Rounding problem in pango

[Chia-I Wu <b90201047 ntu edu tw>]

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, 11 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