private void GetStartEndPoints(out Point start, out Point end, out double startAngle)
{
start = null;
end = null;
startAngle = -1;
// Find the first point so we sweep in a counter-clockwise manner.
double angle1 = Point.GetRadianStandardAngleWithCenter(theCircle.center, endpoint1);
double angle2 = Point.GetRadianStandardAngleWithCenter(theCircle.center, endpoint2);
// Define to vectors: vect1: A----->B
// vect2: B----->C
// Cross product vect1 and vect2.
// If the result is positive, the sequence A-->B-->C is Counter-clockwise.
// If the result is negative, the sequence A-->B-->C is clockwise.
Point vect1 = Point.MakeVector(this.middlePoint, this.endpoint1);
Point vect2 = Point.MakeVector(this.endpoint2, this.middlePoint);
if (Point.CrossProduct(vect1, vect2) > 0)
{
start = endpoint1;
end = endpoint2;
startAngle = angle1;
}
else
{
start = endpoint2;
end = endpoint1;
startAngle = angle2;
}
}
public override List <Segment> Segmentize()
{
if (approxSegments.Any())
{
return(approxSegments);
}
// How much we will change the angle measure as we create segments.
double angleIncrement = Angle.toRadians(this.minorMeasure / Figure.NUM_SEGS_TO_APPROX_ARC);
// Find the first point so we sweep in a counter-clockwise manner.
double angle1 = Point.GetRadianStandardAngleWithCenter(theCircle.center, endpoint1);
double angle2 = Point.GetRadianStandardAngleWithCenter(theCircle.center, endpoint2);
Point firstPoint = null;
Point secondPoint = null;
double angle = -1;
GetStartEndPoints(angle1, angle2, out firstPoint, out secondPoint, out angle);
for (int i = 1; i <= Figure.NUM_SEGS_TO_APPROX_ARC; i++)
{
// Save this as an approximating point.
approxPoints.Add(firstPoint);
// Get the next point.
angle += angleIncrement;
secondPoint = Point.GetPointFromAngle(theCircle.center, theCircle.radius, angle);
// Make the segment.
approxSegments.Add(new Segment(firstPoint, secondPoint));
// Rotate points.
firstPoint = secondPoint;
}
// Save this as an approximating point.
approxPoints.Add(secondPoint);
return(approxSegments);
}
