/// <summary>
/// does this polygon overlap with the other, within the given screen dimensions
/// </summary>
/// <param name="other">other polygon object</param>
/// <param name="image_width">image width</param>
/// <param name="image_height">image height</param>
/// <returns></returns>
public bool overlaps(polygon2D other, int image_width, int image_height)
{
int i;
bool retval = false;
i = 0;
while ((i < x_points.Count) && (retval == false))
{
if (other.isInside(x_points[i] * 1000 / image_width, y_points[i] * 1000 / image_height)) retval = true;
i++;
}
i = 0;
while ((i < other.x_points.Count) && (retval == false))
{
if (isInside((float)other.x_points[i] * image_width / 1000, (float)other.y_points[i] * image_height / 1000)) retval = true;
i++;
}
return (retval);
/// <summary>
/// returns a grey scale histogram for the given image within the given perimeter region
/// </summary>
/// <param name="bmp">image data</param>
/// <param name="wdth">width of the image</param>
/// <param name="hght">height of the image</param>
/// <param name="bytes_per_pixel">number of bytes per pixel</param>
/// <param name="levels">histogram levels</param>
/// <param name="perimeter">perimeter region inside which to calculate the histogram</param>
/// <returns></returns>
public static float[] GetGreyHistogram(byte[] bmp,
int wdth, int hght,
int bytes_per_pixel,
int levels,
polygon2D perimeter)
{
float[] hist = new float[levels];
int tx = (int)perimeter.left();
int ty = (int)perimeter.top();
int bx = (int)perimeter.right();
int by = (int)perimeter.bottom();
for (int y = ty; y <= by; y++)
{
if ((y > -1) && (y < hght))
{
for (int x = tx; x <= bx; x++)
{
if ((x > -1) && (x < wdth))
{
if (perimeter.isInside(x, y))
{
int n = ((y * wdth) + x) * bytes_per_pixel;
float intensity = 0;
for (int col = 0; col < bytes_per_pixel; col++)
intensity += bmp[n + col];
intensity /= bytes_per_pixel;
int bucket = (int)Math.Round(intensity * levels / 255);
if (bucket >= levels) bucket = levels - 1;
hist[bucket]++;
}
}
}
}
}
// normalise the histogram
float max = 1;
for (int level = 0; level < levels; level++)
if (hist[level] > max) max = hist[level];
for (int level = 0; level < levels; level++)
hist[level] = hist[level] / max;
return (hist);
}
/// <summary>
/// return true if this polygon overlaps with another
/// </summary>
/// <param name="other"></param>
/// <returns></returns>
public bool overlaps(polygon2D other)
{
int i;
bool retval = false;
i = 0;
while ((i < x_points.Count) && (retval == false))
{
if (other.isInside(x_points[i],y_points[i])) retval=true;
i++;
}
i = 0;
while ((i < other.x_points.Count) && (retval == false))
{
if (isInside((float)other.x_points[i], (float)other.y_points[i])) retval = true;
i++;
}
return (retval);
