1/* 2 * Copyright (C) 2009 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#include "SkHarfBuzzFont.h" 18#include "SkFontHost.h" 19#include "SkPaint.h" 20#include "SkPath.h" 21 22// HB_Fixed is a 26.6 fixed point format. 23static inline HB_Fixed SkScalarToHarfbuzzFixed(SkScalar value) { 24#ifdef SK_SCALAR_IS_FLOAT 25 return static_cast<HB_Fixed>(value * 64); 26#else 27 // convert .16 to .6 28 return value >> (16 - 6); 29#endif 30} 31 32static HB_Bool stringToGlyphs(HB_Font hbFont, const HB_UChar16* characters, 33 hb_uint32 length, HB_Glyph* glyphs, 34 hb_uint32* glyphsSize, HB_Bool isRTL) { 35 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 36 SkPaint paint; 37 38 paint.setTypeface(font->getTypeface()); 39 paint.setTextEncoding(SkPaint::kUTF16_TextEncoding); 40 int numGlyphs = paint.textToGlyphs(characters, length * sizeof(uint16_t), 41 reinterpret_cast<uint16_t*>(glyphs)); 42 43 // HB_Glyph is 32-bit, but Skia outputs only 16-bit numbers. So our 44 // |glyphs| array needs to be converted. 45 for (int i = numGlyphs - 1; i >= 0; --i) { 46 uint16_t value; 47 // We use a memcpy to avoid breaking strict aliasing rules. 48 memcpy(&value, reinterpret_cast<char*>(glyphs) + sizeof(uint16_t) * i, sizeof(uint16_t)); 49 glyphs[i] = value; 50 } 51 52 *glyphsSize = numGlyphs; 53 return 1; 54} 55 56static void glyphsToAdvances(HB_Font hbFont, const HB_Glyph* glyphs, 57 hb_uint32 numGlyphs, HB_Fixed* advances, int flags) { 58 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 59 SkPaint paint; 60 61 font->setupPaint(&paint); 62 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); 63 64 SkAutoMalloc storage(numGlyphs * (sizeof(SkScalar) + sizeof(uint16_t))); 65 SkScalar* scalarWidths = reinterpret_cast<SkScalar*>(storage.get()); 66 uint16_t* glyphs16 = reinterpret_cast<uint16_t*>(scalarWidths + numGlyphs); 67 68 // convert HB 32bit glyphs to skia's 16bit 69 for (hb_uint32 i = 0; i < numGlyphs; ++i) { 70 glyphs16[i] = SkToU16(glyphs[i]); 71 } 72 paint.getTextWidths(glyphs16, numGlyphs * sizeof(uint16_t), scalarWidths); 73 74 for (hb_uint32 i = 0; i < numGlyphs; ++i) { 75 advances[i] = SkScalarToHarfbuzzFixed(scalarWidths[i]); 76 } 77} 78 79static HB_Bool canRender(HB_Font hbFont, const HB_UChar16* characters, 80 hb_uint32 length) { 81 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 82 SkPaint paint; 83 84 paint.setTypeface(font->getTypeface()); 85 paint.setTextEncoding(SkPaint::kUTF16_TextEncoding); 86 return paint.containsText(characters, length * sizeof(uint16_t)); 87} 88 89static HB_Error getOutlinePoint(HB_Font hbFont, HB_Glyph glyph, int flags, 90 hb_uint32 index, HB_Fixed* xPos, HB_Fixed* yPos, 91 hb_uint32* resultingNumPoints) { 92 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 93 SkPaint paint; 94 95 font->setupPaint(&paint); 96 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); 97 if (flags & HB_ShaperFlag_UseDesignMetrics) { 98 paint.setHinting(SkPaint::kNo_Hinting); 99 } 100 101 SkPath path; 102 uint16_t glyph16 = SkToU16(glyph); 103 paint.getTextPath(&glyph16, sizeof(glyph16), 0, 0, &path); 104 int numPoints = path.countPoints(); 105 if (index >= numPoints) { 106 return HB_Err_Invalid_SubTable; 107 } 108 109 SkPoint pt = path.getPoint(index); 110 *xPos = SkScalarToHarfbuzzFixed(pt.fX); 111 *yPos = SkScalarToHarfbuzzFixed(pt.fY); 112 *resultingNumPoints = numPoints; 113 114 return HB_Err_Ok; 115} 116 117static void getGlyphMetrics(HB_Font hbFont, HB_Glyph glyph, 118 HB_GlyphMetrics* metrics) { 119 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 120 SkPaint paint; 121 122 font->setupPaint(&paint); 123 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding); 124 125 SkScalar width; 126 SkRect bounds; 127 uint16_t glyph16 = SkToU16(glyph); 128 paint.getTextWidths(&glyph16, sizeof(glyph16), &width, &bounds); 129 130 metrics->x = SkScalarToHarfbuzzFixed(bounds.fLeft); 131 metrics->y = SkScalarToHarfbuzzFixed(bounds.fTop); 132 metrics->width = SkScalarToHarfbuzzFixed(bounds.width()); 133 metrics->height = SkScalarToHarfbuzzFixed(bounds.height()); 134 135 metrics->xOffset = SkScalarToHarfbuzzFixed(width); 136 // We can't actually get the |y| correct because Skia doesn't export 137 // the vertical advance. However, nor we do ever render vertical text at 138 // the moment so it's unimportant. 139 metrics->yOffset = 0; 140} 141 142static HB_Fixed getFontMetric(HB_Font hbFont, HB_FontMetric metric) 143{ 144 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(hbFont->userData); 145 SkPaint paint; 146 SkPaint::FontMetrics skiaMetrics; 147 148 font->setupPaint(&paint); 149 paint.getFontMetrics(&skiaMetrics); 150 151 switch (metric) { 152 case HB_FontAscent: 153 return SkScalarToHarfbuzzFixed(-skiaMetrics.fAscent); 154 default: 155 SkDebugf("--- unknown harfbuzz metric enum %d\n", metric); 156 return 0; 157 } 158} 159 160static HB_FontClass gSkHarfBuzzFontClass = { 161 stringToGlyphs, 162 glyphsToAdvances, 163 canRender, 164 getOutlinePoint, 165 getGlyphMetrics, 166 getFontMetric, 167}; 168 169const HB_FontClass& SkHarfBuzzFont::GetFontClass() { 170 return gSkHarfBuzzFontClass; 171} 172 173HB_Error SkHarfBuzzFont::GetFontTableFunc(void* voidface, const HB_Tag tag, 174 HB_Byte* buffer, HB_UInt* len) { 175 SkHarfBuzzFont* font = reinterpret_cast<SkHarfBuzzFont*>(voidface); 176 uint32_t uniqueID = SkTypeface::UniqueID(font->getTypeface()); 177 178 const size_t tableSize = SkFontHost::GetTableSize(uniqueID, tag); 179 if (!tableSize) { 180 return HB_Err_Invalid_Argument; 181 } 182 // If Harfbuzz specified a NULL buffer then it's asking for the size. 183 if (!buffer) { 184 *len = tableSize; 185 return HB_Err_Ok; 186 } 187 188 if (*len < tableSize) { 189 // is this right, or should we just copy less than the full table? 190 return HB_Err_Invalid_Argument; 191 } 192 SkFontHost::GetTableData(uniqueID, tag, 0, tableSize, buffer); 193 return HB_Err_Ok; 194} 195 196