/// <summary>
/// Uses a FloodFill scanline algorithm to get a targets bounds
/// </summary>
public MotionHelper GetBoundsFromMotion(ref byte[,] motion, Point size, Point seed)
{
MotionHelper helper = new MotionHelper(motion, size.X, size.Y, seed.X, seed.Y);
DoNextScanLine(seed.X, seed.Y, ref helper); // +2 and +1 are for creating an empty box around the whole shape, (1's never at the end /start of an array)
helper.Shape = new byte[helper.MaxX - helper.MinX + 4, helper.MaxY - helper.MinY + 4];
for (int x = helper.MinX; x < helper.MaxX; x++)
for (int y = helper.MinY; y < helper.MaxY; y++)
if (helper.Motion[x, y] == 2)
{
helper.Shape[x - helper.MinX + 2, y - helper.MinY + 2] = 1;
}
return helper;
}
/// <summary>
/// Recursave function for scanlines
/// </summary>
public void DoNextScanLine(int x, int y, ref MotionHelper motion)
{
// 2 3 4
// 2 O O O
// 3 O X O
// 4 O O O
if (x >= motion.Width || y >= motion.Height)
return;
if (motion.Motion[x, y] == 0)
return;
if (x > motion.MaxX)
motion.MaxX = x;
if (x < motion.MinX)
motion.MinX = x;
if (y > motion.MaxY)
motion.MaxY = y;
if (y < motion.MinY)
motion.MinY = y;
int y1;
//draw current scanline from start position to the top
y1 = y;
while (y1 < motion.Height && motion.Motion[x, y1] == 1)
{
motion.Motion[x, y1] = 2;
if (y1 > motion.MaxY)
motion.MaxY = y1;
y1++;
}
//draw current scanline from start position to the bottom
y1 = y - 1;
while (y1 >= 0 && motion.Motion[x, y1] == 1)
{
motion.Motion[x, y1] = 2;
if (y1 < motion.MinY)
motion.MinY = y1;
y1--;
}
//test for new scanlines to the left
y1 = y;
while (y1 < motion.Height && (motion.Motion[x, y1] == 2))
{
if (x > 0 && motion.Motion[x -1, y1] == 1)
{
DoNextScanLine(x - 1, y1, ref motion);
}
y1++;
}
y1 = y - 1;
while (y1 >= 0 && (motion.Motion[x, y1] == 2))
{
if (x > 0 && motion.Motion[x - 1, y1] == 1)
{
DoNextScanLine(x - 1, y1, ref motion);
}
y1--;
}
//test for new scanlines to the right
y1 = y;
while (y1 < motion.Height && (motion.Motion[x, y1] == 2))
{
if (x < motion.Width - 1 && motion.Motion[x + 1, y1] == 1)
{
DoNextScanLine(x + 1, y1, ref motion);
}
y1++;
}
y1 = y - 1;
while (y1 >= 0 && (motion.Motion[x, y1] == 2))
{
if (x < motion.Width - 1 && motion.Motion[x + 1, y1] == 1)
{
DoNextScanLine(x + 1, y1, ref motion);
}
y1--;
}
}