Removing HTML canvas alpha channel

Question

I have a very large html canvas element covering a solid background. I would assume that a lot of cpu could be saved when scrolling/panning if the browser did not blend the canvas to elements behind it (in this case, a solid color).

Is it possible to remove the canvas alpha channel? Should this be left up to browsers to detect and optimize for? Or would speed gains be insignificant?

Answer 1

MDN suggests setting the alpha option in the canvas context:

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 });