After http://crrev.com/202755, timing functions can now produce values outside the range [0, 1]. Unfortunately, these values are getting clamped when they are used for blending. This CL removes that extra clamping and adds unit tests for this extrapolation.

BUG=178299
R=ajuma@chromium.org

Review URL: https://codereview.chromium.org/15972006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@203808 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 106 insertions, 16 deletions

diff --git a/cc/animation/transform_operation.cc b/cc/animation/transform_operation.cc
index e1468bf..854901d 100644
--- a/cc/animation/transform_operation.cc
+++ b/cc/animation/transform_operation.cc
@@ -74,12 +74,6 @@ static bool ShareSameAxis(const TransformOperation* from,
 }
 
 static double BlendDoubles(double from, double to, double progress) {
-  if (progress <= 0.0)
-    return from;
-
-  if (progress >= 1.0)
-    return to;
-
   return from * (1 - progress) + to * progress;
 }
 
diff --git a/cc/animation/transform_operations.cc b/cc/animation/transform_operations.cc
index 8826d29..d74f1a5 100644
--- a/cc/animation/transform_operations.cc
+++ b/cc/animation/transform_operations.cc
@@ -164,16 +164,6 @@ bool TransformOperations::BlendInternal(const TransformOperations& from,
     return true;
   }
 
-  if (progress <= 0.0) {
-    *result = from.Apply();
-    return true;
-  }
-
-  if (progress >= 1.0) {
-    *result = Apply();
-    return true;
-  }
-
   if (!ComputeDecomposedTransform() || !from.ComputeDecomposedTransform())
     return false;
 
diff --git a/cc/animation/transform_operations_unittest.cc b/cc/animation/transform_operations_unittest.cc
index 7e344c7..8fc9b94 100644
--- a/cc/animation/transform_operations_unittest.cc
+++ b/cc/animation/transform_operations_unittest.cc
@@ -432,6 +432,22 @@ TEST(TransformOperationTest, BlendRotationFromIdentity) {
 
     EXPECT_TRANSFORMATION_MATRIX_EQ(
         expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = -0.5;
+
+    expected.MakeIdentity();
+    expected.RotateAbout(gfx::Vector3dF(0, 0, 1), -180);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = 1.5;
+
+    expected.MakeIdentity();
+    expected.RotateAbout(gfx::Vector3dF(0, 0, 1), 540);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
   }
 }
 
@@ -450,6 +466,22 @@ TEST(TransformOperationTest, BlendTranslationFromIdentity) {
 
     EXPECT_TRANSFORMATION_MATRIX_EQ(
         expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = -0.5;
+
+    expected.MakeIdentity();
+    expected.Translate3d(-1, -1, -1);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = 1.5;
+
+    expected.MakeIdentity();
+    expected.Translate3d(3, 3, 3);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
   }
 }
 
@@ -468,6 +500,22 @@ TEST(TransformOperationTest, BlendScaleFromIdentity) {
 
     EXPECT_TRANSFORMATION_MATRIX_EQ(
         expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = -0.5;
+
+    expected.MakeIdentity();
+    expected.Scale3d(0, 0, 0);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = 1.5;
+
+    expected.MakeIdentity();
+    expected.Scale3d(4, 4, 4);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
   }
 }
 
@@ -487,6 +535,24 @@ TEST(TransformOperationTest, BlendSkewFromIdentity) {
 
     EXPECT_TRANSFORMATION_MATRIX_EQ(
         expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = -0.5;
+
+    expected.MakeIdentity();
+    expected.SkewX(-1);
+    expected.SkewY(-1);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
+
+    progress = 1.5;
+
+    expected.MakeIdentity();
+    expected.SkewX(3);
+    expected.SkewY(3);
+
+    EXPECT_TRANSFORMATION_MATRIX_EQ(
+        expected, operations.Blend(*identity_operations[i], progress));
   }
 }
 
@@ -601,5 +667,45 @@ TEST(TransformOperationTest, BlendPerspectiveToIdentity) {
   }
 }
 
+TEST(TransformOperationTest, ExtrapolatePerspectiveBlending) {
+  TransformOperations operations1;
+  operations1.AppendPerspective(1000);
+
+  TransformOperations operations2;
+  operations2.AppendPerspective(500);
+
+  gfx::Transform expected;
+  expected.ApplyPerspectiveDepth(250);
+
+  EXPECT_TRANSFORMATION_MATRIX_EQ(
+      expected, operations1.Blend(operations2, -0.5));
+
+  expected.MakeIdentity();
+  expected.ApplyPerspectiveDepth(1250);
+
+  EXPECT_TRANSFORMATION_MATRIX_EQ(
+      expected, operations1.Blend(operations2, 1.5));
+}
+
+TEST(TransformOperationTest, ExtrapolateMatrixBlending) {
+  gfx::Transform transform1;
+  transform1.Translate3d(1, 1, 1);
+  TransformOperations operations1;
+  operations1.AppendMatrix(transform1);
+
+  gfx::Transform transform2;
+  transform2.Translate3d(3, 3, 3);
+  TransformOperations operations2;
+  operations2.AppendMatrix(transform2);
+
+  gfx::Transform expected;
+  EXPECT_TRANSFORMATION_MATRIX_EQ(
+      expected, operations1.Blend(operations2, 1.5));
+
+  expected.Translate3d(4, 4, 4);
+  EXPECT_TRANSFORMATION_MATRIX_EQ(
+      expected, operations1.Blend(operations2, -0.5));
+}
+
 }  // namespace
 }  // namespace cc