FontCollection.cpp revision bb601b67dd05947f92cc23092bfb8a059c2e3377
1/* 2 * Copyright (C) 2013 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// #define VERBOSE_DEBUG 18 19#define LOG_TAG "Minikin" 20#include <cutils/log.h> 21 22#include "MinikinInternal.h" 23#include <minikin/CmapCoverage.h> 24#include <minikin/FontCollection.h> 25 26using std::vector; 27 28namespace android { 29 30template <typename T> 31static inline T max(T a, T b) { 32 return a>b ? a : b; 33} 34 35uint32_t FontCollection::sNextId = 0; 36 37FontCollection::FontCollection(const vector<FontFamily*>& typefaces) : 38 mMaxChar(0) { 39 AutoMutex _l(gMinikinLock); 40 mId = sNextId++; 41 vector<uint32_t> lastChar; 42 size_t nTypefaces = typefaces.size(); 43#ifdef VERBOSE_DEBUG 44 ALOGD("nTypefaces = %d\n", nTypefaces); 45#endif 46 const FontStyle defaultStyle; 47 for (size_t i = 0; i < nTypefaces; i++) { 48 FontFamily* family = typefaces[i]; 49 MinikinFont* typeface = family->getClosestMatch(defaultStyle).font; 50 if (typeface == NULL) { 51 ALOGE("FontCollection: closest match was null"); 52 // TODO: we shouldn't hit this, as there should be more robust 53 // checks upstream to prevent empty/invalid FontFamily objects 54 continue; 55 } 56 family->RefLocked(); 57 FontInstance dummy; 58 mInstances.push_back(dummy); // emplace_back would be better 59 FontInstance* instance = &mInstances.back(); 60 instance->mFamily = family; 61 instance->mCoverage = new SparseBitSet; 62#ifdef VERBOSE_DEBUG 63 ALOGD("closest match = %p, family size = %d\n", typeface, family->getNumFonts()); 64#endif 65 const uint32_t cmapTag = MinikinFont::MakeTag('c', 'm', 'a', 'p'); 66 size_t cmapSize = 0; 67 bool ok = typeface->GetTable(cmapTag, NULL, &cmapSize); 68 UniquePtr<uint8_t[]> cmapData(new uint8_t[cmapSize]); 69 ok = typeface->GetTable(cmapTag, cmapData.get(), &cmapSize); 70 CmapCoverage::getCoverage(*instance->mCoverage, cmapData.get(), cmapSize); 71#ifdef VERBOSE_DEBUG 72 ALOGD("font coverage length=%d, first ch=%x\n", instance->mCoverage->length(), 73 instance->mCoverage->nextSetBit(0)); 74#endif 75 mMaxChar = max(mMaxChar, instance->mCoverage->length()); 76 lastChar.push_back(instance->mCoverage->nextSetBit(0)); 77 } 78 nTypefaces = mInstances.size(); 79 size_t nPages = (mMaxChar + kPageMask) >> kLogCharsPerPage; 80 size_t offset = 0; 81 for (size_t i = 0; i < nPages; i++) { 82 Range dummy; 83 mRanges.push_back(dummy); 84 Range* range = &mRanges.back(); 85#ifdef VERBOSE_DEBUG 86 ALOGD("i=%d: range start = %d\n", i, offset); 87#endif 88 range->start = offset; 89 for (size_t j = 0; j < nTypefaces; j++) { 90 if (lastChar[j] < (i + 1) << kLogCharsPerPage) { 91 const FontInstance* instance = &mInstances[j]; 92 mInstanceVec.push_back(instance); 93 offset++; 94 uint32_t nextChar = instance->mCoverage->nextSetBit((i + 1) << kLogCharsPerPage); 95#ifdef VERBOSE_DEBUG 96 ALOGD("nextChar = %d (j = %d)\n", nextChar, j); 97#endif 98 lastChar[j] = nextChar; 99 } 100 } 101 range->end = offset; 102 } 103} 104 105FontCollection::~FontCollection() { 106 for (size_t i = 0; i < mInstances.size(); i++) { 107 delete mInstances[i].mCoverage; 108 mInstances[i].mFamily->UnrefLocked(); 109 } 110} 111 112// Implement heuristic for choosing best-match font. Here are the rules: 113// 1. If first font in the collection has the character, it wins. 114// 2. If a font matches both language and script, it gets a score of 4. 