1 Reply Latest reply on Jul 23, 2008 7:24 AM by (Adam_Twardoch)

    Request for comment on a change to the AFKDO autohint tool

    Level 1
      The autohint tool now spends about 2/3 of its time maintaining some data that is supposed to help avoid stomping on manual hinting, and to notice when a glyph needs re-hinting. I am considering dropping this functionality because: 1) it would speed up autohinting by a factor of 2 or 3, and 2) the autohint tool would no longer make the <PostScript Name>.plist file and would thereby avoid clutter. Does anyone care either way?<br /><br />The idea was that if you have carefully manually hinted a glyph in FontLab, you don't want that work replaced by running the autohint tool on your saved font file. By default, therefore, the autohinter will not hint any glyph which already has hints. However,  you do want to re-hint any glyph which is edited after being hinted. In order to catch the latter case, the autohinter makes a file named <PostScript Name>.plist, which contains a condensed form of each glyph's outline. When hinting the selected glyphs in a font file, the autohint tool checks if the glyph outlines in the file differ from those in the <PostScript Name>.plist file; if so it will re-hint the glyph.<br /><br />The two rules can work against each other. If you manually hint a glyph, then autohint the font, the manually hinted glyph will not be re-hinted. However, if you then edit that glyph, the next time you run the autohint tool on the font, the autohint tool will notice that that the outline has changed since the last time the autohint tool saw it, and the autohint tool will then re-hint the glyph.<br /><br />I suspect that very few people manually hint glyphs, and those that do,  do so rarely enough that they remember which glyphs they did. I would like to change the autohint tool so that by default it re-hints all selected glyphs, and you can skip glyphs only by either explicitly saying which glyphs to hint, or which glyphs to not hint. Also, the only place you can manually hint a glyph in most people's workflow is in FontLab, and this is preserved in the FontLab vfb file, while the auto-hint tool works on the saved Type1 or OpenType/CFF font file.<br /><br />- Read Roberts