1640120 - Emoji rendered at wrong size while pinch zooming

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Jamie Nicol [:jnicol]]

While pinch zooming, emojis a rendered at a different size than their surrounding text. The size also jumps periodically as you zoom, rather than changing smoothly with the zoom.

While zooming we rasterize text in local raster space rather than in screen space. The scale of the local space changes in increments, to avoid excessive rasterization, so that explains where the jumps in size come from. The rasterized emojis should however be getting scaled to the correct screen size when rendering, but that is not happening for some reason.

I noticed this on https://turnip.exchange, but it happens on any website where the emojis are text (often websites embed images instead). I noticed it on android, but it might affect other platforms with desktop zooming too (emojis are bitmaps on android but are vectors on some platforms, so that might be an important distinction).

Comment 1

[Jamie Nicol [:jnicol]]

Regression from bug 1617160

Comment 2

[Lee Salzman [:lsalzman]]

Attachment: Bug 1640120 - select proper local-space target size for bitmap fonts in WR FT backend. r?aosmond

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/43f4185c1299
select proper local-space target size for bitmap fonts in WR FT backend. r=aosmond

Comment 4

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/43f4185c1299