| // Copyright 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 "cc/base/math_util.h" | 
 |  | 
 | #include <algorithm> | 
 | #include <cmath> | 
 | #include <limits> | 
 |  | 
 | #include "base/trace_event/trace_event_argument.h" | 
 | #include "base/values.h" | 
 | #include "ui/gfx/geometry/quad_f.h" | 
 | #include "ui/gfx/geometry/rect.h" | 
 | #include "ui/gfx/geometry/rect_conversions.h" | 
 | #include "ui/gfx/geometry/rect_f.h" | 
 | #include "ui/gfx/geometry/vector2d_f.h" | 
 | #include "ui/gfx/geometry/vector3d_f.h" | 
 | #include "ui/gfx/transform.h" | 
 |  | 
 | namespace cc { | 
 |  | 
 | const double MathUtil::kPiDouble = 3.14159265358979323846; | 
 | const float MathUtil::kPiFloat = 3.14159265358979323846f; | 
 |  | 
 | static HomogeneousCoordinate ProjectHomogeneousPoint( | 
 |     const gfx::Transform& transform, | 
 |     const gfx::PointF& p) { | 
 |   SkMScalar z = | 
 |       -(transform.matrix().get(2, 0) * p.x() + | 
 |         transform.matrix().get(2, 1) * p.y() + transform.matrix().get(2, 3)) / | 
 |       transform.matrix().get(2, 2); | 
 |  | 
 |   // In this case, the layer we are trying to project onto is perpendicular to | 
 |   // ray (point p and z-axis direction) that we are trying to project. This | 
 |   // happens when the layer is rotated so that it is infinitesimally thin, or | 
 |   // when it is co-planar with the camera origin -- i.e. when the layer is | 
 |   // invisible anyway. | 
 |   if (!std::isfinite(z)) | 
 |     return HomogeneousCoordinate(0.0, 0.0, 0.0, 1.0); | 
 |  | 
 |   HomogeneousCoordinate result(p.x(), p.y(), z, 1.0); | 
 |   transform.matrix().mapMScalars(result.vec, result.vec); | 
 |   return result; | 
 | } | 
 |  | 
 | static HomogeneousCoordinate ProjectHomogeneousPoint( | 
 |     const gfx::Transform& transform, | 
 |     const gfx::PointF& p, | 
 |     bool* clipped) { | 
 |   HomogeneousCoordinate h = ProjectHomogeneousPoint(transform, p); | 
 |   *clipped = h.w() <= 0; | 
 |   return h; | 
 | } | 
 |  | 
 | static HomogeneousCoordinate MapHomogeneousPoint( | 
 |     const gfx::Transform& transform, | 
 |     const gfx::Point3F& p) { | 
 |   HomogeneousCoordinate result(p.x(), p.y(), p.z(), 1.0); | 
 |   transform.matrix().mapMScalars(result.vec, result.vec); | 
 |   return result; | 
 | } | 
 |  | 
 | static HomogeneousCoordinate ComputeClippedPointForEdge( | 
 |     const HomogeneousCoordinate& h1, | 
 |     const HomogeneousCoordinate& h2) { | 
 |   // Points h1 and h2 form a line in 4d, and any point on that line can be | 
 |   // represented as an interpolation between h1 and h2: | 
 |   //    p = (1-t) h1 + (t) h2 | 
 |   // | 
 |   // We want to compute point p such that p.w == epsilon, where epsilon is a | 
 |   // small non-zero number. (but the smaller the number is, the higher the risk | 
 |   // of overflow) | 
 |   // To do this, we solve for t in the following equation: | 
 |   //    p.w = epsilon = (1-t) * h1.w + (t) * h2.w | 
 |   // | 
 |   // Once paramter t is known, the rest of p can be computed via | 
 |   //    p = (1-t) h1 + (t) h2. | 
 |  | 
 |   // Technically this is a special case of the following assertion, but its a | 
 |   // good idea to keep it an explicit sanity check here. | 
 |   DCHECK_NE(h2.w(), h1.w()); | 
 |   // Exactly one of h1 or h2 (but not both) must be on the negative side of the | 
 |   // w plane when this is called. | 
 |   DCHECK(h1.ShouldBeClipped() ^ h2.ShouldBeClipped()); | 
 |  | 
 |   // ...or any positive non-zero small epsilon | 
 |   SkMScalar w = 0.00001f; | 
 |   SkMScalar t = (w - h1.w()) / (h2.w() - h1.w()); | 
 |  | 
 |   SkMScalar x = (SK_MScalar1 - t) * h1.x() + t * h2.x(); | 
 |   SkMScalar y = (SK_MScalar1 - t) * h1.y() + t * h2.y(); | 
 |   SkMScalar z = (SK_MScalar1 - t) * h1.z() + t * h2.z(); | 
 |  | 
 |   return HomogeneousCoordinate(x, y, z, w); | 
 | } | 
 |  | 
 | static inline void ExpandBoundsToIncludePoint(float* xmin, | 
 |                                               float* xmax, | 
 |                                               float* ymin, | 
 |                                               float* ymax, | 
 |                                               const gfx::PointF& p) { | 
 |   *xmin = std::min(p.x(), *xmin); | 
 |   *xmax = std::max(p.x(), *xmax); | 
 |   *ymin = std::min(p.y(), *ymin); | 
 |   *ymax = std::max(p.y(), *ymax); | 
 | } | 
 |  | 
 | static inline void AddVertexToClippedQuad(const gfx::PointF& new_vertex, | 
