Merge branch 'stb-truetype-gpos-request' of https://github.com/danielmaciel/stb into working
This commit is contained in:
Sean Barrett
commit
6d59a4913f
241
stb_truetype.h
241
stb_truetype.h
@ -22,6 +22,7 @@
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// Mikko Mononen: compound shape support, more cmap formats
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// Tor Andersson: kerning, subpixel rendering
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// Dougall Johnson: OpenType / Type 2 font handling
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// Daniel Ribeiro Maciel: basic GPOS-based kerning
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//
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// Misc other:
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// Ryan Gordon
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@ -701,7 +702,7 @@ struct stbtt_fontinfo
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int numGlyphs; // number of glyphs, needed for range checking
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int loca,head,glyf,hhea,hmtx,kern; // table locations as offset from start of .ttf
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int loca,head,glyf,hhea,hmtx,kern,gpos; // table locations as offset from start of .ttf
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int index_map; // a cmap mapping for our chosen character encoding
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int indexToLocFormat; // format needed to map from glyph index to glyph
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@ -1344,6 +1345,7 @@ static int stbtt_InitFont_internal(stbtt_fontinfo *info, unsigned char *data, in
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info->hhea = stbtt__find_table(data, fontstart, "hhea"); // required
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info->hmtx = stbtt__find_table(data, fontstart, "hmtx"); // required
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info->kern = stbtt__find_table(data, fontstart, "kern"); // not required
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info->gpos = stbtt__find_table(data, fontstart, "GPOS"); // not required
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if (!cmap || !info->head || !info->hhea || !info->hmtx)
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return 0;
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@ -2262,7 +2264,7 @@ STBTT_DEF void stbtt_GetGlyphHMetrics(const stbtt_fontinfo *info, int glyph_inde
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}
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}
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STBTT_DEF int stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
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static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
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{
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stbtt_uint8 *data = info->data + info->kern;
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stbtt_uint32 needle, straw;
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@ -2292,9 +2294,242 @@ STBTT_DEF int stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int glyph1,
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return 0;
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}
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static stbtt_int32 stbtt__GetCoverageIndex(stbtt_uint8 *coverageTable, int glyph)
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{
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stbtt_uint16 coverageFormat = ttUSHORT(coverageTable);
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switch(coverageFormat) {
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case 1: {
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stbtt_uint16 glyphCount = ttUSHORT(coverageTable + 2);
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// Binary search.
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stbtt_int32 l=0, r=glyphCount-1, m;
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int straw, needle=glyph;
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while (l <= r) {
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m = (l + r) >> 1;
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stbtt_uint8 *glyphArray = coverageTable + 4;
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stbtt_uint16 glyphID = ttUSHORT(glyphArray + 2 * m);
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straw = glyphID;
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if (needle < straw)
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r = m - 1;
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else if (needle > straw)
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l = m + 1;
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else {
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return m;
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}
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}
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} break;
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case 2: {
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stbtt_uint16 rangeCount = ttUSHORT(coverageTable + 2);
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stbtt_uint8 *rangeArray = coverageTable + 4;
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// Binary search.
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stbtt_int32 l=0, r=rangeCount-1, m;
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int strawStart, strawEnd, needle=glyph;
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while (l <= r) {
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m = (l + r) >> 1;
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stbtt_uint8 *rangeRecord = rangeArray + 6 * m;
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strawStart = ttUSHORT(rangeRecord);
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strawEnd = ttUSHORT(rangeRecord + 2);
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if (needle < strawStart)
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r = m - 1;
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else if (needle > strawEnd)
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l = m + 1;
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else {
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stbtt_uint16 startCoverageIndex = ttUSHORT(rangeRecord + 4);
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return startCoverageIndex + glyph - strawStart;
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}
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}
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} break;
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default: {
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// There are no other cases.
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STBTT_assert(false);
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} break;
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}
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return -1;
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}
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static stbtt_int32 stbtt__GetGlyphClass(stbtt_uint8 *classDefTable, int glyph)
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{
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stbtt_uint16 classDefFormat = ttUSHORT(classDefTable);
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switch(classDefFormat)
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{
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case 1: {
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stbtt_uint16 startGlyphID = ttUSHORT(classDefTable + 2);
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stbtt_uint16 glyphCount = ttUSHORT(classDefTable + 4);
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stbtt_uint8 *classDef1ValueArray = classDefTable + 6;
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if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount)
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return (stbtt_int32)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID));
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classDefTable = classDef1ValueArray + 2 * glyphCount;
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} break;
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case 2: {
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stbtt_uint16 classRangeCount = ttUSHORT(classDefTable + 2);
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stbtt_uint8 *classRangeRecords = classDefTable + 4;
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// Binary search.
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stbtt_int32 l=0, r=classRangeCount-1, m;
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int strawStart, strawEnd, needle=glyph;
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while (l <= r) {
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m = (l + r) >> 1;
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stbtt_uint8 *classRangeRecord = classRangeRecords + 6 * m;
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strawStart = ttUSHORT(classRangeRecord);
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strawEnd = ttUSHORT(classRangeRecord + 2);
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if (needle < strawStart)
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r = m - 1;
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else if (needle > strawEnd)
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l = m + 1;
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else
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return (stbtt_int32)ttUSHORT(classRangeRecord + 4);
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}
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classDefTable = classRangeRecords + 6 * classRangeCount;
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} break;
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default: {
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// There are no other cases.
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STBTT_assert(false);
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} break;
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}
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return -1;
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}
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// Define to STBTT_assert(x) if you want to break on unimplemented formats.
