diff options
| -rw-r--r-- | lib/stb_truetype.h | 624 |
1 files changed, 345 insertions, 279 deletions
diff --git a/lib/stb_truetype.h b/lib/stb_truetype.h index 62595a1..bbf2284 100644 --- a/lib/stb_truetype.h +++ b/lib/stb_truetype.h @@ -1,5 +1,5 @@ -// stb_truetype.h - v1.24 - public domain -// authored from 2009-2020 by Sean Barrett / RAD Game Tools +// stb_truetype.h - v1.26 - public domain +// authored from 2009-2021 by Sean Barrett / RAD Game Tools // // ======================================================================= // @@ -58,6 +58,8 @@ // // VERSION HISTORY // +// 1.26 (2021-08-28) fix broken rasterizer +// 1.25 (2021-07-11) many fixes // 1.24 (2020-02-05) fix warning // 1.23 (2020-02-02) query SVG data for glyphs; query whole kerning table (but only kern not GPOS) // 1.22 (2019-08-11) minimize missing-glyph duplication; fix kerning if both 'GPOS' and 'kern' are defined @@ -270,8 +272,8 @@ //// SAMPLE PROGRAMS //// // -// Incomplete text-in-3d-api example, which draws quads properly aligned to be lossless -// +// Incomplete text-in-3d-api example, which draws quads properly aligned to be lossless. +// See "tests/truetype_demo_win32.c" for a complete version. #if 0 #define STB_TRUETYPE_IMPLEMENTATION // force following include to generate implementation #include "stb_truetype.h" @@ -297,6 +299,8 @@ void my_stbtt_initfont(void) void my_stbtt_print(float x, float y, char *text) { // assume orthographic projection with units = screen pixels, origin at top left + glEnable(GL_BLEND); + glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glEnable(GL_TEXTURE_2D); glBindTexture(GL_TEXTURE_2D, ftex); glBegin(GL_QUADS); @@ -304,10 +308,10 @@ void my_stbtt_print(float x, float y, char *text) if (*text >= 32 && *text < 128) { stbtt_aligned_quad q; stbtt_GetBakedQuad(cdata, 512,512, *text-32, &x,&y,&q,1);//1=opengl & d3d10+,0=d3d9 - glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y0); - glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y0); - glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y1); - glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y1); + glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y0); + glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y0); + glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y1); + glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y1); } ++text; } @@ -853,6 +857,7 @@ STBTT_DEF int stbtt_GetGlyphShape(const stbtt_fontinfo *info, int glyph_index, s STBTT_DEF void stbtt_FreeShape(const stbtt_fontinfo *info, stbtt_vertex *vertices); // frees the data allocated above +STBTT_DEF unsigned char *stbtt_FindSVGDoc(const stbtt_fontinfo *info, int gl); STBTT_DEF int stbtt_GetCodepointSVG(const stbtt_fontinfo *info, int unicode_codepoint, const char **svg); STBTT_DEF int stbtt_GetGlyphSVG(const stbtt_fontinfo *info, int gl, const char **svg); // fills svg with the character's SVG data. @@ -1539,12 +1544,12 @@ STBTT_DEF int stbtt_FindGlyphIndex(const stbtt_fontinfo *info, int unicode_codep search += 2; { - stbtt_uint16 offset, start; + stbtt_uint16 offset, start, last; stbtt_uint16 item = (stbtt_uint16) ((search - endCount) >> 1); - STBTT_assert(unicode_codepoint <= ttUSHORT(data + endCount + 2*item)); start = ttUSHORT(data + index_map + 14 + segcount*2 + 2 + 2*item); - if (unicode_codepoint < start) + last = ttUSHORT(data + endCount + 2*item); + if (unicode_codepoint < start || unicode_codepoint > last) return 0; offset = ttUSHORT(data + index_map + 14 + segcount*6 + 2 + 2*item); @@ -1871,7 +1876,7 @@ static int stbtt__GetGlyphShapeTT(const stbtt_fontinfo *info, int glyph_index, s if (comp_verts) STBTT_free(comp_verts, info->userdata); return 0; } - if (num_vertices > 0) STBTT_memcpy(tmp, vertices, num_vertices*sizeof(stbtt_vertex)); + if (num_vertices > 0 && vertices) STBTT_memcpy(tmp, vertices, num_vertices*sizeof(stbtt_vertex)); STBTT_memcpy(tmp+num_vertices, comp_verts, comp_num_verts*sizeof(stbtt_vertex)); if (vertices) STBTT_free(vertices, info->userdata); vertices = tmp; @@ -2134,7 +2139,7 @@ static int stbtt__run_charstring(const stbtt_fontinfo *info, int glyph_index, st subrs = stbtt__cid_get_glyph_subrs(info, glyph_index); has_subrs = 1; } - // fallthrough + // FALLTHROUGH case 0x1D: // callgsubr if (sp < 1) return STBTT__CSERR("call(g|)subr stack"); v = (int) s[--sp]; @@ -2239,7 +2244,7 @@ static int stbtt__run_charstring(const stbtt_fontinfo *info, int glyph_index, st } break; default: - if (b0 != 255 && b0 != 28 && (b0 < 32 || b0 > 254)) + if (b0 != 255 && b0 != 28 && b0 < 32) return STBTT__CSERR("reserved operator"); // push immediate @@ -2351,7 +2356,7 @@ STBTT_DEF int stbtt_GetKerningTable(const stbtt_fontinfo *info, stbtt_kerningent return length; } -static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2) +static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2) { stbtt_uint8 *data = info->data + info->kern; stbtt_uint32 needle, straw; @@ -2381,243 +2386,225 @@ static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph return 0; } -static stbtt_int32 stbtt__GetCoverageIndex(stbtt_uint8 *coverageTable, int glyph) -{ - stbtt_uint16 coverageFormat = ttUSHORT(coverageTable); - switch(coverageFormat) { - case 1: { - stbtt_uint16 glyphCount = ttUSHORT(coverageTable + 2); - - // Binary search. - stbtt_int32 l=0, r=glyphCount-1, m; - int straw, needle=glyph; - while (l <= r) { - stbtt_uint8 *glyphArray = coverageTable + 4; - stbtt_uint16 glyphID; - m = (l + r) >> 1; - glyphID = ttUSHORT(glyphArray + 2 * m); - straw = glyphID; - if (needle < straw) - r = m - 1; - else if (needle > straw) - l = m + 1; - else { - return m; - } +static stbtt_int32 stbtt__GetCoverageIndex(stbtt_uint8 *coverageTable, int glyph) +{ + stbtt_uint16 coverageFormat = ttUSHORT(coverageTable); + switch (coverageFormat) { + case 1: { + stbtt_uint16 glyphCount = ttUSHORT(coverageTable + 2); + + // Binary search. + stbtt_int32 l=0, r=glyphCount-1, m; + int straw, needle=glyph; + while (l <= r) { + stbtt_uint8 *glyphArray = coverageTable + 4; + stbtt_uint16 glyphID; + m = (l + r) >> 1; + glyphID = ttUSHORT(glyphArray + 2 * m); + straw = glyphID; + if (needle < straw) + r = m - 1; + else if (needle > straw) + l = m + 1; + else { + return m; } - } break; - - case 2: { - stbtt_uint16 rangeCount = ttUSHORT(coverageTable + 2); - stbtt_uint8 *rangeArray = coverageTable + 4; - - // Binary search. - stbtt_int32 l=0, r=rangeCount-1, m; - int strawStart, strawEnd, needle=glyph; - while (l <= r) { - stbtt_uint8 *rangeRecord; - m = (l + r) >> 1; - rangeRecord = rangeArray + 6 * m; - strawStart = ttUSHORT(rangeRecord); - strawEnd = ttUSHORT(rangeRecord + 2); - if (needle < strawStart) - r = m - 1; - else if (needle > strawEnd) - l = m + 1; - else { - stbtt_uint16 startCoverageIndex = ttUSHORT(rangeRecord + 4); - return startCoverageIndex + glyph - strawStart; - } + } + break; + } + + case 2: { + stbtt_uint16 rangeCount = ttUSHORT(coverageTable + 2); + stbtt_uint8 *rangeArray = coverageTable + 4; + + // Binary search. + stbtt_int32 l=0, r=rangeCount-1, m; + int strawStart, strawEnd, needle=glyph; + while (l <= r) { + stbtt_uint8 *rangeRecord; + m = (l + r) >> 1; + rangeRecord = rangeArray + 6 * m; + strawStart = ttUSHORT(rangeRecord); + strawEnd = ttUSHORT(rangeRecord + 2); + if (needle < strawStart) + r = m - 1; + else if (needle > strawEnd) + l = m + 1; + else { + stbtt_uint16 startCoverageIndex = ttUSHORT(rangeRecord + 4); + return startCoverageIndex + glyph - strawStart; } - } break; + } + break; + } - default: { - // There are no other cases. - STBTT_assert(0); - } break; - } + default: return -1; // unsupported + } - return -1; + return -1; } static stbtt_int32 stbtt__GetGlyphClass(stbtt_uint8 *classDefTable, int glyph) { - stbtt_uint16 classDefFormat = ttUSHORT(classDefTable); - switch(classDefFormat) - { - case 1: { - stbtt_uint16 startGlyphID = ttUSHORT(classDefTable + 2); - stbtt_uint16 glyphCount = ttUSHORT(classDefTable + 4); - stbtt_uint8 *classDef1ValueArray = classDefTable + 6; - - if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount) - return (stbtt_int32)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID)); - - classDefTable = classDef1ValueArray + 2 * glyphCount; - } break; - - case 2: { - stbtt_uint16 classRangeCount = ttUSHORT(classDefTable + 2); - stbtt_uint8 *classRangeRecords = classDefTable + 4; - - // Binary search. - stbtt_int32 l=0, r=classRangeCount-1, m; - int strawStart, strawEnd, needle=glyph; - while (l <= r) { - stbtt_uint8 *classRangeRecord; - m = (l + r) >> 1; - classRangeRecord = classRangeRecords + 6 * m; - strawStart = ttUSHORT(classRangeRecord); - strawEnd = ttUSHORT(classRangeRecord + 2); - if (needle < strawStart) - r = m - 1; - else if (needle > strawEnd) - l = m + 1; - else - return (stbtt_int32)ttUSHORT(classRangeRecord + 4); - } + stbtt_uint16 classDefFormat = ttUSHORT(classDefTable); + switch (classDefFormat) + { + case 1: { + stbtt_uint16 startGlyphID = ttUSHORT(classDefTable + 2); + stbtt_uint16 glyphCount = ttUSHORT(classDefTable + 4); + stbtt_uint8 *classDef1ValueArray = classDefTable + 6; - classDefTable = classRangeRecords + 6 * classRangeCount; - } break; + if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount) + return (stbtt_int32)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID)); + break; + } - default: { - // There are no other cases. - STBTT_assert(0); - } break; - } + case 2: { + stbtt_uint16 classRangeCount = ttUSHORT(classDefTable + 2); + stbtt_uint8 *classRangeRecords = classDefTable + 4; + + // Binary search. + stbtt_int32 l=0, r=classRangeCount-1, m; + int strawStart, strawEnd, needle=glyph; + while (l <= r) { + stbtt_uint8 *classRangeRecord; + m = (l + r) >> 1; + classRangeRecord = classRangeRecords + 6 * m; + strawStart = ttUSHORT(classRangeRecord); + strawEnd = ttUSHORT(classRangeRecord + 2); + if (needle < strawStart) + r = m - 1; + else if (needle > strawEnd) + l = m + 1; + else + return (stbtt_int32)ttUSHORT(classRangeRecord + 4); + } + break; + } - return -1; + default: + return -1; // Unsupported definition type, return an error. + } + + // "All glyphs not assigned to a class fall into class 0". (OpenType spec) + return 0; } // Define to STBTT_assert(x) if you want to break on unimplemented formats. #define STBTT_GPOS_TODO_assert(x) -static stbtt_int32 stbtt__GetGlyphGPOSInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2) -{ - stbtt_uint16 lookupListOffset; - stbtt_uint8 *lookupList; - stbtt_uint16 lookupCount; - stbtt_uint8 *data; - stbtt_int32 i; - - if (!info->gpos) return 0; - - data = info->data + info->gpos; - - if (ttUSHORT(data+0) != 1) return 0; // Major version 1 - if (ttUSHORT(data+2) != 0) return 0; // Minor version 0 - - lookupListOffset = ttUSHORT(data+8); - lookupList = data + lookupListOffset; - lookupCount = ttUSHORT(lookupList); - - for (i=0; i<lookupCount; ++i) { - stbtt_uint16 lookupOffset = ttUSHORT(lookupList + 2 + 2 * i); - stbtt_uint8 *lookupTable = lookupList + lookupOffset; - - stbtt_uint16 lookupType = ttUSHORT(lookupTable); - stbtt_uint16 subTableCount = ttUSHORT(lookupTable + 4); - stbtt_uint8 *subTableOffsets = lookupTable + 6; - switch(lookupType) { - case 2: { // Pair Adjustment Positioning Subtable - stbtt_int32 sti; - for (sti=0; sti<subTableCount; sti++) { - stbtt_uint16 subtableOffset = ttUSHORT(subTableOffsets + 2 * sti); - stbtt_uint8 *table = lookupTable + subtableOffset; - stbtt_uint16 posFormat = ttUSHORT(table); - stbtt_uint16 coverageOffset = ttUSHORT(table + 2); - stbtt_int32 coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1); - if (coverageIndex == -1) continue; - - switch (posFormat) { - case 1: { - stbtt_int32 l, r, m; - int straw, needle; - stbtt_uint16 valueFormat1 = ttUSHORT(table + 4); - stbtt_uint16 valueFormat2 = ttUSHORT(table + 6); - stbtt_int32 valueRecordPairSizeInBytes = 2; - stbtt_uint16 pairSetCount = ttUSHORT(table + 8); - stbtt_uint16 pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex); - stbtt_uint8 *pairValueTable = table + pairPosOffset; - stbtt_uint16 pairValueCount = ttUSHORT(pairValueTable); - stbtt_uint8 *pairValueArray = pairValueTable + 2; - // TODO: Support more formats. - STBTT_GPOS_TODO_assert(valueFormat1 == 4); - if (valueFormat1 != 4) return 0; - STBTT_GPOS_TODO_assert(valueFormat2 == 0); - if (valueFormat2 != 0) return 0; - - STBTT_assert(coverageIndex < pairSetCount); - STBTT__NOTUSED(pairSetCount); - - needle=glyph2; - r=pairValueCount-1; - l=0; - - // Binary search. - while (l <= r) { - stbtt_uint16 secondGlyph; - stbtt_uint8 *pairValue; - m = (l + r) >> 1; - pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m; - secondGlyph = ttUSHORT(pairValue); - straw = secondGlyph; - if (needle < straw) - r = m - 1; - else if (needle > straw) - l = m + 1; - else { - stbtt_int16 xAdvance = ttSHORT(pairValue + 2); - return xAdvance; - } - } - } break; - - case 2: { - stbtt_uint16 valueFormat1 = ttUSHORT(table + 4); - stbtt_uint16 valueFormat2 = ttUSHORT(table + 6); - - stbtt_uint16 classDef1Offset = ttUSHORT(table + 8); - stbtt_uint16 classDef2Offset = ttUSHORT(table + 10); - int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1); - int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2); - - stbtt_uint16 class1Count = ttUSHORT(table + 12); - stbtt_uint16 class2Count = ttUSHORT(table + 14); - STBTT_assert(glyph1class < class1Count); - STBTT_assert(glyph2class < class2Count); - - // TODO: Support more formats. - STBTT_GPOS_TODO_assert(valueFormat1 == 4); - if (valueFormat1 != 4) return 0; - STBTT_GPOS_TODO_assert(valueFormat2 == 0); - if (valueFormat2 != 0) return 0; - - if (glyph1class >= 0 && glyph1class < class1Count && glyph2class >= 0 && glyph2class < class2Count) { - stbtt_uint8 *class1Records = table + 16; - stbtt_uint8 *class2Records = class1Records + 2 * (glyph1class * class2Count); - stbtt_int16 xAdvance = ttSHORT(class2Records + 2 * glyph2class); - return xAdvance; - } - } break; - - default: { - // There are no other cases. - STBTT_assert(0); - break; - }; - } - } - break; - }; +static stbtt_int32 stbtt__GetGlyphGPOSInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2) +{ + stbtt_uint16 lookupListOffset; + stbtt_uint8 *lookupList; + stbtt_uint16 