chromium/src/third_party/blink/renderer/platform/text/writing_direction_mode.h

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_WRITING_DIRECTION_MODE_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_WRITING_DIRECTION_MODE_H_

#include "third_party/blink/renderer/platform/platform_export.h"
#include "third_party/blink/renderer/platform/text/text_direction.h"
#include "third_party/blink/renderer/platform/text/writing_mode.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"

namespace blink {

// This class packs |WritingMode| and |TextDirection|, two enums that are often
// used and passed around together, into the size of the minimum memory align.
class PLATFORM_EXPORT WritingDirectionMode {
  DISALLOW_NEW();

 public:
  WritingDirectionMode(WritingMode writing_mode, TextDirection direction)
      : writing_mode_(writing_mode), direction_(direction) {}

  //
  // Inline direction functions.
  //
  TextDirection Direction() const { return direction_; }
  void SetDirection(TextDirection direction) { direction_ = direction; }

  bool IsLtr() const { return blink::IsLtr(direction_); }
  bool IsRtl() const { return blink::IsRtl(direction_); }

  //
  // Block direction functions.
  //
  WritingMode GetWritingMode() const { return writing_mode_; }
  void SetWritingMode(WritingMode writing_mode) {
    writing_mode_ = writing_mode;
  }

  bool IsHorizontal() const { return IsHorizontalWritingMode(writing_mode_); }

  // Block progression increases in the opposite direction to normal; modes
  // vertical-rl.
  bool IsFlippedBlocks() const {
    return IsFlippedBlocksWritingMode(writing_mode_);
  }

  // Bottom of the line occurs earlier in the block; modes vertical-lr.
  bool IsFlippedLines() const {
    return IsFlippedLinesWritingMode(writing_mode_);
  }

  //
  // Functions for both inline and block directions.
  //
  bool IsHorizontalLtr() const { return IsHorizontal() && IsLtr(); }

  bool operator==(const WritingDirectionMode& other) const {
    return writing_mode_ == other.writing_mode_ &&
           direction_ == other.direction_;
  }
  bool operator!=(const WritingDirectionMode& other) const {
    return !operator==(other);
  }

 private:
  WritingMode writing_mode_;
  TextDirection direction_;
};

PLATFORM_EXPORT std::ostream& operator<<(std::ostream&,
                                         const WritingDirectionMode&);

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_TEXT_WRITING_DIRECTION_MODE_H_