In my earlier post I put together an image processing class (http://drowningintechnicaldebt.com/blogs/shawnweisfeld/archive/2006/11/06/Bitmap-Processing-in-C_2300_.aspx). I needed a method that built a bounding box around a given shape. Here is the code:
public static void BoundingBox(Bitmap b, ref Point upperLeft, ref Point lowerRight)
{
ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
Queue<Point> q = new Queue<Point>();
q.Enqueue(upperLeft);
int jump = 10;
while (q.Count > 0)
{
Point p = q.Dequeue();
AddToStack(q, b, i, new Point(p.X + jump, p.Y), ref upperLeft, ref lowerRight);
AddToStack(q, b, i, new Point(p.X - jump, p.Y), ref upperLeft, ref lowerRight);
AddToStack(q, b, i, new Point(p.X, p.Y + jump), ref upperLeft, ref lowerRight);
AddToStack(q, b, i, new Point(p.X, p.Y - jump), ref upperLeft, ref lowerRight);
}
i.UnlockBitmap();
}
private static void AddToStack(Queue<Point> q, Bitmap b, ImagerBitmap i, Point p, ref Point upperLeft, ref Point lowerRight)
{
if (p.X < b.Width
&& p.Y < b.Height
&& i.GetGreyPixel(p.X, p.Y) != 0)
{
if (upperLeft.X > p.X)
{
upperLeft.X = p.X;
q.Enqueue(p);
}
if (upperLeft.Y > p.Y)
{
upperLeft.Y = p.Y;
q.Enqueue(p);
}
if (lowerRight.X < p.X)
{
lowerRight.X = p.X;
q.Enqueue(p);
}
if (lowerRight.Y < p.Y)
{
lowerRight.Y = p.Y;
q.Enqueue(p);
}
}
}