Mozart: Compute hits using 4x4 matrix.

services/gfx/compositor/graph/transform_pair.h

+// Copyright 2016 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.
+
+#ifndef SERVICES_GFX_COMPOSITOR_GRAPH_TRANSFORM_PAIR_H_
+#define SERVICES_GFX_COMPOSITOR_GRAPH_TRANSFORM_PAIR_H_
+
+#include "third_party/skia/include/utils/SkMatrix44.h"
+
+namespace compositor {
+
+// Contains information about a transformation and its inverse.
+// The inverse is computed lazily and cached.
+class TransformPair {
+ public:
+  TransformPair(const SkMatrix44& forward);
+  ~TransformPair();
+
+  // Gets the forward transformation.
+  const SkMatrix44& forward() const { return forward_; }
+
+  // Gets the inverse transformation.
+  const SkMatrix44& GetInverse() const;
+
+  // Maps a point using the inverse transformation.
+  const SkPoint InverseMapPoint(const SkPoint& point) const;
+
+ private:
+  const SkMatrix44 forward_;
+  mutable SkMatrix44 cached_inverse_;
+  mutable bool cached_inverse_valid_ = false;
+};
+
+}  // namespace compositor
+
+#endif  // SERVICES_GFX_COMPOSITOR_GRAPH_TRANSFORM_PAIR_H_