New issue
Advanced search Search tips

Issue 740291 link

Starred by 1 user
Status: Untriaged
Owner: ----
Cc:
lfg@chromium.org
kenrb@chromium.org
wfh@chromium.org
creis@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 3
Type: Bug



Sign in to add a comment

No OOPIF support for subpixel text rendering

Project Member Reported by lukasza@chromium.org, Jul 8 2017 
REPRO:

1. Launch chrome (I've tested with 60.0.3112.50).
2. Navigate to http://anforowicz.github.io/pixel-diff/index.html
3. Take a screenshot of the page
Repeat with and without --site-per-process

EXPECTED: screenshots are the same

ACTUAL: screenshots differ (I've used https://online-image-comparison.com to compare, but the difference is also slightly visible without extra tools - when zoomed-in, the letters in one of the modes have a visibly yellowish border [i.e. look to the left of the first "F"])

NOTES: This is different and probably more important than the 1-pixel difference I was seeing in layout tests and discussing on chat.
no-oopifs.png
52.3 KB View Download
with-oopifs.png
57.9 KB View Download

Comment 1 by lukasza@chromium.org, Jul 10 2017

Cc: lfg@chromium.org
Components: Blink>Layout>Subpixel
Summary: No OOPIF support for subpixel text rendering (was: Text renders differently in OOPIFs)
lfg@ suggested and I can confirm that the difference above is caused by subpixel font rendering - there is no difference between the screenshots if I tweak (*) the code to always use gfx::FontRenderParams::SUBPIXEL_RENDERING_NONE.

(*) tweak the code = hardcode gfx::FontRenderParams::SUBPIXEL_RENDERING_NONE in:
- ui/gfx/font_render_params_linux.cc: ConvertFontconfigHintStyle(int rgba)
- chrome/browser/ui/libgtkui/gtk_ui.cc: GetGtkFontRenderParams()
- chrome/browser/renderer_preferences_util.cc: UpdateFromSystemSettings(content::RendererPreferences*)

Comment 2 by e...@chromium.org, Jul 10 2017

Components: -Blink>Layout>Subpixel
(Blink>Layout>Subpixel is for subpixel layout, not subpixel rendering)
►

Sign in to add a comment