Web Animations: Split image slice interpolation out of LengthBoxStyleInterpolation

Source/core/animation/ImageSliceStyleInterpolation.cpp

Index: Source/core/animation/ImageSliceStyleInterpolation.cpp
diff --git a/Source/core/animation/ImageSliceStyleInterpolation.cpp b/Source/core/animation/ImageSliceStyleInterpolation.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..923604f9b6093f157ea25f8a4d05c22c115fca19
--- /dev/null
+++ b/Source/core/animation/ImageSliceStyleInterpolation.cpp
@@ -0,0 +1,99 @@
+// Copyright 2015 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/ImageSliceStyleInterpolation.h"
+
+#include "core/css/CSSBorderImageSliceValue.h"
+#include "core/css/CSSPrimitiveValue.h"
+#include "core/css/Rect.h"
+#include "core/css/resolver/StyleBuilder.h"
+
+namespace blink {
+
+bool ImageSliceStyleInterpolation::usesDefaultInterpolation(const CSSValue& start, const CSSValue& end)
+{
+    if (!start.isBorderImageSliceValue() || !end.isBorderImageSliceValue())
+        return true;
+    const CSSBorderImageSliceValue& startSlice = toCSSBorderImageSliceValue(start);
+    const CSSBorderImageSliceValue& endSlice = toCSSBorderImageSliceValue(end);
+    return startSlice.slices()->top()->isPercentage() != endSlice.slices()->top()->isPercentage()
+        || startSlice.m_fill != endSlice.m_fill;
+}
+
+// PassDecompositionResult is required because the Windows compiler fails to call the OwnPtr(OwnPtr&&) constructor.
+struct PassDecompositionResult {
+    PassOwnPtrWillBeRawPtr<InterpolableValue> interpolableValue;
+    ImageSliceStyleInterpolation::Metadata metadata;
+};
+
+struct DecompositionResult {
+    DecompositionResult(const PassDecompositionResult& o)
+        : interpolableValue(o.interpolableValue)
+        , metadata(o.metadata)
+    { }
+    OwnPtrWillBeRawPtr<InterpolableValue> interpolableValue;
+    ImageSliceStyleInterpolation::Metadata metadata;
+};
+
+static PassDecompositionResult decompose(const CSSBorderImageSliceValue& value)
+{
+    const size_t kQuadSides = 4;
+    OwnPtrWillBeRawPtr<InterpolableList> interpolableList = InterpolableList::create(kQuadSides);
+    const Quad& quad = *value.slices();
+    interpolableList->set(0, InterpolableNumber::create(quad.top()->getDoubleValue()));
+    interpolableList->set(1, InterpolableNumber::create(quad.right()->getDoubleValue()));
+    interpolableList->set(2, InterpolableNumber::create(quad.bottom()->getDoubleValue()));
+    interpolableList->set(3, InterpolableNumber::create(quad.left()->getDoubleValue()));
+    bool isPercentage = quad.top()->isPercentage();
+    ASSERT(quad.bottom()->isPercentage() == isPercentage
+        && quad.left()->isPercentage() == isPercentage
+        && quad.right()->isPercentage() == isPercentage);
+    return PassDecompositionResult {
+        interpolableList.release(),
+        ImageSliceStyleInterpolation::Metadata {isPercentage, value.m_fill},
+    };
+}
+
+static PassRefPtr<CSSBorderImageSliceValue> compose(const InterpolableValue& value, const ImageSliceStyleInterpolation::Metadata& metadata)
+{
+    const InterpolableList& interpolableList = toInterpolableList(value);
+    CSSPrimitiveValue::UnitType type = metadata.isPercentage ? CSSPrimitiveValue::CSS_PERCENTAGE : CSSPrimitiveValue::CSS_NUMBER;
+    RefPtrWillBeRawPtr<Quad> quad = Quad::create();
+    quad->setTop(CSSPrimitiveValue::create(clampTo(toInterpolableNumber(interpolableList.get(0))->value(), 0), type));
+    quad->setRight(CSSPrimitiveValue::create(clampTo(toInterpolableNumber(interpolableList.get(1))->value(), 0), type));
+    quad->setBottom(CSSPrimitiveValue::create(clampTo(toInterpolableNumber(interpolableList.get(2))->value(), 0), type));
+    quad->setLeft(CSSPrimitiveValue::create(clampTo(toInterpolableNumber(interpolableList.get(3))->value(), 0), type));
+    return CSSBorderImageSliceValue::create(CSSPrimitiveValue::create(quad.release()), metadata.fill);
+}
+
+PassRefPtrWillBeRawPtr<ImageSliceStyleInterpolation> ImageSliceStyleInterpolation::maybeCreate(const CSSValue& start, const CSSValue& end, CSSPropertyID property)
+{
+    if (!start.isBorderImageSliceValue() || !end.isBorderImageSliceValue())
+        return nullptr;
+
+    DecompositionResult startDecompose = decompose(toCSSBorderImageSliceValue(start));
+    DecompositionResult endDecompose = decompose(toCSSBorderImageSliceValue(end));
+    if (!(startDecompose.metadata == endDecompose.metadata))
+        return nullptr;
+
+    return adoptRefWillBeNoop(new ImageSliceStyleInterpolation(
+        startDecompose.interpolableValue.release(),
+        endDecompose.interpolableValue.release(),
+        property,
+        startDecompose.metadata
+    ));
+}
+
+void ImageSliceStyleInterpolation::apply(StyleResolverState& state) const
+{
+    StyleBuilder::applyProperty(m_id, state, compose(*m_cachedValue, m_metadata).get());
+}
+
+DEFINE_TRACE(ImageSliceStyleInterpolation)
+{
+    StyleInterpolation::trace(visitor);
+}
+
+} // namespace blink