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Explainer https://github.com/w3c/paint-timing/blob/main/presentation-timestamps.md Specification https://w3c.github.io/paint-timing/#painttimingmixin Summary Expose "paintTime" and "presentationTime" in element timing, LCP, long animation frames, and paint timing. "paintTime" means the time when the rendering phase ended and the browser started the paint phase. "presentationTime" means the time when the "pixels reached the screen", which is somewhat implementation-defined. This feature entry omits event timing, which would be done separately. Blink component Blink>PerformanceAPIs Web Feature ID performancetiming Motivation So far the spec defined the paint time as the time after the "rendering update", when the document hands over rendering to the UA. However, in chromium the exposed paint time (in event timing, element timing, LCP and paint-timing) was different - the approximated VSync time from the compositor, which is important in terms of UX. This created confusion and incompatibility This proposal defines both these timestamps, and exposes them in an identical way in all the relevant entries. Initial public proposal https://github.com/w3c/paint-timing/issues/62 TAG review https://github.com/w3ctag/design-reviews/issues/1013 TAG review status Pending Risks Interoperability and Compatibility No information provided Gecko: Positive (https://github.com/mozilla/standards-positions/issues/1110) Firefox folks took part of the WebPerfWG meeting where this was discussed/resolved. WebKit: In development (https://github.com/WebKit/standards-positions/issues/426) Web developers: No signals Other signals: WebView application risks Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications? No information provided Debuggability No information provided Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)? Yes Is this feature fully tested by web-platform-tests? No Flag name on about://flags No information provided Finch feature name PaintTimingMixin Rollout plan Will ship enabled for all users Requires code in //chrome? False Tracking bug https://issues.chromium.org/issues/378827535 Estimated milestones Shipping on desktop 144 Shipping on Android 144 Shipping on WebView 144 Anticipated spec changes Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (eg links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (eg, changing to naming or structure of the API in a non-backward-compatible way). None. This is already part of interop 2025. Note that the TAG review was delayed because some things in the explainer were missing initially. Link to entry on the Chrome Platform Status https://chromestatus.com/feature/5162859838046208?gate=5137700305502208 Links to previous Intent discussions Intent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/67347e70.2b0a0220.3644d.01e9.GAE%40google.com This intent message was generated by Chrome Platform Status. -- You received this message because you are subscribed to the Google Groups "blink-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/69282c58.050a0220.107b62.0e01.GAE%40google.com.
