Web Animations CSS: Support animation of stroke-dasharray property

Source/core/animation/AnimatableSVGLengthVector.cpp

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/animation/AnimatableSVGLengthVector.h"
+
+#include "bindings/v8/ExceptionStatePlaceholder.h"
+#include "platform/FloatConversion.h"
+#include <algorithm>
+
+namespace WebCore {
+
+namespace {
+
+int lowestCommonMultiple(int a, int b)
+{
+    ASSERT(a > 0);
+    ASSERT(b > 0);
+    int maxCandidate = std::max(a, b);
+    int result = 1;
+    for (int i = 2; i <= maxCandidate; ++i) {
+        bool isFactorOfA = !(a % i);
+        bool isFactorOfB = !(b % i);
+        while (isFactorOfA || isFactorOfB) {
+            bool hit = false;
+            if (isFactorOfA) {
+                a /= i;
+                hit = true;
+                isFactorOfA = !(a % i);
+            }
+            if (isFactorOfB) {
+                b /= i;
+                hit = true;
+                isFactorOfB = !(b % i);
+            }
+            if (hit)
+                result *= i;
+        }
+    }
+    ASSERT(!(result % a) && !(result % b));
+    return result;
+}
+
+} // namespace
+
+PassRefPtr<AnimatableValue> AnimatableSVGLengthVector::interpolateTo(const AnimatableValue* value, double fraction) const
+{
+    Vector<SVGLength> from = m_lengths;
+    Vector<SVGLength> to = toAnimatableSVGLengthVector(value)->toSVGLengthVector();
+
+    // 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.
+    static SVGLength* zeroPixels = 0;
+    if (!zeroPixels) {
+        zeroPixels = new SVGLength;
+        zeroPixels->newValueSpecifiedUnits(LengthTypePX, 0, IGNORE_EXCEPTION);
+    }
+    if (from.isEmpty()) {
+        from.append(*zeroPixels);
+        from.append(*zeroPixels);
+    }
+    if (to.isEmpty()) {
+        to.append(*zeroPixels);
+        to.append(*zeroPixels);
+    }
+
+    const size_t fromLength = from.size();
+    const size_t toLength = to.size();
+
+    size_t resultLength = lowestCommonMultiple(fromLength, toLength);
+    Vector<SVGLength> result(resultLength);
+    for (size_t i = 0; i < resultLength; ++i) {
+        result[i] = to[i % toLength].blend(from[i % fromLength], narrowPrecisionToFloat(fraction));
+        if (result[i].valueInSpecifiedUnits() < 0)
+            result[i].setValueInSpecifiedUnits(0);
+    }
+    return create(result);
+}
+
+PassRefPtr<AnimatableValue> AnimatableSVGLengthVector::addWith(const AnimatableValue* value) const
+{
+    RELEASE_ASSERT_WITH_MESSAGE(false, "Web Animations not yet implemented: AnimatableSVGLengthVector::addWith()");
+    return 0;
+}
+
+bool AnimatableSVGLengthVector::equalTo(const AnimatableValue* value) const
+{
+    return m_lengths == toAnimatableSVGLengthVector(value)->toSVGLengthVector();
+}
+
+} // namespace WebCore