Update: Here is "VX" with FreeSerifItalic. There is overlap in LibreOffice also.
For the most part truetypetracer produces valid and nice input data for testing openvoronoi. But sometimes I see wiggles, and now this:
It is frustrating to try to track down bugs in downstream algorithms that take this as input, and assume all line-segments are non-intersecting when in fact the are not!
I seem to have only 13 .ttf files in my /usr/share/fonts/truetype/freefont folder, but maybe there are more elsewhere. I should find a font that is properly designed without wiggles and without overlaps. The other approach is to write a pre-processor that looks at input data and either rejects or cleans it. Looking for all pair-wise intersections of N line-segments is a slow N^2 algorithm - at least for a naive implementation (without bounding-boxes or binning or other tricks).
Unlike the wiggles, this overlap doesn't happen in Inkscape:
Here is G-code generated with ttt-4.0 and drawn in LinuxCNC:
Here is a screenshot from LibreOffice 3:
and GIMP:
sort of nonBalkan scripth...
It appears that there should be "kerning" offset in addition to the normal offset to the right we apply when rendering the next character. I'm not sure how to retrieve this from the TTF or the freetype interface.
Maybe along these lines:
http://www.freetype.org/freetype2/docs/tutorial/step2.html
I work with this type of thing from time to time. Every font is different and these problems are common. for printing this stuff does not show up. For machining we need better lines than the stock font is done in. I always zoom in like that and have to fix the lines to be able to cut correctly. get used to it or create your own lines for the font. Maybe somebody out there has created machine friendly fonts, I have been looking!