From c67eaed8468c36629597aead9a768c9fe711ad85 Mon Sep 17 00:00:00 2001 From: Eskil Abrahamsen Blomfeldt Date: Fri, 5 Feb 2021 12:36:37 +0100 Subject: [PATCH] Fix crash when requesting A32 glyph on Wayland On Wayland we aren't getting any information about the subpixel layout of the screen. On Freetype, this triggers an assert / memory corruption when explicitly requesting a subpixel antialiased glyph (via QRawFont) because it needs to know the layout to render the glyphs. It might be possible to get this information in the Wayland plugin, but at least we should have a failsafe which doesn't crash when the problem occurs. This simply falls back to using A8 antialiasing when it doesn't know the subpixel layout. [ChangeLog][Freetype] Fixed crash when calling QRawFont::alphaMapForGlyph() with subpixel antialiasing on Wayland. Fixes: QTBUG-90236 Change-Id: Iddee2e171a81664ae9e3989115881f23262b2182 Reviewed-by: Allan Sandfeld Jensen (cherry picked from commit ef763e195892a6d8ce207f5d947fe508f645cb6d) Reviewed-by: Qt Cherry-pick Bot --- src/gui/text/freetype/qfontengine_ft.cpp | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/gui/text/freetype/qfontengine_ft.cpp b/src/gui/text/freetype/qfontengine_ft.cpp index 42cf147901d..59300b6ecaa 100644 --- a/src/gui/text/freetype/qfontengine_ft.cpp +++ b/src/gui/text/freetype/qfontengine_ft.cpp @@ -1078,7 +1078,11 @@ QFontEngineFT::Glyph *QFontEngineFT::loadGlyph(QGlyphSet *set, uint glyph, renderMode = FT_RENDER_MODE_MONO; break; case Format_A32: - Q_ASSERT(hsubpixel || vfactor != 1); + if (!hsubpixel && vfactor == 1) { + qWarning("Format_A32 requested, but subpixel layout is unknown."); + return nullptr; + } + renderMode = hsubpixel ? FT_RENDER_MODE_LCD : FT_RENDER_MODE_LCD_V; break; case Format_A8: