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| 1 /* | |
| 2 * Copyright 2011 Google Inc. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license that can be | |
| 5 * found in the LICENSE file. | |
| 6 */ | |
| 7 | |
| 8 | |
| 9 #include "SkAdvancedTypefaceMetrics.h" | |
| 10 #include "SkTypes.h" | |
| 11 | |
| 12 SkAdvancedTypefaceMetrics::~SkAdvancedTypefaceMetrics() {} | |
| 13 | |
| 14 const int16_t kInvalidAdvance = SK_MinS16; | |
| 15 const int16_t kDontCareAdvance = SK_MinS16 + 1; | |
| 16 | |
| 17 static void stripUninterestingTrailingAdvancesFromRange( | |
| 18 SkAdvancedTypefaceMetrics::WidthRange* range) { | |
| 19 SkASSERT(range); | |
| 20 | |
| 21 int expectedAdvanceCount = range->fEndId - range->fStartId + 1; | |
| 22 if (range->fAdvance.count() < expectedAdvanceCount) { | |
| 23 return; | |
| 24 } | |
| 25 | |
| 26 for (int i = expectedAdvanceCount - 1; i >= 0; --i) { | |
| 27 if (range->fAdvance[i] != kDontCareAdvance && | |
| 28 range->fAdvance[i] != kInvalidAdvance && | |
| 29 range->fAdvance[i] != 0) { | |
| 30 range->fEndId = range->fStartId + i; | |
| 31 break; | |
| 32 } | |
| 33 } | |
| 34 } | |
| 35 | |
| 36 static void zeroWildcardsInRange(SkAdvancedTypefaceMetrics::WidthRange* range) { | |
| 37 SkASSERT(range); | |
| 38 if (range->fType != SkAdvancedTypefaceMetrics::WidthRange::kRange) { | |
| 39 return; | |
| 40 } | |
| 41 SkASSERT(range->fAdvance.count() == range->fEndId - range->fStartId + 1); | |
| 42 | |
| 43 // Zero out wildcards. | |
| 44 for (int i = 0; i < range->fAdvance.count(); ++i) { | |
| 45 if (range->fAdvance[i] == kDontCareAdvance) { | |
| 46 range->fAdvance[i] = 0; | |
| 47 } | |
| 48 } | |
| 49 } | |
| 50 | |
| 51 void SkAdvancedTypefaceMetrics::FinishRange( | |
| 52 SkAdvancedTypefaceMetrics::WidthRange* range, | |
| 53 int endId, | |
| 54 SkAdvancedTypefaceMetrics::WidthRange::MetricType type) { | |
| 55 range->fEndId = endId; | |
| 56 range->fType = type; | |
| 57 stripUninterestingTrailingAdvancesFromRange(range); | |
| 58 int newLength; | |
| 59 if (type == SkAdvancedTypefaceMetrics::WidthRange::kRange) { | |
| 60 newLength = range->fEndId - range->fStartId + 1; | |
| 61 } else { | |
| 62 if (range->fEndId == range->fStartId) { | |
| 63 range->fType = SkAdvancedTypefaceMetrics::WidthRange::kRange; | |
| 64 } | |
| 65 newLength = 1; | |
| 66 } | |
| 67 SkASSERT(range->fAdvance.count() >= newLength); | |
| 68 range->fAdvance.setCount(newLength); | |
| 69 zeroWildcardsInRange(range); | |
| 70 } | |
| 71 | |
| 72 void SkAdvancedTypefaceMetrics::setGlyphWidths( | |
| 73 int num_glyphs, | |
| 74 const uint32_t* subsetGlyphIDs, | |
| 75 uint32_t subsetGlyphIDsLength, | |
| 76 SkAdvancedTypefaceMetrics::GetAdvance getAdvance) { | |
| 77 // Assuming that on average, the ASCII representation of an advance plus | |
| 78 // a space is 8 characters and the ASCII representation of a glyph id is 3 | |
| 79 // characters, then the following cut offs for using different range types | |
| 80 // apply: | |
| 81 // The cost of stopping and starting the range is 7 characers | |
| 82 // a. Removing 4 0's or don't care's is a win | |
| 83 // The cost of stopping and starting the range plus a run is 22 | |
| 84 // characters | |
| 85 // b. Removing 3 repeating advances is a win | |
| 86 // c. Removing 2 repeating advances and 3 don't cares is a win | |
| 87 // When not currently in a range the cost of a run over a range is 16 | |
| 88 // characaters, so: | |
| 89 // d. Removing a leading 0/don't cares is a win because it is omitted | |
| 90 // e. Removing 2 repeating advances is a win | |
| 91 | |
| 92 WidthRange* prevRange = nullptr; | |
| 93 int16_t lastAdvance = kInvalidAdvance; | |
| 94 int repeatedAdvances = 0; | |
| 95 int wildCardsInRun = 0; | |
| 96 int trailingWildCards = 0; | |
| 97 uint32_t subsetIndex = 0; | |
| 98 | |
| 99 // Limit the loop count to glyph id ranges provided. | |
| 100 int firstIndex = 0; | |
| 101 int lastIndex = num_glyphs; | |
| 102 if (subsetGlyphIDs) { | |
