Web Animations API: Length properties responsive to style changes

Source/core/animation/Interpolation.cpp

 // Copyright 2014 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 "config.h"
 #include "core/animation/Interpolation.h"
 
 #include "core/css/CSSCalculationValue.h"
 #include "core/css/resolver/AnimatedStyleBuilder.h"
 #include "core/css/resolver/StyleBuilder.h"
@@ skipping 118 matching lines @@
                 next = CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(subValue->value(), toUnitType(position)));
             return constructCalcExpression(next, list, position + 1);
         }
         position++;
     }
     return previous;
 }
 
 }
 
-PassRefPtrWillBeRawPtr<CSSValue> LengthStyleInterpolation::interpolableValueToLength(InterpolableValue* value)
+PassRefPtrWillBeRawPtr<CSSValue> LengthStyleInterpolation::interpolableValueToLength(InterpolableValue* value, ValueRange range)
 {
     InterpolableList* listValue = toInterpolableList(value);
     unsigned unitCount = 0;
     for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
         const InterpolableNumber* subValue = toInterpolableNumber(listValue->get(i));
         if (subValue->value()) {
             unitCount++;
         }
     }
 
     switch (unitCount) {
     case 0:
         return CSSPrimitiveValue::create(0, CSSPrimitiveValue::CSS_PX);
     case 1:
         for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
             const InterpolableNumber* subValue = toInterpolableNumber(listValue->get(i));
-            if (subValue->value()) {
-                return CSSPrimitiveValue::create(subValue->value(), toUnitType(i));
+            double value = subValue->value();
+            if (value) {
+                if (range == ValueRangeNonNegative && value < 0)
+                    return CSSPrimitiveValue::create(0, CSSPrimitiveValue::CSS_PX);
+                return CSSPrimitiveValue::create(value, toUnitType(i));

[alancutter (OOO until 2018), 2014/05/12 09:17:36]

As discussed we should retain the unit here even if the value goes negative.
We should simply clamp value.

[Eric Willigers, 2014/05/12 09:42:37]

Done.

             }
         }

[alancutter (OOO until 2018), 2014/05/12 09:17:36]

This is unrelated to your change but can we add an ASSERT_NOT_REACHED() after
this for loop?
I'm surprised the compilers aren't complaining about a potential exit function
without return here.

[Eric Willigers, 2014/05/12 09:42:37]

Done.

     default:
-        return CSSPrimitiveValue::create(CSSCalcValue::create(constructCalcExpression(nullptr, listValue, 0)));
+        return CSSPrimitiveValue::create(CSSCalcValue::create(constructCalcExpression(nullptr, listValue, 0), range));
     }
 }
 
 void LengthStyleInterpolation::apply(StyleResolverState& state) const
 {
-    StyleBuilder::applyProperty(m_id, state, interpolableValueToLength(m_cachedValue.get()).get());
+    StyleBuilder::applyProperty(m_id, state, interpolableValueToLength(m_cachedValue.get(), m_range).get());
 }
 
 void LengthStyleInterpolation::trace(Visitor* visitor)
 {
     StyleInterpolation::trace(visitor);
 }
 
 void DefaultStyleInterpolation::apply(StyleResolverState& state) const
 {
     StyleBuilder::applyProperty(m_id, state, toInterpolableBool(m_cachedValue.get())->value() ? m_endCSSValue.get() : m_startCSSValue.get());
 }
 
 void DefaultStyleInterpolation::trace(Visitor* visitor)
 {
     StyleInterpolation::trace(visitor);
     visitor->trace(m_startCSSValue);
     visitor->trace(m_endCSSValue);
 }
 
 }