optimization - 删除 HTML Canvas alpha channel

Question

我有一个覆盖纯色背景的非常大的 html Canvas 元素。我假设如果浏览器没有将 Canvas 与其背后的元素混合(在本例中为纯色)，则在滚动/平移时可以节省大量 CPU。

是否可以删除 Canvas alpha channel ？这应该留给浏览器来检测和优化吗？还是速度提升微不足道？

Answer 1

MDN suggests在 Canvas 上下文中设置 alpha 选项:

If your application uses canvas and doesn’t need a transparent backdrop, set the alpha option to false when creating a drawing context with HTMLCanvasElement.getContext(). This information can be used internally by the browser to optimize rendering.

var ctx = canvas.getContext('2d', { alpha: false });