115// 3. If a font matches just language, it gets a score of 2. 116// 4. Matching the "compact" or "elegant" variant adds one to the score. 117// 5. Highest score wins, with ties resolved to the first font. 118const FontCollection::FontInstance* FontCollection::getInstanceForChar(uint32_t ch, 119 FontLanguage lang, int variant) const { 120 if (ch >= mMaxChar) { 121 return NULL; 122 } 123 const Range& range = mRanges[ch >> kLogCharsPerPage]; 124#ifdef VERBOSE_DEBUG 125 ALOGD("querying range %d:%d\n", range.start, range.end); 126#endif 127 const FontInstance* bestInstance = NULL; 128 int bestScore = -1; 129 for (size_t i = range.start; i < range.end; i++) { 130 const FontInstance* instance = mInstanceVec[i]; 131 if (instance->mCoverage->get(ch)) { 132 FontFamily* family = instance->mFamily; 133 // First font family in collection always matches 134 if (mInstances[0].mFamily == family) { 135 return instance; 136 } 137 int score = lang.match(family->lang()) * 2; 138 if (variant != 0 && variant == family->variant()) { 139 score++; 140 } 141 if (score > bestScore) { 142 bestScore = score; 143 bestInstance = instance; 144 } 145 } 146 } 147 return bestInstance; 148} 149 150const uint32_t NBSP = 0xa0; 151const uint32_t ZWJ = 0x200c; 152const uint32_t ZWNJ = 0x200d; 153// Characters where we want to continue using existing font run instead of 154// recomputing the best match in the fallback list. 155static const uint32_t stickyWhitelist[] = { '!', ',', '.', ':', ';', '?', NBSP, ZWJ, ZWNJ }; 156 157static bool isStickyWhitelisted(uint32_t c) { 158 for (size_t i = 0; i < sizeof(stickyWhitelist) / sizeof(stickyWhitelist[0]); i++) { 159 if (stickyWhitelist[i] == c) return true; 160 } 161 return false; 162} 163 164void FontCollection::itemize(const uint16_t *string, size_t string_size, FontStyle style, 165 vector<Run>* result) const { 166 FontLanguage lang = style.getLanguage(); 167 int variant = style.getVariant(); 168 const FontInstance* lastInstance = NULL; 169 Run* run = NULL; 170 int nShorts; 171 for (size_t i = 0; i < string_size; i += nShorts) { 172 nShorts = 1; 173 uint32_t ch = string[i]; 174 // sigh, decode UTF-16 by hand here 175 if ((ch & 0xfc00) == 0xd800) { 176 if ((i + 1) < string_size) { 177 ch = 0x10000 + ((ch & 0x3ff) << 10) + (string[i + 1] & 0x3ff); 178 nShorts = 2; 179 } 180 } 181 // Continue using existing font as long as it has coverage and is whitelisted 182 if (lastInstance == NULL 183 || !(isStickyWhitelisted(ch) && lastInstance->mCoverage->get(ch))) { 184 const FontInstance* instance = getInstanceForChar(ch, lang, variant); 185 if (i == 0 || instance != lastInstance) { 186 Run dummy; 187 result->push_back(dummy); 188 run = &result->back(); 189 if (instance == NULL) { 190 run->fakedFont.font = NULL; 191 } else { 192 run->fakedFont = instance->mFamily->getClosestMatch(style); 193 } 194 lastInstance = instance; 195 run->start = i; 196 } 197 } 198 run->end = i + nShorts; 199 } 200} 201 202MinikinFont* FontCollection::baseFont(FontStyle style) { 203 return baseFontFaked(style).font; 204} 205 206FakedFont FontCollection::baseFontFaked(FontStyle style) { 207 if (mInstances.empty()) { 208 return FakedFont(); 209 } 210 return mInstances[0].mFamily->getClosestMatch(style); 211} 212 213uint32_t FontCollection::getId() const { 214 return mId; 215} 216 217} // namespace android 218