[WIP] Add optional ImageData argument to getImageData #4748
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Optional argument, if provided, will be used instead of creating a new ImageData object. This avoids creating a large amount of unnecessary garbage when getting image data from a canvas at a high frequency.
dsanders11
changed the title
domenic
added
topic: canvas
needs implementer interest
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Closing in favor of #4785. |
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Optional argument, if provided, will be used instead of creating a new ImageData object. This avoids creating a large amount of unnecessary garbage when getting image data from a canvas at a high frequency.
See #3802 for original discussion and my comment #3802 (comment) for more in-depth discussion on why this change is beneficial. The TL;DR is simple: using
getImageDatato process video data being written to acanvascreates a large amount of garbage when trying to process at any reasonable FPS, and garbage collection does not handle this well, instead lots of CPU is burned and memory usage is highly variable. Reusing a singleImageDatafor frame data eliminates this issue. It's an easy performance win.Creating a PR for this for higher visibility, because the issue wasn't going anywhere and wasn't going to be getting a response.
(See WHATWG Working Mode: Changes for more details.)
/canvas.html ( diff )