lookupCount; + stbtt_uint8 *data; + stbtt_int32 i, sti; + + if (!info->gpos) return 0; + + data = info->data + info->gpos; + + if (ttUSHORT(data+0) != 1) return 0; // Major version 1 + if (ttUSHORT(data+2) != 0) return 0; // Minor version 0 + + lookupListOffset = ttUSHORT(data+8); + lookupList = data + lookupListOffset; + lookupCount = ttUSHORT(lookupList); + + for (i=0; i<lookupCount; ++i) { + stbtt_uint16 lookupOffset = ttUSHORT(lookupList + 2 + 2 * i); + stbtt_uint8 *lookupTable = lookupList + lookupOffset; + + stbtt_uint16 lookupType = ttUSHORT(lookupTable); + stbtt_uint16 subTableCount = ttUSHORT(lookupTable + 4); + stbtt_uint8 *subTableOffsets = lookupTable + 6; + if (lookupType != 2) // Pair Adjustment Positioning Subtable + continue; + + for (sti=0; sti<subTableCount; sti++) { + stbtt_uint16 subtableOffset = ttUSHORT(subTableOffsets + 2 * sti); + stbtt_uint8 *table = lookupTable + subtableOffset; + stbtt_uint16 posFormat = ttUSHORT(table); + stbtt_uint16 coverageOffset = ttUSHORT(table + 2); + stbtt_int32 coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1); + if (coverageIndex == -1) continue; + + switch (posFormat) { + case 1: { + stbtt_int32 l, r, m; + int straw, needle; + stbtt_uint16 valueFormat1 = ttUSHORT(table + 4); + stbtt_uint16 valueFormat2 = ttUSHORT(table + 6); + if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats? + stbtt_int32 valueRecordPairSizeInBytes = 2; + stbtt_uint16 pairSetCount = ttUSHORT(table + 8); + stbtt_uint16 pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex); + stbtt_uint8 *pairValueTable = table + pairPosOffset; + stbtt_uint16 pairValueCount = ttUSHORT(pairValueTable); + stbtt_uint8 *pairValueArray = pairValueTable + 2; + + if (coverageIndex >= pairSetCount) return 0; + + needle=glyph2; + r=pairValueCount-1; + l=0; + + // Binary search. + while (l <= r) { + stbtt_uint16 secondGlyph; + stbtt_uint8 *pairValue; + m = (l + r) >> 1; + pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m; + secondGlyph = ttUSHORT(pairValue); + straw = secondGlyph; + if (needle < straw) + r = m - 1; + else if (needle > straw) + l = m + 1; + else { + stbtt_int16 xAdvance = ttSHORT(pairValue + 2); + return xAdvance; + } + } + } else + return 0; + break; + } + + case 2: { + stbtt_uint16 valueFormat1 = ttUSHORT(table + 4); + stbtt_uint16 valueFormat2 = ttUSHORT(table + 6); + if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats? + stbtt_uint16 classDef1Offset = ttUSHORT(table + 8); + stbtt_uint16 classDef2Offset = ttUSHORT(table + 10); + int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1); + int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2); + + stbtt_uint16 class1Count = ttUSHORT(table + 12); + stbtt_uint16 class2Count = ttUSHORT(table + 14); + stbtt_uint8 *class1Records, *class2Records; + stbtt_int16 xAdvance; + + if (glyph1class < 0 || glyph1class >= class1Count) return 0; // malformed + if (glyph2class < 0 || glyph2class >= class2Count) return 0; // malformed + + class1Records = table + 16; + class2Records = class1Records + 2 * (glyph1class * class2Count); + xAdvance = ttSHORT(class2Records + 2 * glyph2class); + return xAdvance; + } else + return 0; + break; + } default: - // TODO: Implement other stuff. - break; - } - } + return 0; // Unsupported position format + } + } + } - return 0; + return 0; } STBTT_DEF int stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int g1, int g2) @@ -3075,6 +3062,23 @@ static void stbtt__handle_clipped_edge(float *scanline, int x, stbtt__active_edg } } +static float