/// <summary>
/// This looks long direction until a spot large enough to hold size is available
/// </summary>
/// <param name="size">The size of the rectangle to return</param>
/// <param name="start">The point that the rectangle would like to be centered over</param>
/// <param name="direction">
/// The direction to slide the rectangle until an empty space is found
/// NOTE: Set dir.Y to be negative to match screen coords
/// </param>
public static Rect GetFreeSpot(Size size, Point desiredPos, Vector direction, List<Rect> existing)
{
double halfWidth = size.Width / 2d;
double halfHeight = size.Height / 2d;
if (existing.Count == 0)
{
// There is nothing blocking this, center the rectangle over the position
return new Rect(desiredPos.X - halfWidth, desiredPos.Y - halfHeight, size.Width, size.Height);
}
// Direction unit
Vector dirUnit = direction.ToUnit();
if (Math2D.IsInvalid(dirUnit))
{
dirUnit = Math3D.GetRandomVector_Circular_Shell(1).ToVector2D();
}
// Calculate step distance (5% of the average of all the sizes)
double stepDist = UtilityCore.Iterate<Size>(size, existing.Select(o => o.Size)).
SelectMany(o => new[] { o.Width, o.Height }).
Average();
stepDist *= .05;
// Keep walking along direction until the rectangle doesn't intersect any existing rectangles
Point point = new Point();
Rect rect = new Rect();
for (int cntr = 0; cntr < 5000; cntr++)
{
point = desiredPos + (dirUnit * (stepDist * cntr));
rect = new Rect(point.X - halfWidth, point.Y - halfHeight, size.Width, size.Height);
if (!existing.Any(o => o.IntersectsWith(rect)))
{
break;
}
}
return rect;
}