Web Animations CSS: Support animation of stroke-dasharray property

Source/core/animation/AnimatableStrokeDasharrayList.cpp

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
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+ */
+
+#include "config.h"
+#include "core/animation/AnimatableStrokeDasharrayList.h"
+
+#include "bindings/v8/ExceptionStatePlaceholder.h"
+#include "core/animation/AnimatableSVGLength.h"
+
+namespace WebCore {
+
+AnimatableStrokeDasharrayList::AnimatableStrokeDasharrayList(const Vector<SVGLength>& lengths)
+{
+    Vector<RefPtr<AnimatableValue> > values;
+    for (size_t i = 0; i < lengths.size(); ++i)
+        values.append(AnimatableSVGLength::create(lengths[i]));

[dstockwell, 2013/10/13 23:38:22]

can't this be m_values.append ?

[Steve Block, 2013/10/14 01:01:00]

Done.

+    m_values.swap(values);
+}
+
+Vector<SVGLength> AnimatableStrokeDasharrayList::toSVGLengthVector() const
+{
+    Vector<SVGLength> lengths(m_values.size());
+    for (size_t i = 0; i < m_values.size(); ++i) {
+        lengths[i] = toAnimatableSVGLength(m_values[i].get())->toSVGLength();
+        if (lengths[i].valueInSpecifiedUnits() < 0)
+            lengths[i].setValueInSpecifiedUnits(0);
+    }
+    return lengths;
+}
+
+PassRefPtr<AnimatableValue> AnimatableStrokeDasharrayList::interpolateTo(const AnimatableValue* value, double fraction) const
+{
+    Vector<RefPtr<AnimatableValue> > from = m_values;
+    Vector<RefPtr<AnimatableValue> > to = toAnimatableStrokeDasharrayList(value)->m_values;
+
+    // The spec states that if the sum of all values is zero, this should be
+    // treated like a value of 'none', which means that a solid line is drawn.
+    // Since we animate to and from values of zero, treat a value of 'none' the
+    // same.
+    if (from.isEmpty() || to.isEmpty()) {

[dstockwell, 2013/10/13 23:35:52]

Does it make sense to push this empty-list logic down into AnimatableRepeatable?
virtual valuesForEmptyList()

[Steve Block, 2013/10/14 01:01:00]

We could, but it doesn't buy us much. We still need
AnimatableStrokeDasharrayList::interpolateTo() to be a wrapper around an
AnimatableRepeatable helper method (rather than calling
AnimatableRepeatable::interpolateTo() directly) so that the return value is a
AnimatableStrokeDasharrayList, rather than a AnimatableRepeatable.

I think we should wait to see what other derived classes of AnimatableRepeatable
look like.

+        DEFINE_STATIC_LOCAL(RefPtr<AnimatableSVGLength>, zeroPixels, ());
+        if (!zeroPixels) {
+            SVGLength length;
+            length.newValueSpecifiedUnits(LengthTypePX, 0, IGNORE_EXCEPTION);
+            zeroPixels = AnimatableSVGLength::create(length);
+        }
+        if (from.isEmpty()) {
+            from.append(zeroPixels);
+            from.append(zeroPixels);
+        }
+        if (to.isEmpty()) {
+            to.append(zeroPixels);
+            to.append(zeroPixels);
+        }
+    }
+
+    Vector<RefPtr<AnimatableValue> > interpolatedValues;
+    bool success = interpolateLists(from, to, fraction, interpolatedValues);
+    ASSERT(success);
+    return adoptRef(new AnimatableStrokeDasharrayList(interpolatedValues));
+}
+
+} // namespace WebCore