Bug 1236750 - Add typed getters for layer transform matrices. r=kats

--HG--
extra : source : bf19963d10d6cc021092662176845192764f9cf0

gfx/layers/LayerMetricsWrapper.h

@@ -7,6 +7,7 @@
 #define GFX_LAYERMETRICSWRAPPER_H
 
 #include "Layers.h"
+#include "UnitTransforms.h"
 
 namespace mozilla {
 namespace layers {
@@ -299,6 +300,11 @@ public:
     return gfx::Matrix4x4();
   }
 
+  CSSTransformMatrix GetTransformTyped() const
+  {
+    return ViewAs<CSSTransformMatrix>(GetTransform());
+  }
+
   bool TransformIsPerspective() const
   {
     MOZ_ASSERT(IsValid());

gfx/layers/Layers.cpp

@@ -895,6 +895,12 @@ Layer::GetTransform() const
   return transform;
 }
 
+const CSSTransformMatrix
+Layer::GetTransformTyped() const
+{
+  return ViewAs<CSSTransformMatrix>(GetTransform());
+}
+
 const Matrix4x4
 Layer::GetLocalTransform()
 {
@@ -912,6 +918,12 @@ Layer::GetLocalTransform()
   return transform;
 }
 
+const LayerToParentLayerMatrix4x4
+Layer::GetLocalTransformTyped()
+{
+  return ViewAs<LayerToParentLayerMatrix4x4>(GetLocalTransform());
+}
+
 bool
 Layer::HasTransformAnimation() const
 {

gfx/layers/Layers.h

@@ -1276,6 +1276,9 @@ public:
   virtual Layer* GetFirstChild() const { return nullptr; }
   virtual Layer* GetLastChild() const { return nullptr; }
   const gfx::Matrix4x4 GetTransform() const;
+  // Same as GetTransform(), but returns the transform as a strongly-typed
+  // matrix. Eventually this will replace GetTransform().
+  const CSSTransformMatrix GetTransformTyped() const;
   const gfx::Matrix4x4& GetBaseTransform() const { return mTransform; }
   // Note: these are virtual because ContainerLayerComposite overrides them.
   virtual float GetPostXScale() const { return mPostXScale; }
@@ -1346,10 +1349,17 @@ public:
 
   /**
    * Returns the local transform for this layer: either mTransform or,
-   * for shadow layers, GetShadowTransform()
+   * for shadow layers, GetShadowTransform(), in either case with the
+   * pre- and post-scales applied.
    */
   const gfx::Matrix4x4 GetLocalTransform();
 
+  /**
+   * Same as GetLocalTransform(), but returns a strongly-typed matrix.
+   * Eventually, this will replace GetLocalTransform().
+   */
+  const LayerToParentLayerMatrix4x4 GetLocalTransformTyped();
+
   /**
    * Returns the local opacity for this layer: either mOpacity or,
    * for shadow layers, GetShadowOpacity()