/// <summary>
/// Calculate the clip location
/// </summary>
/// <param name="hitSegment">the hitting segment</param>
/// <param name="beginNode">begin node</param>
/// <param name="spineVector"></param>
/// <param name="pressureDelta"></param>
/// <returns>the clip location. not-clip if return StrokeFIndices.BeforeFirst</returns>
private double CalculateClipLocation(
ContourSegment hitSegment, StrokeNodeData beginNode, Vector spineVector, double pressureDelta)
{
double findex = StrokeFIndices.BeforeFirst;
bool clipIt = hitSegment.IsArc ? true
//? (WhereIsVectorAboutArc(beginNode.Position - hitSegment.Begin - hitSegment.Radius,
// -hitSegment.Radius, hitSegment.Vector - hitSegment.Radius) == HitResult.Hit)
: (WhereIsVectorAboutVector(
beginNode.Position - hitSegment.Begin, hitSegment.Vector) == HitResult.Left);
if (clipIt)
{
findex = hitSegment.IsArc
? ClipTestArc(spineVector, pressureDelta,
(hitSegment.Begin + hitSegment.Radius - beginNode.Position) / beginNode.PressureFactor,
hitSegment.Radius / beginNode.PressureFactor)
: ClipTest(spineVector, pressureDelta,
(hitSegment.Begin - beginNode.Position) / beginNode.PressureFactor,
(hitSegment.End - beginNode.Position) / beginNode.PressureFactor);
// NTRAID#WINDOWS-1384646-2005/11/17-WAYNEZEN,
// ClipTest returns StrokeFIndices.AfterLast to indicate a false hit test.
// But the caller CutTest expects StrokeFIndices.BeforeFirst when there is no hit.
if ( findex == StrokeFIndices.AfterLast )
{
findex = StrokeFIndices.BeforeFirst;
}
else
{
System.Diagnostics.Debug.Assert(findex >= 0 && findex <= 1);
}
}
return findex;
}
/// <summary>
/// Helper function to Hit-test against the two stroke nodes only (excluding the connecting quad).
/// </summary>
/// <param name="hitSegment"></param>
/// <param name="beginNode"></param>
/// <param name="endNode"></param>
/// <param name="result"></param>
/// <returns></returns>
private bool HitTestStrokeNodes(
ContourSegment hitSegment, StrokeNodeData beginNode, StrokeNodeData endNode, ref StrokeFIndices result)
{
// First, find out if hitSegment intersects with either of the ink nodes
bool isHit = false;
for (int node = 0; node < 2; node++)
{
Point position;
double pressureFactor;
if (node == 0)
{
if (isHit && DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst))
{
continue;
}
position = beginNode.Position;
pressureFactor = beginNode.PressureFactor;
}
else
{
if (isHit && DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
continue;
}
position = endNode.Position;
pressureFactor = endNode.PressureFactor;
}
Vector hitBegin, hitEnd;
// Adjust the segment for the node's pressure factor
if (hitSegment.IsArc)
{
hitBegin = hitSegment.Begin - position + hitSegment.Radius;
hitEnd = hitSegment.Radius;
}
else
{
hitBegin = hitSegment.Begin - position;
hitEnd = hitBegin + hitSegment.Vector;
}
if (pressureFactor != 1)
{
System.Diagnostics.Debug.Assert(DoubleUtil.IsZero(pressureFactor) == false);
hitBegin /= pressureFactor;
hitEnd /= pressureFactor;
}
// Hit-test the node against the segment
if (hitSegment.IsArc
? HitTestPolygonCircle(_vertices, hitBegin, hitEnd)
: HitTestPolygonSegment(_vertices, hitBegin, hitEnd))
{
isHit = true;
if (node == 0)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
if (DoubleUtil.AreClose(result.EndFIndex, StrokeFIndices.AfterLast))
{
break;
}
}
else
{
result.EndFIndex = StrokeFIndices.AfterLast;
if (beginNode.IsEmpty)
{
result.BeginFIndex = StrokeFIndices.BeforeFirst;
break;
}
if (DoubleUtil.AreClose(result.BeginFIndex, StrokeFIndices.BeforeFirst))
{
break;
}
}
}
}
return isHit;
}