[ft-devel] global font metrics are rounded?

[Chia-I Wu]

Hi,

freetype rounds the global font metrics in ft_recompute_scaled_metrics
in a conservative way.  That is, ascender is ceiled and descender is
floored.  This gives unpleasant gaps between lines in big5 art, i.e.
ascii art with big5 characters:

http://homepage.ntu.edu.tw/~r94221003/big5art1.png

Xft also rounds global font metrics.  However, it rounds by flooring
ascender and ceiling descender.  Thus when rounding is disabled in
freetype, the gaps are gone (note that glyphs in the menu bar are also
affected):

http://homepage.ntu.edu.tw/~r94221003/big5art2.png

For comparison, this is what windows users expect to see:

http://homepage.ntu.edu.tw/~r94221003/big5artwin.png
(different resolutions and different font)

To sum up, I think freetype should not round global font metrics (nor
glyph metrics) and let clients decide how to deal with them, despite
that clients are able to get the unrounded values by scaling themselves.

As the effect is large (all apps using Xft), I need your opinions.

-- 
Regards,
olv