Re: [Devel] Trimmed monospace font: bug, feature or my fault?

[Stepan Roh]

On Tue, 13 Apr 2004, Werner LEMBERG wrote:

>
> > I have monospaced TrueType (indicated with Panose setting, all
> > widths are the same) font based on Bitstream Vera Sans Mono.  When
> > shown in some GTK+ or KDE/Qt (I got reports of other toolkits
> > behaving the same too) application the glyphs are trimmed (maybe cut
> > is better word) to their width.  Non-monospaced fonts are not
> > trimmed.  It is best shown on monospaced Oblique font face - even
> > the original Bitstream font - for example M is cut a bit in the
> > upper right corner and lower left corner.
> >
> > Now the strange part comes: when transformation matrix is set to
> > some non-identity (like (1, 0.0001, 0, 1) which is visually the same
> > as identity) the trimming stops.  I'm setting the matrix in
> > fontconfig.
>
> While the bounding glyph box should include all glyphs, the advance
> width can be smaller than the maximum horizontal extension; the
> difference is called `italic correction'.  Maybe your applicataion
> simply renders glyph by glyph, overwriting the pixels which are
> already there, thus not taking into account horizontal `overshoot'?

I tested it on KWord and Abiword and I got reports of same behaviour from
plain old xterm. They all behave this way:

non-monospaced font (oblique or not oblique - does not matter), arbitrary
transformation matrix - everything is shown, even parts of glyphs outside
their width

monospaced font (oblique or not oblique), transformation matrix set to
identity - parts of glyphs outside their width are trimmed with same
bounding box for oblique and not oblique font face

monospaced font (oblique or not oblique), transformation matrix set to
non-identity (even transformation producing the same results as identity
(on screen) thanks to rounding) - everything is shown, no trimming happens

I can post screenshots on web, if you want.

(CC me please)

Have a nice day.

Stepan Roh