 |                                           gfx::PointF clipped_quad[8], | 
 |                                           int* num_vertices_in_clipped_quad) { | 
 |   clipped_quad[*num_vertices_in_clipped_quad] = new_vertex; | 
 |   (*num_vertices_in_clipped_quad)++; | 
 | } | 
 |  | 
 | static inline void AddVertexToClippedQuad3d(const gfx::Point3F& new_vertex, | 
 |                                             gfx::Point3F clipped_quad[8], | 
 |                                             int* num_vertices_in_clipped_quad) { | 
 |   clipped_quad[*num_vertices_in_clipped_quad] = new_vertex; | 
 |   (*num_vertices_in_clipped_quad)++; | 
 | } | 
 |  | 
 | gfx::Rect MathUtil::MapEnclosingClippedRect(const gfx::Transform& transform, | 
 |                                             const gfx::Rect& src_rect) { | 
 |   if (transform.IsIdentityOrIntegerTranslation()) { | 
 |     gfx::Vector2d offset(static_cast<int>(transform.matrix().getFloat(0, 3)), | 
 |                          static_cast<int>(transform.matrix().getFloat(1, 3))); | 
 |     return src_rect + offset; | 
 |   } | 
 |   gfx::RectF mapped_rect = MapClippedRect(transform, gfx::RectF(src_rect)); | 
 |  | 
 |   // gfx::ToEnclosingRect crashes if called on a RectF with any NaN coordinate. | 
 |   if (std::isnan(mapped_rect.x()) || std::isnan(mapped_rect.y()) || | 
 |       std::isnan(mapped_rect.right()) || std::isnan(mapped_rect.bottom())) | 
 |     return gfx::Rect(); | 
 |  | 
 |   return gfx::ToEnclosingRect(mapped_rect); | 
 | } | 
 |  | 
 | gfx::RectF MathUtil::MapClippedRect(const gfx::Transform& transform, | 
 |                                     const gfx::RectF& src_rect) { | 
 |   if (transform.IsIdentityOrTranslation()) { | 
 |     gfx::Vector2dF offset(transform.matrix().getFloat(0, 3), | 
 |                           transform.matrix().getFloat(1, 3)); | 
 |     return src_rect + offset; | 
 |   } | 
 |  | 
 |   // Apply the transform, but retain the result in homogeneous coordinates. | 
 |  | 
 |   SkMScalar quad[4 * 2];  // input: 4 x 2D points | 
 |   quad[0] = src_rect.x(); | 
 |   quad[1] = src_rect.y(); | 
 |   quad[2] = src_rect.right(); | 
 |   quad[3] = src_rect.y(); | 
 |   quad[4] = src_rect.right(); | 
 |   quad[5] = src_rect.bottom(); | 
 |   quad[6] = src_rect.x(); | 
 |   quad[7] = src_rect.bottom(); | 
 |  | 
 |   SkMScalar result[4 * 4];  // output: 4 x 4D homogeneous points | 
 |   transform.matrix().map2(quad, 4, result); | 
 |  | 
 |   HomogeneousCoordinate hc0(result[0], result[1], result[2], result[3]); | 
 |   HomogeneousCoordinate hc1(result[4], result[5], result[6], result[7]); | 
 |   HomogeneousCoordinate hc2(result[8], result[9], result[10], result[11]); | 
 |   HomogeneousCoordinate hc3(result[12], result[13], result[14], result[15]); | 
 |   return ComputeEnclosingClippedRect(hc0, hc1, hc2, hc3); | 
 | } | 
 |  | 
 | gfx::Rect MathUtil::ProjectEnclosingClippedRect(const gfx::Transform& transform, | 
 |                                                 const gfx::Rect& src_rect) { | 
 |   if (transform.IsIdentityOrIntegerTranslation()) { | 
 |     gfx::Vector2d offset(static_cast<int>(transform.matrix().getFloat(0, 3)), | 
 |                          static_cast<int>(transform.matrix().getFloat(1, 3))); | 
 |     return src_rect + offset; | 
 |   } | 
 |   gfx::RectF projected_rect = | 
 |       ProjectClippedRect(transform, gfx::RectF(src_rect)); | 
 |  | 
 |   // gfx::ToEnclosingRect crashes if called on a RectF with any NaN coordinate. | 
 |   if (std::isnan(projected_rect.x()) || std::isnan(projected_rect.y()) || | 
 |       std::isnan(projected_rect.right()) || std::isnan(projected_rect.bottom())) | 
 |     return gfx::Rect(); | 
 |  | 
 |   return gfx::ToEnclosingRect(projected_rect); | 
 | } | 
 |  | 
 | gfx::RectF MathUtil::ProjectClippedRect(const gfx::Transform& transform, | 
 |                                         const gfx::RectF& src_rect) { | 
 |   if (transform.IsIdentityOrTranslation()) { | 
 |     gfx::Vector2dF offset(transform.matrix().getFloat(0, 3), | 
 |                           transform.matrix().getFloat(1, 3)); | 
 |     return src_rect + offset; | 
 |   } | 
 |  | 
 |   // Perform the projection, but retain the result in homogeneous coordinates. | 
 |   gfx::QuadF q = gfx::QuadF(src_rect); | 
 |   HomogeneousCoordinate h1 = ProjectHomogeneousPoint(transform, q.p1()); | 
 |   HomogeneousCoordinate h2 = ProjectHomogeneousPoint(transform, q.p2()); | 
 |   HomogeneousCoordinate h3 = ProjectHomogeneousPoint(transform, q.p3()); | 
 |   HomogeneousCoordinate h4 = ProjectHomogeneousPoint(transform, q.p4()); | 
 |  | 
 |   return ComputeEnclosingClippedRect(h1, h2, h3, h4); | 
 | } | 
 |  | 
 | gfx::Rect MathUtil::MapEnclosedRectWith2dAxisAlignedTransform( | 
 |     const gfx::Transform& transform, | 
 |     const gfx::Rect& rect) { | 
 |   DCHECK(transform.Preserves2dAxisAlignment()); | 
 |  | 
 |   if (transform.IsIdentityOrIntegerTranslation()) { | 
 |     gfx::Vector2d offset(static_cast<int>(transform.matrix().getFloat(0, 3)), | 
 |                          static_cast<int>(transform.matrix().getFloat(1, 3))); | 
 |     return rect + offset; | 
 |   } | 
 |   if (transform.IsIdentityOrTranslation()) { | 
 |     gfx::Vector2dF offset(transform.matrix().getFloat(0, 3), | 
 |                           transform.matrix().getFloat(1, 3)); | 
 |     return gfx::ToEnclosedRect(gfx::RectF(rect) + offset); | 
 |   } | 
 |  | 
 |   SkMScalar quad[2 * 2];  // input: 2 x 2D points | 
 |   quad[0] = rect.x(); | 
 |   quad[1] = rect.y(); | 
 |   quad[2] = rect.right(); | 
 |   quad[3] = rect.bottom(); | 
 |  | 
 |   SkMScalar result[4 * 2];  // output: 2 x 4D homogeneous points | 
 |   transform.matrix().map2(quad, 2, result); | 
 |  | 
 |   HomogeneousCoordinate hc0(result[0], result[1], result[2], result[3]); | 
 |   HomogeneousCoordinate hc1(result[4], result[5], result[6], result[7]); | 
 |   DCHECK(!hc0.ShouldBeClipped()); | 
 |   DCHECK(!hc1.ShouldBeClipped()); | 
 |  | 
 |   gfx::PointF top_left(hc0.CartesianPoint2d()); | 
 |   gfx::PointF bottom_right(hc1.CartesianPoint2d()); | 
 |   return gfx::ToEnclosedRect(gfx::BoundingRect(top_left, bottom_right)); | 
 | } | 
 |  | 
 | void MathUtil::MapClippedQuad(const gfx::Transform& transform, | 
 |                               const gfx::QuadF& src_quad, | 
 |                               gfx::PointF clipped_quad[8], | 
 |                               int* num_vertices_in_clipped_quad) { | 
 |   HomogeneousCoordinate h1 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p1())); | 
 |   HomogeneousCoordinate h2 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p2())); | 
 |   HomogeneousCoordinate h3 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p3())); | 
 |   HomogeneousCoordinate h4 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p4())); | 
 |  | 
 |   // The order of adding the vertices to the array is chosen so that | 
 |   // clockwise / counter-clockwise orientation is retained. | 
 |  | 
 |   *num_vertices_in_clipped_quad = 0; | 
 |  | 
 |   if (!h1.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         h1.CartesianPoint2d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h1.ShouldBeClipped() ^ h2.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         ComputeClippedPointForEdge(h1, h2).CartesianPoint2d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h2.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         h2.CartesianPoint2d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h2.ShouldBeClipped() ^ h3.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         ComputeClippedPointForEdge(h2, h3).CartesianPoint2d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h3.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         h3.CartesianPoint2d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h3.ShouldBeClipped() ^ h4.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         ComputeClippedPointForEdge(h3, h4).CartesianPoint2d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h4.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         h4.CartesianPoint2d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h4.ShouldBeClipped() ^ h1.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad( | 
 |         ComputeClippedPointForEdge(h4, h1).CartesianPoint2d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   DCHECK_LE(*num_vertices_in_clipped_quad, 8); | 
 | } | 
 |  | 
 | bool MathUtil::MapClippedQuad3d(const gfx::Transform& transform, | 
 |                                 const gfx::QuadF& src_quad, | 
 |                                 gfx::Point3F clipped_quad[8], | 
 |                                 int* num_vertices_in_clipped_quad) { | 
 |   HomogeneousCoordinate h1 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p1())); | 
 |   HomogeneousCoordinate h2 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p2())); | 
 |   HomogeneousCoordinate h3 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p3())); | 
