/// <summary>
/// Generates a trapezoid polygon on the XY plane with the midpoint of each edge
/// centred on the origin and with a different top and bottom width.
/// </summary>
/// <param name="depth">The depth of the trapezoid</param>
/// <param name="topWidth">The width of the top of the trapezoid</param>
/// <param name="baseWidth">The width of the base of the trapezoid</param>
/// <returns></returns>
public static PolyCurve Trapezoid(double depth, double topWidth, double baseWidth)
{
double xT = topWidth / 2;
double xB = baseWidth / 2;
double y = depth / 2;
PolyCurve result = new PolyCurve(new Line(xT, y, -xT, y));
result.AddLine(-xB, -y);
result.AddLine(xB, -y);
result.AddLine(xT, y);
return(result);
}
/// <summary>
/// Extract a portion of this curve as a new curve
/// </summary>
/// <param name="subDomain">The subdomain of this curve to
/// be extracted as a new curve</param>
/// <returns></returns>
public override Curve Extract(Interval subDomain)
{
var result = new PolyCurve();
Interval subDomainAdj = subDomain;
if (subDomain.IsDecreasing)
{
subDomainAdj = new Interval(subDomain.Start, 1.0);
}
PopulateWithSubCurves(subDomainAdj, result);
// If looping, do a second pass:
if (Closed && subDomain.IsDecreasing)
{
PopulateWithSubCurves(new Maths.Interval(0.0, subDomain.End), result);
}
return(result);
}
/// <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>
/// 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> SplitByLineXY2(Vector splitPt, Vector splitDir, double splitWidth = 0)
{
var result = new List <PlanarRegion>();
// Offset splitting line by half splitWidth in each direction:
Vector offsetDir = splitDir.PerpendicularXY().Unitize();
Vector offset = offsetDir * splitWidth / 2;
Vector leftPt = splitPt + offset;
Vector rightPt = splitPt - offset;
// Find intersection points on perimeter:
var perimeterInts = new List <CurveLineIntersection>();
// Left side:
IList <CurveLineIntersection> leftInts = Intersect.CurveLineXYIntersections(Perimeter, leftPt, splitDir);
perimeterInts.AddRange(leftInts);
IList <CurveLineIntersection> rightInts;
// Shortcut: If the split has no width, left and right intersections will be the same
if (splitWidth == 0)
{
rightInts = leftInts;
}
else
{
rightInts = Intersect.CurveLineXYIntersections(Perimeter, rightPt, splitDir);
perimeterInts.AddRange(rightInts);
}
// If no intersections on the perimeter, the region does not need to be split:
if (leftInts.Count <= 1 && rightInts.Count <= 1)
{
result.Add(this);
return(result);
}
// Voids which do not intersect but will need to be placed:
CurveCollection freeVoids = new CurveCollection();
// Find intersection points on voids:
foreach (var voidCrv in Voids)
{
// Left side:
var leftVoidInts = Intersect.CurveLineXYIntersections(voidCrv, leftPt, splitDir);
foreach (var vI in leftVoidInts)
{
leftInts.Add(vI);
}
IList <CurveLineIntersection> rightVoidInts;
// Shortcut: If the split has no width, left and right intersections will be the same
if (splitWidth == 0)
{
rightVoidInts = leftVoidInts;
}
else
{
rightVoidInts = Intersect.CurveLineXYIntersections(voidCrv, rightPt, splitDir);
}
foreach (var vI in rightVoidInts)
{
rightInts.Add(vI);
}
if (leftVoidInts.Count <= 1 && rightVoidInts.Count <= 1)
{
// Void is wholly to one side or the other...
