///<summary>
/// Adds a limited mitre join connecting the two reflex offset segments.
///</summary>
/// <remarks>
/// A limited mitre is a mitre which is beveled at the distance
/// determined by the mitre ratio limit.
/// </remarks>
/// <param name="offset0">The first offset segment</param>
/// <param name="offset1">The second offset segment</param>
/// <param name="distance">The offset distance</param>
/// <param name="mitreLimit">The mitre limit ratio</param>
private void AddLimitedMitreJoin(
LineSegment offset0,
LineSegment offset1,
double distance,
double mitreLimit)
{
Coordinate basePt = _seg0.P1;
double ang0 = AngleUtility.Angle(basePt, _seg0.P0);
double ang1 = AngleUtility.Angle(basePt, _seg1.P1);
// oriented angle between segments
double angDiff = AngleUtility.AngleBetweenOriented(_seg0.P0, basePt, _seg1.P1);
// half of the interior angle
double angDiffHalf = angDiff / 2;
// angle for bisector of the interior angle between the segments
double midAng = AngleUtility.Normalize(ang0 + angDiffHalf);
// rotating this by PI gives the bisector of the reflex angle
double mitreMidAng = AngleUtility.Normalize(midAng + Math.PI);
// the miterLimit determines the distance to the mitre bevel
double mitreDist = mitreLimit * distance;
// the bevel delta is the difference between the buffer distance
// and half of the length of the bevel segment
double bevelDelta = mitreDist * Math.Abs(Math.Sin(angDiffHalf));
double bevelHalfLen = distance - bevelDelta;
// compute the midpoint of the bevel segment
double bevelMidX = basePt.X + mitreDist * Math.Cos(mitreMidAng);
double bevelMidY = basePt.Y + mitreDist * Math.Sin(mitreMidAng);
Coordinate bevelMidPt = new Coordinate(bevelMidX, bevelMidY);
// compute the mitre midline segment from the corner point to the bevel segment midpoint
LineSegment mitreMidLine = new LineSegment(basePt, bevelMidPt);
// finally the bevel segment endpoints are computed as offsets from
// the mitre midline
Coordinate bevelEndLeft = mitreMidLine.PointAlongOffset(1.0, bevelHalfLen);
Coordinate bevelEndRight = mitreMidLine.PointAlongOffset(1.0, -bevelHalfLen);
if (_side == Positions.Left)
{
_vertexList.AddPt(bevelEndLeft);
_vertexList.AddPt(bevelEndRight);
}
else
{
_vertexList.AddPt(bevelEndRight);
_vertexList.AddPt(bevelEndLeft);
}
}
public void TestNormalize()
{
Assert.AreEqual(AngleUtility.Normalize(0.0), 0.0, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-0.5 * Math.PI), -0.5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-Math.PI), Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-1.5 * Math.PI), .5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-2 * Math.PI), 0.0, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-2.5 * Math.PI), -0.5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-3 * Math.PI), Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(-4 * Math.PI), 0.0, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(0.5 * Math.PI), 0.5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(Math.PI), Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(1.5 * Math.PI), -0.5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(2 * Math.PI), 0.0, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(2.5 * Math.PI), 0.5 * Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(3 * Math.PI), Math.PI, Tolerance);
Assert.AreEqual(AngleUtility.Normalize(4 * Math.PI), 0.0, Tolerance);
}