stbtt__sized_trapezoid_area(float height, float top_width, float bottom_width) +{ + STBTT_assert(top_width >= 0); + STBTT_assert(bottom_width >= 0); + return (top_width + bottom_width) / 2.0f * height; +} + +static float stbtt__position_trapezoid_area(float height, float tx0, float tx1, float bx0, float bx1) +{ + return stbtt__sized_trapezoid_area(height, tx1 - tx0, bx1 - bx0); +} + +static float stbtt__sized_triangle_area(float height, float width) +{ + return height * width / 2; +} + static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, int len, stbtt__active_edge *e, float y_top) { float y_bottom = y_top+1; @@ -3129,13 +3133,13 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, float height; // simple case, only spans one pixel int x = (int) x_top; - height = sy1 - sy0; + height = (sy1 - sy0) * e->direction; STBTT_assert(x >= 0 && x < len); - scanline[x] += e->direction * (1-((x_top - x) + (x_bottom-x))/2) * height; - scanline_fill[x] += e->direction * height; // everything right of this pixel is filled + scanline[x] += stbtt__position_trapezoid_area(height, x_top, x+1.0f, x_bottom, x+1.0f); + scanline_fill[x] += height; // everything right of this pixel is filled } else { int x,x1,x2; - float y_crossing, step, sign, area; + float y_crossing, y_final, step, sign, area; // covers 2+ pixels if (x_top > x_bottom) { // flip scanline vertically; signed area is the same @@ -3148,29 +3152,79 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, dy = -dy; t = x0, x0 = xb, xb = t; } + STBTT_assert(dy >= 0); + STBTT_assert(dx >= 0); x1 = (int) x_top; x2 = (int) x_bottom; // compute intersection with y axis at x1+1 - y_crossing = (x1+1 - x0) * dy + y_top; + y_crossing = y_top + dy * (x1+1 - x0); + + // compute intersection with y axis at x2 + y_final = y_top + dy * (x2 - x0); + + // x1 x_top x2 x_bottom + // y_top +------|-----+------------+------------+--------|---+------------+ + // | | | | | | + // | | | | | | + // sy0 | Txxxxx|............|............|............|............| + // y_crossing | *xxxxx.......|............|............|............| + // | | xxxxx..|............|............|............| + // | | /- xx*xxxx........|............|............| + // | | dy < | xxxxxx..|............|............| + // y_final | | \- | xx*xxx.........|............| + // sy1 | | | | xxxxxB...|............| + // | | | | | | + // | | | | | | + // y_bottom +------------+------------+------------+------------+------------+ + // + // goal is to measure the area covered by '.' in each pixel + + // if x2 is right at the right edge of x1, y_crossing can blow up, github #1057 + // @TODO: maybe test against sy1 rather than y_bottom? + if (y_crossing > y_bottom) + y_crossing = y_bottom; sign = e->direction; - // area of the rectangle covered from y0..y_crossing + + // area of the rectangle covered from sy0..y_crossing area = sign * (y_crossing-sy0); - // area of the triangle (x_top,y0), (x+1,y0), (x+1,y_crossing) - scanline[x1] += area * (1-((x_top - x1)+(x1+1-x1))/2); - step = sign * dy; + // area of the triangle (x_top,sy0), (x1+1,sy0), (x1+1,y_crossing) + scanline[x1] += stbtt__sized_triangle_area(area, x1+1 - x_top); + + // check if final y_crossing is blown up; no test case for this + if (y_final > y_bottom) { + y_final = y_bottom; + dy = (y_final - y_crossing ) / (x2 - (x1+1)); // if denom=0, y_final = y_crossing, so y_final <= y_bottom + } + + // in second pixel, area covered by line segment found in first pixel + // is always a rectangle 1 wide * the height of that line segment; this + // is