 |   HomogeneousCoordinate h4 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(src_quad.p4())); | 
 |  | 
 |   // The order of adding the vertices to the array is chosen so that | 
 |   // clockwise / counter-clockwise orientation is retained. | 
 |  | 
 |   *num_vertices_in_clipped_quad = 0; | 
 |  | 
 |   if (!h1.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         h1.CartesianPoint3d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h1.ShouldBeClipped() ^ h2.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         ComputeClippedPointForEdge(h1, h2).CartesianPoint3d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h2.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         h2.CartesianPoint3d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h2.ShouldBeClipped() ^ h3.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         ComputeClippedPointForEdge(h2, h3).CartesianPoint3d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h3.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         h3.CartesianPoint3d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h3.ShouldBeClipped() ^ h4.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         ComputeClippedPointForEdge(h3, h4).CartesianPoint3d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (!h4.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         h4.CartesianPoint3d(), clipped_quad, num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   if (h4.ShouldBeClipped() ^ h1.ShouldBeClipped()) { | 
 |     AddVertexToClippedQuad3d( | 
 |         ComputeClippedPointForEdge(h4, h1).CartesianPoint3d(), | 
 |         clipped_quad, | 
 |         num_vertices_in_clipped_quad); | 
 |   } | 
 |  | 
 |   DCHECK_LE(*num_vertices_in_clipped_quad, 8); | 
 |   return (*num_vertices_in_clipped_quad >= 4); | 
 | } | 
 |  | 
 | gfx::RectF MathUtil::ComputeEnclosingRectOfVertices( | 
 |     const gfx::PointF vertices[], | 
 |     int num_vertices) { | 
 |   if (num_vertices < 2) | 
 |     return gfx::RectF(); | 
 |  | 
 |   float xmin = std::numeric_limits<float>::max(); | 
 |   float xmax = -std::numeric_limits<float>::max(); | 
 |   float ymin = std::numeric_limits<float>::max(); | 
 |   float ymax = -std::numeric_limits<float>::max(); | 
 |  | 
 |   for (int i = 0; i < num_vertices; ++i) | 
 |     ExpandBoundsToIncludePoint(&xmin, &xmax, &ymin, &ymax, vertices[i]); | 
 |  | 
 |   return gfx::RectF(gfx::PointF(xmin, ymin), | 
 |                     gfx::SizeF(xmax - xmin, ymax - ymin)); | 
 | } | 
 |  | 
 | gfx::RectF MathUtil::ComputeEnclosingClippedRect( | 
 |     const HomogeneousCoordinate& h1, | 
 |     const HomogeneousCoordinate& h2, | 
 |     const HomogeneousCoordinate& h3, | 
 |     const HomogeneousCoordinate& h4) { | 
 |   // This function performs clipping as necessary and computes the enclosing 2d | 
 |   // gfx::RectF of the vertices. Doing these two steps simultaneously allows us | 
 |   // to avoid the overhead of storing an unknown number of clipped vertices. | 
 |  | 
 |   // If no vertices on the quad are clipped, then we can simply return the | 
 |   // enclosing rect directly. | 
 |   bool something_clipped = h1.ShouldBeClipped() || h2.ShouldBeClipped() || | 
 |                            h3.ShouldBeClipped() || h4.ShouldBeClipped(); | 
 |   if (!something_clipped) { | 
 |     gfx::QuadF mapped_quad = gfx::QuadF(h1.CartesianPoint2d(), | 
 |                                         h2.CartesianPoint2d(), | 
 |                                         h3.CartesianPoint2d(), | 
 |                                         h4.CartesianPoint2d()); | 
 |     return mapped_quad.BoundingBox(); | 
 |   } | 
 |  | 
 |   bool everything_clipped = h1.ShouldBeClipped() && h2.ShouldBeClipped() && | 
 |                             h3.ShouldBeClipped() && h4.ShouldBeClipped(); | 
 |   if (everything_clipped) | 
 |     return gfx::RectF(); | 
 |  | 
 |   float xmin = std::numeric_limits<float>::max(); | 
 |   float xmax = -std::numeric_limits<float>::max(); | 
 |   float ymin = std::numeric_limits<float>::max(); | 
 |   float ymax = -std::numeric_limits<float>::max(); | 
 |  | 
 |   if (!h1.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, &xmax, &ymin, &ymax, | 
 |                                h1.CartesianPoint2d()); | 
 |  | 
 |   if (h1.ShouldBeClipped() ^ h2.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, | 
 |                                &xmax, | 
 |                                &ymin, | 
