| private PerpendicularLineTo ( Point p ) : Line? | ||
| p | Point | |
| return | Line? | |
private static Point FindTangentPoint(Ray ray, Rect rectangle, CornerRadius cornerRadius)
{
var toMid = ray.PerpendicularLineTo(rectangle.CenterPoint());
Debug.Assert(toMid != null, "Cannot find tangent if line goes through center");
if (toMid == null)
{
// failing silently in release
return(rectangle.CenterPoint());
}
//Debug.Assert(!rectangle.Contains(toMid.Value.StartPoint), "Cannot find tangent if line intersects rectangle");
if (toMid.Value.Direction.Axis() != null)
{
return(ray.Point.Closest(rectangle.TopLeft, rectangle.TopRight, rectangle.BottomRight, rectangle.BottomLeft));
}
Circle corner;
switch (toMid.Value.Direction.Quadrant())
{
case Quadrant.NegativeXPositiveY:
corner = CreateTopRight(rectangle.TopRight, cornerRadius.TopRight);
break;
case Quadrant.PositiveXPositiveY:
corner = CreateTopLeft(rectangle.TopLeft, cornerRadius.TopLeft);
break;
case Quadrant.PositiveXNegativeY:
corner = CreateBottomLeft(rectangle.BottomLeft, cornerRadius.BottomLeft);
break;
case Quadrant.NegativeXNegativeY:
corner = CreateBottomRight(rectangle.BottomRight, cornerRadius.BottomRight);
break;
default:
throw new ArgumentOutOfRangeException();
}
// ReSharper disable once CompareOfFloatsByEqualityOperator
if (corner.Radius == 0)
{
return(corner.Center);
}
var lineToCenter = ray.PerpendicularLineTo(corner.Center);
Debug.Assert(lineToCenter != null, "Ray cannot go through center here");
if (lineToCenter == null)
{
// this should never happen but failing silently
// the balloons should not throw much.
return(corner.Center);
}
return(corner.Center - corner.Radius * lineToCenter.Value.Direction);
}
private static Point FindTangentPoint(Ray toCenter, Ellipse ellipse)
{
var toEllipseCenter = toCenter.PerpendicularLineTo(ellipse.Center);
Debug.Assert(toEllipseCenter != null, "Ray should not go through ellipse center here");
if (toEllipseCenter == null)
{
// this should never happen but failing silently
// the balloons should not throw much returning random point.
return(ellipse.Center);
}
return(ellipse.PointOnCircumference(toEllipseCenter.Value.Direction.Negated()));
}
private static Point FindTangentPoint(Ray toCenter, Ellipse ellipse)
{
var toEllipseCenter = toCenter.PerpendicularLineTo(ellipse.CenterPoint);
Debug.Assert(toEllipseCenter != null, "Ray should not go through ellipse center here");
if (toEllipseCenter == null)
{
// this should never happen but failing silently
// the balloons should not throw much returning random point.
return ellipse.CenterPoint;
}
return ellipse.PointOnCircumference(toEllipseCenter.Value.Direction.Negated());
}
private static Point FindTangentPoint(Ray ray, Rect rectangle, CornerRadius cornerRadius)
{
var toMid = ray.PerpendicularLineTo(rectangle.CenterPoint());
Debug.Assert(toMid != null, "Cannot find tangent if line goes through center");
if (toMid == null)
{
// failing silently in release
return rectangle.CenterPoint();
}
// Debug.Assert(!rectangle.Contains(toMid.Value.StartPoint), "Cannot find tangent if line intersects rectangle");
if (toMid.Value.Direction.Axis() != null)
{
return ray.Point.Closest(rectangle.TopLeft, rectangle.TopRight, rectangle.BottomRight, rectangle.BottomLeft);
}
Circle corner;
switch (toMid.Value.Direction.Quadrant())
{
case Quadrant.NegativeXPositiveY:
corner = CreateTopRight(rectangle.TopRight, cornerRadius.TopRight);
break;
case Quadrant.PositiveXPositiveY:
corner = CreateTopLeft(rectangle.TopLeft, cornerRadius.TopLeft);
break;
case Quadrant.PositiveXNegativeY:
corner = CreateBottomLeft(rectangle.BottomLeft, cornerRadius.BottomLeft);
break;
case Quadrant.NegativeXNegativeY:
corner = CreateBottomRight(rectangle.BottomRight, cornerRadius.BottomRight);
break;
default:
throw new ArgumentOutOfRangeException();
}
// ReSharper disable once CompareOfFloatsByEqualityOperator
if (corner.Radius == 0)
{
return corner.Center;
}
var lineToCenter = ray.PerpendicularLineTo(corner.Center);
Debug.Assert(lineToCenter != null, "Ray cannot go through center here");
if (lineToCenter == null)
{
// this should never happen but failing silently
// the balloons should not throw much.
return corner.Center;
}
return corner.Center - corner.Radius * lineToCenter.Value.Direction;
}