/// <summary>
/// Populate another polycurve with the portions of this one which lie within
/// the specified subDomain
/// </summary>
/// <param name="subDomain"></param>
/// <param name="result"></param>
private void PopulateWithSubCurves(Interval subDomain, PolyCurve result)
{
double segCount = SegmentCount;
double segStart = 0;
foreach (Curve subCrv in SubCurves)
{
double subSC = subCrv.SegmentCount;
double segEnd = segStart + subSC;
Interval crvDom = new Interval(segStart / segCount, segEnd / segCount);
if (subDomain.Contains(crvDom))
{
result.Add(subCrv.Duplicate());
}
else if (subDomain.Overlaps(crvDom))
{
Curve subSubCrv = subCrv.Extract(crvDom.ParameterOf(subDomain.Overlap(crvDom)));
if (subSubCrv != null)
{
result.Add(subSubCrv);
}
}
segStart = segEnd;
}
}
/// <summary>
/// Get a closed polycurve containing the edges of this section of the path.
/// The edges of the path must have been generated first.
/// </summary>
/// <returns></returns>
public static PolyCurve GetBoundaryCurve <TPath>(this TPath path)
where TPath : IWidePath
{
var result = new PolyCurve();
if (path.StartCapLeft != null)
{
result.Add(path.StartCapLeft);
}
if (path.LeftEdge != null)
{
result.Add(path.LeftEdge, true);
}
if (path.EndCapLeft != null)
{
result.Add(path.EndCapLeft, true);
}
if (path.EndCapRight != null)
{
result.Add(path.EndCapRight.Reversed(), true);
}
if (path.RightEdge != null)
{
result.Add(path.RightEdge.Reversed(), true);
}
if (path.StartCapRight != null)
{
result.Add(path.StartCapRight.Reversed(), true);
}
result.Close();
return(result);
}
/// <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);
}
/// <summary>
/// Offset this curve on the XY plane by varying distances for
/// each span.
/// </summary>
/// <param name="distances">The offset distance.
/// Positive numbers will result in the offset curve being to the right-hand
/// side, looking along the curve. Negative numbers to the left.</param>
/// <param name="tidy">If true (default) collapsed segments will be removed.</param>
/// <returns></returns>
public override Curve Offset(IList <double> distances, bool tidy = true, bool copyAttributes = true)
{
//TODO: Implement collapsed segments tidying
var result = new PolyCurve();
int distIndex = 0;
// Offset sub curves:
foreach (Curve crv in SubCurves)
{
Curve offsetCrv = crv.Offset(distances.SubListFrom(distIndex));
distIndex += crv.SegmentCount;
if (distIndex > distances.Count - 1)
{
distIndex = distances.Count - 1;
}
if (offsetCrv != null)
{
if (result.SubCurves.Count > 0)
{
// Adjust offset curve ends to node out
Curve prevCrv = result.SubCurves.Last();
MatchEnds(prevCrv.End, offsetCrv.Start);
}
result.Add(offsetCrv);
if (copyAttributes && offsetCrv.Attributes == null)
{
offsetCrv.Attributes = Attributes;
}
}
}
// Match end to start
if (Closed && result.SubCurves.Count > 1)
{
MatchEnds(result.SubCurves.Last().End, result.SubCurves.First().Start);
}
if (tidy)
{
List <Curve> originals = new List <Curve>();
originals.AddRange(SubCurves);
// Removed flipped segments
int j = 0;
while (j < result.SubCurves.Count)
{
Curve offset = result.SubCurves[j];
Curve original = originals[j];
if (IsOffsetCurveFlipped(original, offset))
{
if (result.SubCurves.Count > 0)
{
Curve previous = result.SubCurves.GetWrapped(j - 1);
Curve subsequent = result.SubCurves.GetWrapped(j + 1);
bool worked = MatchEnds(previous.End, subsequent.Start);
//TODO: Deal with failed matches (for e.g. when adjacent edges are parallel)
//if (!worked)
//return null; //TEMP: prevents invalid offsets, but a bit overkilly!
}
result.SubCurves.RemoveAt(j);
originals.RemoveAt(j);
//j--;
}
else
{
j++;
}
}
if (!result.IsValid)
{
return(null);
}
}
return(result);
}