 |                                &ymax, | 
 |                                ComputeClippedPointForEdge(h1, h2) | 
 |                                    .CartesianPoint2d()); | 
 |  | 
 |   if (!h2.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, &xmax, &ymin, &ymax, | 
 |                                h2.CartesianPoint2d()); | 
 |  | 
 |   if (h2.ShouldBeClipped() ^ h3.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, | 
 |                                &xmax, | 
 |                                &ymin, | 
 |                                &ymax, | 
 |                                ComputeClippedPointForEdge(h2, h3) | 
 |                                    .CartesianPoint2d()); | 
 |  | 
 |   if (!h3.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, &xmax, &ymin, &ymax, | 
 |                                h3.CartesianPoint2d()); | 
 |  | 
 |   if (h3.ShouldBeClipped() ^ h4.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, | 
 |                                &xmax, | 
 |                                &ymin, | 
 |                                &ymax, | 
 |                                ComputeClippedPointForEdge(h3, h4) | 
 |                                    .CartesianPoint2d()); | 
 |  | 
 |   if (!h4.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, &xmax, &ymin, &ymax, | 
 |                                h4.CartesianPoint2d()); | 
 |  | 
 |   if (h4.ShouldBeClipped() ^ h1.ShouldBeClipped()) | 
 |     ExpandBoundsToIncludePoint(&xmin, | 
 |                                &xmax, | 
 |                                &ymin, | 
 |                                &ymax, | 
 |                                ComputeClippedPointForEdge(h4, h1) | 
 |                                    .CartesianPoint2d()); | 
 |  | 
 |   return gfx::RectF(gfx::PointF(xmin, ymin), | 
 |                     gfx::SizeF(xmax - xmin, ymax - ymin)); | 
 | } | 
 |  | 
 | gfx::QuadF MathUtil::MapQuad(const gfx::Transform& transform, | 
 |                              const gfx::QuadF& q, | 
 |                              bool* clipped) { | 
 |   if (transform.IsIdentityOrTranslation()) { | 
 |     gfx::QuadF mapped_quad(q); | 
 |     mapped_quad += gfx::Vector2dF(transform.matrix().getFloat(0, 3), | 
 |                                   transform.matrix().getFloat(1, 3)); | 
 |     *clipped = false; | 
 |     return mapped_quad; | 
 |   } | 
 |  | 
 |   HomogeneousCoordinate h1 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p1())); | 
 |   HomogeneousCoordinate h2 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p2())); | 
 |   HomogeneousCoordinate h3 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p3())); | 
 |   HomogeneousCoordinate h4 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p4())); | 
 |  | 
 |   *clipped = h1.ShouldBeClipped() || h2.ShouldBeClipped() || | 
 |             h3.ShouldBeClipped() || h4.ShouldBeClipped(); | 
 |  | 
 |   // Result will be invalid if clipped == true. But, compute it anyway just in | 
 |   // case, to emulate existing behavior. | 
 |   return gfx::QuadF(h1.CartesianPoint2d(), | 
 |                     h2.CartesianPoint2d(), | 
 |                     h3.CartesianPoint2d(), | 
 |                     h4.CartesianPoint2d()); | 
 | } | 
 |  | 
 | gfx::QuadF MathUtil::MapQuad3d(const gfx::Transform& transform, | 
 |                                const gfx::QuadF& q, | 
 |                                gfx::Point3F* p, | 
 |                                bool* clipped) { | 
 |   if (transform.IsIdentityOrTranslation()) { | 
 |     gfx::QuadF mapped_quad(q); | 
 |     mapped_quad += gfx::Vector2dF(transform.matrix().getFloat(0, 3), | 
 |                                   transform.matrix().getFloat(1, 3)); | 
 |     *clipped = false; | 
 |     p[0] = gfx::Point3F(mapped_quad.p1().x(), mapped_quad.p1().y(), 0.0f); | 
 |     p[1] = gfx::Point3F(mapped_quad.p2().x(), mapped_quad.p2().y(), 0.0f); | 
 |     p[2] = gfx::Point3F(mapped_quad.p3().x(), mapped_quad.p3().y(), 0.0f); | 
 |     p[3] = gfx::Point3F(mapped_quad.p4().x(), mapped_quad.p4().y(), 0.0f); | 
 |     return mapped_quad; | 
 |   } | 
 |  | 
 |   HomogeneousCoordinate h1 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p1())); | 
 |   HomogeneousCoordinate h2 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p2())); | 
 |   HomogeneousCoordinate h3 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p3())); | 
 |   HomogeneousCoordinate h4 = | 
 |       MapHomogeneousPoint(transform, gfx::Point3F(q.p4())); | 
