public string Serialize()
{
if (!IsValid)
{
return(string.Empty);
}
if (!Lookup.TryKeyword(Values[0].AsEnum <EMediaFeatureName>(), out string Name))
{
throw new CssSyntaxErrorException("Could not find media-feature name");
}
StringBuilder sb = new StringBuilder();
/* 1) Append a "(" (U+0028), followed by the media feature name, converted to ASCII lowercase, to s. */
sb.Append(UnicodeCommon.CHAR_LEFT_PARENTHESES);
if (Context == EMediaFeatureContext.Boolean)
{
sb.Append(Name);
}
else if (Context == EMediaFeatureContext.Range)
{
sb.Append(Name);
if (Operators.Length == 0 && Values.Length == 2)
{
/* If a value is given append a ":" (U+003A), followed by a single SPACE (U+0020), followed by the serialized media feature value. */
sb.Append(UnicodeCommon.CHAR_COLON);
sb.Append(UnicodeCommon.CHAR_SPACE);
sb.Append(Values[1].Serialize());
}
else
{
/* Serialize all value/operator pairs */
for (int i = 1; i < Operators.Length; i++)
{
CssValue B = Values[i];
EMediaOperator op = Operators[i - 1];
if (!Lookup.TryKeyword(op, out string outComparator))
{
throw new CssSyntaxErrorException("Unable to find the specified comparator within the CSS enum LUT");
}
sb.Append(B.Serialize());
sb.Append(outComparator);
}
}
}
/* 3) Append a ")" (U+0029) to s. */
sb.Append(UnicodeCommon.CHAR_RIGHT_PARENTHESES);
return(sb.ToString());
}
static bool Compare(Document document, CssValue ValueA, CssValue ValueB, EMediaOperator Op)
{
/* An Excerpt:
* "If a media feature references a concept which does not exist on the device where the UA is running (for example, speech UAs do not have a concept of “width”), the media feature must always evaluate to false."
*/
double A, B;
/* First resolve these values to numbers we can compare */
if (ValueA.Type == ECssValueTypes.KEYWORD)
{
if (!Lookup.TryEnum(ValueA.AsString(), out EMediaFeatureName _))
{/* If we cant find this keyword then we treat it as if it were an unsupported feature */
return(false);
}
A = (double)Resolve_Media_Name_Value(document, ValueA.AsEnum <EMediaFeatureName>());
}
else
{
A = ValueA.AsDecimal();
}
if (ValueB.Type == ECssValueTypes.KEYWORD)
{
if (!Lookup.TryEnum(ValueB.AsString(), out EMediaFeatureName _))
{/* If we cant find this keyword then we treat it as if it were an unsupported feature */
return(false);
}
B = (double)Resolve_Media_Name_Value(document, ValueB.AsEnum <EMediaFeatureName>());
}
else
{
B = ValueB.AsDecimal();
}
/* Compare them and return the result */
switch (Op)
{
case EMediaOperator.EqualTo:
{
return(A == B);
}
case EMediaOperator.LessThan:
{
return(A < B);
}
case EMediaOperator.GreaterThan:
{
return(A > B);
}
case EMediaOperator.LessThanEq:
{
return(A < B || (A == B));
}
case EMediaOperator.GreaterThanEq:
{
return(A > B || (A == B));
}
}
return(false);
}
