The beyond-64k hmtx table doesn't encode LSB. If subsetting brings
the glyph under 64k (which currently is the only mode we support),
then we need to encode the LSB, which wasn't available. We need to
fetch xMin from glyf table and set it as LSB.
Replace the font argument with a hb_paint_context_t
that carries the font, the palette index and the
foreground color.
The hb_font_paint_glyph() api now takes the palette
index and the foreground color as extra arguments.
Update all callers and regenerate test results.
hb_font_draw_glyph(), hb_font_draw_glyph_func_t and
hb_font_funcs_set_draw_glyph_func() are just alternative
names for hb_font_get_glyph_shape and friends, to better
align with hb_font_paint_glyph.
This gives best performance for short strings, now that we have a h-advance cache as well.
The en-words benchmark in particular, now ot-font is faster than ft.
Second to last line is of interest:
Before:
-----------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------------------------------------------
BM_Shape/en-words.txt/Roboto-Regular.ttf/hb 29.8 ms 29.8 ms 23
BM_Shape/en-words.txt/Roboto-Regular.ttf/ft 30.4 ms 30.4 ms 23
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/hb 16.3 ms 16.3 ms 43
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/ft 16.5 ms 16.5 ms 42
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/var/hb 18.0 ms 18.0 ms 39
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/var/ft 17.8 ms 17.8 ms 39
After:
behdad@Behdads-MacBook-Pro harfbuzz % ninja -Cbuild && build/perf/benchmark-shape --benchmark_filter=en-words
-----------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations
-----------------------------------------------------------------------------------------------------
BM_Shape/en-words.txt/Roboto-Regular.ttf/hb 30.0 ms 30.0 ms 23
BM_Shape/en-words.txt/Roboto-Regular.ttf/ft 30.3 ms 30.3 ms 23
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/hb 16.3 ms 16.3 ms 43
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/ft 16.4 ms 16.4 ms 43
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/var/hb 17.6 ms 17.6 ms 40
BM_Shape/en-words.txt/SourceSerifVariable-Roman.ttf/var/ft 17.8 ms 17.8 ms 39
Behdad Esfahbod
Matthias Clasen
Khaled Hosny