1612513 - Make WebRender text items represent glyph positions relative to the prim rect instead of absolutely

Status: NEW

(Core :: Graphics: WebRender, enhancement)

Description

[Jeff Muizelaar [:jrmuizel]]

Currently WebRender needs to do this subtraction when it receives the glyphs.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Attachment: PoC

Comment 2

[Jeff Muizelaar [:jrmuizel]]

This proof of concept subtracts the primitive rect origin from every glyph position when we're constructing the glyph buffer on the Gecko side. Since we store the glyph positions using advances in the TextRun it should be possible to just do the subtraction from the initial point instead of for every glyph.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

Attachment: PoC v2

This moves the offset earlier so that it only needs to happen once and not per glyph

Comment 4

[Jeff Muizelaar [:jrmuizel]]

Attachment: POC v3

This version just uses a framePt of (0,0) to achieve the same affect.

Comment 5

[Aria Beingessner [:Gankra]]

NB part of the motivation of this is that it would led us build the interning key without actually creating a new Vec for the data. Although miko's interning work might make that unnecessary..?

Comment 6

[Jeff Muizelaar [:jrmuizel]]

The latest version has failures here: https://treeherder.mozilla.org/#/jobs?repo=try&revision=b8857f5124c612e47ae4a81b3c371bdba74bee5b&selectedJob=287400038

Comment 7

[Jeff Muizelaar [:jrmuizel]]

Doing it later in the pipeline seems to reduce failures but still has them: https://treeherder.mozilla.org/#/jobs?repo=try&revision=742776e69b58e5abc622ce93b36f6556d2a82f40&selectedJob=287461755