Sounds like a valuable improvement, thank you! I see you're talking with @mmocny on the CL <https://chromium-review.googlesource.com/c/chromium/src/+/6624567>, that's great. I wonder if this was just an oversight in our initial design? Seems like a bug to me. Think we can just switch it (and put the change on the changelog <https://chromium.googlesource.com/chromium/src/+/refs/heads/main/docs/speed/metrics_changelog/cls.md>) without causing compat issues? Or might we need to give devs a way to opt-in to the new semantics? mmocny@ is the expert here though, so I'm happy with whatever he wants to do.
Cheers, Rick On Tue, Jul 22, 2025 at 5:00 PM Ane Diaz De Tuesta <aned...@gmail.com> wrote: > Hi all, > I'd like to announce an Intent to Prototype for: > > > - *Feature name:* Layout Instability Attribution in CSS Pixels > > > - *Contact:* anediaz@gmail > > > - *Explainer:* > > https://github.com/anediaz/layout-shift-attribution-in-css-pixels/blob/main/Explainer.md > > > - *Summary:* The Layout Instability API currently reports attribution > rectangles (`prevRect` and `currentRect`) in device pixels, which vary > based on resolution and `devicePixelRatio`. This change proposes reporting > them in CSS pixels for consistency with other layout and performance APIs. > > > - *Motivation:* This will align attribution with other Web APIs, such > as `getBoundingClientRect()` and make layout shift data easier to > visualize, debug, and combine across devices and tools. > > > - *Initial public proposal:* > https://issues.chromium.org/issues/399058544 > > > - *TAG review:* Not yet requested > > > - *Risks:* None known. This change only affects how attribution data > is reported, and is gated behind a runtime flag. > > > - *Interoperability:* > - Mozilla: No signal > - WebKit: No signal > > > - *Estimated milestones:* N/A (this is a prototype only) > > > - *Footprint:* This will be implemented behind a runtime flag. > > > - *Link to entry on Chrome Platform Status: * > https://chromestatus.com/feature/5155103518228480 > > > This Intent is to begin prototyping the feature and gather feedback. > > Thank you for your help and time. > Cheers, > Ane Diaz de Tuesta > > -- > 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 blink-dev+unsubscr...@chromium.org. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACBGQem%2BV6_UiLktmqwDCSXC3RJaMpmNm%3DSxv%2BH6%3DY4yCk5Msg%40mail.gmail.com > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CACBGQem%2BV6_UiLktmqwDCSXC3RJaMpmNm%3DSxv%2BH6%3DY4yCk5Msg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- 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 blink-dev+unsubscr...@chromium.org. To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAFUtAY-Jauz3a5n_D2HDMLSY3Gz8a71B41svhejmN5UvU2B1wA%40mail.gmail.com.
