> 1. Download > https://www.google.com/fonts#UsePlace:use/Collection:Open+Sans > 2. Load OpenSans-Regular.ttf in ftview, look at sizes 10, 13, 15, 19 > 3. Press A and B and compare where the bytecode and the autohinter > align the top of capital letters, also press h to compare with the > unhinted outline.
[At 10 ppem the auto-hinter *enlarges* glyphs, so you probably mean a different size] > I've noticed similar behavior by the autohinter in other fonts. > Snapping 1 pixel too low like at the above sizes makes glyphs look > like someone stepped on them, 1 pixel too high is a bit less of an > issue I think, depending on the size. Bytecode and the CFF hinter > do that, too, sometimes, but e.g. the CFF hinter in general and the > bytecode in this example give me a better overall consistency > impression.. > > What is the cause and is there anything to be done about it? The auto-hinter tries to align lowercase glyphs with the grid (cf. the AF_BLUE_STRING_LATIN_SMALL string in file `afblue.dat', as used in the AF_BLUE_STRINGSET_LATN set assigning the AF_BLUE_PROPERTY_LATIN_X_HEIGHT property). This is essential to increase legibility at small sizes. This alignment happens *before* hinting; it is done by scaling all glyphs vertically. Internally, the auto-hinter rounds the x-height more often up than down, but if a there is a rounding down, the uppercase glyphs are also scaled down, causing the effect you are observing. Cf. the `increase-x-height' property as documented in `ftautoh.h'. Werner _______________________________________________ Freetype-devel mailing list Freetype-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/freetype-devel