Define step timing function for the cc animation framework.

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 422 matching lines @@
   EXPECT_FLOAT_EQ(0.f, curve->GetValue(base::TimeDelta::FromSecondsD(0.f)));
   EXPECT_LT(0.f, curve->GetValue(base::TimeDelta::FromSecondsD(0.25f)));
   EXPECT_GT(0.25f, curve->GetValue(base::TimeDelta::FromSecondsD(0.25f)));
   EXPECT_NEAR(curve->GetValue(base::TimeDelta::FromSecondsD(0.5f)), 0.5f,
               0.00015f);
   EXPECT_LT(0.75f, curve->GetValue(base::TimeDelta::FromSecondsD(0.75f)));
   EXPECT_GT(1.f, curve->GetValue(base::TimeDelta::FromSecondsD(0.75f)));
   EXPECT_FLOAT_EQ(1.f, curve->GetValue(base::TimeDelta::FromSecondsD(1.f)));
 }
 
+// Tests a step timing function if the change of values occur at the start.
+TEST(KeyframedAnimationCurveTest, StepsTimingFunctionStepAtStart) {
+  scoped_ptr<KeyframedFloatAnimationCurve> curve(
+      KeyframedFloatAnimationCurve::Create());
+  const int num_steps = 36;
+  const float steps_start_offset = 1.0f;
+  curve->AddKeyframe(FloatKeyframe::Create(
+      base::TimeDelta(), 0.f,
+      StepsTimingFunction::Create(num_steps, steps_start_offset)));
+  curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0),
+                                           num_steps, nullptr));
+
+  const float time_threshold = 0.0001f;
+
+  for (float i = 0.f; i < num_steps; i += 1.f) {
+    const base::TimeDelta time1 =
+        base::TimeDelta::FromSecondsD(i / num_steps - time_threshold);
+    const base::TimeDelta time2 =
+        base::TimeDelta::FromSecondsD(i / num_steps + time_threshold);
+    EXPECT_FLOAT_EQ(std::ceil(i), curve->GetValue(time1));
+    EXPECT_FLOAT_EQ(std::ceil(i) + 1.f, curve->GetValue(time2));
+  }
+  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::ceil(i), curve->GetValue(time));
+  }
+}
+
+// Tests a step timing function if the change of values occur at the middle.
+TEST(KeyframedAnimationCurveTest, StepsTimingFunctionStepAtMiddle) {
+  scoped_ptr<KeyframedFloatAnimationCurve> curve(
+      KeyframedFloatAnimationCurve::Create());
+  const int num_steps = 36;
+  const float steps_start_offset = 0.5f;
+  curve->AddKeyframe(FloatKeyframe::Create(
+      base::TimeDelta(), 0.f,
+      StepsTimingFunction::Create(num_steps, steps_start_offset)));
+  curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0),
+                                           num_steps, nullptr));
+
+  const float time_threshold = 0.0001f;
+
+  EXPECT_FLOAT_EQ(0.f, curve->GetValue(base::TimeDelta()));
+  for (float i = 0.5f; i < num_steps; i += 1.f) {
+    const base::TimeDelta time1 =
+        base::TimeDelta::FromSecondsD(i / num_steps - time_threshold);
+    const base::TimeDelta time2 =
+        base::TimeDelta::FromSecondsD(i / num_steps + time_threshold);
+    EXPECT_FLOAT_EQ(std::floor(i), curve->GetValue(time1));
+    EXPECT_FLOAT_EQ(std::floor(i) + 1.f, curve->GetValue(time2));
+  }
+  EXPECT_FLOAT_EQ(num_steps,
+                  curve->GetValue(base::TimeDelta::FromSecondsD(1.0)));
+
+  for (float i = 0.25f; 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 step timing function if the change of values occur at the end.
+TEST(KeyframedAnimationCurveTest, StepsTimingFunctionStepAtEnd) {
+  scoped_ptr<KeyframedFloatAnimationCurve> curve(
+      KeyframedFloatAnimationCurve::Create());
+  const int num_steps = 36;
+  const float steps_start_offset = 0.0f;
+  curve->AddKeyframe(FloatKeyframe::Create(
+      base::TimeDelta(), 0.f,
+      StepsTimingFunction::Create(num_steps, steps_start_offset)));
+  curve->AddKeyframe(FloatKeyframe::Create(base::TimeDelta::FromSecondsD(1.0),
+                                           num_steps, nullptr));
+
+  const float time_threshold = 0.0001f;
+
+  EXPECT_FLOAT_EQ(0.f, curve->GetValue(base::TimeDelta()));
+  for (float i = 1.f; i <= num_steps; i += 1.f) {
+    const base::TimeDelta time1 =
+        base::TimeDelta::FromSecondsD(i / num_steps - time_threshold);
+    const base::TimeDelta time2 =
+        base::TimeDelta::FromSecondsD(i / num_steps + time_threshold);
+    EXPECT_FLOAT_EQ(std::floor(i) - 1.f, curve->GetValue(time1));
+    EXPECT_FLOAT_EQ(std::floor(i), curve->GetValue(time2));
+  }
+  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 that animated bounds are computed as expected.
 TEST(KeyframedAnimationCurveTest, AnimatedBounds) {
   scoped_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 224 matching lines @@
   curve->SetTimingFunction(
       CubicBezierTimingFunction::Create(0.5f, -0.5f, 0.5f, 1.5f).Pass());
   EXPECT_LE(curve->GetValue(base::TimeDelta::FromSecondsD(1.f)),
             0.f);  // c(.25) < 0
   EXPECT_GE(curve->GetValue(base::TimeDelta::FromSecondsD(3.f)),
             9.f);  // c(.75) > 1
 }
 
 }  // namespace
 }  // namespace cc