public override void Run()
{
Result = new ConnectedComponentImage(InputImage.Width, InputImage.Height, -1);
var cursor = new ImageCursor(InputImage, 1); // per semplicità ignora i bordi (1 pixel)
int[] neighborLabels = new int[Metric == MetricType.CityBlock ? 2 : 4];
int nextLabel = 0;
var equivalences = new DisjointSets(InputImage.PixelCount);
do
{ // prima scansione
if (InputImage[cursor] == Foreground)
{
int labelCount = 0;
if (Result[cursor.West] >= 0)
{
neighborLabels[labelCount++] = Result[cursor.West];
}
if (Result[cursor.North] >= 0)
{
neighborLabels[labelCount++] = Result[cursor.North];
}
if (Metric == MetricType.Chessboard)
{ // anche le diagonali
if (Result[cursor.Northwest] >= 0)
{
neighborLabels[labelCount++] = Result[cursor.Northwest];
}
if (Result[cursor.Northeast] >= 0)
{
neighborLabels[labelCount++] = Result[cursor.Northeast];
}
}
if (labelCount == 0)
{
equivalences.MakeSet(nextLabel); // crea un nuovo set
Result[cursor] = nextLabel++; // le etichette iniziano da 0
}
else
{
int l = Result[cursor] = neighborLabels[0]; // seleziona la prima
for (int i = 1; i < labelCount; i++) // equivalenze
{
if (neighborLabels[i] != l)
{
equivalences.MakeUnion(neighborLabels[i], l); // le rende equivalenti
}
}
}
}
} while (cursor.MoveNext());
//rende le etichette numeri consecutivi
int totalLabels;
int[] corresp = equivalences.Renumber(nextLabel, out totalLabels);
//seconda e ultima scansione
cursor.Restart();
do
{
int l = Result[cursor];
if (l >= 0)
{
Result[cursor] = corresp[l];
}
}while(cursor.MoveNext());
Result.ComponentCount = totalLabels;
}