contours2svg inprogress

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
//compiled with g++ -Wall -c "%f" -I/usr/local/include/opencv4
//built with: g++ -Wall -o "%e" "%f" `pkg-config --cflags --libs opencv4`

using namespace cv;
using namespace std;

/// Function header
void thresh_callback(int, void* );
void vectorOutput(  vector<vector<Point>>, vector<Vec4i> hierarchy);
void contour2svg(vector<vector<Point>> contours);
void svgHeader();
void polyline();
void svgFooter();

Mat src; Mat src_gray;
int thresh = 50;
int max_thresh = 215;
RNG rng(12345);  //random number generator




/** @function main */
int main( int argc, char** argv ){

    VideoCapture cap;
    // open the default camera, use something different from 0 otherwise;
    if(!cap.open(0))
        return 0;
     // Create mat with alpha channel
    Mat mat(800, 800, CV_8UC4);


for(;;){
    Mat frame;
    cap >> frame;
    src = frame;
  /// Convert image to gray and blur it
  cv::cvtColor(src, src_gray, COLOR_BGRA2GRAY, 0);
  blur( src_gray, src_gray, Size(3,3) );

  thresh_callback( 0 , 0 );

  if( waitKey(1) == 113 ) break; // stop capturing by pressing q
}
  return(0);
}
/*******************/
/*                 */
/*    FUNCTIONS    */
/*                 */
/*******************/
void contour2svg(){
    svgHeader();
    polyline();
    svgFooter();
    }
void svgHeader(){
cout<< "<svg width=\"800\" height=\"800\" version=\"1.1\" xmlns=\"http://www.w3.org/2000/svg\">" << endl;
    };

void polyline(){
//actual function might be: cout points(Cordinates)
    cout << "<polyline\n" << endl;
    cout << /*points*/ "\n"   << endl;
    cout << " stroke=\"red\" fill=\"transparent\" stroke-width=\"5\"/>" << endl;
    }

void svgFooter(){
    cout << "</svg>" << endl;
    };


void vectorOutput(   vector<vector<Point> > contours, int i){
for(auto vec: contours){
   cout << vec << "\n";
}
};

/** @function thresh_callback */
void thresh_callback(int, void* ){
  Mat canny_output;
  vector<vector<Point> > contours;
  vector<Vec4i> hierarchy;

  /// Detect edges using canny
  Canny( src_gray, canny_output, thresh, thresh*2, 3 );
  /// Find contours
  findContours( canny_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point() );

  /// Draw contours
/*void cv::drawContours     (
        InputOutputArray    image,
        InputArrayOfArrays      contours,
        int     contourIdx,
        const Scalar &      color,
        int     thickness = 1, //can be a FLOAT
        int     lineType = LINE_8,
        InputArray      hierarchy = noArray(),
        int     maxLevel = INT_MAX,
        Point   offset = Point()  //can be Point() or Point(x,y) cordinates
    )*/

  Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 );
  for(unsigned int i = 0; i< contours.size(); i++ ){
//Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
      Scalar color = Scalar( 0, 0,255 ); //BGR, set to red
       drawContours( drawing, contours, i, color, 0.1, 8, hierarchy, 1, Point(0,0) );

     //vectorOutput( contours, i);

      }
sleep(0.25); //slow down there flashy flashy

  /// Show in a window
    //createTrackbar( " Canny thresh:", "Source", &thresh, max_thresh, thresh_callback );
    namedWindow("Name", 1); //what does 1 mean?
    cv::imshow("Name", drawing);
}