freeVoids.Add(voidCrv);
}
}
// Tag left and right intersections
foreach (var lI in leftInts)
{
lI.Side = HandSide.Left;
}
foreach (var rI in rightInts)
{
rI.Side = HandSide.Right;
}
// Determine direction of travel along cutting lines:
int rightDir = RightCutterDirectionOfTravel(perimeterInts);
// 'Fake' intersection to represent perimeter start:
CurveLineIntersection startInt = new CurveLineIntersection(Perimeter, 0, double.NaN);
// Loop through intersections and build up new sub-regions by traversing connected
// intersections along the perimeter, cutting lines and void curves
CurveLineIntersection currentInt = startInt;
CurveLineIntersection nextStartInt = null;
PolyCurve newPerimeter = null;
PlanarRegion newRegion = null;
// The cutter to travel along (Undefined is perimeter or void cuve):
HandSide travelSide = HandSide.Undefined;
int segmentCount = perimeterInts.Count + 1; //TODO: Include void intersections
for (int i = 0; i < segmentCount; i++) // Loop through intersections
{
CurveLineIntersection nextInt;
// Travel to next intersection, along the cutters or perimeter
if (travelSide == HandSide.Left)
{
// Travel along left cutter
if (rightDir == 1)
{
nextInt = leftInts.ItemWithPrevious(cLI => cLI.LineParameter, currentInt.LineParameter);
}
else
{
nextInt = leftInts.ItemWithNext(cLI => cLI.LineParameter, currentInt.LineParameter);
}
}
else if (travelSide == HandSide.Right)
{
// Travel along right cutter
if (rightDir == 1)
{
nextInt = rightInts.ItemWithNext(cLI => cLI.LineParameter, currentInt.LineParameter);
}
else
{
nextInt = rightInts.ItemWithPrevious(cLI => cLI.LineParameter, currentInt.LineParameter);
}
}
else
{
// Travel to next intersection on perimeter
nextInt = perimeterInts.ItemWithNext(cLI => cLI.CurveParameter, currentInt.CurveParameter);
// 'Fake' intersection to represent perimeter end:
if (nextInt == null)
{
nextInt = new CurveLineIntersection(Perimeter, 1, double.NaN);
}
if (nextStartInt == null)
{
nextStartInt = nextInt;
}
}
if (nextInt != null && currentInt.Curve == nextInt.Curve && // Check both ints on same curve
(travelSide == HandSide.Undefined || currentInt.Curve != Perimeter))
{
Curve curve = nextInt.Curve;
Interval subDomain = new Interval(currentInt.CurveParameter, nextInt.CurveParameter);
Vector crvPt = curve.PointAt(subDomain.Mid);
HandSide side = SideOfSplit(crvPt, leftPt, rightPt, offsetDir);
if (side != HandSide.Undefined)
{
// TODO: Adjust void curve direction
// Add perimeter to outputs
Curve subCrv = curve.Extract(subDomain);
if (newPerimeter == null)
{
newPerimeter = new PolyCurve(subCrv.Explode());
newRegion = new PlanarRegion(newPerimeter);
result.Add(newRegion);
}
else
{
newPerimeter.Add(subCrv, true, true);
}
}
else
{
//Traversing the gap, need a new start Point
startInt = nextInt;
}
}
// Next side to travel:
if (travelSide != HandSide.Undefined &&
(nextInt == null || nextInt.Curve == Perimeter))
{
travelSide = HandSide.Undefined;
}
else
{
travelSide = nextInt.Side;
}
if (nextInt == null || nextInt == startInt || nextInt.CurveParameter >= 1)
{
// Reset to start next segment
nextInt = nextStartInt;
startInt = nextStartInt;
nextStartInt = null;
if (newPerimeter != null)
{
newPerimeter.Close();
}
newPerimeter = null;
newRegion = null;
travelSide = HandSide.Undefined;
}
currentInt = nextInt;
}
if (newPerimeter != null)
{
newPerimeter.Close();
}
//TODO: Assign un-intersected voids
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);
}
/// <summary>
/// Creates a new polycurve as a copy of another one
/// </summary>
/// <param name="other"></param>
public PolyCurve(PolyCurve other)
: this(other.FastDuplicateSubCurves(), other.Attributes)
{
}
/// <summary>
/// Extract from this PolyCurve a chain of subcurves, starting with the
/// longest and continuing to select the longest edge until no more can
/// be added without adding an edge which is within an angle tolerance of
/// an existing curve within the chain.
/// </summary>
/// <returns></returns>
public PolyCurve ExtractLongCurveChain(Angle maxAngle)
{
Curve longest = SubCurves.GetLongest();
if (longest != null)
{
var tangents = new List <Vector>();
tangents.Add(longest.TangentAt(0.5));
var result = new PolyCurve(longest);
int iL = SubCurves.IndexOf(longest);
int i0 = iL - 1;
int i1 = iL + 1;
bool closed = Closed;
bool tryPre = closed || i0 >= 0;
bool tryPost = closed || i1 < SubCurves.Count;
while (tryPre || tryPost)
{
Curve pre = tryPre ? SubCurves.GetWrapped(i0, closed) : null;
Curve post = tryPost ? SubCurves.GetWrapped(i1, closed) : null;
if (post != null && (pre == null || post.Length > pre.Length))
{
Vector tang = post.TangentAt(0.5);
if (result.SubCurves.Contains(post.GUID) || tangents.MaximumAngleBetween(tang).Abs() > maxAngle)
{
tryPost = false;
}
else
{
result.SubCurves.Add(post);
tangents.Add(tang);
i1++;
if (!closed && i1 >= SubCurves.Count)
{
tryPost = false;
}
}
}
else if (pre != null)
{
Vector tang = pre.TangentAt(0.5);
if (result.SubCurves.Contains(pre.GUID) || tangents.MaximumAngleBetween(tang).Abs() > maxAngle)
{
tryPre = false;
}
else
{
result.SubCurves.Insert(0, pre);
tangents.Add(tang);
i0--;
if (!closed && i0 < 0)
{
tryPre = false;
}
}
}
else
{
tryPre = false;
tryPost = false;
}
}
return(result);
}
return(null);
}