newer freetypes render differently and breaks VTK unit tests / VTK fonts are incorrect(?)
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
If you use VTK_USE_SYSTEM_FREETYPE and your freetype is 2.3.6 or newer, some VTK unit tests will fail. See attached images.
This problem exists, but is worked around, in VTK's CVS version of freetype (2.3.11 at this time).
After painstaking regression through freetype CVS, the source of the problem was committed on 2008-05-18:
* src/pshinter/pshalgo.c (ps_hints_apply): Reset scale values after
correction for pixel boundary. Without this patch, the effect can
be cumulative under certain circumstances, making glyphs taller and
taller after each call. This fixes Savannah bug #19976.
https://savannah.nongnu.org/bugs/?19976
Werner (a freetype dev) thinks: "I suspect that the font is badly hinted; it seems to miss hints (both ghost and normal) at least for the `i'. This, in combination with a not-yet fixed problem within FreeType (which sometimes displaces horizontal strokes too much vertically) probably causes the effects you can see."
We need to convert the VTK C++-ified fonts to a standard format so that Werner can debug. I have no idea how. Anyone?