public static IgesCircularArc ToIgesCircle(this Entity entity)
{
var(center, startAngle, endAngle, color) = entity.MapEntity <(Point, double, double, CadColor?)>(
aggregate => throw new ArgumentException(nameof(entity)),
arc => (arc.Center, arc.StartAngle, arc.EndAngle, arc.Color),
circle => (circle.Center, 0.0, 360.0, circle.Color),
ellipse => throw new ArgumentException(nameof(entity)),
image => throw new ArgumentException(nameof(entity)),
line => throw new ArgumentException(nameof(entity)),
location => throw new ArgumentException(nameof(entity)),
polyline => throw new ArgumentException(nameof(entity)),
spline => throw new ArgumentException(nameof(entity)),
text => throw new ArgumentException(nameof(entity))
);
startAngle *= MathHelper.DegreesToRadians;
endAngle *= MathHelper.DegreesToRadians;
// TODO: if normal isn't z-axis, create a transformation matrix
var fromUnit = entity.GetUnitCircleProjection();
var startPoint = fromUnit.Transform(new Point(Math.Cos(startAngle), Math.Sin(startAngle), 0.0));
var endPoint = fromUnit.Transform(new Point(Math.Cos(endAngle), Math.Sin(endAngle), 0.0));
var result = new IgesCircularArc()
{
PlaneDisplacement = center.Z,
Center = new IgesPoint(center.X, center.Y, 0),
StartPoint = new IgesPoint(startPoint.X, startPoint.Y, 0),
EndPoint = new IgesPoint(endPoint.X, endPoint.Y, 0)
};
AssignColor(result, color);
return(result);
}
public static IgesCircularArc ToIgesCircle(this Entity entity)
{
Point center;
double startAngle, endAngle;
CadColor?color;
switch (entity.Kind)
{
case EntityKind.Arc:
var arc = (Arc)entity;
center = arc.Center;
startAngle = arc.StartAngle;
endAngle = arc.EndAngle;
color = arc.Color;
break;
case EntityKind.Circle:
var circle = (Circle)entity;
center = circle.Center;
startAngle = 0.0;
endAngle = 360.0;
color = circle.Color;
break;
default:
throw new ArgumentException();
}
startAngle *= MathHelper.DegreesToRadians;
endAngle *= MathHelper.DegreesToRadians;
// TODO: if normal isn't z-axis, create a transformation matrix
var fromUnit = entity.GetUnitCircleProjection();
var startPoint = fromUnit.Transform(new Point(Math.Cos(startAngle), Math.Sin(startAngle), 0.0));
var endPoint = fromUnit.Transform(new Point(Math.Cos(endAngle), Math.Sin(endAngle), 0.0));
var result = new IgesCircularArc()
{
PlaneDisplacement = center.Z,
Center = new IgesPoint(center.X, center.Y, 0),
StartPoint = new IgesPoint(startPoint.X, startPoint.Y, 0),
EndPoint = new IgesPoint(endPoint.X, endPoint.Y, 0)
};
AssignColor(result, color);
return(result);
}
public void WriteLineWithStructureTest()
{
var file = new IgesFile();
var circle = new IgesCircularArc()
{
StructureEntity = new IgesLine()
};
file.Entities.Add(circle);
VerifyFileContains(file, @"
110 1 0 0 0 00000000D 1
110 0 0 1 0 D 2
100 2 -1 0 0 00000000D 3
100 0 0 1 0 D 4
110,0.,0.,0.,0.,0.,0.; 1P 1
100,0.,0.,0.,0.,0.,0.,0.; 3P 2
");
}
public static Entity ToArc(this IgesCircularArc arc)
{
var center = TransformPoint(arc, arc.ProperCenter);
var startPoint = TransformPoint(arc, arc.ProperStartPoint);
var endPoint = TransformPoint(arc, arc.ProperEndPoint);
// all points have the same Z-value, so the normal will be the transformed Z-axis vector
var igesNormal = TransformPoint(arc, IgesVector.ZAxis);
var normal = new Vector(igesNormal.X, igesNormal.Y, igesNormal.Z).Normalize();
// find radius from start/end points
var startVector = startPoint - center;
var endVector = endPoint - center;
var startRadius = startVector.Length;
var endRadius = endVector.Length;
// these should be very close, if not identical, but not necessarily
var radius = (startRadius + endRadius) / 2;
// if start/end points are the same, it's a circle. otherwise it's an arc
if (startPoint.CloseTo(endPoint))
{
return(new Circle(center, radius, normal, GetColor(arc), arc));
}
else
{
// project back to unit circle to find start/end angles
var primitiveCircle = new PrimitiveEllipse(center, radius, normal);
var fromUnit = primitiveCircle.FromUnitCircle;
Debug.Assert(AreAllValuesValid(fromUnit));
var toUnit = fromUnit.Inverse();
Debug.Assert(AreAllValuesValid(toUnit));
var startUnit = toUnit.Transform(startPoint);
var endUnit = toUnit.Transform(endPoint);
var startAngle = ((Vector)startUnit).ToAngle();
var endAngle = ((Vector)endUnit).ToAngle();
return(new Arc(center, radius, startAngle, endAngle, normal, GetColor(arc), arc));
}
}