On Mon, 11 May 2015 07:56:19 +0000 Louis Semprini <[email protected]> wrote:
> What is the most reliable and non-font-dependent way to detect > whether a string being shaped by hb_shape() has led to any missing > glyphs, and to identify where those glyphs occur? > > When I use the word "missing glyph" here I mean a glyph that is not > what the user intended for that code point in that context, whether > that be a little tofu box, a magical hex box, a space glyph (with or > without zero advance), a diamond, or anything else that has > substituted for the glyph that the user really wanted. In so far as the glyph is not just a function of the Unicode scalar value, there need not be any indicator. There are a number of fallbacks that may occur even in a well-constructed font: 1) Optional ligatures may be missing from the font. 2) Indic conjuncts may have a fallback form - Devanagari has two levels of fallback. 3) As Konstantin mentioned, the default glyph for the base codepoint may be returned if the requested variation sequence is not supported by the font. Also, how many glyphs a pair of regional indicators should yield is quite undefined - it may be a choice of the font designer to render them as letters. Richard. _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
