From 62d1425e0b7d7333ed9907beb671a4cd1033b9c5 Mon Sep 17 00:00:00 2001
From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Wed, 3 Aug 2011 15:04:23 +1200
Subject: [PATCH] Bug 505115 - Part 11b - Layout changes to use a z component
 for -moz-transform-origin. r=roc

---
 gfx/thebes/gfx3DMatrix.cpp    | 11 +++++++++++
 gfx/thebes/gfx3DMatrix.h      |  1 +
 layout/base/nsDisplayList.cpp | 19 +++++++++++--------
 layout/base/nsLayoutUtils.cpp | 10 ++++------
 layout/base/nsLayoutUtils.h   |  2 +-
 5 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/gfx/thebes/gfx3DMatrix.cpp b/gfx/thebes/gfx3DMatrix.cpp
index d03a7d2b522..710d94459ae 100644
--- a/gfx/thebes/gfx3DMatrix.cpp
+++ b/gfx/thebes/gfx3DMatrix.cpp
@@ -147,6 +147,17 @@ gfx3DMatrix::Translation(float aX, float aY, float aZ)
   return matrix;
 }
 
+gfx3DMatrix
+gfx3DMatrix::Translation(const gfxPoint3D& aPoint)
+{
+  gfx3DMatrix matrix;
+
+  matrix._41 = aPoint.x;
+  matrix._42 = aPoint.y;
+  matrix._43 = aPoint.z;
+  return matrix;
+}
+
 gfx3DMatrix
 gfx3DMatrix::Scale(float aFactor)
 {
diff --git a/gfx/thebes/gfx3DMatrix.h b/gfx/thebes/gfx3DMatrix.h
index f1d594a5d7b..afb8b638c3a 100644
--- a/gfx/thebes/gfx3DMatrix.h
+++ b/gfx/thebes/gfx3DMatrix.h
@@ -153,6 +153,7 @@ public:
    * \param aZ Translation on Z-axis.
    */
   static gfx3DMatrix Translation(float aX, float aY, float aZ);
+  static gfx3DMatrix Translation(const gfxPoint3D& aPoint);
 
   /**
    * Create a scale matrix. Scales uniformly along all axes.
diff --git a/layout/base/nsDisplayList.cpp b/layout/base/nsDisplayList.cpp
index 3cb51fdd3c6..151e59ce88c 100644
--- a/layout/base/nsDisplayList.cpp
+++ b/layout/base/nsDisplayList.cpp
@@ -2298,9 +2298,9 @@ nsDisplayTransform::GetFrameBoundsForTransform(const nsIFrame* aFrame)
  * to get from (0, 0) of the frame to the transform origin.
  */
 static
-gfxPoint GetDeltaToMozTransformOrigin(const nsIFrame* aFrame,
-                                      float aFactor,
-                                      const nsRect* aBoundsOverride)
+gfxPoint3D GetDeltaToMozTransformOrigin(const nsIFrame* aFrame,
+                                        float aFactor,
+                                        const nsRect* aBoundsOverride)
 {
   NS_PRECONDITION(aFrame, "Can't get delta for a null frame!");
   NS_PRECONDITION(aFrame->GetStyleDisplay()->HasTransform(),
@@ -2315,8 +2315,8 @@ gfxPoint GetDeltaToMozTransformOrigin(const nsIFrame* aFrame,
                          nsDisplayTransform::GetFrameBoundsForTransform(aFrame));
 
   /* Allows us to access named variables by index. */
-  gfxPoint result;
-  gfxFloat* coords[2] = {&result.x, &result.y};
+  gfxPoint3D result;
+  gfxFloat* coords[3] = {&result.x, &result.y, &result.z};
   const nscoord* dimensions[2] =
     {&boundingRect.width, &boundingRect.height};
 
@@ -2338,6 +2338,8 @@ gfxPoint GetDeltaToMozTransformOrigin(const nsIFrame* aFrame,
       *coords[index] = NSAppUnitsToFloatPixels(coord.GetCoordValue(), aFactor);
     }
   }
+
+  *coords[2] = NSAppUnitsToFloatPixels(display->mTransformOrigin[2].GetCoordValue(), aFactor);
   
   /* Adjust based on the origin of the rectangle. */
   result.x += NSAppUnitsToFloatPixels(boundingRect.x, aFactor);
@@ -2363,9 +2365,10 @@ nsDisplayTransform::GetResultingTransformMatrix(const nsIFrame* aFrame,
   /* Account for the -moz-transform-origin property by translating the
    * coordinate space to the new origin.
    */
-  gfxPoint toMozOrigin = GetDeltaToMozTransformOrigin(aFrame, aFactor, aBoundsOverride);
-  gfxPoint newOrigin = gfxPoint(NSAppUnitsToFloatPixels(aOrigin.x, aFactor),
-                                NSAppUnitsToFloatPixels(aOrigin.y, aFactor));
+  gfxPoint3D toMozOrigin = GetDeltaToMozTransformOrigin(aFrame, aFactor, aBoundsOverride);
+  gfxPoint3D newOrigin = gfxPoint3D(NSAppUnitsToFloatPixels(aOrigin.x, aFactor),
+                                    NSAppUnitsToFloatPixels(aOrigin.y, aFactor),
+                                    0.0f);
 
   /* Get the underlying transform matrix.  This requires us to get the
    * bounds of the frame.
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index d8977ba8ddf..2bc81129e99 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -1002,16 +1002,14 @@ nsLayoutUtils::GetPopupFrameForEventCoordinates(nsPresContext* aPresContext,
 }
 
 gfx3DMatrix
-nsLayoutUtils::ChangeMatrixBasis(const gfxPoint &aOrigin,
+nsLayoutUtils::ChangeMatrixBasis(const gfxPoint3D &aOrigin,
                                  const gfx3DMatrix &aMatrix)
 {
   /* These are translation matrices from world-to-origin of relative frame and
-   * vice-versa.  Although I could use the gfxMatrix::Translate function to
-   * accomplish this, I'm hoping to reduce the overall number of matrix
-   * operations by hardcoding as many of the matrices as possible.
+   * vice-versa.
    */
-  gfx3DMatrix worldToOrigin = gfx3DMatrix::From2D(gfxMatrix(1.0, 0.0, 0.0, 1.0, -aOrigin.x, -aOrigin.y));
-  gfx3DMatrix originToWorld = gfx3DMatrix::From2D(gfxMatrix(1.0, 0.0, 0.0, 1.0,  aOrigin.x,  aOrigin.y));
+  gfx3DMatrix worldToOrigin = gfx3DMatrix::Translation(-aOrigin);
+  gfx3DMatrix originToWorld = gfx3DMatrix::Translation(aOrigin);
 
   /* Multiply all three to get the transform! */
   return worldToOrigin * aMatrix * originToWorld;
diff --git a/layout/base/nsLayoutUtils.h b/layout/base/nsLayoutUtils.h
index 6bab2c00683..fb470d56969 100644
--- a/layout/base/nsLayoutUtils.h
+++ b/layout/base/nsLayoutUtils.h
@@ -461,7 +461,7 @@ public:
    * @return A matrix equivalent to aMatrix, but operating in the coordinate system with
    *         origin aOrigin.
    */
-  static gfx3DMatrix ChangeMatrixBasis(const gfxPoint &aOrigin, const gfx3DMatrix &aMatrix);
+  static gfx3DMatrix ChangeMatrixBasis(const gfxPoint3D &aOrigin, const gfx3DMatrix &aMatrix);
 
   /**
    * Find IDs corresponding to a scrollable content element in the child process.