javascript - GetImageData 和多个图像

Question

当图像被绘制到 Canvas 中时，如何在js中使用getImageData()？ (我分别需要每个图像的数据。)

Answer 1

这是一种方法:

// get the imageData for the second image

context.drawImage(secondImage,0,0);
var imageData2=context.getImageData(0,0,canvas.width,canvas.height);
context.clearRect(0,0,canvas.width,canvas.height);

// get the imageData for the first image

context.drawImage(firstImage,0,0);
var imageData1=context.getImageData(0,0,canvas.width,canvas.height);

// and now redraw the second image back on the canvas

context.drawImage(secondImage,0,0);