[meta] Draw highlighters on platform

NEW
Unassigned

Status

P3
normal
a year ago
2 months ago

People

(Reporter: zer0, Unassigned, NeedInfo)

Tracking

Firefox Tracking Flags

(Not tracked)

Details

(Reporter)

Description

a year ago
This meta is for the investigation and implementation about how to draw the highlighters on platform code instead of the current approach that uses the Anonymous Content API.
Summary: [meta] draws highlighters on platform → [meta] Draw highlighters on platform
We had a chat about this this week.

It sounds like the big problems are that devtools need to recompute a lot of complex state that is already known to layout, and that devtools overlays don't respond to APZ.

The discussed solution was to add a DOM API that lets devtools request specific (hardcoded) overlays for given elements, and then platform can emit display items to draw the required overlay during normal display list building. This would let the overlay items pick up the same async scrolling metadata as the rest of the content for that element.

They generally want the overlays to be on top of all web content, so we'd probably want to temporarily store an generated items somewhere (on the builder somewhere?) and then append them to the top of the final display list.

They also want to override any clips set by content so that overlays can cover the whole page, but we need to make sure we don't escape the content area and into the UI (for non-e10s). Not entirely sure how that could work, but it seems feasible.

What do you think Markus?
Flags: needinfo?(mstange)
Priority: -- → P3

Updated

2 months ago
Product: Firefox → DevTools
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