/// <summary>
/// Find all the unassigned neighbors of the given pixel and update stats of the given island
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
protected void FindNeighbors(Bitmap b, BlobIsland island)
{
// keep iterating while there are items on the stack
while (this.FindNeighborsStack.Count > 0)
{
// get top of stack
Point p = (Point)this.FindNeighborsStack.Pop();
// if out of bounds then ignore
if (p.X < 0)
break;
if (p.Y < 0)
break;
if (p.X >= this.width)
break;
if (p.Y >= this.height)
break;
// continue if this pixel is not assigned to an island
if (this.map[p.Y * this.width + p.X] == -1)
{
// continue only if the pixel is not black
Color pixel = b.GetPixel(p.X, p.Y);
// if any components not zero consider it a 'set' pixel
if ((pixel.R + pixel.G + pixel.B) > 0)
{
// mark pixel with our index
this.map[p.Y * this.width + p.X] = island.index;
// bump pixel count
island.pixelCount++;
// if this is an edge pixel then flag island as belonging to an edge
if ((p.X == 0) || (p.Y == 0) || (p.X == this.width - 1) || (p.Y == this.height - 1))
island.edgeConnected = true;
// push neighbors onto stack and keep trying
this.FindNeighborsStack.Push(new Point(p.X, p.Y - 1));
this.FindNeighborsStack.Push(new Point(p.X - 1, p.Y));
this.FindNeighborsStack.Push(new Point(p.X + 1, p.Y));
this.FindNeighborsStack.Push(new Point(p.X, p.Y + 1));
}
}
}
}
/// <summary>
/// Create an island at the given location. Count and flag all 4np pixels
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
protected BlobIsland CreateIsland(int x, int y, int index, Bitmap b)
{
// create new island
BlobIsland island = new BlobIsland();
// set seed location
island.seedLocation = new Point(x, y);
// reset pixel count
island.pixelCount = 0;
// defaults to not edge connected until proven otherwise
island.edgeConnected = false;
// set index
island.index = index;
// discover island starting at this location
this.FindNeighborsStack.Clear();
this.FindNeighborsStack.Push(island.seedLocation);
this.FindNeighbors(b, island);
// return island
return island;
}