 |  | 
 |   *clipped = h1.ShouldBeClipped() || h2.ShouldBeClipped() || | 
 |              h3.ShouldBeClipped() || h4.ShouldBeClipped(); | 
 |  | 
 |   // Result will be invalid if clipped == true. But, compute it anyway just in | 
 |   // case, to emulate existing behavior. | 
 |   p[0] = h1.CartesianPoint3d(); | 
 |   p[1] = h2.CartesianPoint3d(); | 
 |   p[2] = h3.CartesianPoint3d(); | 
 |   p[3] = h4.CartesianPoint3d(); | 
 |  | 
 |   return gfx::QuadF(h1.CartesianPoint2d(), | 
 |                     h2.CartesianPoint2d(), | 
 |                     h3.CartesianPoint2d(), | 
 |                     h4.CartesianPoint2d()); | 
 | } | 
 |  | 
 | gfx::PointF MathUtil::MapPoint(const gfx::Transform& transform, | 
 |                                const gfx::PointF& p, | 
 |                                bool* clipped) { | 
 |   HomogeneousCoordinate h = MapHomogeneousPoint(transform, gfx::Point3F(p)); | 
 |  | 
 |   if (h.w() > 0) { | 
 |     *clipped = false; | 
 |     return h.CartesianPoint2d(); | 
 |   } | 
 |  | 
 |   // The cartesian coordinates will be invalid after dividing by w. | 
 |   *clipped = true; | 
 |  | 
 |   // Avoid dividing by w if w == 0. | 
 |   if (!h.w()) | 
 |     return gfx::PointF(); | 
 |  | 
 |   // This return value will be invalid because clipped == true, but (1) users of | 
 |   // this code should be ignoring the return value when clipped == true anyway, | 
 |   // and (2) this behavior is more consistent with existing behavior of WebKit | 
 |   // transforms if the user really does not ignore the return value. | 
 |   return h.CartesianPoint2d(); | 
 | } | 
 |  | 
 | gfx::Point3F MathUtil::MapPoint(const gfx::Transform& transform, | 
 |                                 const gfx::Point3F& p, | 
 |                                 bool* clipped) { | 
 |   HomogeneousCoordinate h = MapHomogeneousPoint(transform, p); | 
 |  | 
 |   if (h.w() > 0) { | 
 |     *clipped = false; | 
 |     return h.CartesianPoint3d(); | 
 |   } | 
 |  | 
 |   // The cartesian coordinates will be invalid after dividing by w. | 
 |   *clipped = true; | 
 |  | 
 |   // Avoid dividing by w if w == 0. | 
 |   if (!h.w()) | 
 |     return gfx::Point3F(); | 
 |  | 
 |   // This return value will be invalid because clipped == true, but (1) users of | 
 |   // this code should be ignoring the return value when clipped == true anyway, | 
 |   // and (2) this behavior is more consistent with existing behavior of WebKit | 
 |   // transforms if the user really does not ignore the return value. | 
 |   return h.CartesianPoint3d(); | 
 | } | 
 |  | 
 | gfx::QuadF MathUtil::ProjectQuad(const gfx::Transform& transform, | 
 |                                  const gfx::QuadF& q, | 
 |                                  bool* clipped) { | 
 |   gfx::QuadF projected_quad; | 
 |   bool clipped_point; | 
 |   projected_quad.set_p1(ProjectPoint(transform, q.p1(), &clipped_point)); | 
 |   *clipped = clipped_point; | 
 |   projected_quad.set_p2(ProjectPoint(transform, q.p2(), &clipped_point)); | 
 |   *clipped |= clipped_point; | 
 |   projected_quad.set_p3(ProjectPoint(transform, q.p3(), &clipped_point)); | 
 |   *clipped |= clipped_point; | 
 |   projected_quad.set_p4(ProjectPoint(transform, q.p4(), &clipped_point)); | 
 |   *clipped |= clipped_point; | 
 |  | 
 |   return projected_quad; | 
 | } | 
 |  | 
 | gfx::PointF MathUtil::ProjectPoint(const gfx::Transform& transform, | 
 |                                    const gfx::PointF& p, | 
 |                                    bool* clipped) { | 
 |   HomogeneousCoordinate h = ProjectHomogeneousPoint(transform, p, clipped); | 
 |   // Avoid dividing by w if w == 0. | 
 |   if (!h.w()) | 
 |     return gfx::PointF(); | 
 |  | 
 |   // This return value will be invalid if clipped == true, but (1) users of | 
 |   // this code should be ignoring the return value when clipped == true anyway, | 
 |   // and (2) this behavior is more consistent with existing behavior of WebKit | 
 |   // transforms if the user really does not ignore the return value. | 
 |   return h.CartesianPoint2d(); | 
 | } | 
 |  | 
 | gfx::Point3F MathUtil::ProjectPoint3D(const gfx::Transform& transform, | 
 |                                       const gfx::PointF& p, | 
 |                                       bool* clipped) { | 
 |   HomogeneousCoordinate h = ProjectHomogeneousPoint(transform, p, clipped); | 
 |   if (!h.w()) | 
 |     return gfx::Point3F(); | 