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#define STBTT_GPOS_TODO_assert(x)
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static stbtt_int32 stbtt__GetGlyphGPOSInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
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{
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if (!info->gpos) return 0;
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stbtt_uint8 *data = info->data + info->gpos;
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if (ttUSHORT(data+0) != 1) return 0; // Major version 1
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if (ttUSHORT(data+2) != 0) return 0; // Minor version 0
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stbtt_uint16 lookupListOffset = ttUSHORT(data+8);
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stbtt_uint8 *lookupList = data + lookupListOffset;
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stbtt_uint16 lookupCount = ttUSHORT(lookupList);
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for (stbtt_int32 i=0; i<lookupCount; ++i) {
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stbtt_uint16 lookupOffset = ttUSHORT(lookupList + 2 + 2 * i);
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stbtt_uint8 *lookupTable = lookupList + lookupOffset;
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stbtt_uint16 lookupType = ttUSHORT(lookupTable);
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stbtt_uint16 subTableCount = ttUSHORT(lookupTable + 4);
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stbtt_uint8 *subTableOffsets = lookupTable + 6;
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switch(lookupType) {
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case 2: { // Pair Adjustment Positioning Subtable
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for (stbtt_int32 sti=0; sti<subTableCount; sti++) {
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stbtt_uint16 subtableOffset = ttUSHORT(subTableOffsets + 2 * sti);
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stbtt_uint8 *table = lookupTable + subtableOffset;
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stbtt_uint16 posFormat = ttUSHORT(table);
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stbtt_uint16 coverageOffset = ttUSHORT(table + 2);
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stbtt_int32 coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1);
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if (coverageIndex == -1) continue;
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switch (posFormat) {
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case 1: {
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stbtt_uint16 valueFormat1 = ttUSHORT(table + 4);
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stbtt_uint16 valueFormat2 = ttUSHORT(table + 6);
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// TODO: Support more formats.
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STBTT_GPOS_TODO_assert(valueFormat1 == 4);
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if (valueFormat1 != 4) return 0;
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STBTT_GPOS_TODO_assert(valueFormat2 == 0);
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if (valueFormat2 != 0) return 0;
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stbtt_int32 valueRecordPairSizeInBytes = 2;
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stbtt_uint16 pairSetCount = ttUSHORT(table + 8);
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STBTT_assert(coverageIndex < pairSetCount);
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stbtt_uint16 pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex);
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stbtt_uint8 *pairValueTable = table + pairPosOffset;
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stbtt_uint16 pairValueCount = ttUSHORT(pairValueTable);
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stbtt_uint8 *pairValueArray = pairValueTable + 2;
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// Binary search.
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stbtt_int32 l=0, r=pairValueCount-1, m;
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int straw, needle=glyph2;
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while (l <= r) {
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m = (l + r) >> 1;
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stbtt_uint8 *pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m;
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stbtt_uint16 secondGlyph = ttUSHORT(pairValue);
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straw = secondGlyph;
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if (needle < straw)
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r = m - 1;
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else if (needle > straw)
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l = m + 1;
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else {
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stbtt_int16 xAdvance = ttSHORT(pairValue + 2);
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return xAdvance;
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}
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}
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} break;
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case 2: {
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stbtt_uint16 valueFormat1 = ttUSHORT(table + 4);
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stbtt_uint16 valueFormat2 = ttUSHORT(table + 6);
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// TODO: Support more formats.
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STBTT_GPOS_TODO_assert(valueFormat1 == 4);
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if (valueFormat1 != 4) return 0;
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STBTT_GPOS_TODO_assert(valueFormat2 == 0);
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if (valueFormat2 != 0) return 0;
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stbtt_uint16 classDef1Offset = ttUSHORT(table + 8);
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stbtt_uint16 classDef2Offset = ttUSHORT(table + 10);
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int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1);
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int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2);
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stbtt_uint16 class1Count = ttUSHORT(table + 12);
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stbtt_uint16 class2Count = ttUSHORT(table + 14);
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STBTT_assert(glyph1class < class1Count);
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STBTT_assert(glyph2class < class2Count);
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if (glyph1class >= 0 && glyph1class < class1Count && glyph2class >= 0 && glyph2class < class2Count) {
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stbtt_uint8 *class1Records = table + 16;
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stbtt_uint8 *class2Records = class1Records + 2 * (glyph1class * class2Count);
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stbtt_int16 xAdvance = ttSHORT(class2Records + 2 * glyph2class);
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return xAdvance;
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}
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} break;
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default: {
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// There are no other cases.
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STBTT_assert(false);
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} break;
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}
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}
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} break;
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default: {
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// TODO: Implement other stuff.
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} break;
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}
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}
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return 0;
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}
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STBTT_DEF int stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int g1, int g2)
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{
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int xAdvance = 0;
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if (info->gpos)
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xAdvance += stbtt__GetGlyphGPOSInfoAdvance(info, g1, g2);
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if (info->kern)
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xAdvance += stbtt__GetGlyphKernInfoAdvance(info, g1, g2);
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return xAdvance;
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}
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STBTT_DEF int stbtt_GetCodepointKernAdvance(const stbtt_fontinfo *info, int ch1, int ch2)
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{
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if (!info->kern) // if no kerning table, don't waste time looking up both codepoint->glyphs
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if (!info->kern && !info->gpos) // if no kerning table, don't waste time looking up both codepoint->glyphs
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return 0;
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return stbtt_GetGlyphKernAdvance(info, stbtt_FindGlyphIndex(info,ch1), stbtt_FindGlyphIndex(info,ch2));
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}
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