/// <summary>
/// create a box of the given width and height at center.
/// </summary>
/// <param name="c"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="center"></param>
/// <returns></returns>
static internal void CreateRectangle(Curve c, double width, double height, Point center)
{
double w = width / 2;
double h = height / 2;
double x = center.X;
double y = center.Y;
Point[] p = new Point[] { new Point(x - w, y - h), new Point(x + w, y - h), new Point(x + w, y + h), new Point(x - w, y + h) };
c.AddSegs(new LineSegment(p[0], p[1]), new LineSegment(p[1], p[2]), new LineSegment(p[2], p[3]), new LineSegment(p[3], p[0]));
}
/// <summary>
/// Creates a curve resembling a diamond large enough to inscribe within it a rectangle of the
/// given width and height at center.
/// </summary>
/// <param name="width">the width of the inscribed rectangle</param>
/// <param name="height">the height of the inscribed rectangle</param>
/// <param name="center">the diamond center</param>
/// <returns></returns>
static public ICurve CreateDiamond(double width, double height, Point center)
{
double w = width;
double h = height;
double x = center.X;
double y = center.Y;
Curve c = new Curve();
Point[] p = new Point[] { new Point(x, y - h), new Point(x + w, y), new Point(x, y + h), new Point(x - w, y) };
c.AddSegs(new LineSegment(p[0], p[1]), new LineSegment(p[1], p[2]), new LineSegment(p[2], p[3]), new LineSegment(p[3], p[0]));
return(c);
}
/// <summary>
/// Following "Biarc approximation of NURBS curves", Les A. Piegl, and Wayne Tiller. The paper has a bug in V, where they write that v=p0+p4, it is p0-p4.
/// Also I treat special cases differently.
/// </summary>
/// <param name="p0"></param>
/// <param name="ts"></param>
/// <param name="p4"></param>
/// <param name="te"></param>
/// <returns></returns>
internal static ICurve BiArc(Point p0, Point ts, Point p4, Point te) {
Debug.Assert(ApproximateComparer.Close(ts.LengthSquared, 1));
Debug.Assert(ApproximateComparer.Close(te.LengthSquared, 1));
var v = p0 - p4;
if (v.Length < ApproximateComparer.DistanceEpsilon)
return null;
var vtse = v * (ts - te);
var tste = -ts * te;
//solving a quadratic equation
var a = 2 * (tste - 1);
var b = 2 * vtse;
var c = v * v;
double al;
if (Math.Abs(a) < ApproximateComparer.DistanceEpsilon) { //we have b*al+c=0
if (Math.Abs(b) > ApproximateComparer.DistanceEpsilon) {
al = -c / b;
}
else {
return null;
}
}
else {
var d = b * b - 4 * a * c;
Debug.Assert(d >= -ApproximateComparer.Tolerance);
if (d < 0)
d = 0;
d = Math.Sqrt(d);
al = (-b + d) / (2 * a);
if (al < 0)
al = (-b - d) / (2 * a);
}
var p1 = p0 + al * ts;
var p3 = p4 + al * te;
var p2 = 0.5 * (p1 + p3);
var curve = new Curve();
curve.AddSegs(ArcOn(p0, p1, p2), ArcOn(p2, p3, p4));
//bad input for BiArc. we shouldn't allow such cases during bundle bases construction
if (ts * (p4 - p0) <= 0 && ts * te <= 0) {
//switch to Bezier
var curve2 = StandardBezier(p0, ts, p4, te);
#if DEBUG && TEST_MSAGL
/*List<DebugCurve> dc = new List<DebugCurve>();
dc.Add(new DebugCurve(curve));
dc.Add(new DebugCurve(0.3, "black", curve2));
dc.Add(new DebugCurve(0.1, "red", new LineSegment(p0, p0 + 3 * ts)));
dc.Add(new DebugCurve(0.1, "blue", new LineSegment(p4, p4 + 3 * te)));
LayoutAlgorithmSettings.ShowDebugCurvesEnumeration(dc);*/
#endif
return curve2;
}
return curve;
}
/// <summary>
/// Creates a curve resembling a diamond large enough to inscribe within it a rectangle of the
/// given width and height at center.
/// </summary>
/// <param name="width">the width of the inscribed rectangle</param>
/// <param name="height">the height of the inscribed rectangle</param>
/// <param name="center">the diamond center</param>
/// <returns></returns>
static public ICurve CreateDiamond(double width, double height, Point center) {
double w = width;
double h = height;
double x = center.X;
double y = center.Y;
Curve c = new Curve();
Point[] p = new Point[] { new Point(x, y - h), new Point(x + w, y), new Point(x, y + h), new Point(x - w, y) };
c.AddSegs(new LineSegment(p[0], p[1]), new LineSegment(p[1], p[2]), new LineSegment(p[2], p[3]), new LineSegment(p[3], p[0]));
return c;
}
/// <summary>
/// create a box of the given width and height at center.
/// </summary>
/// <param name="c"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="center"></param>
/// <returns></returns>
static internal void CreateRectangle(Curve c, double width, double height, Point center)
{
double w = width / 2;
double h = height / 2;
double x = center.X;
double y = center.Y;
Point[] p = new Point[] { new Point(x - w, y - h), new Point(x + w, y - h), new Point(x + w, y + h), new Point(x - w, y + h) };
c.AddSegs(new LineSegment(p[0], p[1]), new LineSegment(p[1], p[2]), new LineSegment(p[2], p[3]), new LineSegment(p[3], p[0]));
}
private Curve ExtendCurveToEndpoints(Curve curve) {
Point p = this.EdgePathPoint(0);
if (!ApproximateComparer.Close(p, curve.Start)) {
Curve nc = new Curve();
nc.AddSegs(new LineSegment(p, curve.Start), curve);
curve = nc;
}
p = this.EdgePathPoint(edgePath.Count);
if (!ApproximateComparer.Close(p, curve.End))
curve.AddSegment(new LineSegment(curve.End, p));
return curve;
}
static ICurve GetTrimmedCurveForHookingUpAnywhere(ICurve curve, PolylinePoint lastPointInside, IntersectionInfo x0, IntersectionInfo x1) {
var clockwise =
Point.GetTriangleOrientation(x1.IntersectionPoint, x0.IntersectionPoint, lastPointInside.Point) ==
TriangleOrientation.Clockwise;
double rightX = x0.Par0;
double leftX = x1.Par0;
ICurve tr0, tr1;
Curve ret;
if (clockwise) {
if (rightX < leftX)
return curve.Trim(rightX, leftX);
tr0 = curve.Trim(rightX, curve.ParEnd);
tr1 = curve.Trim(curve.ParStart, leftX);
ret = new Curve();
return ret.AddSegs(tr0, tr1);
}
if (leftX < rightX)
return curve.Trim(leftX, rightX);
tr0 = curve.Trim(leftX, curve.ParEnd);
tr1 = curve.Trim(curve.ParStart, rightX);
ret = new Curve();
return ret.AddSegs(tr0, tr1);
}