 |   return h.CartesianPoint3d(); | 
 | } | 
 |  | 
 | gfx::RectF MathUtil::ScaleRectProportional(const gfx::RectF& input_outer_rect, | 
 |                                            const gfx::RectF& scale_outer_rect, | 
 |                                            const gfx::RectF& scale_inner_rect) { | 
 |   gfx::RectF output_inner_rect = input_outer_rect; | 
 |   float scale_rect_to_input_scale_x = | 
 |       scale_outer_rect.width() / input_outer_rect.width(); | 
 |   float scale_rect_to_input_scale_y = | 
 |       scale_outer_rect.height() / input_outer_rect.height(); | 
 |  | 
 |   gfx::Vector2dF top_left_diff = | 
 |       scale_inner_rect.origin() - scale_outer_rect.origin(); | 
 |   gfx::Vector2dF bottom_right_diff = | 
 |       scale_inner_rect.bottom_right() - scale_outer_rect.bottom_right(); | 
 |   output_inner_rect.Inset(top_left_diff.x() / scale_rect_to_input_scale_x, | 
 |                           top_left_diff.y() / scale_rect_to_input_scale_y, | 
 |                           -bottom_right_diff.x() / scale_rect_to_input_scale_x, | 
 |                           -bottom_right_diff.y() / scale_rect_to_input_scale_y); | 
 |   return output_inner_rect; | 
 | } | 
 |  | 
 | static inline bool NearlyZero(double value) { | 
 |   return std::abs(value) < std::numeric_limits<double>::epsilon(); | 
 | } | 
 |  | 
 | static inline float ScaleOnAxis(double a, double b, double c) { | 
 |   if (NearlyZero(b) && NearlyZero(c)) | 
 |     return std::abs(a); | 
 |   if (NearlyZero(a) && NearlyZero(c)) | 
 |     return std::abs(b); | 
 |   if (NearlyZero(a) && NearlyZero(b)) | 
 |     return std::abs(c); | 
 |  | 
 |   // Do the sqrt as a double to not lose precision. | 
 |   return static_cast<float>(std::sqrt(a * a + b * b + c * c)); | 
 | } | 
 |  | 
 | gfx::Vector2dF MathUtil::ComputeTransform2dScaleComponents( | 
 |     const gfx::Transform& transform, | 
 |     float fallback_value) { | 
 |   if (transform.HasPerspective()) | 
 |     return gfx::Vector2dF(fallback_value, fallback_value); | 
 |   float x_scale = ScaleOnAxis(transform.matrix().getDouble(0, 0), | 
 |                               transform.matrix().getDouble(1, 0), | 
 |                               transform.matrix().getDouble(2, 0)); | 
 |   float y_scale = ScaleOnAxis(transform.matrix().getDouble(0, 1), | 
 |                               transform.matrix().getDouble(1, 1), | 
 |                               transform.matrix().getDouble(2, 1)); | 
 |   return gfx::Vector2dF(x_scale, y_scale); | 
 | } | 
 |  | 
 | float MathUtil::SmallestAngleBetweenVectors(const gfx::Vector2dF& v1, | 
 |                                             const gfx::Vector2dF& v2) { | 
 |   double dot_product = gfx::DotProduct(v1, v2) / v1.Length() / v2.Length(); | 
 |   // Clamp to compensate for rounding errors. | 
 |   dot_product = std::max(-1.0, std::min(1.0, dot_product)); | 
 |   return static_cast<float>(Rad2Deg(std::acos(dot_product))); | 
 | } | 
 |  | 
 | gfx::Vector2dF MathUtil::ProjectVector(const gfx::Vector2dF& source, | 
 |                                        const gfx::Vector2dF& destination) { | 
 |   float projected_length = | 
 |       gfx::DotProduct(source, destination) / destination.LengthSquared(); | 
 |   return gfx::Vector2dF(projected_length * destination.x(), | 
 |                         projected_length * destination.y()); | 
 | } | 
 |  | 
 | scoped_ptr<base::Value> MathUtil::AsValue(const gfx::Size& s) { | 
 |   scoped_ptr<base::DictionaryValue> res(new base::DictionaryValue()); | 
 |   res->SetDouble("width", s.width()); | 
 |   res->SetDouble("height", s.height()); | 
 |   return std::move(res); | 
 | } | 
 |  | 
 | scoped_ptr<base::Value> MathUtil::AsValue(const gfx::Rect& r) { | 
 |   scoped_ptr<base::ListValue> res(new base::ListValue()); | 
 |   res->AppendInteger(r.x()); | 
 |   res->AppendInteger(r.y()); | 
 |   res->AppendInteger(r.width()); | 
 |   res->AppendInteger(r.height()); | 
 |   return std::move(res); | 
 | } | 
 |  | 
 | bool MathUtil::FromValue(const base::Value* raw_value, gfx::Rect* out_rect) { | 
 |   const base::ListValue* value = nullptr; | 
 |   if (!raw_value->GetAsList(&value)) | 
 |     return false; | 
 |  | 
 |   if (value->GetSize() != 4) | 
 |     return false; | 
 |  | 
 |   int x, y, w, h; | 
 |   bool ok = true; | 
 |   ok &= value->GetInteger(0, &x); | 
 |   ok &= value->GetInteger(1, &y); | 
 |   ok &= value->GetInteger(2, &w); | 
 |   ok &= value->GetInteger(3, &h); | 
 |   if (!ok) | 
 |     return false; | 
