diff options
Diffstat (limited to 'text/shape.h')
| -rw-r--r-- | text/shape.h | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/text/shape.h b/text/shape.h index fdec7ee..7b12009 100644 --- a/text/shape.h +++ b/text/shape.h @@ -6,7 +6,8 @@ /* Shaping (docs/design/004-text.md): a run of characters (one script, one * direction) to glyphs and their positions, as HarfBuzz 10 shapes it with - * its default, Arabic and Hebrew shapers, glyph for glyph and unit for unit. + * its default, Arabic, Hebrew, Hangul and Indic shapers, glyph for glyph and + * unit for unit. * * What a font's shaping needs travels in a symbol file (its shaping * section), written by the build tool: @@ -31,15 +32,22 @@ * no plan positions marks without * GPOS; x_bearing INT16_MIN: none), * u32 0 - * Offsets are from the section's start. A plan: + * Offsets are from the section's start. A plan (VEGA_PLAN_BYTES): * u32 script (ISO 15924 as a tag: 'Latn'), u8 direction, u8 native * direction (of its script; 0 when it has none), u8 shaper, u8 flags, * u32 global mask, u32 kern mask, u32 masks[VEGA_PLAN_MASKS], u32 first - * GSUB step, u32 GSUB steps, u32 first GPOS step, u32 GPOS steps. - * A step, a lookup to run: u16 lookup index, u8 flags, u8 0, u32 mask. */ -enum { VEGA_SHAPING_HEADER = 80, VEGA_PLAN_BYTES = 88, VEGA_STEP_BYTES = 8, VEGA_PLAN_MASKS = 14 }; + * GSUB step, u32 GSUB steps, u32 first GPOS step, u32 GPOS steps, + * u8 shaper flags, u8 0[3], + * the stages the shaper asks whether a feature would substitute in + * (VEGA_PLAN_STAGES of: u16 first step, counted from the plan's first + * GSUB step, u16 steps, u32 0), u32 0. + * A step, a lookup to run: u16 lookup index, u8 flags, u8 0, u32 mask; or + * a pause, where the shaper does its part: u16 VEGA_STEP_PAUSE, u8 which + * (VEGA_PAUSE_...), u8 0, u32 0. */ +enum { VEGA_SHAPING_HEADER = 80, VEGA_PLAN_BYTES = 144, VEGA_STEP_BYTES = 8, VEGA_PLAN_MASKS = 16, + VEGA_PLAN_STAGES = 5 }; enum { VEGA_SHAPE_LTR = 1, VEGA_SHAPE_RTL = 2 }; -enum { VEGA_SHAPER_DEFAULT, VEGA_SHAPER_ARABIC, VEGA_SHAPER_HEBREW, VEGA_SHAPER_HANGUL }; +enum { VEGA_SHAPER_DEFAULT, VEGA_SHAPER_ARABIC, VEGA_SHAPER_HEBREW, VEGA_SHAPER_HANGUL, VEGA_SHAPER_INDIC }; /* Plan flags: GPOS runs; mark advances are zeroed after it (by GDEF); glyph * classes come from Unicode (the font has none); the font positions marks * (a 'mark' feature); automatic fractions; the kern table kerns; marks are @@ -47,12 +55,24 @@ enum { VEGA_SHAPER_DEFAULT, VEGA_SHAPER_ARABIC, VEGA_SHAPER_HEBREW, VEGA_SHAPER_ * it where it was. */ enum { VEGA_PLAN_GPOS = 1, VEGA_PLAN_ZERO_MARKS = 2, VEGA_PLAN_GUESS_CLASSES = 4, VEGA_PLAN_GPOS_MARK = 8, VEGA_PLAN_FRACTIONS = 16, VEGA_PLAN_KERN = 32, VEGA_PLAN_FALLBACK_MARKS = 64, VEGA_PLAN_ADJUST_ZEROING = 128 }; -/* The masks a plan names, for the features set glyph by glyph. */ -enum { VEGA_MASK_ISOL, VEGA_MASK_FINA, VEGA_MASK_FIN2, VEGA_MASK_FIN3, VEGA_MASK_MEDI, VEGA_MASK_MED2, - VEGA_MASK_INIT, VEGA_MASK_RTLM, VEGA_MASK_FRAC, VEGA_MASK_NUMR, VEGA_MASK_DNOM, VEGA_MASK_LJMO, VEGA_MASK_VJMO, - VEGA_MASK_TJMO }; -/* Step flags. */ +/* The masks a plan names, for the features set glyph by glyph: those of + * every shaper, then each shaper's own. */ +enum { VEGA_MASK_RTLM, VEGA_MASK_FRAC, VEGA_MASK_NUMR, VEGA_MASK_DNOM, VEGA_MASK_SHAPER }; +enum { VEGA_MASK_ISOL = VEGA_MASK_SHAPER, VEGA_MASK_FINA, VEGA_MASK_FIN2, VEGA_MASK_FIN3, VEGA_MASK_MEDI, + VEGA_MASK_MED2, VEGA_MASK_INIT }; /* Arabic */ +enum { VEGA_MASK_LJMO = VEGA_MASK_SHAPER, VEGA_MASK_VJMO, VEGA_MASK_TJMO }; /* Hangul */ +enum { VEGA_MASK_RPHF = VEGA_MASK_SHAPER, VEGA_MASK_PREF, VEGA_MASK_BLWF, VEGA_MASK_ABVF, VEGA_MASK_HALF, + VEGA_MASK_PSTF, VEGA_MASK_INDIC_INIT }; /* Indic */ +/* The stages a plan names: Indic's, whose features decide a consonant's + * position by whether they would substitute it. */ +enum { VEGA_STAGE_RPHF, VEGA_STAGE_PREF, VEGA_STAGE_BLWF, VEGA_STAGE_PSTF, VEGA_STAGE_VATU }; +/* Shaper flags: Indic's font follows the old specification (deva, not + * dev2). */ +enum { VEGA_INDIC_OLD_SPEC = 1 }; +/* Step flags; pauses, which the shaper tells apart. */ enum { VEGA_STEP_AUTO_ZWNJ = 1, VEGA_STEP_AUTO_ZWJ = 2, VEGA_STEP_RANDOM = 4, VEGA_STEP_PER_SYLLABLE = 8 }; +enum { VEGA_STEP_PAUSE = 0xFFFF }; +enum { VEGA_PAUSE_SYLLABLES = 1, VEGA_PAUSE_INITIAL_REORDERING, VEGA_PAUSE_FINAL_REORDERING, VEGA_PAUSE_CLEAR_SYLLABLES }; typedef struct { const unsigned char *p; uint32_t size; } VegaTable; /* Which glyphs may be in a set, as three 64-bit patterns of glyph bits |