Added support of calc() for SVGLength

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

Index: third_party/WebKit/Source/core/svg/SVGLength.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGLength.cpp b/third_party/WebKit/Source/core/svg/SVGLength.cpp
index eb915deaae0bfbcfba087d24b208e0c90dc2c5fa..8d2c7e30c5f8fb3977002c085bcfa39699ed755e 100644
--- a/third_party/WebKit/Source/core/svg/SVGLength.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGLength.cpp
@@ -71,12 +71,38 @@ bool SVGLength::operator==(const SVGLength& other) const
     return m_unitMode == other.m_unitMode && m_value == other.m_value;
 }
 
+bool isCalcCSSUnitType(CSSPrimitiveValue::UnitType type)

[fs, 2016/07/16 21:13:02]

Make this static (and isSupportedCSSUnitType too, while at it) and move to down
just before it is used.

[Shanmuga Pandi, 2016/07/18 13:35:33]

Done.

+{
+    return (type >= CSSPrimitiveValue::UnitType::Calc && type <= CSSPrimitiveValue::UnitType::CalcPercentageWithLengthAndNumber);

[fs, 2016/07/16 21:13:02]

Drop parenthesis.

[Shanmuga Pandi, 2016/07/18 13:35:33]

Done.

+}
+
+float SVGLength::resolveCalcValue(const SVGLengthContext& context) const

[fs, 2016/07/16 21:13:02]

We could consider going through CSSPrimitiveValue::convertToLength here instead
to avoid special-case resolving code. (This should hopefully allow us to get rid
of m_unitMode eventually.)

[Shanmuga Pandi, 2016/07/18 13:35:33]

Done.

+{
+    CSSLengthArray lengthArray;
+    m_value->accumulateLengthArray(lengthArray);
+    float value = 0;

[fs, 2016/07/16 21:13:02]

If we end up keeping this I suggest making this 'double', and then converting
(narrowing) to float when returning.

+    for (size_t i = 0; i < CSSPrimitiveValue::LengthUnitTypeCount; i++) {
+        double entry = lengthArray.values[i];
+        if (entry)
+            value += context.convertValueToUserUnits(entry, unitMode(), SVGLength::toUnitType(i));
+    }
+    return value;
+}
+
 float SVGLength::value(const SVGLengthContext& context) const
 {
+    if (isCalculated())
+        return resolveCalcValue(context);
+
     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(
@@ -86,7 +112,8 @@ void SVGLength::setValue(float value, const SVGLengthContext& context)
 
 bool isSupportedCSSUnitType(CSSPrimitiveValue::UnitType type)
 {
-    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number || type == CSSPrimitiveValue::UnitType::Percentage)
+    return (CSSPrimitiveValue::isLength(type) || type == CSSPrimitiveValue::UnitType::Number
+        || type == CSSPrimitiveValue::UnitType::Percentage || isCalcCSSUnitType(type))
         && type != CSSPrimitiveValue::UnitType::QuirkyEms;
 }
 
@@ -139,11 +166,11 @@ SVGParsingError SVGLength::setValueAsString(const String& string)
         return SVGParseStatus::ExpectedLength;
 
     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;
+

[fs, 2016/07/16 21:13:02]

Drop.

[Shanmuga Pandi, 2016/07/18 13:35:32]

Done.

     return SVGParseStatus::NoError;
 }
 
@@ -246,7 +273,14 @@ void SVGLength::calculateAnimatedValue(SVGAnimationElement* animationElement,
 
     ASSERT(unitMode() == lengthModeForAnimatedLengthAttribute(animationElement->attributeName()));
 
-    CSSPrimitiveValue::UnitType newUnit = percentage < 0.5 ? fromLength->typeWithCalcResolved() : toLength->typeWithCalcResolved();
+    CSSPrimitiveValue::UnitType newUnit = CSSPrimitiveValue::UnitType::UserUnits;
+    if (percentage < 0.5) {
+        if (!fromLength->isCalculated())

[fs, 2016/07/16 21:13:02]

Test for this code? (Preferably i think this would just construct a calc()
expression if the units fall in different categories et.c, but we can fix that
up later I guess...)

[Shanmuga Pandi, 2016/07/18 13:35:32]

Yes. We could just construct a calc_expression later.
Have added some test cases for this on svg_calc_interpolation.html

[fs, 2016/07/18 13:56:48]

Please add a TODO about constructing a calc() expression here.

+            newUnit = fromLength->typeWithCalcResolved();
+    } else {
+        if (!toLength->isCalculated())
+            newUnit = toLength->typeWithCalcResolved();
+    }
     animatedNumber = lengthContext.convertValueFromUserUnits(animatedNumber, unitMode(), newUnit);
     m_value = CSSPrimitiveValue::create(animatedNumber, newUnit);
 }