1 files changed, 58 insertions, 3 deletions
diff --git a/src/3rdparty/webkit/WebCore/platform/graphics/transforms/RotateTransformOperation.cpp b/src/3rdparty/webkit/WebCore/platform/graphics/transforms/RotateTransformOperation.cpp
index 4887ceee88..919d174f9c 100644
--- a/src/3rdparty/webkit/WebCore/platform/graphics/transforms/RotateTransformOperation.cpp
+++ b/src/3rdparty/webkit/WebCore/platform/graphics/transforms/RotateTransformOperation.cpp
@@ -22,6 +22,11 @@
 #include "config.h"
 #include "RotateTransformOperation.h"
 
+#include <algorithm>
+#include <wtf/MathExtras.h>
+
+using namespace std;
+
 namespace WebCore {
 
 PassRefPtr<TransformOperation> RotateTransformOperation::blend(const TransformOperation* from, double progress, bool blendToIdentity)
@@ -30,11 +35,61 @@ PassRefPtr<TransformOperation> RotateTransformOperation::blend(const TransformOp
         return this;
     
     if (blendToIdentity)
-        return RotateTransformOperation::create(m_angle - m_angle * progress, m_type);
+        return RotateTransformOperation::create(m_x, m_y, m_z, m_angle - m_angle * progress, m_type);
     
     const RotateTransformOperation* fromOp = static_cast<const RotateTransformOperation*>(from);
-    double fromAngle = fromOp ? fromOp->m_angle : 0;
-    return RotateTransformOperation::create(fromAngle + (m_angle - fromAngle) * progress, m_type);
+    
+    // Optimize for single axis rotation
+    if (!fromOp || (fromOp->m_x == 0 && fromOp->m_y == 0 && fromOp->m_z == 1) || 
+                   (fromOp->m_x == 0 && fromOp->m_y == 1 && fromOp->m_z == 0) || 
+                   (fromOp->m_x == 1 && fromOp->m_y == 0 && fromOp->m_z == 0)) {
+        double fromAngle = fromOp ? fromOp->m_angle : 0;
+        return RotateTransformOperation::create(fromOp ? fromOp->m_x : m_x, 
+                                                fromOp ? fromOp->m_y : m_y, 
+                                                fromOp ? fromOp->m_z : m_z, 
+                                                fromAngle + (m_angle - fromAngle) * progress, m_type);
+    }
+
+    const RotateTransformOperation* toOp = this;
+
+    // Create the 2 rotation matrices
+    TransformationMatrix fromT;
+    TransformationMatrix toT;
+    fromT.rotate3d((float)(fromOp ? fromOp->m_x : 0),
+                   (float)(fromOp ? fromOp->m_y : 0),
+                   (float)(fromOp ? fromOp->m_z : 1),
+                   (float)(fromOp ? fromOp->m_angle : 0));
+
+    toT.rotate3d((float)(toOp ? toOp->m_x : 0),
+                 (float)(toOp ? toOp->m_y : 0),
+                 (float)(toOp ? toOp->m_z : 1),
+                 (float)(toOp ? toOp->m_angle : 0));
+    
+    // Blend them
+    toT.blend(fromT, progress);
+    
+    // Extract the result as a quaternion
+    TransformationMatrix::DecomposedType decomp;
+    toT.decompose(decomp);
+    
+    // Convert that to Axis/Angle form
+    double x = -decomp.quaternionX;
+    double y = -decomp.quaternionY;
+    double z = -decomp.quaternionZ;
+    double length = sqrt(x * x + y * y + z * z);
+    double angle = 0;
+    
+    if (length > 0.00001) {
+        x /= length;
+        y /= length;
+        z /= length;
+        angle = rad2deg(acos(decomp.quaternionW) * 2);
+    } else {
+        x = 0;
+        y = 0;
+        z = 1;
+    }
+    return RotateTransformOperation::create(x, y, z, angle, ROTATE_3D);
 }
 
 } // namespace WebCore