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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_GFX_QUAD_F_H_
      6 #define UI_GFX_QUAD_F_H_
      7 
      8 #include <algorithm>
      9 #include <cmath>
     10 #include <string>
     11 
     12 #include "ui/gfx/gfx_export.h"
     13 #include "ui/gfx/point_f.h"
     14 #include "ui/gfx/rect_f.h"
     15 
     16 namespace gfx {
     17 
     18 // A Quad is defined by four corners, allowing it to have edges that are not
     19 // axis-aligned, unlike a Rect.
     20 class GFX_EXPORT QuadF {
     21  public:
     22   QuadF() {}
     23   QuadF(const PointF& p1, const PointF& p2, const PointF& p3, const PointF& p4)
     24       : p1_(p1),
     25         p2_(p2),
     26         p3_(p3),
     27         p4_(p4) {}
     28 
     29   explicit QuadF(const RectF& rect)
     30       : p1_(rect.x(), rect.y()),
     31         p2_(rect.right(), rect.y()),
     32         p3_(rect.right(), rect.bottom()),
     33         p4_(rect.x(), rect.bottom()) {}
     34 
     35   void operator=(const RectF& rect);
     36 
     37   void set_p1(const PointF& p) { p1_ = p; }
     38   void set_p2(const PointF& p) { p2_ = p; }
     39   void set_p3(const PointF& p) { p3_ = p; }
     40   void set_p4(const PointF& p) { p4_ = p; }
     41 
     42   const PointF& p1() const { return p1_; }
     43   const PointF& p2() const { return p2_; }
     44   const PointF& p3() const { return p3_; }
     45   const PointF& p4() const { return p4_; }
     46 
     47   // Returns true if the quad is an axis-aligned rectangle.
     48   bool IsRectilinear() const;
     49 
     50   // Returns true if the points of the quad are in counter-clockwise order. This
     51   // assumes that the quad is convex, and that no three points are collinear.
     52   bool IsCounterClockwise() const;
     53 
     54   // Returns true if the |point| is contained within the quad, or lies on on
     55   // edge of the quad.
     56   bool Contains(const gfx::PointF& point) const;
     57 
     58   // Returns a rectangle that bounds the four points of the quad. The points of
     59   // the quad may lie on the right/bottom edge of the resulting rectangle,
     60   // rather than being strictly inside it.
     61   RectF BoundingBox() const {
     62     float rl = std::min(std::min(p1_.x(), p2_.x()), std::min(p3_.x(), p4_.x()));
     63     float rr = std::max(std::max(p1_.x(), p2_.x()), std::max(p3_.x(), p4_.x()));
     64     float rt = std::min(std::min(p1_.y(), p2_.y()), std::min(p3_.y(), p4_.y()));
     65     float rb = std::max(std::max(p1_.y(), p2_.y()), std::max(p3_.y(), p4_.y()));
     66     return RectF(rl, rt, rr - rl, rb - rt);
     67   }
     68 
     69   // Add a vector to the quad, offseting each point in the quad by the vector.
     70   void operator+=(const Vector2dF& rhs);
     71   // Subtract a vector from the quad, offseting each point in the quad by the
     72   // inverse of the vector.
     73   void operator-=(const Vector2dF& rhs);
     74 
     75   // Scale each point in the quad by the |scale| factor.
     76   void Scale(float scale) { Scale(scale, scale); }
     77 
     78   // Scale each point in the quad by the scale factors along each axis.
     79   void Scale(float x_scale, float y_scale);
     80 
     81   // Returns a string representation of quad.
     82   std::string ToString() const;
     83 
     84  private:
     85   PointF p1_;
     86   PointF p2_;
     87   PointF p3_;
     88   PointF p4_;
     89 };
     90 
     91 inline bool operator==(const QuadF& lhs, const QuadF& rhs) {
     92   return
     93       lhs.p1() == rhs.p1() && lhs.p2() == rhs.p2() &&
     94       lhs.p3() == rhs.p3() && lhs.p4() == rhs.p4();
     95 }
     96 
     97 inline bool operator!=(const QuadF& lhs, const QuadF& rhs) {
     98   return !(lhs == rhs);
     99 }
    100 
    101 // Add a vector to a quad, offseting each point in the quad by the vector.
    102 GFX_EXPORT QuadF operator+(const QuadF& lhs, const Vector2dF& rhs);
    103 // Subtract a vector from a quad, offseting each point in the quad by the
    104 // inverse of the vector.
    105 GFX_EXPORT QuadF operator-(const QuadF& lhs, const Vector2dF& rhs);
    106 
    107 }  // namespace gfx
    108 
    109 #endif  // UI_GFX_QUAD_F_H_
    110