diff options
Diffstat (limited to 'chromium/third_party/brotli/src/woff2/transform.cc')
-rw-r--r-- | chromium/third_party/brotli/src/woff2/transform.cc | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/chromium/third_party/brotli/src/woff2/transform.cc b/chromium/third_party/brotli/src/woff2/transform.cc new file mode 100644 index 00000000000..bb3a27a4f79 --- /dev/null +++ b/chromium/third_party/brotli/src/woff2/transform.cc @@ -0,0 +1,264 @@ +// Copyright 2013 Google Inc. All Rights Reserved. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. +// +// Library for preprocessing fonts as part of the WOFF 2.0 conversion. + +#include "./transform.h" + +#include <complex> // for std::abs + +#include "./buffer.h" +#include "./font.h" +#include "./glyph.h" +#include "./table_tags.h" + +namespace woff2 { + +namespace { + +const int FLAG_ARG_1_AND_2_ARE_WORDS = 1 << 0; +const int FLAG_WE_HAVE_INSTRUCTIONS = 1 << 8; + +void WriteBytes(std::vector<uint8_t>* out, const uint8_t* data, size_t len) { + if (len == 0) return; + size_t offset = out->size(); + out->resize(offset + len); + memcpy(&(*out)[offset], data, len); +} + +void WriteBytes(std::vector<uint8_t>* out, const std::vector<uint8_t>& in) { + for (int i = 0; i < in.size(); ++i) { + out->push_back(in[i]); + } +} + +void WriteUShort(std::vector<uint8_t>* out, int value) { + out->push_back(value >> 8); + out->push_back(value & 255); +} + +void WriteLong(std::vector<uint8_t>* out, int value) { + out->push_back((value >> 24) & 255); + out->push_back((value >> 16) & 255); + out->push_back((value >> 8) & 255); + out->push_back(value & 255); +} + +void Write255UShort(std::vector<uint8_t>* out, int value) { + if (value < 253) { + out->push_back(value); + } else if (value < 506) { + out->push_back(255); + out->push_back(value - 253); + } else if (value < 762) { + out->push_back(254); + out->push_back(value - 506); + } else { + out->push_back(253); + out->push_back(value >> 8); + out->push_back(value & 0xff); + } +} + +// Glyf table preprocessing, based on +// GlyfEncoder.java +// but only the "sbbox" and "cbbox" options are supported. +class GlyfEncoder { + public: + explicit GlyfEncoder(int num_glyphs) + : sbbox_(false), cbbox_(true), n_glyphs_(num_glyphs) { + bbox_bitmap_.resize(((num_glyphs + 31) >> 5) << 2); + } + + bool Encode(int glyph_id, const Glyph& glyph) { + if (glyph.composite_data_size > 0) { + WriteCompositeGlyph(glyph_id, glyph); + } else if (glyph.contours.size() > 0) { + WriteSimpleGlyph(glyph_id, glyph); + } else { + WriteUShort(&n_contour_stream_, 0); + } + return true; + } + + void GetTransformedGlyfBytes(std::vector<uint8_t>* result) { + WriteLong(result, 0); // version + WriteUShort(result, n_glyphs_); + WriteUShort(result, 0); // index_format, will be set later + WriteLong(result, n_contour_stream_.size()); + WriteLong(result, n_points_stream_.size()); + WriteLong(result, flag_byte_stream_.size()); + WriteLong(result, glyph_stream_.size()); + WriteLong(result, composite_stream_.size()); + WriteLong(result, bbox_bitmap_.size() + bbox_stream_.size()); + WriteLong(result, instruction_stream_.size()); + WriteBytes(result, n_contour_stream_); + WriteBytes(result, n_points_stream_); + WriteBytes(result, flag_byte_stream_); + WriteBytes(result, glyph_stream_); + WriteBytes(result, composite_stream_); + WriteBytes(result, bbox_bitmap_); + WriteBytes(result, bbox_stream_); + WriteBytes(result, instruction_stream_); + } + + private: + void WriteInstructions(const Glyph& glyph) { + Write255UShort(&glyph_stream_, glyph.instructions_size); + WriteBytes(&instruction_stream_, + glyph.instructions_data, glyph.instructions_size); + } + + void WriteSimpleGlyph(int glyph_id, const Glyph& glyph) { + int num_contours = glyph.contours.size(); + WriteUShort(&n_contour_stream_, num_contours); + if (sbbox_) { + WriteBbox(glyph_id, glyph); + } + // TODO: check that bbox matches, write bbox if not + for (int i = 0; i < num_contours; i++) { + Write255UShort(&n_points_stream_, glyph.contours[i].size()); + } + int lastX = 0; + int lastY = 0; + for (int i = 0; i < num_contours; i++) { + int num_points = glyph.contours[i].size(); + for (int j = 0; j < num_points; j++) { + int x = glyph.contours[i][j].x; + int y = glyph.contours[i][j].y; + int dx = x - lastX; + int dy = y - lastY; + WriteTriplet(glyph.contours[i][j].on_curve, dx, dy); + lastX = x; + lastY = y; + } + } + if (num_contours > 0) { + WriteInstructions(glyph); + } + } + + void WriteCompositeGlyph(int glyph_id, const Glyph& glyph) { + WriteUShort(&n_contour_stream_, -1); + if (cbbox_) { + WriteBbox(glyph_id, glyph); + } + WriteBytes(&composite_stream_, + glyph.composite_data, + glyph.composite_data_size); + if (glyph.have_instructions) { + WriteInstructions(glyph); + } + } + + void WriteBbox(int glyph_id, const Glyph& glyph) { + bbox_bitmap_[glyph_id >> 3] |= 0x80 >> (glyph_id & 7); + WriteUShort(&bbox_stream_, glyph.x_min); + WriteUShort(&bbox_stream_, glyph.y_min); + WriteUShort(&bbox_stream_, glyph.x_max); + WriteUShort(&bbox_stream_, glyph.y_max); + } + + void WriteTriplet(bool on_curve, int x, int y) { + int abs_x = std::abs(x); + int abs_y = std::abs(y); + int on_curve_bit = on_curve ? 0 : 128; + int x_sign_bit = (x < 0) ? 0 : 1; + int y_sign_bit = (y < 0) ? 0 : 1; + int xy_sign_bits = x_sign_bit + 2 * y_sign_bit; + if (x == 0 && abs_y < 1280) { + flag_byte_stream_.push_back(on_curve_bit + + ((abs_y & 0xf00) >> 7) + y_sign_bit); + glyph_stream_.push_back(abs_y & 0xff); + } else if (y == 0 && abs_x < 1280) { + flag_byte_stream_.push_back(on_curve_bit + 10 + + ((abs_x & 0xf00) >> 7) + x_sign_bit); + glyph_stream_.push_back(abs_x & 0xff); + } else if (abs_x < 65 && abs_y < 65) { + flag_byte_stream_.push_back(on_curve_bit + 20 + + ((abs_x - 1) & 0x30) + + (((abs_y - 1) & 0x30) >> 2) + + xy_sign_bits); + glyph_stream_.push_back((((abs_x - 1) & 0xf) << 4) | ((abs_y - 1) & 0xf)); + } else if (abs_x < 769 && abs_y < 769) { + flag_byte_stream_.push_back(on_curve_bit + 84 + + 12 * (((abs_x - 1) & 0x300) >> 8) + + (((abs_y - 1) & 0x300) >> 6) + xy_sign_bits); + glyph_stream_.push_back((abs_x - 1) & 0xff); + glyph_stream_.push_back((abs_y - 1) & 0xff); + } else if (abs_x < 4096 && abs_y < 4096) { + flag_byte_stream_.push_back(on_curve_bit + 120 + xy_sign_bits); + glyph_stream_.push_back(abs_x >> 4); + glyph_stream_.push_back(((abs_x & 0xf) << 4) | (abs_y >> 8)); + glyph_stream_.push_back(abs_y & 0xff); + } else { + flag_byte_stream_.push_back(on_curve_bit + 124 + xy_sign_bits); + glyph_stream_.push_back(abs_x >> 8); + glyph_stream_.push_back(abs_x & 0xff); + glyph_stream_.push_back(abs_y >> 8); + glyph_stream_.push_back(abs_y & 0xff); + } + } + + std::vector<uint8_t> n_contour_stream_; + std::vector<uint8_t> n_points_stream_; + std::vector<uint8_t> flag_byte_stream_; + std::vector<uint8_t> composite_stream_; + std::vector<uint8_t> bbox_bitmap_; + std::vector<uint8_t> bbox_stream_; + std::vector<uint8_t> glyph_stream_; + std::vector<uint8_t> instruction_stream_; + bool sbbox_; + bool cbbox_; + int n_glyphs_; +}; + +} // namespace + +bool TransformGlyfAndLocaTables(Font* font) { + Font::Table* transformed_glyf = &font->tables[kGlyfTableTag ^ 0x80808080]; + Font::Table* transformed_loca = &font->tables[kLocaTableTag ^ 0x80808080]; + + int num_glyphs = NumGlyphs(*font); + GlyfEncoder encoder(num_glyphs); + for (int i = 0; i < num_glyphs; ++i) { + Glyph glyph; + const uint8_t* glyph_data; + size_t glyph_size; + if (!GetGlyphData(*font, i, &glyph_data, &glyph_size) || + (glyph_size > 0 && !ReadGlyph(glyph_data, glyph_size, &glyph))) { + return FONT_COMPRESSION_FAILURE(); + } + encoder.Encode(i, glyph); + } + encoder.GetTransformedGlyfBytes(&transformed_glyf->buffer); + + const Font::Table* head_table = font->FindTable(kHeadTableTag); + if (head_table == NULL || head_table->length < 52) { + return FONT_COMPRESSION_FAILURE(); + } + transformed_glyf->buffer[7] = head_table->data[51]; // index_format + + transformed_glyf->tag = kGlyfTableTag ^ 0x80808080; + transformed_glyf->length = transformed_glyf->buffer.size(); + transformed_glyf->data = transformed_glyf->buffer.data(); + + transformed_loca->tag = kLocaTableTag ^ 0x80808080; + transformed_loca->length = 0; + transformed_loca->data = NULL; + + return true; +} + +} // namespace woff2 |