text_contents.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_ENTITY_CONTENTS_TEXT_CONTENTS_H_
#define FLUTTER_IMPELLER_ENTITY_CONTENTS_TEXT_CONTENTS_H_
 
#include <memory>
 
#include "impeller/entity/contents/content_context.h"
#include "impeller/entity/contents/contents.h"
#include "impeller/entity/contents/pipelines.h"
#include "impeller/geometry/color.h"
#include "impeller/geometry/stroke_parameters.h"
#include "impeller/typographer/font_glyph_pair.h"
#include "impeller/typographer/text_frame.h"
 
namespace impeller {
 
class LazyGlyphAtlas;
class Context;
 
class TextContents final : public Contents {
 public:
  TextContents();
 
  ~TextContents();
 
  void SetTextFrame(const std::shared_ptr<TextFrame>& frame);
 
  void SetColor(Color color);
 
  /// @brief Force the text color to apply to the rendered glyphs, even if those
  ///        glyphs are bitmaps.
  ///
  ///        This is used to ensure that mask blurs work correctly on emoji.
  void SetForceTextColor(bool value);
 
  /// Must be set after text frame.
  void SetTextProperties(Color color,
                         const std::optional<StrokeParameters>& stroke);
 
  Color GetColor() const;
 
  // |Contents|
  void SetInheritedOpacity(Scalar opacity) override;
 
  // The offset is only used for computing the subpixel glyph position.
  void SetOffset(Vector2 offset);
 
  std::optional<Rect> GetTextFrameBounds() const;
 
  // |Contents|
  std::optional<Rect> GetCoverage(const Entity& entity) const override;
 
  void SetScale(Scalar scale) { scale_ = scale; }
 
  // |Contents|
  bool Render(const ContentContext& renderer,
              const Entity& entity,
              RenderPass& pass) const override;
 
  static void ComputeVertexData(
      GlyphAtlasPipeline::VertexShader::PerVertexData* vtx_contents,
      const std::shared_ptr<TextFrame>& frame,
      Scalar scale,
      const Matrix& entity_transform,
      Vector2 offset,
      std::optional<GlyphProperties> glyph_properties,
      const std::shared_ptr<GlyphAtlas>& atlas);
 
 private:
  std::optional<GlyphProperties> GetGlyphProperties() const;
 
  std::shared_ptr<TextFrame> frame_;
  Scalar scale_ = 1.0;
  Scalar inherited_opacity_ = 1.0;
  Vector2 offset_;
  bool force_text_color_ = false;
  Color color_;
  GlyphProperties properties_;
 
  TextContents(const TextContents&) = delete;
 
  TextContents& operator=(const TextContents&) = delete;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_ENTITY_CONTENTS_TEXT_CONTENTS_H_