1 /* 2 * Copyright (C) 2017 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 <stdlib.h> 18 #include <stdint.h> 19 20 #include "FontUtils.h" 21 22 namespace minikin { 23 24 static uint16_t readU16(const uint8_t* data, size_t offset) { 25 return data[offset] << 8 | data[offset + 1]; 26 } 27 28 static uint32_t readU32(const uint8_t* data, size_t offset) { 29 return ((uint32_t)data[offset]) << 24 | ((uint32_t)data[offset + 1]) << 16 | 30 ((uint32_t)data[offset + 2]) << 8 | ((uint32_t)data[offset + 3]); 31 } 32 33 bool analyzeStyle(const uint8_t* os2_data, size_t os2_size, int* weight, bool* italic) { 34 const size_t kUsWeightClassOffset = 4; 35 const size_t kFsSelectionOffset = 62; 36 const uint16_t kItalicFlag = (1 << 0); 37 if (os2_size < kFsSelectionOffset + 2) { 38 return false; 39 } 40 uint16_t weightClass = readU16(os2_data, kUsWeightClassOffset); 41 *weight = weightClass / 100; 42 uint16_t fsSelection = readU16(os2_data, kFsSelectionOffset); 43 *italic = (fsSelection & kItalicFlag) != 0; 44 return true; 45 } 46 47 void analyzeAxes(const uint8_t* fvar_data, size_t fvar_size, std::unordered_set<uint32_t>* axes) { 48 const size_t kMajorVersionOffset = 0; 49 const size_t kMinorVersionOffset = 2; 50 const size_t kOffsetToAxesArrayOffset = 4; 51 const size_t kAxisCountOffset = 8; 52 const size_t kAxisSizeOffset = 10; 53 54 axes->clear(); 55 56 if (fvar_size < kAxisSizeOffset + 2) { 57 return; 58 } 59 const uint16_t majorVersion = readU16(fvar_data, kMajorVersionOffset); 60 const uint16_t minorVersion = readU16(fvar_data, kMinorVersionOffset); 61 const uint32_t axisOffset = readU16(fvar_data, kOffsetToAxesArrayOffset); 62 const uint32_t axisCount = readU16(fvar_data, kAxisCountOffset); 63 const uint32_t axisSize = readU16(fvar_data, kAxisSizeOffset); 64 65 if (majorVersion != 1 || minorVersion != 0 || axisOffset != 0x10 || axisSize != 0x14) { 66 return; // Unsupported version. 67 } 68 if (fvar_size < axisOffset + axisOffset * axisCount) { 69 return; // Invalid table size. 70 } 71 for (uint32_t i = 0; i < axisCount; ++i) { 72 size_t axisRecordOffset = axisOffset + i * axisSize; 73 uint32_t tag = readU32(fvar_data, axisRecordOffset); 74 axes->insert(tag); 75 } 76 } 77 } // namespace minikin 78
