circle_geometry.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_GEOMETRY_CIRCLE_GEOMETRY_H_
#define FLUTTER_IMPELLER_ENTITY_GEOMETRY_CIRCLE_GEOMETRY_H_
 
#include "impeller/entity/geometry/geometry.h"
 
namespace impeller {
 
// Geometry class that can generate vertices (with or without texture
// coordinates) for either filled or stroked circles
class CircleGeometry final : public Geometry {
 public:
  explicit CircleGeometry(const Point& center, Scalar radius);
 
  explicit CircleGeometry(const Point& center,
                          Scalar radius,
                          Scalar stroke_width);
 
  ~CircleGeometry() override;
 
  // |Geometry|
  bool CoversArea(const Matrix& transform, const IRect& rect) const override;
 
  // |Geometry|
  bool IsAxisAlignedRect() const override;
 
  // |Geometry|
  Scalar ComputeAlphaCoverage(const Matrix& transform) const override;
 
  Scalar GetRadius() const;
  Scalar GetStrokeWidth() const;
  Point GetCenter() const;
 
  // |Geometry|
  std::optional<Rect> GetCoverage(const Matrix& transform) const override;
 
  // |Geometry|
  GeometryResult GetPositionBuffer(const ContentContext& renderer,
                                   const Entity& entity,
                                   RenderPass& pass) const override;
 
  // Set the number of pixels to add to the edge(s) of the circle for
  // SDF-based antialiasing
  void SetAntialiasPadding(Scalar extra_pixels);
 
  Scalar GetAntialiasPadding() const;
 
 private:
  Point center_;
  Scalar radius_;
  Scalar stroke_width_;
  Scalar padding_pixels_;
 
  CircleGeometry(const CircleGeometry&) = delete;
 
  CircleGeometry& operator=(const CircleGeometry&) = delete;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_ENTITY_GEOMETRY_CIRCLE_GEOMETRY_H_