ui: Create the gfx::QuadF class.

ui/gfx/quad_f.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ui/gfx/quad_f.h"
+
+#include <cmath>
+#include <limits>
+
+#include "base/stringprintf.h"
+
+namespace gfx {
+
+QuadF::QuadF() {
+}
+
+QuadF::QuadF(const PointF& p1,
+             const PointF& p2,
+             const PointF& p3,
+             const PointF& p4)
+    : p1_(p1),
+      p2_(p2),
+      p3_(p3),
+      p4_(p4) {
+}
+
+QuadF::QuadF(const RectF& rect)
+    : p1_(rect.x(), rect.y()),
+      p2_(rect.right(), rect.y()),
+      p3_(rect.right(), rect.bottom()),
+      p4_(rect.x(), rect.bottom()) {
+}
+
+QuadF::~QuadF() {
+}
+
+void QuadF::operator=(const QuadF& quad) {
+  p1_ = quad.p1_;
+  p2_ = quad.p2_;
+  p3_ = quad.p3_;
+  p4_ = quad.p4_;
+}
+
+void QuadF::operator=(const RectF& rect) {
+  p1_ = PointF(rect.x(), rect.y());
+  p2_ = PointF(rect.right(), rect.y());
+  p3_ = PointF(rect.right(), rect.bottom());
+  p4_ = PointF(rect.x(), rect.bottom());
+}
+
+std::string QuadF::ToString() const {
+  return base::StringPrintf("%s;%s;%s;%s",
+                            p1_.ToString().c_str(),
+                            p2_.ToString().c_str(),
+                            p3_.ToString().c_str(),
+                            p4_.ToString().c_str());
+}
+
+static inline bool WithinEpsilon(float a, float b)
+{

[sky, 2012/11/02 15:49:43]

{ on previous line.

[danakj, 2012/11/02 15:55:00]

Done.

+  return std::abs(a - b) < std::numeric_limits<float>::epsilon();
+}
+
+bool QuadF::IsRectilinear() const {
+  return (WithinEpsilon(p1_.x(), p2_.x()) && WithinEpsilon(p2_.y(), p3_.y()) &&
+          WithinEpsilon(p3_.x(), p4_.x()) && WithinEpsilon(p4_.y(), p1_.y()))
+      || (WithinEpsilon(p1_.y(), p2_.y()) && WithinEpsilon(p2_.x(), p3_.x()) &&

[sky, 2012/11/02 15:49:43]

|| on previous line (wrap if you need to).

[danakj, 2012/11/02 15:55:00]

Done.

+          WithinEpsilon(p3_.y(), p4_.y()) && WithinEpsilon(p4_.x(), p1_.x()));
+}
+
+bool QuadF::IsCounterClockwise() const {
+  // Compute if the first three points turn counter-clockwise. If the quad is
+  // convex, this will match the result for all other triples of points as well.
+  return CrossProduct(p2_ - p1_, p3_ - p2_) < 0;
+}
+
+static inline bool PointIsInTriangle(const PointF& point,
+                                     const PointF& r1,
+                                     const PointF& r2,
+                                     const PointF& r3) {
+  // Compute the barycentric coordinates of |point| relative to the triangle
+  // (r1, r2, r3). This algorithm comes from Christer Ericson's Real-Time
+  // Collision Detection.
+  Vector2dF v0 = r2 - r1;
+  Vector2dF v1 = r3 - r1;
+  Vector2dF v2 = point - r1;
+
+  double dot00 = DotProduct(v0, v0);
+  double dot01 = DotProduct(v0, v1);
+  double dot11 = DotProduct(v1, v1);
+  double dot20 = DotProduct(v2, v0);
+  double dot21 = DotProduct(v2, v1);
+
+  double denom = dot00 * dot11 - dot01 * dot01;
+
+  double v = (dot11 * dot20 - dot01 * dot21) / denom;
+  double w = (dot00 * dot21 - dot01 * dot20) / denom;
+  double u = 1 - v - w;
+
+  // Use the barycentric coordinates to test if |point| is inside the
+  // triangle (r1, r2, r2).
+  return (v >= 0) && (w >= 0) && (u >= 0);
+}
+
+bool QuadF::Contains(const PointF& point) const {
+  return PointIsInTriangle(point, p1_, p2_, p3_)
+      || PointIsInTriangle(point, p1_, p3_, p4_);
+}
+
+RectF QuadF::BoundingBox() const {
+  float rl = std::min(std::min(p1_.x(), p2_.x()), std::min(p3_.x(), p4_.x()));
+  float rr = std::max(std::max(p1_.x(), p2_.x()), std::max(p3_.x(), p4_.x()));
+  float rt = std::min(std::min(p1_.y(), p2_.y()), std::min(p3_.y(), p4_.y()));
+  float rb = std::max(std::max(p1_.y(), p2_.y()), std::max(p3_.y(), p4_.y()));
+  return RectF(rl, rt, rr - rl, rb - rt);
+}
+
+void QuadF::Scale(float x_scale, float y_scale) {
+  p1_ = p1_.Scale(x_scale, y_scale);
+  p2_ = p2_.Scale(x_scale, y_scale);
+  p3_ = p3_.Scale(x_scale, y_scale);
+  p4_ = p4_.Scale(x_scale, y_scale);
+}
+
+void QuadF::operator+=(const Vector2dF& rhs) {
+  p1_ += rhs;
+  p2_ += rhs;
+  p3_ += rhs;
+  p4_ += rhs;
+}
+
+void QuadF::operator-=(const Vector2dF& rhs) {
+  p1_ -= rhs;
+  p2_ -= rhs;
+  p3_ -= rhs;
+  p4_ -= rhs;
+}
+
+QuadF operator+(const QuadF& lhs, const Vector2dF& rhs) {
+  QuadF result = lhs;
+  result += rhs;
+  return result;
+}
+
+QuadF operator-(const QuadF& lhs, const Vector2dF& rhs) {
+  QuadF result = lhs;
+  result -= rhs;
+  return result;
+}
+
+}  // namespace gfx