CanvasKit.MakeImageFromEncoded, when used with Browser APIs for loading/decoding images.
- `CanvasKit.MakeImageFromCanvasImageSource` takes either an HTMLImageElement,
SVGImageElement, HTMLVideoElement, HTMLCanvasElement, ImageBitmap, or OffscreenCanvas and returns
an SkImage. This function is an alternative to `CanvasKit.MakeImageFromEncoded` for creating
SkImages when loading and decoding images. In the future, codesize of CanvasKit may be able to be
reduced by removing image codecs in wasm, if browser APIs for decoding images are used along with
`CanvasKit.MakeImageFromCanvasImageSource` instead of `CanvasKit.MakeImageFromEncoded`.
- Three usage examples of `CanvasKit.MakeImageFromCanvasImageSource` in core.spec.ts. These
examples use browser APIs to decode images including 2d canvas, bitmaprenderer canvas,
HTMLImageElement and Blob.
- Added support for asynchronous callbacks in perfs and tests.
Here are notes on the image decoding approaches we tested and perfed in the process of finding ways
to use Browser APIs to decode images:
1. pipeline:
ArrayBuffer → ImageData → ctx.putImageData →
context.getImageData → Uint8Array → CanvasKit.MakeImage
❌ Problem: ImageData constructor expects decoded bytes already.
2. interface.js - CanvasKit.ExperimentalCanvas2DMakeImageFromEncoded (async function)
pipeline:
ArrayBuffer → Blob -> HTMLImageElement ->
draw on Canvas2d -> context.getImageData → Uint8Array →
CanvasKit.MakeImage
✅ Works
⏱ Performance: 3rd place (in my testing locally)
3. interface.js - CanvasKit.ExperimentalCanvas2DMakeImageFromEncoded2 (async function)
ArrayBuffer → Blob → ImageBitmap → draw on Canvas2d →
context.getImageData → Uint8Array → CanvasKit.MakeImage
✅ Works
⏱ Performance: 2nd place (in my testing locally)
4. interface.js - CanvasKit.ExperimentalCanvas2DMakeImageFromEncoded3 (async function)
ArrayBuffer → Blob → ImageBitmap →
draw on canvas 1 using bitmaprenderer context →
draw canvas 1 on canvas 2 using drawImage → context2d.getImageData →
Uint8Array → CanvasKit.MakeImage
✅ Works
⏱ Performance: 1st place (in my testing locally) - quite surprising, this in some ways seems to be a more roundabout way of CanvasKit.ExperimentalCanvas2DMakeImageFromEncoded2, but it seems bitmaprenderer context is fairly fast.
Bug: skia:10360
Change-Id: I6fe94b8196dfd1ad0d8929f04bb1697da537ca18
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/295390
Reviewed-by: Kevin Lubick <kjlubick@google.com>
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