Re: [ft-devel] Seams with disjoint composite

[Werner LEMBERG]

> I was playing with Unicode box characters, and noticed that DejaVu
> Sans creates the glyph for ▟ out of three quadrant boxes.  At
> different sizes I can see very noticeable seams where the sub-glyphs
> meet.  I thought FreeType would handle these cases better, but seems
> like I'm wrong.  Any ideas?  Does FreeType combine all contours
> together and rasterize them in one pass, or raster them separately
> and combine?

They are rasterized in a single pass.  However, the DejaVu font
doesn't contain the necessary bytecode to properly handle the rounding
issues which inevitably happen if subglyphs are combined -- in ftview,
press key `f' to force autohinting, and you won't see seams.  I've
just confirmed that exactly the same issue is present with the Windows
rasterizer, so it's not a FreeType problem.

Of course, a much simpler (and probably even better) solution is to
avoid subglyphs if they touch at longer lines.


    Werner