GNOME Bugzilla – Bug 327852
rounding problem due to freetype not rounding metrics anymore
Last modified: 2006-02-26 21:40:27 UTC
Date: Wed, 18 Jan 2006 01:23:58 -0500 From: Chia-I Wu <b90201047@ntu.edu.tw> To: gtk-i18n-list@gnome.org Subject: Rounding problem in pango Hi, The next release of freetype will not round the font metrics. (http://lists.gnu.org/archive/html/freetype-devel/2005-12/msg00027.html) As a result, the extents of layout will usually non-integral. This can cause some problems. For example, consider a layout with a single line which has ascent and descent 14.4 and 0 logically, 15 and 0 actually. When a GtkLabel is created with such a layout, it will have height round(14.4) and the layout will be paint at (0, 0). Then if the glyphs are bitmaps, pango draws them with the baseline at round(14.4) and the top 1 pixel is clipped out. I think outline glyphs also suffer from this, perhaps milder. In this image, comparision of GtkLabel rendering with freetype 2.1.10 (right) and cvs (left) is shown: http://www.olv.idv.tw/~olvaffe/tmp/freetype2/pango.rounding.png -- Regards, olv
The URL doesn't work, but I've observed this with FreeType HEAD.
Seems like this can use a fix in Cairo: https://bugs.freedesktop.org/show_bug.cgi?id=5862 and Xft already does this. Remains FT2 backend, which probably is not worth a change at this point... Closing for now, until we get a report about FT2.
David Turner reverted that change btw...