/// <summary>
/// Find the next connecting perimeter segment along the cutting curve
/// </summary>
/// <param name="segments"></param>
/// <param name="tFrom"></param>
/// <param name="backwards"></param>
/// <returns></returns>
private static PerimeterSegment FindNextPerimeterSegment(IList <PerimeterSegment> segments, double tFrom, bool backwards)
{
PerimeterSegment next = null;
if (backwards)
{
foreach (var pSeg in segments)
{
if (pSeg.CutterDomain.Start < tFrom)
{
if (next == null || next.CutterDomain.Start < pSeg.CutterDomain.Start)
{
next = pSeg;
}
}
}
}
else
{
foreach (var pSeg in segments)
{
if (pSeg.CutterDomain.Start > tFrom)
{
if (next == null || next.CutterDomain.Start > pSeg.CutterDomain.Start)
{
next = pSeg;
}
}
}
}
return(next);
}
/// <summary>
/// Split this region into two (or more) sub-regions along a straight line
/// </summary>
/// <param name="splitPt">A point on the splitting line</param>
/// <param name="splitDir">The direction of the line</param>
/// <param name="splitWidth">Optional. The width of the split.</param>
/// <returns>The resultant list of regions. If the line does not bisect
/// this region and the region could not be split, this collection will contain
/// only the original region.</returns>
public IList <PlanarRegion> SplitByLineXY(Vector splitPt, Vector splitDir, double splitWidth = 0)
{
var result = new List <PlanarRegion>();
var lineInts = new List <double>();
var outerInts = Intersect.CurveLineXY(Perimeter, splitPt, splitDir, null, 0, 1, false, lineInts);
if (outerInts.Count > 1)
{
// Sort intersections by position along curve:
var sortedInts = new SortedList <double, double>(outerInts.Count);
for (int i = 0; i < outerInts.Count; i++)
{
sortedInts.Add(outerInts[i], lineInts[i]);
}
outerInts = sortedInts.Keys.ToList();
lineInts = sortedInts.Values.ToList();
int offset = lineInts.IndexOfMin();
outerInts.Shift(offset);
lineInts.Shift(offset);
// Create segments data structure
var segments = new List <PerimeterSegment>(outerInts.Count - 1);
for (int i = 0; i < outerInts.Count; i++)
{
double t0 = outerInts[i];
double t1 = outerInts.GetWrapped(i + 1);
double tC0 = lineInts[i];
double tC1 = lineInts.GetWrapped(i + 1);
var segment = new PerimeterSegment(Perimeter, t0, t1, tC0, tC1);
segments.Add(segment);
}
//TODO: void intersections
bool backwards = true;
while (segments.Count > 0)
{
var offsets = new List <double>();
PerimeterSegment segment = segments.First();
PolyCurve newPerimeter = segment.Extract().ToPolyCurve();
for (int i = 0; i < newPerimeter.SegmentCount; i++)
{
offsets.Add(0);
}
PerimeterSegment nextSegment = FindNextPerimeterSegment(segments, segment.CutterDomain.End, backwards);
while (nextSegment != null && nextSegment != segment)
{
Curve nextCurve = nextSegment.Extract();
newPerimeter.AddLine(nextCurve.StartPoint);
offsets.Add(splitWidth / 2);
newPerimeter.Add(nextCurve);
for (int i = 0; i < nextCurve.SegmentCount; i++)
{
offsets.Add(0);
}
segments.Remove(nextSegment);
nextSegment = FindNextPerimeterSegment(segments, nextSegment.CutterDomain.End, backwards);
}
segments.RemoveAt(0);
if (!newPerimeter.Closed)
{
/*if (splitWidth > 0)
* {
* // Temporary bodge to get rid of 'blades' at ends of split
* Vector endToEnd = (newPerimeter.StartPoint - newPerimeter.EndPoint).Unitize();
* var line = new Line(
* newPerimeter.EndPoint - endToEnd * splitWidth / 4,
* newPerimeter.StartPoint + endToEnd * splitWidth / 4);
* newPerimeter.AddLine(line.StartPoint);
* offsets.Add(0);
* newPerimeter.Add(line);
* offsets.Add(splitWidth / 2);
* newPerimeter.Close();
* offsets.Add(0);
* }
* else
* {*/
newPerimeter.Close();
offsets.Add(splitWidth / 2);
//}
}
backwards = !backwards;
if (splitWidth > 0)
{
var newNewPerimeter = newPerimeter.OffsetInwards(offsets);
// Check offset has not inverted perimeter:
// TODO: Do this automatically when offsetting?
if (newNewPerimeter != null && newNewPerimeter.IsClockwiseXY() == newPerimeter.IsClockwiseXY())
{
newPerimeter = newNewPerimeter.ToPolyCurve();
}
else
{
newPerimeter = null;
}
}
if (newPerimeter != null)
{
result.Add(new PlanarRegion(newPerimeter, Attributes?.Duplicate()));
}
}
// OLD VERSION:
/*for (int i = 0; i < outerInts.Count; i++)
* {
* double t0 = outerInts[i];
* double t1 = outerInts.GetWrapped(i + 1);
* Curve newPerimeter = Perimeter.Extract(new Interval(t0, t1))?.ToPolyCurve();
* //TODO: Cut through and include voids
* if (!newPerimeter.Closed)
* {
* ((PolyCurve)newPerimeter).Close();
* if (splitWidth > 0)
* {
* var offsets = new double[newPerimeter.SegmentCount];
* offsets[offsets.Length - 1] = splitWidth / 2;
* var newNewPerimeter = newPerimeter.OffsetInwards(offsets);
* // Check offset has not inverted perimeter:
* // TODO: Do this automatically when offsetting?
* if (newNewPerimeter != null && newNewPerimeter.IsClockwiseXY() == newPerimeter.IsClockwiseXY())
* {
* newPerimeter = newNewPerimeter;
* }
* else newPerimeter = null;
* }
* }
* if (newPerimeter != null) result.Add(new PlanarRegion(newPerimeter, Attributes?.Duplicate()));
* }*/
}
else
{
result.Add(this); //Return the original
}
return(result);
}
