text_frame.h

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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.
 
#ifndef FLUTTER_IMPELLER_TYPOGRAPHER_TEXT_FRAME_H_
#define FLUTTER_IMPELLER_TYPOGRAPHER_TEXT_FRAME_H_
 
#include "impeller/typographer/glyph_atlas.h"
#include "impeller/typographer/text_run.h"
 
namespace impeller {
 
//------------------------------------------------------------------------------
/// @brief      Represents a collection of shaped text runs.
///
///             This object is typically the entrypoint in the Impeller type
///             rendering subsystem.
///
class TextFrame {
 public:
  TextFrame();
 
  TextFrame(std::vector<TextRun>& runs, Rect bounds, bool has_color);
 
  ~TextFrame();
 
  void CollectUniqueFontGlyphPairs(FontGlyphMap& glyph_map,
                                   Scalar scale,
                                   Point offset,
                                   const GlyphProperties& properties) const;
 
  static Point ComputeSubpixelPosition(
      const TextRun::GlyphPosition& glyph_position,
      AxisAlignment alignment,
      Point offset,
      Scalar scale);
 
  static Scalar RoundScaledFontSize(Scalar scale, Scalar point_size);
 
  //----------------------------------------------------------------------------
  /// @brief      The conservative bounding box for this text frame.
  ///
  /// @return     The bounds rectangle. If there are no glyphs in this text
  ///             frame and empty Rectangle is returned instead.
  ///
  Rect GetBounds() const;
 
  //----------------------------------------------------------------------------
  /// @brief      The number of runs in this text frame.
  ///
  /// @return     The run count.
  ///
  size_t GetRunCount() const;
 
  //----------------------------------------------------------------------------
  /// @brief      Returns a reference to all the text runs in this frame.
  ///
  /// @return     The runs in this frame.
  ///
  const std::vector<TextRun>& GetRuns() const;
 
  //----------------------------------------------------------------------------
  /// @brief      Returns the paint color this text frame was recorded with.
  ///
  ///             Non-bitmap/COLR fonts always use a black text color here, but
  ///             COLR fonts can potentially use the paint color in the glyph
  ///             atlas, so this color must be considered as part of the cache
  ///             key.
  bool HasColor() const;
 
  //----------------------------------------------------------------------------
  /// @brief      The type of atlas this run should be emplaced in.
  GlyphAtlas::Type GetAtlasType() const;
 
  TextFrame& operator=(TextFrame&& other) = default;
 
  TextFrame(const TextFrame& other) = default;
 
 private:
  std::vector<TextRun> runs_;
  Rect bounds_;
  bool has_color_;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_TYPOGRAPHER_TEXT_FRAME_H_