// find objects
public static Dictionary <Tuple <int, int>, List <Tuple <int, int> > > Groups(int[,] image)
{
// union find to store sets of all pixels in object
UnionFind <Tuple <int, int> > unionFind = new UnionFind <Tuple <int, int> >();
for (int x = 0; x < image.GetLength(0); x++)
{
for (int y = 0; y < image.GetLength(1); y++)
{
if (image[x, y] == 0)
{
continue;
}
Tuple <int, int> xy = new Tuple <int, int>(x, y);
unionFind.Make(xy);
if (x > 0)
{
unionFind.Union(xy, new Tuple <int, int>(x - 1, y));
}
if (y > 0)
{
unionFind.Union(xy, new Tuple <int, int>(x, y - 1));
}
}
}
// turns union find "inside out": (pixel->set identifier)->(set identifier->all pixels in set)
Dictionary <Tuple <int, int>, List <Tuple <int, int> > > labels = new Dictionary <Tuple <int, int>, List <Tuple <int, int> > >();
for (int x = 0; x < image.GetLength(0); x++)
{
for (int y = 0; y < image.GetLength(1); y++)
{
if (image[x, y] == 0)
{
continue;
}
Tuple <int, int> xy = new Tuple <int, int>(x, y), label = unionFind.Find(xy);
List <Tuple <int, int> > list;
if (!labels.TryGetValue(label, out list))
{
list = new List <Tuple <int, int> >();
labels[label] = list;
}
list.Add(xy);
}
}
return(labels);
}
private void inputImageBox_MouseDown(object sender, MouseEventArgs e)
{
if (this.data == null)
{
return;
}
int xx = e.X - (inputImageBox.Width - inputImageBox.Image.Width) / 2;
int yy = e.Y - (inputImageBox.Height - inputImageBox.Image.Height) / 2;
switch (currentStep)
{
case 5: // Compactness
decimal r = (decimal)Operations.Compactness(this.prevData, xx, yy);
decimal rLow = Math.Floor(r * 100) / 100;
decimal rHigh = Math.Ceiling(r * 100) / 100;
minComp.Value = Math.Min(minComp.Value, rLow);
maxComp.Value = Math.Max(maxComp.Value, rHigh);
break;
case 6: // Area
decimal a = (decimal)Operations.Area(Operations.Perimeter(this.prevData, xx, yy));
decimal aLow = Math.Floor(a * 100) / 100;
decimal aHigh = Math.Ceiling(a * 100) / 100;
minArea.Value = Math.Min(minArea.Value, aLow);
maxArea.Value = Math.Max(maxArea.Value, aHigh);
break;
case 7: // Convexity
UnionFind <Tuple <int, int> > unionFind = new UnionFind <Tuple <int, int> >();
for (int x = 0; x < this.prevData.GetLength(0); x++)
{
for (int y = 0; y < this.prevData.GetLength(1); y++)
{
if (this.prevData[x, y] == 0)
{
continue;
}
Tuple <int, int> xy = new Tuple <int, int>(x, y);
unionFind.Make(xy);
if (x > 0)
{
unionFind.Union(xy, new Tuple <int, int>(x - 1, y));
}
if (y > 0)
{
unionFind.Union(xy, new Tuple <int, int>(x, y - 1));
}
}
}
Tuple <int, int> root;
try
{
root = unionFind.Find(new Tuple <int, int>(xx, yy));
}
catch
{
return;
}
List <Tuple <int, int> > points = new List <Tuple <int, int> >();
for (int x = 0; x < this.prevData.GetLength(0); x++)
{
for (int y = 0; y < this.prevData.GetLength(1); y++)
{
if (this.prevData[x, y] == 0)
{
continue;
}
Tuple <int, int> pos = new Tuple <int, int>(x, y);
if (unionFind.Find(pos) == root)
{
points.Add(pos);
}
}
}
double hullArea = Operations.PolygonArea(Operations.ConvexHull(points));
double area = Operations.Area(Operations.Perimeter(this.prevData, xx, yy));
decimal c = (decimal)(area / hullArea);
decimal cLow = Math.Floor(c * 100) / 100;
decimal cHigh = Math.Ceiling(c * 100) / 100;
minConv.Value = Math.Min(minConv.Value, cLow);
maxConv.Value = Math.Max(maxConv.Value, cHigh);
break;
default:
break;
}
}