// https://drafts.csswg.org/css-transitions/#transition-shorthand-property
// [ none | <single-transition-property> ] || <time> || <easing-function> || <time>
private static void CompileTransition(StylePropertyReader reader, out List <TimeValue> outDelay, out List <TimeValue> outDuration,
out List <StylePropertyName> outProperty, out List <EasingFunction> outTimingFunction)
{
s_TransitionDelayList.Clear();
s_TransitionDurationList.Clear();
s_TransitionPropertyList.Clear();
s_TransitionTimingFunctionList.Clear();
bool isValid = true;
bool noneFound = false;
var valueCount = reader.valueCount;
int transitionCount = 0;
int i = 0;
do
{
// If none is present and there are more transitions the shorthand is considered invalid
if (noneFound)
{
isValid = false;
break;
}
var transitionProperty = InitialStyle.transitionProperty[0];
var transitionDuration = InitialStyle.transitionDuration[0];
var transitionDelay = InitialStyle.transitionDelay[0];
var transitionTimingFunction = InitialStyle.transitionTimingFunction[0];
bool durationFound = false;
bool delayFound = false;
bool propertyFound = false;
bool timingFunctionFound = false;
bool commaFound = false;
for (; i < valueCount && !commaFound; ++i)
{
var valueType = reader.GetValueType(i);
switch (valueType)
{
case StyleValueType.Keyword:
if (reader.IsKeyword(i, StyleValueKeyword.None) && transitionCount == 0)
{
noneFound = true;
propertyFound = true;
transitionProperty = new StylePropertyName("none");
}
else
{
isValid = false;
}
break;
case StyleValueType.Dimension:
var time = reader.ReadTimeValue(i);
if (!durationFound)
{
// transition-duration
durationFound = true;
transitionDuration = time;
}
else if (!delayFound)
{
// transition-delay
delayFound = true;
transitionDelay = time;
}
else
{
isValid = false;
}
break;
case StyleValueType.Enum:
var str = reader.ReadAsString(i);
if (!timingFunctionFound && StylePropertyUtil.TryGetEnumIntValue(StyleEnumType.EasingMode, str, out var intValue))
{
// transition-timing-function
timingFunctionFound = true;
transitionTimingFunction = (EasingMode)intValue;
}
else if (!propertyFound)
{
// transition-property
propertyFound = true;
transitionProperty = new StylePropertyName(str);
}
else
{
isValid = false;
}
break;
case StyleValueType.CommaSeparator:
commaFound = true;
++transitionCount;
break;
default:
isValid = false;
break;
}
}
s_TransitionDelayList.Add(transitionDelay);
s_TransitionDurationList.Add(transitionDuration);
s_TransitionPropertyList.Add(transitionProperty);
s_TransitionTimingFunctionList.Add(transitionTimingFunction);
}while (i < valueCount && isValid);
if (isValid)
{
outProperty = s_TransitionPropertyList;
outDelay = s_TransitionDelayList;
outDuration = s_TransitionDurationList;
outTimingFunction = s_TransitionTimingFunctionList;
}
else
{
outProperty = InitialStyle.transitionProperty;
outDelay = InitialStyle.transitionDelay;
outDuration = InitialStyle.transitionDuration;
outTimingFunction = InitialStyle.transitionTimingFunction;
}
}