exactly what the variable 'area' stores. it also gets a contribution + // from the line segment within it. the THIRD pixel will get the first + // pixel's rectangle contribution, the second pixel's rectangle contribution, + // and its own contribution. the 'own contribution' is the same in every pixel except + // the leftmost and rightmost, a trapezoid that slides down in each pixel. + // the second pixel's contribution to the third pixel will be the + // rectangle 1 wide times the height change in the second pixel, which is dy. + + step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x, + // which multiplied by 1-pixel-width is how much pixel area changes for each step in x + // so the area advances by 'step' every time + for (x = x1+1; x < x2; ++x) { - scanline[x] += area + step/2; + scanline[x] += area + step/2; // area of trapezoid is 1*step/2 area += step; } - y_crossing += dy * (x2 - (x1+1)); - - STBTT_assert(STBTT_fabs(area) <= 1.01f); + STBTT_assert(STBTT_fabs(area) <= 1.01f); // accumulated error from area += step unless we round step down + STBTT_assert(sy1 > y_final-0.01f); - scanline[x2] += area + sign * (1-((x2-x2)+(x_bottom-x2))/2) * (sy1-y_crossing); + // area covered in the last pixel is the rectangle from all the pixels to the left, + // plus the trapezoid filled by the line segment in this pixel all the way to the right edge + scanline[x2] += area + sign * stbtt__position_trapezoid_area(sy1-y_final, (float) x2, x2+1.0f, x_bottom, x2+1.0f); + // the rest of the line is filled based on the total height of the line segment in this pixel scanline_fill[x2] += sign * (sy1-sy0); } } else { @@ -3178,6 +3232,9 @@ static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, // clipping logic. since this does not match the intended use // of this library, we use a different, very slow brute // force implementation + // note though that this does happen some of the time because + // x_top and x_bottom can be extrapolated at the top & bottom of + // the shape and actually lie outside the bounding box int x; for (x=0; x < len; ++x) { // cases: @@ -4414,15 +4471,14 @@ static int stbtt__compute_crossings_x(float x, float y, int nverts, stbtt_vertex float y_frac; int winding = 0; - orig[0] = x; - orig[1] = y; - // make sure y never passes through a vertex of the shape y_frac = (float) STBTT_fmod(y, 1.0f); if (y_frac < 0.01f) y += 0.01f; else if (y_frac > 0.99f) y -= 0.01f; + + orig[0] = x; orig[1] = y; // test a ray from (-infinity,y) to (x,y) @@ -4484,35 +4540,35 @@ static float stbtt__cuberoot( float x ) return (float) STBTT_pow( x,1.0f/3.0f); } -// x^3 + c*x^2 + b*x + a = 0 +// x^3 + a*x^2 + b*x + c = 0 static int stbtt__solve_cubic(float a, float b, float c, float* r) { - float s = -a / 3; - float p = b - a*a / 3; - float q = a * (2*a*a - 9*b) / 27 + c; + float s = -a / 3; + float p = b - a*a / 3; + float q = a * (2*a*a - 9*b) / 27 + c; float p3 = p*p*p; - float d = q*q + 4*p3 / 27; - if (d >= 0) { - float z = (float) STBTT_sqrt(d); - float u = (-q + z) / 2; - float v = (-q - z) / 2; - u = stbtt__cuberoot(u); - v = stbtt__cuberoot(v); - r[0] = s + u + v; - return 1; - } else { - float u = (float) STBTT_sqrt(-p/3); - float v = (float) STBTT_acos(-STBTT_sqrt(-27/p3) * q / 2) / 3; // p3 must be negative, since d is negative - float m = (float) STBTT_cos(v); + float d = q*q + 4*p3 / 27; + if (d >= 0) { + float z = (float) STBTT_sqrt(d); + float u = (-q + z) / 2; + float v = (-q - z) / 2; + u = stbtt__cuberoot(u); + v = stbtt__cuberoot(v); + r[0] = s + u + v; + return 1; + } else { + float u = (float) STBTT_sqrt(-p/3); + float v = (float) STBTT_acos(-STBTT_sqrt(-27/p3) * q / 2) / 3; // p3 must be negative, since d is negative + float m = (float) STBTT_cos(v); float n = (float) STBTT_cos(v-3.141592/2)*1.732050808f; - r[0] = s + u * 2 * m; - r[1] = s - u * (m + n); - r[2] = s - u * (m - n); + r[0] = s + u * 2 * m; + r[1] = s - u * (m + n); + r[2] = s - u * (m - n); //STBTT_assert( STBTT_fabs(((r[0]+a)*r[0]+b)*r[0]+c) < 0.05f); // these asserts may not be safe at all scales, though they're in bezier t parameter units so maybe? //STBTT_assert( STBTT_fabs(((r[1]+a)*r[1]+b)*r[1]+c) < 0.05f); //STBTT_assert( STBTT_fabs(((r[2]+a)*r[2]+b)*r[2]+c) < 0.05f); - return 3; + return 3; } } @@ -4589,18 +4645,17 @@ STBTT_DEF unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float sc for (i=0; i < num_verts; ++i) { float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y; - // check against every point here rather than inside line/curve primitives -- @TODO: wrong if multiple 'moves' in a row produce a garbage point, and given culling, probably more efficient to do within line/curve - float dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy); - if (dist2 < min_dist*min_dist) - min_dist = (float) STBTT_sqrt(dist2); - - if (verts[i].type == STBTT_vline) { + if (verts[i].type == STBTT_vline && precompute[i] != 0.0f) { float x1 = verts[i-1].x*scale_x, y1 = verts[i-1].y*scale_y; + float dist,dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy); + if (dist2 < min_dist*min_dist) + min_dist = (float) STBTT_sqrt(dist2); + // coarse culling against bbox //if (sx > STBTT_min(x0,x1)-min_dist && sx < STBTT_max(x0,x1)+min_dist && // sy > STBTT_min(y0,y1)-min_dist && sy < STBTT_max(y0,y1)+min_dist) - float dist = (float) STBTT_fabs((x1-x0)*(y0-sy) - (y1-y0)*(x0-sx)) * precompute[i]; + dist = (float) STBTT_fabs((x1-x0)*(y0-sy) - (y1-y0)*(x0-sx)) * precompute[i]; STBTT_assert(i != 0); if (dist < min_dist) { // check position along line @@ -4627,7 +4682,8 @@ STBTT_DEF unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float sc float ax = x1-x0, ay = y1-y0; float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2; float mx = x0 - sx, my = y0 - sy; - float res[3],px,py,t,it; + float res[3] = {0.f,0.f,0.f}; + float px,py,t,it,dist2; float a_inv = precompute[i]; if (a_inv == 0.0) { // if a_inv is 0, it's 2nd degree so use quadratic formula float a = 3*(ax*bx + ay*by); @@ -4654,6 +4710,10 @@ STBTT_DEF unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float sc float d = (mx*ax+my*ay) * a_inv; num = stbtt__solve_cubic(b, c, d, res); } + dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy); + if (dist2 < min_dist*min_dist) + min_dist = (float) STBTT_sqrt(dist2); + if (num >= 1 && res[0] >= 0.0f && res[0] <= 1.0f) { t = res[0], it = 1.0f - t; px = it*it*x0 + 2*t*it*x1 + t*t*x2; @@ -4913,6 +4973,12 @@ STBTT_DEF int stbtt_CompareUTF8toUTF16_bigendian(const char *s1, int len1, const // FULL VERSION HISTORY // +// 1.25 (2021-07-11) many fixes +// 1.24 (2020-02-05) fix warning +// 1.23 (2020-02-02) query SVG data for glyphs; query whole kerning table (but only kern not GPOS) +// 1.22 (2019-08-11) minimize missing-glyph duplication; fix kerning if both 'GPOS' and 'kern' are defined +// 1.21 (2019-02-25) fix warning +// 1.20 (2019-02-07) PackFontRange skips missing codepoints; GetScaleFontVMetrics() // 1.19 (2018-02-11) OpenType GPOS kerning (horizontal only), STBTT_fmod // 1.18 (2018-01-29) add missing function // 1.17 (2017-07-23) make more arguments const; doc fix |