public BinaryMap Thin(BinaryMap input)
{
BinaryMap intermediate = new BinaryMap(input.Size);
intermediate.Copy(input, new RectangleC(1, 1, input.Width - 2, input.Height - 2), new Point(1, 1));
BinaryMap border = new BinaryMap(input.Size);
BinaryMap skeleton = new BinaryMap(input.Size);
bool removedAnything = true;
for (int i = 0; i < MaxIterations && removedAnything; ++i)
{
removedAnything = false;
for (int j = 0; j < 4; ++j)
{
border.Copy(intermediate);
switch (j)
{
case 0:
border.AndNot(intermediate, new RectangleC(1, 0, border.Width - 1, border.Height), new Point(0, 0));
break;
case 1:
border.AndNot(intermediate, new RectangleC(0, 0, border.Width - 1, border.Height), new Point(1, 0));
break;
case 2:
border.AndNot(intermediate, new RectangleC(0, 1, border.Width, border.Height - 1), new Point(0, 0));
break;
case 3:
border.AndNot(intermediate, new RectangleC(0, 0, border.Width, border.Height - 1), new Point(0, 1));
break;
}
border.AndNot(skeleton);
for (int odd = 0; odd < 2; ++odd)
{
Parallel.For(1, input.Height - 1, delegate(int y)
{
if (y % 2 == odd)
{
for (int xw = 0; xw < input.WordWidth; ++xw)
{
if (border.IsWordNonZero(xw, y))
{
for (int x = xw << BinaryMap.WordShift; x < (xw << BinaryMap.WordShift) + BinaryMap.WordSize; ++x)
{
if (x > 0 && x < input.Width - 1 && border.GetBit(x, y))
{
uint neighbors = intermediate.GetNeighborhood(x, y);
if (IsRemovable[neighbors] ||
IsEnding[neighbors] && IsFalseEnding(intermediate, new Point(x, y)))
{
removedAnything = true;
intermediate.SetBitZero(x, y);
}
else
{
skeleton.SetBitOne(x, y);
}
}
}
}
}
}
});
}
}
}
Logger.Log(skeleton);
return(skeleton);
}