private static void NormalizeHintsOffsets(IList <GradientColorStop> result)
{
// normalize all except last
for (int i = 0; i < result.Count - 1; ++i)
{
GradientColorStop stopColor = result[i];
if (stopColor.GetHintOffsetType() == GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT)
{
double currentStopOffset = stopColor.GetOffset();
double nextStopOffset = result[i + 1].GetOffset();
if (currentStopOffset != nextStopOffset)
{
double hintOffset = (stopColor.GetHintOffset() - currentStopOffset) / (nextStopOffset - currentStopOffset);
stopColor.SetHint(hintOffset, GradientColorStop.HintOffsetType.RELATIVE_BETWEEN_COLORS);
}
else
{
// if stops has the same offset, then no hint needed
stopColor.SetHint(0, GradientColorStop.HintOffsetType.NONE);
}
}
}
// the last color hint is not needed as even with pad and reflect it won't be used
result[result.Count - 1].SetHint(0, GradientColorStop.HintOffsetType.NONE);
}
private static IList <GradientColorStop> CopyStopsAndNormalizeAbsoluteOffsets(IList <GradientColorStop> toNormalize
, double baseVectorLength)
{
double lastUsedOffset = double.NegativeInfinity;
IList <GradientColorStop> copy = new List <GradientColorStop>(toNormalize.Count);
foreach (GradientColorStop stop in toNormalize)
{
double offset = stop.GetOffset();
GradientColorStop.OffsetType offsetType = stop.GetOffsetType();
if (offsetType == GradientColorStop.OffsetType.ABSOLUTE)
{
offsetType = GradientColorStop.OffsetType.RELATIVE;
offset /= baseVectorLength;
}
if (offsetType == GradientColorStop.OffsetType.RELATIVE)
{
if (offset < lastUsedOffset)
{
offset = lastUsedOffset;
}
lastUsedOffset = offset;
}
GradientColorStop result = new GradientColorStop(stop, offset, offsetType);
double hintOffset = stop.GetHintOffset();
GradientColorStop.HintOffsetType hintOffsetType = stop.GetHintOffsetType();
if (hintOffsetType == GradientColorStop.HintOffsetType.ABSOLUTE_ON_GRADIENT)
{
hintOffsetType = GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT;
hintOffset /= baseVectorLength;
}
if (hintOffsetType == GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT)
{
if (hintOffset < lastUsedOffset)
{
hintOffset = lastUsedOffset;
}
lastUsedOffset = hintOffset;
}
result.SetHint(hintOffset, hintOffsetType);
copy.Add(result);
}
return(copy);
}
private static IList <GradientColorStop> AdjustNormalizedStopsToCoverDomain(IList <GradientColorStop> normalizedStops
, double[] targetDomain, GradientSpreadMethod spreadMethod)
{
IList <GradientColorStop> adjustedStops = new List <GradientColorStop>();
GradientColorStop lastColorStop = normalizedStops[normalizedStops.Count - 1];
double originalIntervalEnd = lastColorStop.GetOffset();
double originalIntervalStart = normalizedStops[0].GetOffset();
double originalIntervalLength = originalIntervalEnd - originalIntervalStart;
if (originalIntervalLength <= ZERO_EPSILON)
{
return(JavaUtil.ArraysAsList(new GradientColorStop(lastColorStop, targetDomain[0], GradientColorStop.OffsetType
.RELATIVE), new GradientColorStop(lastColorStop, targetDomain[1], GradientColorStop.OffsetType.RELATIVE
)));
}
double startIntervalsShift = Math.Floor((targetDomain[0] - originalIntervalStart) / originalIntervalLength
);
double iterationOffset = originalIntervalStart + (originalIntervalLength * startIntervalsShift);
bool isIterationInverse = spreadMethod == GradientSpreadMethod.REFLECT && Math.Abs(startIntervalsShift) %
2 != 0;
int currentIterationIndex = isIterationInverse ? normalizedStops.Count - 1 : 0;
double lastComputedOffset = iterationOffset;
while (lastComputedOffset <= targetDomain[1])
{
GradientColorStop currentStop = normalizedStops[currentIterationIndex];
lastComputedOffset = isIterationInverse ? iterationOffset + originalIntervalEnd - currentStop.GetOffset() :
iterationOffset + currentStop.GetOffset() - originalIntervalStart;
GradientColorStop computedStop = new GradientColorStop(currentStop, lastComputedOffset, GradientColorStop.OffsetType
.RELATIVE);
if (lastComputedOffset < targetDomain[0] && !adjustedStops.IsEmpty())
{
adjustedStops[0] = computedStop;
}
else
{
adjustedStops.Add(computedStop);
}
if (isIterationInverse)
{
--currentIterationIndex;
if (currentIterationIndex < 0)
{
iterationOffset += originalIntervalLength;
isIterationInverse = false;
currentIterationIndex = 1;
}
}
else
{
++currentIterationIndex;
if (currentIterationIndex == normalizedStops.Count)
{
iterationOffset += originalIntervalLength;
isIterationInverse = spreadMethod == GradientSpreadMethod.REFLECT;
currentIterationIndex = isIterationInverse ? normalizedStops.Count - 2 : 0;
}
}
// check the next iteration type to set the correct stop color hint for just added stop
if (isIterationInverse)
{
GradientColorStop nextColor = normalizedStops[currentIterationIndex];
// this method should be invoked only after the normalization. it means that
// the hint offset type for each stop is either relative to colors interval
// (i.e. for inverse iteration we need to inverse the hint offset), or is none
// (i.e. the hint offset value should be ignored)
computedStop.SetHint(1 - nextColor.GetHintOffset(), nextColor.GetHintOffsetType());
}
else
{
computedStop.SetHint(currentStop.GetHintOffset(), currentStop.GetHintOffsetType());
}
}
return(adjustedStops);
}