Implement frames() timing function

cc/animation/keyframed_animation_curve_unittest.cc

 // Copyright 2012 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.
 
 #include "cc/animation/keyframed_animation_curve.h"
 
 #include "cc/animation/transform_operations.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/animation/tween.h"
@@ skipping 517 matching lines @@
   }
   EXPECT_FLOAT_EQ(num_steps,
                   curve->GetValue(base::TimeDelta::FromSecondsD(1.0)));
 
   for (float i = 0.5f; i <= num_steps; i += 1.0f) {
     const base::TimeDelta time = base::TimeDelta::FromSecondsD(i / num_steps);
     EXPECT_FLOAT_EQ(std::floor(i), curve->GetValue(time));
   }
 }
 
+// Tests a frames timing function.
+TEST(KeyframedAnimationCurveTest, FramesTimingFunction) {
+  std::unique_ptr<KeyframedFloatAnimationCurve> curve(
+      KeyframedFloatAnimationCurve::Create());
+  curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta(), 0.f,
+                                           FramesTimingFunction::Create(5)));
+  curve->AddKeyframe(
+      FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0), 1.f, nullptr));
+
+  struct Expected {
+    double time;
+    float value;
+  } expectations[] = {
+      {0.0, 0.f},     {0.1999, 0.f},  {0.2001, 0.25f}, {0.3999, 0.25f},
+      {0.4001, 0.5f}, {0.5999, 0.5f}, {0.6001, 0.75f}, {0.7999, 0.75f},
+      {0.8001, 1.f},  {1.0, 1.f},
+  };
+  for (const auto& expectation : expectations) {
+    EXPECT_FLOAT_EQ(
+        expectation.value,
+        curve->GetValue(base::TimeDelta::FromSecondsD(expectation.time)));
+  }
+}
+
 // Tests that animated bounds are computed as expected.
 TEST(KeyframedAnimationCurveTest, AnimatedBounds) {
   std::unique_ptr<KeyframedTransformAnimationCurve> curve(
       KeyframedTransformAnimationCurve::Create());
 
   TransformOperations operations1;
   curve->AddKeyframe(
       TransformKeyframe::Create(base::TimeDelta(), operations1, nullptr));
   operations1.AppendTranslate(2.0, 3.0, -1.0);
   curve->AddKeyframe(TransformKeyframe::Create(
@@ skipping 296 matching lines @@
   curve->AddKeyframe(
       FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0), 2.f, nullptr));
   // Curve timing function producing timing outputs outside of range [0,1].
   curve->SetTimingFunction(
       CubicBezierTimingFunction::Create(0.5f, -0.5f, 0.5f, 1.5f));
 
   EXPECT_FLOAT_EQ(-0.5f, curve->GetValue(base::TimeDelta::FromSecondsD(0.25f)));
   EXPECT_FLOAT_EQ(2.f, curve->GetValue(base::TimeDelta::FromSecondsD(0.75f)));
 }
 
+// Tests that a frames timing function works as expected for inputs outside of
+// range [0,1]
+TEST(KeyframedAnimationCurveTest, FramesTimingInputsOutsideZeroOneRange) {
+  std::unique_ptr<KeyframedFloatAnimationCurve> curve(
+      KeyframedFloatAnimationCurve::Create());
+  curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta(), 0.f,
+                                           FramesTimingFunction::Create(5)));
+  curve->AddKeyframe(
+      FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0), 2.f, nullptr));
+  // Curve timing function producing timing outputs outside of range [0,1].
+  curve->SetTimingFunction(
+      CubicBezierTimingFunction::Create(0.5f, -0.5f, 0.5f, 1.5f));
+
+  EXPECT_FLOAT_EQ(-0.5f, curve->GetValue(base::TimeDelta::FromSecondsD(0.25f)));
+  EXPECT_FLOAT_EQ(2.5f, curve->GetValue(base::TimeDelta::FromSecondsD(0.75f)));
+}
+
 // Tests that an animation with a curve timing function and multiple keyframes
 // works as expected.
 TEST(KeyframedAnimationCurveTest, CurveTimingMultipleKeyframes) {
   std::unique_ptr<KeyframedFloatAnimationCurve> curve(
       KeyframedFloatAnimationCurve::Create());
   curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta(), 0.f, nullptr));
   curve->AddKeyframe(
       FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.f), 1.f, nullptr));
   curve->AddKeyframe(
       FloatKeyframe::Create(base::TimeDelta::FromSecondsD(2.f), 3.f, nullptr));
@@ skipping 76 matching lines @@
               curve->GetValue(base::TimeDelta::FromSecondsD(scale * 3.5f)),
               0.01f);
   EXPECT_FLOAT_EQ(9.f,
                   curve->GetValue(base::TimeDelta::FromSecondsD(scale * 4.f)));
   EXPECT_FLOAT_EQ(9.f,
                   curve->GetValue(base::TimeDelta::FromSecondsD(scale * 5.f)));
 }
 
 }  // namespace
 }  // namespace cc