/// <summary>
/// Convert a chain code contour to a polygon.
/// </summary>
/// <returns>A polygon.</returns>
public CvContourPolygon ConvertToPolygon()
{
CvContourPolygon contour = new CvContourPolygon();
int x = StartingPoint.X;
int y = StartingPoint.Y;
contour.Add(new CvPoint(x, y));
if (ChainCode.Count > 0)
{
CvChainCode lastCode = ChainCode[0];
x += CvBlobConst.ChainCodeMoves[(int)ChainCode[0]][0];
y += CvBlobConst.ChainCodeMoves[(int)ChainCode[0]][1];
for (int i = 1; i < ChainCode.Count; i++)
{
if (lastCode != ChainCode[i])
{
contour.Add(new CvPoint(x, y));
lastCode = ChainCode[i];
}
x += CvBlobConst.ChainCodeMoves[(int)ChainCode[i]][0];
y += CvBlobConst.ChainCodeMoves[(int)ChainCode[i]][1];
}
}
return(contour);
}
/// <summary>
/// Simplify a polygon reducing the number of vertex according the distance "delta".
/// Uses a version of the Ramer-Douglas-Peucker algorithm (http://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm).
/// </summary>
/// <param name="delta">Minimun distance.</param>
/// <returns>A simplify version of the original polygon.</returns>
public CvContourPolygon Simplify(double delta)
{
double furtherDistance = 0.0;
int furtherIndex = 0;
if (Count == 0)
{
return(new CvContourPolygon());
}
for (int i = 1; i < Count; i++)
{
double d = DistancePointPoint(this[i], this[0]);
if (d > furtherDistance)
{
furtherDistance = d;
furtherIndex = i;
}
}
if (furtherDistance < delta)
{
CvContourPolygon result = new CvContourPolygon();
result.Add(this[0]);
return(result);
}
else
{
bool[] pnUseFlag = new bool[Count];
for (int i = 1; i < Count; i++)
{
pnUseFlag[i] = false;
}
pnUseFlag[0] = pnUseFlag[furtherIndex] = true;
SimplifyPolygonRecursive(this, 0, furtherIndex, pnUseFlag, delta);
SimplifyPolygonRecursive(this, furtherIndex, -1, pnUseFlag, delta);
CvContourPolygon result = new CvContourPolygon();
for (int i = 0; i < Count; i++)
{
if (pnUseFlag[i])
{
result.Add(this[i]);
}
}
return(result);
}
}