Added support of calc() for SVGLength

third_party/WebKit/Source/core/svg/SVGLength.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 55 matching lines @@
     return length;
 }
 
 bool SVGLength::operator==(const SVGLength& other) const
 {
     return m_unitMode == other.m_unitMode && m_value == other.m_value;
 }
 
 float SVGLength::value(const SVGLengthContext& context) const
 {
+    if (isCalculated())
+        return context.resolveValue(*asCSSPrimitiveValue(), unitMode());
+
     return context.convertValueToUserUnits(
         m_value->getFloatValue(), unitMode(), m_value->typeWithCalcResolved());
 }
 
+void SVGLength::setValueAsNumber(float value)
+{
+    m_value = CSSPrimitiveValue::create(value, CSSPrimitiveValue::UnitType::UserUnits);
+}
+
 void SVGLength::setValue(float value, const SVGLengthContext& context)
 {
     m_value = CSSPrimitiveValue::create(
         context.convertValueFromUserUnits(value, unitMode(), m_value->typeWithCalcResolved()),
         m_value->typeWithCalcResolved());
 }
 
-bool isSupportedCSSUnitType(CSSPrimitiveValue::UnitType type)
+static bool isCalcCSSUnitType(CSSPrimitiveValue::UnitType type)
 {
-    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number || type == CSSPrimitiveValue::UnitType::Percentage)
+    return type >= CSSPrimitiveValue::UnitType::Calc && type <= CSSPrimitiveValue::UnitType::CalcPercentageWithLengthAndNumber;
+}
+
+static bool isSupportedCSSUnitType(CSSPrimitiveValue::UnitType type)
+{
+    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number
+        || type == CSSPrimitiveValue::UnitType::Percentage || isCalcCSSUnitType(type))
         && type != CSSPrimitiveValue::UnitType::QuirkyEms;
 }
 
 void SVGLength::setUnitType(CSSPrimitiveValue::UnitType type)
 {
     ASSERT(isSupportedCSSUnitType(type));
     m_value = CSSPrimitiveValue::create(m_value->getFloatValue(), type);
 }
 
 float SVGLength::valueAsPercentage() const
@@ skipping 32 matching lines @@
         m_value = CSSPrimitiveValue::create(0, CSSPrimitiveValue::UnitType::UserUnits);
         return SVGParseStatus::NoError;
     }
 
     CSSParserContext svgParserContext(SVGAttributeMode, nullptr);
     const CSSValue* parsed = CSSParser::parseSingleValue(CSSPropertyX, string, svgParserContext);
     if (!parsed || !parsed->isPrimitiveValue())
         return SVGParseStatus::ExpectedLength;
 
     const CSSPrimitiveValue* newValue = toCSSPrimitiveValue(parsed);
-    // TODO(fs): Enable calc for SVG lengths
-    if (newValue->isCalculated() || !isSupportedCSSUnitType(newValue->typeWithCalcResolved()))
+    if (!isSupportedCSSUnitType(newValue->typeWithCalcResolved()))
         return SVGParseStatus::ExpectedLength;
 
     m_value = newValue;
     return SVGParseStatus::NoError;
 }
 
 String SVGLength::valueAsString() const
 {
     return m_value->customCSSText();
 }
@@ skipping 85 matching lines @@
     SVGLength* toLength = toSVGLength(toValue);
     SVGLength* toAtEndOfDurationLength = toSVGLength(toAtEndOfDurationValue);
 
     SVGLengthContext lengthContext(contextElement);
     float animatedNumber = value(lengthContext);
     animationElement->animateAdditiveNumber(percentage, repeatCount, fromLength->value(lengthContext),
         toLength->value(lengthContext), toAtEndOfDurationLength->value(lengthContext), animatedNumber);
 
     ASSERT(unitMode() == lengthModeForAnimatedLengthAttribute(animationElement->attributeName()));
 
-    CSSPrimitiveValue::UnitType newUnit = percentage < 0.5 ? fromLength->typeWithCalcResolved() : toLength->typeWithCalcResolved();
+    // TODO(shanmuga.m): Construct a calc() expression if the units fall in different categories.
+    CSSPrimitiveValue::UnitType newUnit = CSSPrimitiveValue::UnitType::UserUnits;
+    if (percentage < 0.5) {
+        if (!fromLength->isCalculated())
+            newUnit = fromLength->typeWithCalcResolved();
+    } else {
+        if (!toLength->isCalculated())
+            newUnit = toLength->typeWithCalcResolved();
+    }
     animatedNumber = lengthContext.convertValueFromUserUnits(animatedNumber, unitMode(), newUnit);
     m_value = CSSPrimitiveValue::create(animatedNumber, newUnit);
 }
 
 float SVGLength::calculateDistance(SVGPropertyBase* toValue, SVGElement* contextElement)
 {
     SVGLengthContext lengthContext(contextElement);
     SVGLength* toLength = toSVGLength(toValue);
 
     return fabsf(toLength->value(lengthContext) - value(lengthContext));
 }
 
 } // namespace blink