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      1 // Copyright 2011 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 "cc/resources/layer_quad.h"
      6 
      7 #include "base/logging.h"
      8 #include "ui/gfx/quad_f.h"
      9 
     10 namespace cc {
     11 
     12 LayerQuad::Edge::Edge(const gfx::PointF& p, const gfx::PointF& q) {
     13   DCHECK(p != q);
     14 
     15   gfx::Vector2dF tangent(p.y() - q.y(), q.x() - p.x());
     16   float cross2 = p.x() * q.y() - q.x() * p.y();
     17 
     18   set(tangent.x(), tangent.y(), cross2);
     19   scale(1.0f / tangent.Length());
     20 }
     21 
     22 LayerQuad::LayerQuad(const gfx::QuadF& quad) {
     23   // Create edges.
     24   left_ = Edge(quad.p4(), quad.p1());
     25   right_ = Edge(quad.p2(), quad.p3());
     26   top_ = Edge(quad.p1(), quad.p2());
     27   bottom_ = Edge(quad.p3(), quad.p4());
     28 
     29   float sign = quad.IsCounterClockwise() ? -1 : 1;
     30   left_.scale(sign);
     31   right_.scale(sign);
     32   top_.scale(sign);
     33   bottom_.scale(sign);
     34 }
     35 
     36 LayerQuad::LayerQuad(const Edge& left,
     37                      const Edge& top,
     38                      const Edge& right,
     39                      const Edge& bottom)
     40     : left_(left),
     41       top_(top),
     42       right_(right),
     43       bottom_(bottom) {}
     44 
     45 gfx::QuadF LayerQuad::ToQuadF() const {
     46   return gfx::QuadF(left_.Intersect(top_),
     47                     top_.Intersect(right_),
     48                     right_.Intersect(bottom_),
     49                     bottom_.Intersect(left_));
     50 }
     51 
     52 void LayerQuad::ToFloatArray(float flattened[12]) const {
     53   flattened[0] = left_.x();
     54   flattened[1] = left_.y();
     55   flattened[2] = left_.z();
     56   flattened[3] = top_.x();
     57   flattened[4] = top_.y();
     58   flattened[5] = top_.z();
     59   flattened[6] = right_.x();
     60   flattened[7] = right_.y();
     61   flattened[8] = right_.z();
     62   flattened[9] = bottom_.x();
     63   flattened[10] = bottom_.y();
     64   flattened[11] = bottom_.z();
     65 }
     66 
     67 }  // namespace cc
     68