w3c / w3c/element-timing

Image rendering stages: finer granularity

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#54 3 comments 0 reactions 0 assignees View on GitHub

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enhancement
Dominant language
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61
Forks
19
Avg merge
1d 10h
Merged PRs (30d)
1

Description

For image loading, I think the following stages are relevant:

  • Intrinsic dimensions are known (relevant for layout jank)
  • Placeholder paint (e.g. solid color, gradient, blurhash)
  • Preview paint (e.g. first full DC scan, embedded preview shown, top 70% of a sequential image)
  • "Good enough" paint (e.g. far enough in the progressive scan script to be very close to the final image)
  • Final image

It would be good if these could be distinguished, both for the purpose of metrics and for the purpose of html events.

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the five image-loading stages listed in issue #54 and determine how each should be distinguished for metrics and HTML events. Done means the specification clearly defines intrinsic dimensions, placeholder, preview, good-enough, and final image stages for both purposes.

Written by the indexing model from the issue text.

Assessment

Domain
documentation
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
25/100

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