FontCollection.cpp revision 80d113bcd4bbc395218503354af1a5a6dba59b4b
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 "unicode/unistr.h" 23#include "unicode/unorm2.h" 24 25#include "MinikinInternal.h" 26#include <minikin/FontCollection.h> 27 28using std::vector; 29 30namespace android { 31 32template <typename T> 33static inline T max(T a, T b) { 34 return a>b ? a : b; 35} 36 37uint32_t FontCollection::sNextId = 0; 38 39FontCollection::FontCollection(const vector<FontFamily*>& typefaces) : 40 mMaxChar(0) { 41 AutoMutex _l(gMinikinLock); 42 mId = sNextId++; 43 vector<uint32_t> lastChar; 44 size_t nTypefaces = typefaces.size(); 45#ifdef VERBOSE_DEBUG 46 ALOGD("nTypefaces = %zd\n", nTypefaces); 47#endif 48 const FontStyle defaultStyle; 49 for (size_t i = 0; i < nTypefaces; i++) { 50 FontFamily* family = typefaces[i]; 51 MinikinFont* typeface = family->getClosestMatch(defaultStyle).font; 52 if (typeface == NULL) { 53 continue; 54 } 55 family->RefLocked(); 56 const SparseBitSet* coverage = family->getCoverage(); 57 if (coverage == nullptr) { 58 family->UnrefLocked(); 59 continue; 60 } 61 mFamilies.push_back(family); // emplace_back would be better 62 mMaxChar = max(mMaxChar, coverage->length()); 63 lastChar.push_back(coverage->nextSetBit(0)); 64 } 65 nTypefaces = mFamilies.size(); 66 LOG_ALWAYS_FATAL_IF(nTypefaces == 0, 67 "Font collection must have at least one valid typeface"); 68 size_t nPages = (mMaxChar + kPageMask) >> kLogCharsPerPage; 69 size_t offset = 0; 70 // TODO: Use variation selector map for mRanges construction. 71 // A font can have a glyph for a base code point and variation selector pair but no glyph for 72 // the base code point without variation selector. The family won't be listed in the range in 73 // this case. 74 for (size_t i = 0; i < nPages; i++) { 75 Range dummy; 76 mRanges.push_back(dummy); 77 Range* range = &mRanges.back(); 78#ifdef VERBOSE_DEBUG 79 ALOGD("i=%zd: range start = %zd\n", i, offset); 80#endif 81 range->start = offset; 82 for (size_t j = 0; j < nTypefaces; j++) { 83 if (lastChar[j] < (i + 1) << kLogCharsPerPage) { 84 FontFamily* family = mFamilies[j]; 85 mFamilyVec.push_back(family); 86 offset++; 87 uint32_t nextChar = family->getCoverage()->nextSetBit((i + 1) << kLogCharsPerPage); 88#ifdef VERBOSE_DEBUG 89 ALOGD("nextChar = %d (j = %zd)\n", nextChar, j); 90#endif 91 lastChar[j] = nextChar; 92 } 93 } 94 range->end = offset; 95 } 96} 97 98FontCollection::~FontCollection() { 99 for (size_t i = 0; i < mFamilies.size(); i++) { 100 mFamilies[i]->UnrefLocked(); 101 } 102} 103 104// Implement heuristic for choosing best-match font. Here are the rules: 105// 1. If first font in the collection has the character, it wins. 106// 2. If a font matches both language and script, it gets a score of 4. 107// 3. If a font matches just language, it gets a score of 2. 108// 4. Matching the "compact" or "elegant" variant adds one to the score. 109// 5. Highest score wins, with ties resolved to the first font. 110FontFamily* FontCollection::getFamilyForChar(uint32_t ch, uint32_t vs, 111 FontLanguage lang, int variant) const { 112 if (ch >= mMaxChar) { 113 return NULL; 114 } 115 const Range& range = mRanges[ch >> kLogCharsPerPage]; 116#ifdef VERBOSE_DEBUG 117 ALOGD("querying range %zd:%zd\n", range.start, range.end); 118#endif 119 FontFamily* bestFamily = nullptr; 120 int bestScore = -1; 121 for (size_t i = range.start; i < range.end; i++) { 122 FontFamily* family = mFamilyVec[i]; 123 if (vs == 0 ? family->getCoverage()->get(ch) : family->hasVariationSelector(ch, vs)) { 124 // First font family in collection always matches 125 if (mFamilies[0] == family) { 126 return family; 127 } 128 int score = lang.match(family->lang()) * 2; 129 if (family->variant() == 0 || family->variant() == variant) { 130 score++; 131 } 132 if (score > bestScore) { 133 bestScore = score; 134 bestFamily = family; 135 } 136 } 137 } 138 if (bestFamily == nullptr && vs != 0) { 139 // If no fonts support the codepoint and variation selector pair, 140 // fallback to select a font family that supports just the base 141 // character, ignoring the variation selector. 