| 103 firstIndex = static_cast<int>(subsetGlyphIDs[0]); | |
| 104 lastIndex = | |
| 105 static_cast<int>(subsetGlyphIDs[subsetGlyphIDsLength - 1]) + 1; | |
| 106 } | |
| 107 WidthRange curRange(firstIndex); | |
| 108 | |
| 109 for (int gId = firstIndex; gId <= lastIndex; gId++) { | |
| 110 int16_t advance = kInvalidAdvance; | |
| 111 if (gId < lastIndex) { | |
| 112 // Get glyph id only when subset is nullptr, or the id is in subset. | |
| 113 SkASSERT(!subsetGlyphIDs || (subsetIndex < subsetGlyphIDsLength && | |
| 114 static_cast<uint32_t>(gId) <= subsetGlyphIDs[subsetIndex])); | |
| 115 if (!subsetGlyphIDs || | |
| 116 (subsetIndex < subsetGlyphIDsLength && | |
| 117 static_cast<uint32_t>(gId) == subsetGlyphIDs[subsetIndex])) { | |
| 118 SkAssertResult(getAdvance(gId, &advance)); | |
| 119 ++subsetIndex; | |
| 120 } else { | |
| 121 advance = kDontCareAdvance; | |
| 122 } | |
| 123 } | |
| 124 if (advance == lastAdvance) { | |
| 125 repeatedAdvances++; | |
| 126 trailingWildCards = 0; | |
| 127 } else if (advance == kDontCareAdvance) { | |
| 128 wildCardsInRun++; | |
| 129 trailingWildCards++; | |
| 130 } else if (curRange.fAdvance.count() == | |
| 131 repeatedAdvances + 1 + wildCardsInRun) { // All in run. | |
| 132 if (lastAdvance == 0) { | |
| 133 curRange.fStartId = gId; // reset | |
| 134 curRange.fAdvance.setCount(0); | |
| 135 trailingWildCards = 0; | |
| 136 } else if (repeatedAdvances + 1 >= 2 || trailingWildCards >= 4) { | |
| 137 FinishRange(&curRange, gId - 1, WidthRange::kRun); | |
| 138 prevRange = fGlyphWidths.emplace_back(std::move(curRange)); | |
| 139 curRange = WidthRange(gId); | |
| 140 trailingWildCards = 0; | |
| 141 } | |
| 142 repeatedAdvances = 0; | |
| 143 wildCardsInRun = trailingWildCards; | |
| 144 trailingWildCards = 0; | |
| 145 } else { | |
| 146 if (lastAdvance == 0 && | |
| 147 repeatedAdvances + 1 + wildCardsInRun >= 4) { | |
| 148 FinishRange(&curRange, | |
| 149 gId - repeatedAdvances - wildCardsInRun - 2, | |
| 150 WidthRange::kRange); | |
| 151 prevRange = fGlyphWidths.emplace_back(std::move(curRange)); | |
| 152 curRange = WidthRange(gId); | |
| 153 trailingWildCards = 0; | |
| 154 } else if (trailingWildCards >= 4 && repeatedAdvances + 1 < 2) { | |
| 155 FinishRange(&curRange, gId - trailingWildCards - 1, | |
| 156 WidthRange::kRange); | |
| 157 prevRange = fGlyphWidths.emplace_back(std::move(curRange)); | |
| 158 curRange = WidthRange(gId); | |
| 159 trailingWildCards = 0; | |
| 160 } else if (lastAdvance != 0 && | |
| 161 (repeatedAdvances + 1 >= 3 || | |
| 162 (repeatedAdvances + 1 >= 2 && wildCardsInRun >= 3))) { | |
| 163 FinishRange(&curRange, | |
| 164 gId - repeatedAdvances - wildCardsInRun - 2, | |
| 165 WidthRange::kRange); | |
| 166 (void)fGlyphWidths.emplace_back(std::move(curRange)); | |
| 167 curRange = | |
| 168 WidthRange(gId - repeatedAdvances - wildCardsInRun - 1); | |
| 169 curRange.fAdvance.append(1, &lastAdvance); | |
| 170 FinishRange(&curRange, gId - 1, WidthRange::kRun); | |
| 171 prevRange = fGlyphWidths.emplace_back(std::move(curRange)); | |
| 172 curRange = WidthRange(gId); | |
| 173 trailingWildCards = 0; | |
| 174 } | |
| 175 repeatedAdvances = 0; | |
| 176 wildCardsInRun = trailingWildCards; | |
| 177 trailingWildCards = 0; | |
| 178 } | |
| 179 curRange.fAdvance.append(1, &advance); | |
| 180 if (advance != kDontCareAdvance) { | |
| 181 lastAdvance = advance; | |
| 182 } | |
| 183 } | |
| 184 if (curRange.fStartId == lastIndex) { | |
| 185 if (!prevRange) { | |
| 186 fGlyphWidths.reset(); | |
| 187 return; // https://crbug.com/567031 | |
| 188 } | |
| 189 } else { | |
| 190 FinishRange(&curRange, lastIndex - 1, WidthRange::kRange); | |
| 191 fGlyphWidths.emplace_back(std::move(curRange)); | |
| 192 } | |
| 193 } | |
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Chromium Code Reviews
Issue 2222523003:
SkPDF/SkAdvancedTypefaceMetrics: simplify ATM, PDF takes over (Closed)
Base URL: https://skia.googlesource.com/skia.git@SkPDF_no_kHAdvance