private int[,] ComputeDistanceTransform(PointsSequence curve)
{
// create points transformed to the [0 .. MAX_RESOLUTION] range.
var points = curve.Points.ToArray();
foreach (var i in Enumerable.Range(0, points.Length))
{
points[i].X = 0.5 * Constants.DISTANCE_TRANSFORM_RESOLUTION * (points[i].X + 1);
points[i].Y = 0.5 * Constants.DISTANCE_TRANSFORM_RESOLUTION * (points[i].Y + 1);
}
// close the curve, if needed
if (curve is Polygon)
{
points = points.Concat(Enumerable.Repeat(points.First(), 1)).ToArray();
}
// compute distance transform and return it
double[,] transform = new double[Constants.DISTANCE_TRANSFORM_RESOLUTION, Constants.DISTANCE_TRANSFORM_RESOLUTION];
ChamferDistanceTransform.Compute(points, transform);
int[,] result = new int[Constants.DISTANCE_TRANSFORM_RESOLUTION, Constants.DISTANCE_TRANSFORM_RESOLUTION];
for (int x = 0; x < Constants.DISTANCE_TRANSFORM_RESOLUTION; ++x)
{
for (int y = 0; y < Constants.DISTANCE_TRANSFORM_RESOLUTION; ++y)
{
result[x, y] = (int)Math.Round(16 * transform[x, y]);
Debug.Assert(result[x, y] >= 0);
}
}
return(result);
}
private static double[,] GetDistanceTransform(Point[] l1, Point[] l2)
{
var transform1 = new double[IMAGE_SPACE_WIDTH, IMAGE_SPACE_HEIGHT];
var transform2 = new double[IMAGE_SPACE_WIDTH, IMAGE_SPACE_HEIGHT];
ChamferDistanceTransform.Compute(l1, transform1);
ChamferDistanceTransform.Compute(l2, transform2);
var totalTransform = Min(transform1, transform2);
return(totalTransform);
}