flutter_flutter/sky/engine/platform/geometry/FloatQuad.h

/*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
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 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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#ifndef SKY_ENGINE_PLATFORM_GEOMETRY_FLOATQUAD_H_
#define SKY_ENGINE_PLATFORM_GEOMETRY_FLOATQUAD_H_

#include "flutter/sky/engine/platform/geometry/FloatPoint.h"
#include "flutter/sky/engine/platform/geometry/FloatRect.h"
#include "flutter/sky/engine/platform/geometry/IntRect.h"

namespace blink {

// A FloatQuad is a collection of 4 points, often representing the result of
// mapping a rectangle through transforms. When initialized from a rect, the
// points are in clockwise order from top left.
class PLATFORM_EXPORT FloatQuad {
 public:
  FloatQuad() {}

  FloatQuad(const FloatPoint& p1,
            const FloatPoint& p2,
            const FloatPoint& p3,
            const FloatPoint& p4)
      : m_p1(p1), m_p2(p2), m_p3(p3), m_p4(p4) {}

  FloatQuad(const FloatRect& inRect)
      : m_p1(inRect.location()),
        m_p2(inRect.maxX(), inRect.y()),
        m_p3(inRect.maxX(), inRect.maxY()),
        m_p4(inRect.x(), inRect.maxY()) {}

  FloatPoint p1() const { return m_p1; }
  FloatPoint p2() const { return m_p2; }
  FloatPoint p3() const { return m_p3; }
  FloatPoint p4() const { return m_p4; }

  void setP1(const FloatPoint& p) { m_p1 = p; }
  void setP2(const FloatPoint& p) { m_p2 = p; }
  void setP3(const FloatPoint& p) { m_p3 = p; }
  void setP4(const FloatPoint& p) { m_p4 = p; }

  // isEmpty tests that the bounding box is empty. This will not identify
  // "slanted" empty quads.
  bool isEmpty() const { return boundingBox().isEmpty(); }

  // Tests whether this quad can be losslessly represented by a FloatRect,
  // that is, if two edges are parallel to the x-axis and the other two
  // are parallel to the y-axis. If this method returns true, the
  // corresponding FloatRect can be retrieved with boundingBox().
  bool isRectilinear() const;

  // Tests whether the given point is inside, or on an edge or corner of this
  // quad.
  bool containsPoint(const FloatPoint&) const;

  // Tests whether the four corners of other are inside, or coincident with the
  // sides of this quad. Note that this only works for convex quads, but that
  // includes all quads that originate from transformed rects.
  bool containsQuad(const FloatQuad&) const;

  // Tests whether any part of the rectangle intersects with this quad.
  // This only works for convex quads.
  bool intersectsRect(const FloatRect&) const;

  // Test whether any part of the circle/ellipse intersects with this quad.
  // Note that these two functions only work for convex quads.
  bool intersectsCircle(const FloatPoint& center, float radius) const;
  bool intersectsEllipse(const FloatPoint& center,
                         const FloatSize& radii) const;

  // The center of the quad. If the quad is the result of a affine-transformed
  // rectangle this is the same as the original center transformed.
  FloatPoint center() const {
    return FloatPoint((m_p1.x() + m_p2.x() + m_p3.x() + m_p4.x()) / 4.0,
                      (m_p1.y() + m_p2.y() + m_p3.y() + m_p4.y()) / 4.0);
  }

  FloatRect boundingBox() const;
  IntRect enclosingBoundingBox() const {
    return enclosingIntRect(boundingBox());
  }

  void move(const FloatSize& offset) {
    m_p1 += offset;
    m_p2 += offset;
    m_p3 += offset;
    m_p4 += offset;
  }

  void move(float dx, float dy) {
    m_p1.move(dx, dy);
    m_p2.move(dx, dy);
    m_p3.move(dx, dy);
    m_p4.move(dx, dy);
  }

  void scale(float dx, float dy) {
    m_p1.scale(dx, dy);
    m_p2.scale(dx, dy);
    m_p3.scale(dx, dy);
    m_p4.scale(dx, dy);
  }

  // Tests whether points are in clock-wise, or counter clock-wise order.
  // Note that output is undefined when all points are colinear.
  bool isCounterclockwise() const;

 private:
  FloatPoint m_p1;
  FloatPoint m_p2;
  FloatPoint m_p3;
  FloatPoint m_p4;
};

inline FloatQuad& operator+=(FloatQuad& a, const FloatSize& b) {
  a.move(b);
  return a;
}

inline FloatQuad& operator-=(FloatQuad& a, const FloatSize& b) {
  a.move(-b.width(), -b.height());
  return a;
}

inline bool operator==(const FloatQuad& a, const FloatQuad& b) {
  return a.p1() == b.p1() && a.p2() == b.p2() && a.p3() == b.p3() &&
         a.p4() == b.p4();
}

inline bool operator!=(const FloatQuad& a, const FloatQuad& b) {
  return a.p1() != b.p1() || a.p2() != b.p2() || a.p3() != b.p3() ||
         a.p4() != b.p4();
}

}  // namespace blink

#endif  // SKY_ENGINE_PLATFORM_GEOMETRY_FLOATQUAD_H_