PContourNet

C# library for finding contours in binary images. Ported from java to C# from https://github.com./LingDong-/PContour

From original README:

Similar to OpenCV's cv::findContours and cv::approxPolyDP, the algorithms implement the following papers:

• Suzuki, S. and Abe, K., Topological Structural Analysis of Digitized Binary Images by Border Following
• David Douglas and Thomas Peucker, Algorithms for the reduction of the number of points required to represent a digitized line or its caricature

Usage

int[] bitmap = new int[]
{
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 1, 1, 0, 0,
    0, 1, 1, 1, 1, 1, 0, 0,
    0, 1, 1, 0, 0, 1, 1, 0,
    0, 1, 1, 0, 0, 1, 1, 0,
    0, 1, 1, 1, 1, 1, 0, 0,
    0, 0, 0, 1, 1, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
};

int width = 8;
int height = 8;

// find contours
var contours = PContour.FindContours(bitmap, width, height);

// simplify the polyline
for (int i = 0; i < contours.Count; i++)
{
    contours[i].points = PContour.ApproxPolyDP(contours[i].GetPointsSpan(), 1).ToArray().ToList();
}