/// <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);
}
private static void SimplifyPolygonRecursive(CvContourPolygon p, int i1, int i2, bool[] pnUseFlag, double delta)
{
int endIndex = (i2 < 0) ? p.Count : i2;
if (Math.Abs(i1 - endIndex) <= 1)
{
return;
}
Point firstPoint = p[i1];
Point lastPoint = (i2 < 0) ? p[0] : p[i2];
double furtherDistance = 0.0;
int furtherIndex = 0;
for (int i = i1 + 1; i < endIndex; i++)
{
double d = DistanceLinePoint(firstPoint, lastPoint, p[i]);
if ((d >= delta) && (d > furtherDistance))
{
furtherDistance = d;
furtherIndex = i;
}
}
if (furtherIndex > 0)
{
pnUseFlag[furtherIndex] = true;
SimplifyPolygonRecursive(p, i1, furtherIndex, pnUseFlag, delta);
SimplifyPolygonRecursive(p, furtherIndex, i2, pnUseFlag, delta);
}
}
/// <summary>
/// Write a contour to a SVG file.
/// </summary>
/// <param name="polygon">Polygon contour.</param>
/// <param name="fileName">File name.</param>
public static void WriteContourPolygonSvg(CvContourPolygon polygon, string fileName)
{
if (polygon == null)
{
throw new ArgumentNullException(nameof(polygon));
}
polygon.WriteAsSvg(fileName);
}
/// <summary>
/// Draw a polygon.
/// </summary>
/// <param name="contour">Polygon contour.</param>
/// <param name="img">Image to draw on.</param>
/// <param name="color">Color to draw (default, white).</param>
public static void RenderContourPolygon(CvContourPolygon contour, IplImage img, CvScalar color)
{
if (contour == null)
{
throw new ArgumentNullException("contour");
}
contour.Render(img, color);
}
/// <summary>
/// Calculates convex hull of a contour.
/// Uses the Melkman Algorithm. Code based on the version in http://w3.impa.br/~rdcastan/Cgeometry/.
/// </summary>
/// <param name="polygon">Contour (polygon type).</param>
/// <returns>Convex hull.</returns>
public static CvContourPolygon PolygonContourConvexHull(CvContourPolygon polygon)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
return(polygon.ContourConvexHull());
}
/// <summary>
/// Calculates area of a polygonal contour.
/// </summary>
/// <param name="polygon">Contour (polygon type).</param>
/// <returns>Area of the contour.</returns>
public static double ContourPolygonArea(CvContourPolygon polygon)
{
if (polygon == null)
{
throw new ArgumentNullException(nameof(polygon));
}
return(polygon.Area());
}
/// <summary>
/// Draw a polygon.
/// </summary>
/// <param name="contour">Polygon contour.</param>
/// <param name="img">Image to draw on.</param>
/// <param name="color">Color to draw (default, white).</param>
public static void RenderContourPolygon(CvContourPolygon contour, Mat img, Scalar color)
{
if (contour == null)
{
throw new ArgumentNullException(nameof(contour));
}
contour.Render(img, color);
}
/// <summary>
/// Draw a polygon.
/// </summary>
/// <param name="contour">Polygon contour.</param>
/// <param name="img">Image to draw on.</param>
public static void RenderContourPolygon(CvContourPolygon contour, Mat img)
{
if (contour == null)
{
throw new ArgumentNullException("contour");
}
contour.Render(img);
}
/// <summary>
/// Draw a polygon.
/// </summary>
/// <param name="contour">Polygon contour.</param>
/// <param name="img">Image to draw on.</param>
public static void RenderContourPolygon(CvContourPolygon contour, IplImage img)
{
if (contour == null)
{
throw new ArgumentNullException(nameof(contour));
}
contour.Render(img);
}
/// <summary>
/// Write a contour to a CSV (Comma-separated values) file.
/// </summary>
/// <param name="polygon">Polygon contour.</param>
/// <param name="filename">File name.</param>
public static void WriteContourPolygonCsv(CvContourPolygon polygon, string filename)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
polygon.WriteAsCsv(filename);
}
/// <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="polygon">Contour (polygon type).</param>
/// <param name="delta">Minimun distance.</param>
/// <returns>A simplify version of the original polygon.</returns>
public static CvContourPolygon SimplifyPolygon(CvContourPolygon polygon, double delta)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
return(polygon.Simplify(delta));
}
/// <summary>
/// Calculates perimeter of a chain code contour.
/// </summary>
/// <param name="polygon">Contour (polygon type).</param>
/// <returns>Perimeter of the contour.</returns>
public static double ContourPolygonPerimeter(CvContourPolygon polygon)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
return(polygon.Perimeter());
}
/// <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="polygon">Contour (polygon type).</param>
/// <returns>A simplify version of the original polygon.</returns>
public static CvContourPolygon SimplifyPolygon(CvContourPolygon polygon)
{
if (polygon == null)
{
throw new ArgumentNullException(nameof(polygon));
}
return(polygon.Simplify());
}
/// <summary>
/// Calculates the circularity of a polygon (compactness measure).
/// </summary>
/// <param name="polygon">Contour (polygon type).</param>
/// <returns>Circularity: a non-negative value, where 0 correspond with a circumference.</returns>
public static double ContourPolygonCircularity(CvContourPolygon polygon)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
return(polygon.Circularity());
}
/// <summary>
/// Write a contour to a SVG file.
/// </summary>
/// <param name="polygon">Polygon contour.</param>
/// <param name="fileName">File name.</param>
/// <param name="stroke">Stroke color (black by default).</param>
/// <param name="fill">Fill color (white by default).</param>
public static void WriteContourPolygonSvg(CvContourPolygon polygon, string fileName, CvScalar stroke, CvScalar fill)
{
if (polygon == null)
{
throw new ArgumentNullException("polygon");
}
polygon.WriteAsSvg(fileName, stroke, fill);
}
/// <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);
}
}
/// <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="polygon">Contour (polygon type).</param>
/// <returns>A simplify version of the original polygon.</returns>
public static CvContourPolygon SimplifyPolygon(CvContourPolygon polygon)
{
return(polygon.Simplify());
}
/// <summary>
/// Write a contour to a SVG file.
/// </summary>
/// <param name="polygon">Polygon contour.</param>
/// <param name="fileName">File name.</param>
public static void WriteContourPolygonSvg(CvContourPolygon polygon, string fileName)
{
polygon.WriteAsSvg(fileName);
}
