Wrapper for approxPolyDP

[Stephen Lindberg]

I really want to utilize the polygon approximation function approxPolyDP, which is part of opencv/imgproc
opencv doc reference here

I don't have enough knowledge currently to write the wrapper myself - Are there significant difficulties in wrapping this feature? If I can get it working, I will see if I can make a pull request.

[Stephen Lindberg]

I found a snippet here which describes the implementation
https://forum.openframeworks.cc/t/contour-polyline-simplification/4461

But I change a line in the block

result = cvApproxPoly  
    (  
        &contour,  
        sizeof( CvContour ),  
        storage,  
        CV_POLY_APPROX_DP,  
        cvContourPerimeter( &contour ) * tolerance,  
        0  
    ); 

to

result = cvApproxPoly  
    (  
        &contour,  
        sizeof( CvContour ),  
        storage,  
        CV_POLY_APPROX_DP,  
        tolerance,  
        0  
    ); 

in order to have a consistent tolerance (epsilon, according the algorithm) instead of adjusting it based on the contour perimeter length. This keeps simplified vertices more consistent and defined, rather than jumping around.

[Antoine Villeret]

I'm not sure a wrapper is necessary here, if you need to use the function, just do it like your code snippet does.