142 return getFamilyForChar(ch, 0, lang, variant); 143 } 144 if (bestFamily == nullptr && !mFamilyVec.empty()) { 145 UErrorCode errorCode = U_ZERO_ERROR; 146 const UNormalizer2* normalizer = unorm2_getNFDInstance(&errorCode); 147 if (U_SUCCESS(errorCode)) { 148 UChar decomposed[4]; 149 int len = unorm2_getRawDecomposition(normalizer, ch, decomposed, 4, &errorCode); 150 if (U_SUCCESS(errorCode) && len > 0) { 151 int off = 0; 152 U16_NEXT_UNSAFE(decomposed, off, ch); 153 return getFamilyForChar(ch, vs, lang, variant); 154 } 155 } 156 bestFamily = mFamilies[0]; 157 } 158 return bestFamily; 159} 160 161const uint32_t NBSP = 0xa0; 162const uint32_t ZWJ = 0x200c; 163const uint32_t ZWNJ = 0x200d; 164const uint32_t KEYCAP = 0x20e3; 165const uint32_t HYPHEN = 0x2010; 166const uint32_t NB_HYPHEN = 0x2011; 167 168// Characters where we want to continue using existing font run instead of 169// recomputing the best match in the fallback list. 170static const uint32_t stickyWhitelist[] = { '!', ',', '-', '.', ':', ';', '?', NBSP, ZWJ, ZWNJ, 171 KEYCAP, HYPHEN, NB_HYPHEN }; 172 173static bool isStickyWhitelisted(uint32_t c) { 174 for (size_t i = 0; i < sizeof(stickyWhitelist) / sizeof(stickyWhitelist[0]); i++) { 175 if (stickyWhitelist[i] == c) return true; 176 } 177 return false; 178} 179 180static bool isVariationSelector(uint32_t c) { 181 return (0xFE00 <= c && c <= 0xFE0F) || (0xE0100 <= c && c <= 0xE01EF); 182} 183 184bool FontCollection::hasVariationSelector(uint32_t baseCodepoint, 185 uint32_t variationSelector) const { 186 if (!isVariationSelector(variationSelector)) { 187 return false; 188 } 189 if (baseCodepoint >= mMaxChar) { 190 return false; 191 } 192 // Currently mRanges can not be used here since it isn't aware of the variation sequence. 193 // TODO: Use mRanges for narrowing down the search range. 194 for (size_t i = 0; i < mFamilies.size(); i++) { 195 if (mFamilies[i]->hasVariationSelector(baseCodepoint, variationSelector)) { 196 return true; 197 } 198 } 199 return false; 200} 201 202void FontCollection::itemize(const uint16_t *string, size_t string_size, FontStyle style, 203 vector<Run>* result) const { 204 FontLanguage lang = style.getLanguage(); 205 int variant = style.getVariant(); 206 FontFamily* lastFamily = NULL; 207 Run* run = NULL; 208 209 if (string_size == 0) { 210 return; 211 } 212 213 const uint32_t kEndOfString = 0xFFFFFFFF; 214 215 uint32_t nextCh = 0; 216 uint32_t prevCh = 0; 217 size_t nextUtf16Pos = 0; 218 size_t readLength = 0; 219 U16_NEXT(string, readLength, string_size, nextCh); 220 221 do { 222 const uint32_t ch = nextCh; 223 const size_t utf16Pos = nextUtf16Pos; 224 nextUtf16Pos = readLength; 225 if (readLength < string_size) { 226 U16_NEXT(string, readLength, string_size, nextCh); 227 } else { 228 nextCh = kEndOfString; 229 } 230 231 bool shouldContinueRun = false; 232 if (lastFamily != nullptr) { 233 if (isStickyWhitelisted(ch)) { 234 // Continue using existing font as long as it has coverage and is whitelisted 235 shouldContinueRun = lastFamily->getCoverage()->get(ch); 236 } else if (isVariationSelector(ch)) { 237 // Always continue if the character is a variation selector. 238 shouldContinueRun = true; 239 } 240 } 241 242 if (!shouldContinueRun) { 243 FontFamily* family = 244 getFamilyForChar(ch, isVariationSelector(nextCh) ? nextCh : 0, lang, variant); 245 if (utf16Pos == 0 || family != lastFamily) { 246 size_t start = utf16Pos; 247 // Workaround for Emoji keycap until we implement per-cluster font 248 // selection: if keycap is found in a different font that also 249 // supports previous char, attach previous char to the new run. 250 // Bug 7557244. 251 if (ch == KEYCAP && utf16Pos != 0 && family && family->getCoverage()->get(prevCh)) { 252 const size_t prevChLength = U16_LENGTH(prevCh); 253 run->end -= prevChLength; 254 if (run->start == run->end) { 255 result->pop_back(); 256 } 257 start -= prevChLength; 258 } 259 Run dummy; 260 result->push_back(dummy); 261 run = &result->back(); 262 if (family == NULL) { 263 run->fakedFont.font = NULL; 264 } else { 265 run->fakedFont = family->getClosestMatch(style); 266 } 267 lastFamily = family; 268 run->start = start; 269 } 270 } 271 prevCh = ch; 272 run->end = nextUtf16Pos; // exclusive 273 } while (nextCh != kEndOfString); 274} 275 276MinikinFont* FontCollection::baseFont(FontStyle style) { 277 return baseFontFaked(style).font; 278} 279 280FakedFont FontCollection::baseFontFaked(FontStyle style) { 281 if (mFamilies.empty()) { 282 return FakedFont(); 283 } 284 return mFamilies[0]->getClosestMatch(style); 285} 286 287uint32_t FontCollection::getId() const { 288 return mId; 289} 290 291void FontCollection::purgeFontFamilyHbFontCache() const { 292 assertMinikinLocked(); 293 for (size_t i = 0; i < mFamilies.size(); ++i) { 294 mFamilies[i]->purgeHbFontCache(); 295 } 296} 297 298} // namespace android 299