 |  | 
 |   *out_rect = gfx::Rect(x, y, w, h); | 
 |   return true; | 
 | } | 
 |  | 
 | scoped_ptr<base::Value> MathUtil::AsValue(const gfx::PointF& pt) { | 
 |   scoped_ptr<base::ListValue> res(new base::ListValue()); | 
 |   res->AppendDouble(pt.x()); | 
 |   res->AppendDouble(pt.y()); | 
 |   return std::move(res); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Size& s, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginDictionary(name); | 
 |   res->SetDouble("width", s.width()); | 
 |   res->SetDouble("height", s.height()); | 
 |   res->EndDictionary(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::SizeF& s, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginDictionary(name); | 
 |   res->SetDouble("width", s.width()); | 
 |   res->SetDouble("height", s.height()); | 
 |   res->EndDictionary(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Rect& r, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendInteger(r.x()); | 
 |   res->AppendInteger(r.y()); | 
 |   res->AppendInteger(r.width()); | 
 |   res->AppendInteger(r.height()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Point& pt, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendInteger(pt.x()); | 
 |   res->AppendInteger(pt.y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::PointF& pt, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(pt.x()); | 
 |   res->AppendDouble(pt.y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Point3F& pt, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(pt.x()); | 
 |   res->AppendDouble(pt.y()); | 
 |   res->AppendDouble(pt.z()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Vector2d& v, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendInteger(v.x()); | 
 |   res->AppendInteger(v.y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Vector2dF& v, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(v.x()); | 
 |   res->AppendDouble(v.y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::ScrollOffset& v, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(v.x()); | 
 |   res->AppendDouble(v.y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::QuadF& q, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(q.p1().x()); | 
 |   res->AppendDouble(q.p1().y()); | 
 |   res->AppendDouble(q.p2().x()); | 
 |   res->AppendDouble(q.p2().y()); | 
 |   res->AppendDouble(q.p3().x()); | 
 |   res->AppendDouble(q.p3().y()); | 
 |   res->AppendDouble(q.p4().x()); | 
 |   res->AppendDouble(q.p4().y()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::RectF& rect, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendDouble(rect.x()); | 
 |   res->AppendDouble(rect.y()); | 
 |   res->AppendDouble(rect.width()); | 
 |   res->AppendDouble(rect.height()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::Transform& transform, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   const SkMatrix44& m = transform.matrix(); | 
 |   for (int row = 0; row < 4; ++row) { | 
 |     for (int col = 0; col < 4; ++col) | 
 |       res->AppendDouble(m.getDouble(row, col)); | 
 |   } | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | void MathUtil::AddToTracedValue(const char* name, | 
 |                                 const gfx::BoxF& box, | 
 |                                 base::trace_event::TracedValue* res) { | 
 |   res->BeginArray(name); | 
 |   res->AppendInteger(box.x()); | 
 |   res->AppendInteger(box.y()); | 
 |   res->AppendInteger(box.z()); | 
 |   res->AppendInteger(box.width()); | 
 |   res->AppendInteger(box.height()); | 
 |   res->AppendInteger(box.depth()); | 
 |   res->EndArray(); | 
 | } | 
 |  | 
 | double MathUtil::AsDoubleSafely(double value) { | 
 |   return std::min(value, std::numeric_limits<double>::max()); | 
 | } | 
 |  | 
 | float MathUtil::AsFloatSafely(float value) { | 
 |   return std::min(value, std::numeric_limits<float>::max()); | 
 | } | 
 |  | 
 | gfx::Vector3dF MathUtil::GetXAxis(const gfx::Transform& transform) { | 
 |   return gfx::Vector3dF(transform.matrix().getFloat(0, 0), | 
 |                         transform.matrix().getFloat(1, 0), | 
 |                         transform.matrix().getFloat(2, 0)); | 
 | } | 
 |  | 
 | gfx::Vector3dF MathUtil::GetYAxis(const gfx::Transform& transform) { | 
 |   return gfx::Vector3dF(transform.matrix().getFloat(0, 1), | 
 |                         transform.matrix().getFloat(1, 1), | 
 |                         transform.matrix().getFloat(2, 1)); | 
 | } | 
 |  | 
 | }  // namespace cc |