typeface_stb.cc

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "impeller/typographer/backends/stb/typeface_stb.h"
 
#include <cstring>
 
#include "flutter/fml/logging.h"
 
namespace impeller {
 
// Instantiate a typeface based on a .ttf or other font file
TypefaceSTB::TypefaceSTB(std::unique_ptr<fml::Mapping> typeface_mapping)
    : typeface_mapping_(std::move(typeface_mapping)),
      font_info_(std::make_unique<stbtt_fontinfo>()) {
  // We need an "offset" into the ttf file
  auto offset = stbtt_GetFontOffsetForIndex(typeface_mapping_->GetMapping(), 0);
  if (stbtt_InitFont(font_info_.get(), typeface_mapping_->GetMapping(),
                     offset) == 0) {
    FML_LOG(ERROR) << "Failed to initialize stb font from binary data.";
  } else {
    is_valid_ = true;
  }
}
 
TypefaceSTB::~TypefaceSTB() = default;
 
bool TypefaceSTB::IsValid() const {
  return is_valid_;
}
 
std::size_t TypefaceSTB::GetHash() const {
  if (!IsValid()) {
    return 0u;
  }
  return reinterpret_cast<size_t>(typeface_mapping_->GetMapping());
}
 
bool TypefaceSTB::IsEqual(const Typeface& other) const {
  auto stb_other = reinterpret_cast<const TypefaceSTB*>(&other);
  return stb_other->GetHash() == GetHash();
}
 
const uint8_t* TypefaceSTB::GetTypefaceFile() const {
  return typeface_mapping_->GetMapping();
}
 
const stbtt_fontinfo* TypefaceSTB::GetFontInfo() const {
  return font_info_.get();
}
 
}  // namespace impeller