public ArrowEnterExit fromLeftAtYWithEdgeAtIndex(float y, int index, out Vector2f intersectionPoint)
{
Vector2f v = pathPoints[index];
Vector2f vNext = nextPoint(index);
Edge2f edge = new Edge2f(v, vNext);
bool intersects = edge.intersectionPointWithY(y, out intersectionPoint);
if (!intersects)
{
intersectionPoint = Vector2f.Zero;
return(ArrowEnterExit.DoesntIntersect);
}
if (vNext.y > v.y == isClockwiseOrdered)
{
return(ArrowEnterExit.Enters);
}
return(ArrowEnterExit.Exits);
}
IEnumerable <PenDrawingPath> crosshatches(StripedPath stripedPath)
{
Matrix2f inverseRotation;
PathData pdata;
for (var stripeField = stripedPath.stripeField; stripeField != null; stripeField = stripeField.next)
{
inverseRotation = stripeField.rotation.Inverse();
if (dbugSettings.dontRotateBackFinalPenPaths)
{
inverseRotation = Matrix2f.Identity;
}
pdata = new PathData(SvgParser.SvgPath.RotatedClone(stripedPath.path, stripeField.rotation), _svgFileData.isYAxisInverted);
int lastEnterEdgeIndex = -100;
foreach (int i in pdata.enterFromLeftEdgeIndices)
{
Vector2f edgeLower = pdata.areEnterLeftEdgesPosDelta ? pdata[i] : pdata.nextPoint(i);
Vector2f edgeUpper = pdata.areEnterLeftEdgesPosDelta ? pdata.nextPoint(i) : pdata[i];
Assert.IsTrue(edgeLower.y < edgeUpper.y, "something wrong at index: " + i);
Edge2f leftEdge = new Edge2f(edgeLower, edgeUpper);
Vector2f leftIntersection;
// foreach y: find exit edges that span the y, find closest intersecion point
float y = stripeField.nextStripeYPosAbove(edgeLower.y);
for (; y < stripeField.nextStripeYPosAbove(edgeUpper.y); y += stripeField.interval)
{
if (!leftEdge.intersectionPointWithY(y, out leftIntersection))
{
continue;
//break; // want?
}
float closestXDelta = float.MaxValue;
for (int j = 0; j < pdata.exitFromLeftEdgeIndices.Count; ++j)
{
int jV = pdata.exitFromLeftEdgeIndices[j];
Edge2f jEdge = pdata.edgeAt(jV);
Vector2f intrsection;
if (jEdge.intersectionPointWithY(y, out intrsection))
{
float dif = intrsection.x - leftIntersection.x;
if (dif > 0f && dif < closestXDelta)
{
closestXDelta = dif;
}
}
}
if (closestXDelta < float.MaxValue)
{
PenDrawingPath penPath = new PenDrawingPath();
penPath.addDownUpDrawMove(
(inverseRotation * leftIntersection) * viewBoxToPaperScale,
(inverseRotation * new Vector2f(leftIntersection.x + closestXDelta, y)) * viewBoxToPaperScale,
Color.black);
yield return(penPath);
}
}
lastEnterEdgeIndex = i;
}
}
}