public async Task <bool> Execute(IWorkspace workspace, object arg)
{
var first = await workspace.InputService.GetPoint(new UserDirective("First point"));
if (!first.Cancel && first.HasValue)
{
var second = await workspace.InputService.GetPoint(new UserDirective("Second point"), (p) =>
{
return(new[]
{
new PrimitiveLine(first.Value, p)
});
});
if (!second.Cancel && second.HasValue)
{
var third = await workspace.InputService.GetPoint(new UserDirective("Third point"), (p) =>
{
var a = PrimitiveEllipse.ThreePointArc(first.Value, second.Value, p, workspace.DrawingPlane.Normal);
if (a == null)
{
return(new IPrimitive[0]);
}
else
{
return(new IPrimitive[]
{
a,
new PrimitivePoint(first.Value),
new PrimitivePoint(second.Value)
});
}
});
if (!third.Cancel && third.HasValue)
{
var primitiveArc = PrimitiveEllipse.ThreePointArc(first.Value, second.Value, third.Value, workspace.DrawingPlane.Normal);
if (primitiveArc != null)
{
var arc = new Arc(
primitiveArc.Center,
primitiveArc.MajorAxis.Length,
primitiveArc.StartAngle,
primitiveArc.EndAngle,
primitiveArc.Normal);
workspace.AddToCurrentLayer(arc);
return(true);
}
}
}
}
return(false);
}
private static void TestThreePointArcNormal(Point a, Point b, Point c, Vector idealNormal, Point expectedCenter, double expectedRadius, double expectedStartAngle, double expectedEndAngle)
{
var arc = PrimitiveEllipse.ThreePointArc(a, b, c, idealNormal);
AssertClose(idealNormal, arc.Normal);
AssertClose(expectedCenter, arc.Center);
AssertClose(1.0, arc.MinorAxisRatio);
AssertClose(expectedRadius, arc.MajorAxis.Length);
AssertClose(expectedStartAngle, arc.StartAngle);
AssertClose(expectedEndAngle, arc.EndAngle);
}
