display of text with Qt-4 on Linux

[Gerard V. <ger...@gr...>]

Hi Micha,

I got some remarks about the bad display of text in pixmaps
(this concerns Linux and Qt-4, of course the pixmaps are similar
to what you see on screen) after the release of PyQwt3D-0.1.5.

BadParametricSurfaceDemo.png is an example of what you see on Linux
with Qt-4.3.0 (this depends on the graphics card: on this NVidia
card there are just some badly placed pictures, but on a Matrox card
there are badly colored pixels probably indicating a problem with
antialiasing).

The attached patch contains a fix for Linux (Mac OS X and Qt-4
work better with the old code, Mac OS X and Qt-3 still need fixing,
and I did not change anything for Windows).  The patch contains
all my previous my modifications, including the SVG and PGF support
(sorry but my build system accumulates all patches in a single file).

With the patch, the output looks like ParametricSurfaceDemo.png
(a truetype font like Verdana looks even better than the default
Courier).

I'll let you know when I have fixed Mac OS X and Qt-3 (but that is
low priority).

Gerard