SkBitmap support

[keithluchtel]

Are there plans to add SkBitmap support?

[wcandillon]

That's definitely something that could be done. Could you tell us a little bit about your use-case?

[wcandillon]

Sorry, as a followup, if you are looking to draw a path, get it as an image and then draw on top of it. We offer a couple of capabilities there. You may not need to do that.
But if you do, you best bet would be to use makeImageSnapshot (we even have an open PR to make it faster). If this doesn't fit your use-case perfectly, come back to us, we will be able to help (we have great offscreen rendering capabilities: see #1359 (comment) and we may make these even more user friendly)

[keithluchtel]

Thank you for the update! The reason for wanting SkBitmap would be that after each touch stroke, I can append it to the existing SkBitmap, which would act as a 'cache' of all the previous stroke drawings.

My workaround is this:

  const completedPaths = useValue<SkPath[]>([]);
  const currentPath = useValue<string>('');

  const touchHandler = useTouchHandler({
    onStart: ({x, y}) => {
      currentPath.current = `M ${x} ${y} L${x} ${y}`;
    },
    onActive: ({x, y}) => {
      currentPath.current += ` L ${x} ${y}`;
    },
    onEnd: () => {
      completedPaths.current.push(
        Skia.Path.MakeFromSVGString(currentPath.current) as SkPath,
      );

      currentPath.current = '';
    },
  });

This seems to be working well. Originally I was concerned if the completedPaths array became too large that there'd be a performance hit. I saw on another discussion you recommended possibly using Picture after accumulating enough paths.

If SkBitmap were available, the completedPaths array could be removed, and rendering on the canvas would be a single bitmap blit versus iterating over completedPaths and individually drawing each SkPath.

[wcandillon]

We except your solution to work very well.
if you hit a performance drop, check out this pointer to get an SkImage from all your path on the gpu: #1359 (comment)

The thing is that it would only be faster if you do this every X paths (500 maybe?). If you do this every time you release the gesture, it might not be the performance boost you are looking for.

[wcandillon]

Looks like you're doing something cool, happy hacking :)

[keithluchtel]

Much appreciated. I'll work with these solutions and circle back if I hit any roadblocks. Thanks for your time and help!

[tomdoeslinux]

For drawing pixels, what can I use in react native skia?