1 /* 2 * Copyright (C) 2015 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 #ifndef MINIKIN_FONT_LANGUAGE_H 18 #define MINIKIN_FONT_LANGUAGE_H 19 20 #include <string> 21 #include <vector> 22 23 #include <hb.h> 24 25 namespace minikin { 26 27 // Due to the limits in font fallback score calculation, we can't use anything more than 12 28 // languages. 29 const size_t FONT_LANGUAGES_LIMIT = 12; 30 31 // The language or region code is encoded to 15 bits. 32 const uint16_t INVALID_CODE = 0x7fff; 33 34 class FontLanguages; 35 36 // FontLanguage is a compact representation of a BCP 47 language tag. It 37 // does not capture all possible information, only what directly affects 38 // font rendering. 39 struct FontLanguage { 40 public: 41 enum EmojiStyle : uint8_t { 42 EMSTYLE_EMPTY = 0, 43 EMSTYLE_DEFAULT = 1, 44 EMSTYLE_EMOJI = 2, 45 EMSTYLE_TEXT = 3, 46 }; 47 // Default constructor creates the unsupported language. 48 FontLanguage() 49 : mScript(0ul), 50 mLanguage(INVALID_CODE), 51 mRegion(INVALID_CODE), 52 mHbLanguage(HB_LANGUAGE_INVALID), 53 mSubScriptBits(0ul), 54 mEmojiStyle(EMSTYLE_EMPTY) {} 55 56 // Parse from string 57 FontLanguage(const char* buf, size_t length); 58 59 bool operator==(const FontLanguage other) const { 60 return !isUnsupported() && isEqualScript(other) && mLanguage == other.mLanguage && 61 mRegion == other.mRegion && mEmojiStyle == other.mEmojiStyle; 62 } 63 64 bool operator!=(const FontLanguage other) const { 65 return !(*this == other); 66 } 67 68 bool isUnsupported() const { return mLanguage == INVALID_CODE; } 69 EmojiStyle getEmojiStyle() const { return mEmojiStyle; } 70 hb_language_t getHbLanguage() const { return mHbLanguage; } 71 72 73 bool isEqualScript(const FontLanguage& other) const; 74 75 // Returns true if this script supports the given script. For example, ja-Jpan supports Hira, 76 // ja-Hira doesn't support Jpan. 77 bool supportsHbScript(hb_script_t script) const; 78 79 std::string getString() const; 80 81 // Calculates a matching score. This score represents how well the input languages cover this 82 // language. The maximum score in the language list is returned. 83 // 0 = no match, 1 = script match, 2 = script and primary language match. 84 int calcScoreFor(const FontLanguages& supported) const; 85 86 uint64_t getIdentifier() const { 87 return ((uint64_t)mLanguage << 49) | ((uint64_t)mScript << 17) | ((uint64_t)mRegion << 2) | 88 mEmojiStyle; 89 } 90 91 private: 92 friend class FontLanguages; // for FontLanguages constructor 93 94 // ISO 15924 compliant script code. The 4 chars script code are packed into a 32 bit integer. 95 uint32_t mScript; 96 97 // ISO 639-1 or ISO 639-2 compliant language code. 98 // The two- or three-letter language code is packed into a 15 bit integer. 99 // mLanguage = 0 means the FontLanguage is unsupported. 100 uint16_t mLanguage; 101 102 // ISO 3166-1 or UN M.49 compliant region code. The two-letter or three-digit region code is 103 // packed into a 15 bit integer. 104 uint16_t mRegion; 105 106 // The language to be passed HarfBuzz shaper. 107 hb_language_t mHbLanguage; 108 109 // For faster comparing, use 7 bits for specific scripts. 110 static const uint8_t kBopomofoFlag = 1u; 111 static const uint8_t kHanFlag = 1u << 1; 112 static const uint8_t kHangulFlag = 1u << 2; 113 static const uint8_t kHiraganaFlag = 1u << 3; 114 static const uint8_t kKatakanaFlag = 1u << 4; 115 static const uint8_t kSimplifiedChineseFlag = 1u << 5; 116 static const uint8_t kTraditionalChineseFlag = 1u << 6; 117 uint8_t mSubScriptBits; 118 119 EmojiStyle mEmojiStyle; 120 121 static uint8_t scriptToSubScriptBits(uint32_t script); 122 123 static EmojiStyle resolveEmojiStyle(const char* buf, size_t length, uint32_t script); 124 125 // Returns true if the provide subscript bits has the requested subscript bits. 126 // Note that this function returns false if the requested subscript bits are empty. 127 static bool supportsScript(uint8_t providedBits, uint8_t requestedBits); 128 }; 129 130 // An immutable list of languages. 131 class FontLanguages { 132 public: 133 explicit FontLanguages(std::vector<FontLanguage>&& languages); 134 FontLanguages() : mUnionOfSubScriptBits(0), mIsAllTheSameLanguage(false) {} 135 FontLanguages(FontLanguages&&) = default; 136 137 size_t size() const { return mLanguages.size(); } 138 bool empty() const { return mLanguages.empty(); } 139 const FontLanguage& operator[] (size_t n) const { return mLanguages[n]; } 140 141 private: 142 friend struct FontLanguage; // for calcScoreFor 143 144 std::vector<FontLanguage> mLanguages; 145 uint8_t mUnionOfSubScriptBits; 146 bool mIsAllTheSameLanguage; 147 148 uint8_t getUnionOfSubScriptBits() const { return mUnionOfSubScriptBits; } 149 bool isAllTheSameLanguage() const { return mIsAllTheSameLanguage; } 150 151 // Do not copy and assign. 152 FontLanguages(const FontLanguages&) = delete; 153 void operator=(const FontLanguages&) = delete; 154 }; 155 156 } // namespace minikin 157 158 #endif // MINIKIN_FONT_LANGUAGE_H 159
