1beb827d723e6332748a1_m.jpg";
在图片onload以后生成并添加到body里面