Comment 27 for bug 1001033

Sorry Steve, I didn't mean to pick on FreeMono. I agree that it's not even clear if there's *any* bug here, but there's certainly something surprising.

I also agree that the rendered width is a poor metric, for the reasons you describe. That's why my investigations have focused on glyph metrics, specifically the advance width in pixels as reported by FreeType after the face has been loaded and a scaling size selected.

I believe that even if we could find a way to get consistent advance widths out of FreeType, Sam would still need to change his program, because measuring the width of the rendered text does not seem like it could possibly work in all circumstances. For example, a glyph may have negative xMin or it may have xMax greater than the advance width, as in italic faces. Either the rendered text must have a total width greater than the sum of the advance widths of the characters involved, or it must have chopped off parts of the characters. Still, I am less concerned with whether Sam's program is correctly written than with whether it is possible to write his program correctly, and it seems to me that FreeType reporting differing advance widths is an issue that prevents this.

I will try my Python script and the C test on a wider range of fonts tonight. I apologise that I had not understood until now that the Courier example showed up the same issue.

Sorry, my comment "inconsistent hinting in monospaced font" was not deeply considered, and is clearly misleading. I do not claim to know anything about the hinting specified in the font file, I can only say that for some reason FreeType appears to decide that it should apply auto-hinting, and that the observed result of this auto-hinting process on this particular monospaced font is that different glyphs end up with different advance widths, and that for other font files, including older versions of the same font, for some reason FreeType appears *not* to apply auto-hinting.

I have asked about this on the FreeType mailing list: http://lists.nongnu.org/archive/html/freetype/2012-05/msg00029.html

Thanks for all your help so far Steve.