private static PdfFunction ConstructSingleGradientSegmentFunction(GradientColorStop from, GradientColorStop
to)
{
double exponent = 1d;
float[] fromColor = from.GetRgbArray();
float[] toColor = to.GetRgbArray();
if (from.GetHintOffsetType() == GradientColorStop.HintOffsetType.RELATIVE_BETWEEN_COLORS)
{
double hintOffset = from.GetHintOffset();
if (hintOffset <= 0d + ZERO_EPSILON)
{
fromColor = toColor;
}
else
{
if (hintOffset >= 1d - ZERO_EPSILON)
{
toColor = fromColor;
}
else
{
// similar to css color hint logic
exponent = Math.Log(0.5) / Math.Log(hintOffset);
}
}
}
return(new PdfFunction.Type2(new PdfArray(new float[] { 0f, 1f }), null, new PdfArray(fromColor), new PdfArray
(toColor), new PdfNumber(exponent)));
}
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);
}
public virtual void CornerCasesTest()
{
GradientColorStop stopToTest = new GradientColorStop((float[])null, 1.5, GradientColorStop.OffsetType.AUTO
).SetHint(1.5, GradientColorStop.HintOffsetType.NONE);
NUnit.Framework.Assert.AreEqual(new float[] { 0f, 0f, 0f }, stopToTest.GetRgbArray());
NUnit.Framework.Assert.AreEqual(0, stopToTest.GetOffset(), 1e-10);
NUnit.Framework.Assert.AreEqual(GradientColorStop.OffsetType.AUTO, stopToTest.GetOffsetType());
NUnit.Framework.Assert.AreEqual(0, stopToTest.GetHintOffset(), 1e-10);
NUnit.Framework.Assert.AreEqual(GradientColorStop.HintOffsetType.NONE, stopToTest.GetHintOffsetType());
}
public virtual void NormalizationTest()
{
GradientColorStop stopToTest = new GradientColorStop(new float[] { -0.5f, 1.5f, 0.5f, 0.5f }, 1.5, GradientColorStop.OffsetType
.AUTO).SetHint(1.5, GradientColorStop.HintOffsetType.NONE);
NUnit.Framework.Assert.AreEqual(new float[] { 0f, 1f, 0.5f }, stopToTest.GetRgbArray());
NUnit.Framework.Assert.AreEqual(0, stopToTest.GetOffset(), 1e-10);
NUnit.Framework.Assert.AreEqual(GradientColorStop.OffsetType.AUTO, stopToTest.GetOffsetType());
NUnit.Framework.Assert.AreEqual(0, stopToTest.GetHintOffset(), 1e-10);
NUnit.Framework.Assert.AreEqual(GradientColorStop.HintOffsetType.NONE, stopToTest.GetHintOffsetType());
}
private static void NormalizeAutoStops(IList <GradientColorStop> toNormalize)
{
System.Diagnostics.Debug.Assert(toNormalize[0].GetOffsetType() == GradientColorStop.OffsetType.RELATIVE);
int firstAutoStopIndex = 1;
GradientColorStop firstStopColor = toNormalize[0];
double prevOffset = firstStopColor.GetHintOffsetType() == GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT
? firstStopColor.GetHintOffset() : firstStopColor.GetOffset();
for (int i = 1; i < toNormalize.Count; ++i)
{
GradientColorStop currentStop = toNormalize[i];
if (currentStop.GetOffsetType() == GradientColorStop.OffsetType.AUTO)
{
if (currentStop.GetHintOffsetType() == GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT)
{
double hintOffset = currentStop.GetHintOffset();
NormalizeAutoStops(toNormalize, firstAutoStopIndex, i + 1, prevOffset, hintOffset);
prevOffset = hintOffset;
firstAutoStopIndex = i + 1;
}
}
else
{
if (firstAutoStopIndex < i)
{
// current stop offset is relative
double offset = currentStop.GetOffset();
NormalizeAutoStops(toNormalize, firstAutoStopIndex, i, prevOffset, offset);
}
firstAutoStopIndex = i + 1;
prevOffset = currentStop.GetHintOffsetType() == GradientColorStop.HintOffsetType.RELATIVE_ON_GRADIENT ? currentStop
.GetHintOffset() : currentStop.GetOffset();
}
}
// check whether the last interval has auto
if (firstAutoStopIndex < toNormalize.Count)
{
double lastStopOffset = Math.Max(1, prevOffset);
NormalizeAutoStops(toNormalize, firstAutoStopIndex, toNormalize.Count, prevOffset, lastStopOffset);
}
}
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);
}