205187 2019-12-12 16:12:23 -0800 [GTK] WebKitTestRunner should enable gtk-xft-rgba 2019-12-12 16:14:04 -0800 1 1 1 Unclassified WebKit WebKitGTK WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=54763 P2 Normal --- 204671 1 clopez webkit-unassigned bugs-noreply oldest_to_newest 1598183 0 clopez 2019-12-12 16:12:23 -0800 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 1598184 1 clopez 2019-12-12 16:14:04 -0800 (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