internal static float ConvertSweepAngle(float sweepAngle, float startAngle, SpatialTransform transform, CoordinateSystem targetSystem)
{
PointF x = new PointF(100, 0);
PointF[] startVector = new PointF[] { x };
Matrix rotation = new Matrix();
rotation.Rotate(startAngle);
rotation.TransformVectors(startVector);
PointF[] sweepVector = (PointF[])startVector.Clone();
rotation.Reset();
rotation.Rotate(sweepAngle);
rotation.TransformVectors(sweepVector);
rotation.Dispose();
SizeF startVectorTransformed, sweepVectorTransformed;
if (targetSystem == Graphics.CoordinateSystem.Destination)
{
startVectorTransformed = transform.ConvertToDestination(new SizeF(startVector[0]));
sweepVectorTransformed = transform.ConvertToDestination(new SizeF(sweepVector[0]));
}
else
{
startVectorTransformed = transform.ConvertToSource(new SizeF(startVector[0]));
sweepVectorTransformed = transform.ConvertToSource(new SizeF(sweepVector[0]));
}
// simply return the angle between the start and sweep angle, in the target system.
return((int)Math.Round(Vector.SubtendedAngle(sweepVectorTransformed.ToPointF(), PointF.Empty, startVectorTransformed.ToPointF())));
}
internal static float ConvertStartAngle(float angle, SpatialTransform transform, CoordinateSystem targetSystem)
{
PointF xVector = new PointF(100, 0);
Matrix rotation = new Matrix();
PointF[] angleVector = new PointF[] { xVector };
rotation.Rotate(angle);
rotation.TransformVectors(angleVector);
rotation.Dispose();
SizeF xVectorTransformed, angleVectorTransformed;
if (targetSystem == Graphics.CoordinateSystem.Destination)
{
xVectorTransformed = transform.ConvertToDestination(new SizeF(xVector));
angleVectorTransformed = transform.ConvertToDestination(new SizeF(angleVector[0]));
}
else
{
xVectorTransformed = transform.ConvertToSource(new SizeF(xVector));
angleVectorTransformed = transform.ConvertToSource(new SizeF(angleVector[0]));
}
float xRotationOffset =
(int)Math.Round(Vector.SubtendedAngle(xVectorTransformed.ToPointF(), PointF.Empty, xVector));
float angleTransformed =
(int)Math.Round(Vector.SubtendedAngle(angleVectorTransformed.ToPointF(), PointF.Empty, xVectorTransformed.ToPointF()));
// have to figure out where x-axis moved to and then return the difference between the angle
// and the x-axis, where both are in 'target' coordinates.
float returnAngle = angleTransformed + xRotationOffset;
if (returnAngle < 0)
{
returnAngle += 360;
}
return(returnAngle);
}