Yeah, exactly, that’s what I’m curious about - if the browser’s renderer is adding significant amounts of delay due to additional synchronization, or if the problem with canvas.getImageData() is the same problem we’ve always had and if the delays are similar. This does make it seem like a callback to receive last frame’s image could be much faster than a synchronous read call, and I’d certainly use that if it existed…
canvas.getImageData() would have gotten a lot slower as GPU acceleration of Canvas2D became increasingly more common. The initial versions of Canvas2D were all software rasterized, which means getImageData() likely didn't involve any IPCs and definitely didn't involve any GPU readbacks. It was just a memcpy if that.
