Merged
Conversation
mbostock
requested changes
Apr 11, 2026
Member
mbostock
left a comment
mbostock
left a comment
There was a problem hiding this comment.
I don’t think we should do this. In my experience, setting globalCompositeOperation typically makes the canvas much slower by disabling hardware acceleration. Also browsers haven’t always implemented compositing consistently. I don’t see any performance cost here, but I also don’t a benefit in terms of logical clarity, so I’d rather stick with the common path of clearRect.
mbostock
changed the title
mbostock
approved these changes
Apr 11, 2026
Member
mbostock
left a comment
mbostock
left a comment
There was a problem hiding this comment.
I removed the use of globalCompositeOperation and renamed the test (and made it slightly prettier).
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
adopt globalCompositeOperation in the raster color converter
test the color converter cache for opacity
this does not appear to be faster, clearRect is probably super fast; but it conveys the intent better and avoids a looped operation