NEW 205187
[GTK] WebKitTestRunner should enable gtk-xft-rgba 
https://bugs.webkit.org/show_bug.cgi?id=205187
Summary [GTK] WebKitTestRunner should enable gtk-xft-rgba
Carlos Alberto Lopez Perez
Reported 2019-12-12 16:12:23 PST
When starting WebKitTestRunner we are disabling gtk-xft-rgba, and it seems that without this setting enabled Cairo ignores the fontconfig setting regarding subpixel rendering and prefers to use CAIRO_ANTIALIAS_GRAY instead of CAIRO_ANTIALIAS_SUBPIXEL. That means that when running layout tests, the rendered of all the fonts that don't force a specific antialiasing via -webkit-font-smoothing are antialiased with CAIRO_ANTIALIAS_GRAY. However on a real use case (a desktop of a user) those fonts would be antialiased with CAIRO_ANTIALIAS_SUBPIXEL. Other platforms (Mac) also default to CAIRO_ANTIALIAS_SUBPIXEL. This causes the test compositing/contents-format/subpixel-antialiased-text.html to fail (after enabling support for -webkit-font-smoothing in bug 54763). Before that this test was doing nothing (passing, but not actually testing anything). The issue is that simply flipping the bit to enable gtk-xft-rgba is problematic since it causes news thousands of failures related to the Ahem font, that seems were passing with CAIRO_ANTIALIAS_GRAY but would fail with CAIRO_ANTIALIAS_SUBPIXEL. So, before enabling this we should always disable antialiasing for Ahem font in bug 204671
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Carlos Alberto Lopez Perez
Comment 1 2019-12-12 16:14:04 PST
(In reply to Carlos Alberto Lopez Perez from comment #0) > This causes the test > compositing/contents-format/subpixel-antialiased-text.html to fail (after > enabling support for -webkit-font-smoothing in bug 54763). Before that this > test was doing nothing (passing, but not actually testing anything). Sorry, I mean the test: fast/text/font-antialiasing-save-restore.html
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