/// <summary>
/// Determines whether a point is within the circle.
/// </summary>
/// <param name="point">The point being tested.</param>
/// <returns><c>true</c> if the point is within the circle.</returns>
public override bool Contains(GeoCoordinate point)
{
if (!Bounds.Contains(point))
{
return(false); // Handles clipping cases
}
return(GeoHelper.Distance(point, center, planetRadius) <= radius);
}
/// <summary>
/// Computes the bounding rectangle for the circle.
/// </summary>
private void ComputeBounds()
{
// This is a bit tricky. The approach is to plot points for the edge of
// the circle on the horizonal and vertical axes, clip these to the edges
// of the map (since we don't implement coordinate wraparound) and then
// form the rectangle.
//
// Note that this is a bit of hack and may result in inaccuracies for some
// combinations of planet radii and circle center points.
double left;
double top;
double right;
double bottom;
left = GeoHelper.Plot(center, 270, radius, planetRadius).Longitude;
if (left > center.Longitude)
{
left = -180; // clip
}
right = GeoHelper.Plot(center, 90, radius, planetRadius).Longitude;
if (right < center.Longitude)
{
right = 180; // clip
}
top = GeoHelper.Plot(center, 0, radius, planetRadius).Latitude;
if (top < center.Latitude)
{
top = 90;
}
bottom = GeoHelper.Plot(center, 180, radius, planetRadius).Latitude;
if (bottom > center.Latitude)
{
bottom = -90;
}
base.Bounds = new GeoRectangle(top, right, bottom, left);
}
