| OLD | NEW |
| (Empty) |
| 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 #include "ui/gfx/quad_f.h" | |
| 6 | |
| 7 #include <limits> | |
| 8 | |
| 9 #include "base/strings/stringprintf.h" | |
| 10 | |
| 11 namespace gfx { | |
| 12 | |
| 13 void QuadF::operator=(const RectF& rect) { | |
| 14 p1_ = PointF(rect.x(), rect.y()); | |
| 15 p2_ = PointF(rect.right(), rect.y()); | |
| 16 p3_ = PointF(rect.right(), rect.bottom()); | |
| 17 p4_ = PointF(rect.x(), rect.bottom()); | |
| 18 } | |
| 19 | |
| 20 std::string QuadF::ToString() const { | |
| 21 return base::StringPrintf("%s;%s;%s;%s", | |
| 22 p1_.ToString().c_str(), | |
| 23 p2_.ToString().c_str(), | |
| 24 p3_.ToString().c_str(), | |
| 25 p4_.ToString().c_str()); | |
| 26 } | |
| 27 | |
| 28 static inline bool WithinEpsilon(float a, float b) { | |
| 29 return std::abs(a - b) < std::numeric_limits<float>::epsilon(); | |
| 30 } | |
| 31 | |
| 32 bool QuadF::IsRectilinear() const { | |
| 33 return | |
| 34 (WithinEpsilon(p1_.x(), p2_.x()) && WithinEpsilon(p2_.y(), p3_.y()) && | |
| 35 WithinEpsilon(p3_.x(), p4_.x()) && WithinEpsilon(p4_.y(), p1_.y())) || | |
| 36 (WithinEpsilon(p1_.y(), p2_.y()) && WithinEpsilon(p2_.x(), p3_.x()) && | |
| 37 WithinEpsilon(p3_.y(), p4_.y()) && WithinEpsilon(p4_.x(), p1_.x())); | |
| 38 } | |
| 39 | |
| 40 bool QuadF::IsCounterClockwise() const { | |
| 41 // This math computes the signed area of the quad. Positive area | |
| 42 // indicates the quad is clockwise; negative area indicates the quad is | |
| 43 // counter-clockwise. Note carefully: this is backwards from conventional | |
| 44 // math because our geometric space uses screen coordiantes with y-axis | |
| 45 // pointing downards. | |
| 46 // Reference: http://mathworld.wolfram.com/PolygonArea.html | |
| 47 | |
| 48 // Up-cast to double so this cannot overflow. | |
| 49 double determinant1 = static_cast<double>(p1_.x()) * p2_.y() | |
| 50 - static_cast<double>(p2_.x()) * p1_.y(); | |
| 51 double determinant2 = static_cast<double>(p2_.x()) * p3_.y() | |
| 52 - static_cast<double>(p3_.x()) * p2_.y(); | |
| 53 double determinant3 = static_cast<double>(p3_.x()) * p4_.y() | |
| 54 - static_cast<double>(p4_.x()) * p3_.y(); | |
| 55 double determinant4 = static_cast<double>(p4_.x()) * p1_.y() | |
| 56 - static_cast<double>(p1_.x()) * p4_.y(); | |
| 57 | |
| 58 return determinant1 + determinant2 + determinant3 + determinant4 < 0; | |
| 59 } | |
| 60 | |
| 61 static inline bool PointIsInTriangle(const PointF& point, | |
| 62 const PointF& r1, | |
| 63 const PointF& r2, | |
| 64 const PointF& r3) { | |
| 65 // Compute the barycentric coordinates of |point| relative to the triangle | |
| 66 // (r1, r2, r3). This algorithm comes from Christer Ericson's Real-Time | |
| 67 // Collision Detection. | |
| 68 Vector2dF v0 = r2 - r1; | |
| 69 Vector2dF v1 = r3 - r1; | |
| 70 Vector2dF v2 = point - r1; | |
| 71 | |
| 72 double dot00 = DotProduct(v0, v0); | |
| 73 double dot01 = DotProduct(v0, v1); | |
| 74 double dot11 = DotProduct(v1, v1); | |
| 75 double dot20 = DotProduct(v2, v0); | |
| 76 double dot21 = DotProduct(v2, v1); | |
| 77 | |
| 78 double denom = dot00 * dot11 - dot01 * dot01; | |
| 79 | |
| 80 double v = (dot11 * dot20 - dot01 * dot21) / denom; | |
| 81 double w = (dot00 * dot21 - dot01 * dot20) / denom; | |
| 82 double u = 1 - v - w; | |
| 83 | |
| 84 // Use the barycentric coordinates to test if |point| is inside the | |
| 85 // triangle (r1, r2, r2). | |
| 86 return (v >= 0) && (w >= 0) && (u >= 0); | |
| 87 } | |
| 88 | |
| 89 bool QuadF::Contains(const PointF& point) const { | |
| 90 return PointIsInTriangle(point, p1_, p2_, p3_) | |
| 91 || PointIsInTriangle(point, p1_, p3_, p4_); | |
| 92 } | |
| 93 | |
| 94 void QuadF::Scale(float x_scale, float y_scale) { | |
| 95 p1_.Scale(x_scale, y_scale); | |
| 96 p2_.Scale(x_scale, y_scale); | |
| 97 p3_.Scale(x_scale, y_scale); | |
| 98 p4_.Scale(x_scale, y_scale); | |
| 99 } | |
| 100 | |
| 101 void QuadF::operator+=(const Vector2dF& rhs) { | |
| 102 p1_ += rhs; | |
| 103 p2_ += rhs; | |
| 104 p3_ += rhs; | |
| 105 p4_ += rhs; | |
| 106 } | |
| 107 | |
| 108 void QuadF::operator-=(const Vector2dF& rhs) { | |
| 109 p1_ -= rhs; | |
| 110 p2_ -= rhs; | |
| 111 p3_ -= rhs; | |
| 112 p4_ -= rhs; | |
| 113 } | |
| 114 | |
| 115 QuadF operator+(const QuadF& lhs, const Vector2dF& rhs) { | |
| 116 QuadF result = lhs; | |
| 117 result += rhs; | |
| 118 return result; | |
| 119 } | |
| 120 | |
| 121 QuadF operator-(const QuadF& lhs, const Vector2dF& rhs) { | |
| 122 QuadF result = lhs; | |
| 123 result -= rhs; | |
| 124 return result; | |
| 125 } | |
| 126 | |
| 127 } // namespace gfx | |
| OLD | NEW |