trig.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_GEOMETRY_TRIG_H_
#define FLUTTER_IMPELLER_GEOMETRY_TRIG_H_
 
#include <functional>
#include <vector>
 
#include "flutter/impeller/geometry/point.h"
 
namespace impeller {
 
/// @brief  A structure to store the sine and cosine of an angle.
struct Trig {
  /// Construct a Trig object from a given angle in radians.
  explicit Trig(Radians r)
      : cos(std::cos(r.radians)), sin(std::sin(r.radians)) {}
 
  /// Construct a Trig object from the given cosine and sine values.
  Trig(double cos, double sin) : cos(cos), sin(sin) {}
 
  double cos;
  double sin;
 
  /// @brief  Returns the vector rotated by the represented angle.
  Vector2 operator*(const Vector2& vector) const {
    return Vector2(static_cast<Scalar>(vector.x * cos - vector.y * sin),
                   static_cast<Scalar>(vector.x * sin + vector.y * cos));
  }
 
  /// @brief  Returns the Trig representing the negative version of this angle.
  Trig operator-() const { return Trig(cos, -sin); }
 
  /// @brief  Returns the corresponding point on a circle of a given |radius|.
  Vector2 operator*(double radius) const {
    return Vector2(static_cast<Scalar>(cos * radius),
                   static_cast<Scalar>(sin * radius));
  }
 
  /// @brief  Returns the corresponding point on an ellipse with the given size.
  Vector2 operator*(const Size& ellipse_radii) const {
    return Vector2(static_cast<Scalar>(cos * ellipse_radii.width),
                   static_cast<Scalar>(sin * ellipse_radii.height));
  }
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_GEOMETRY_TRIG_H_