title: OpenCV drawContours in Java
body: <p>I'm trying to draw contours around object in image but i get error
   <code>OpenCV Error: Unsupported format or combination of formats ([Start]FindContours supports only CV_8UC1 images when mode != CV_RETR_FLOODFILL otherwise supports CV_32SC1 images only) in cvStartFindContours, file C:\builds\master_PackSlaveAddon-win64-vc12-static\opencv\modules\imgproc\src\contours.cpp, line 198</code></p>
  
  <p>I tried to convert image but error is still there how to use DrawContour?</p>
  
  <pre class="lang-java prettyprint-override"><code> Mat imageInMat = Imgcodecs.imread("C:/Users/ja/workspace/imgtomath/bin/imgtomath/lena.png");
           if(imageInMat.empty()== true)
               {System.out.println("Error no image found!!");}
  
           imageInMat.convertTo(imageInMat, CvType.CV_32SC1);
  
           List&lt;MatOfPoint&gt; contours = new ArrayList&lt;MatOfPoint&gt;();
              Mat hierarchy = new Mat();
              Imgproc.findContours(imageInMat, contours, hierarchy, Imgproc.RETR_FLOODFILL, Imgproc.CHAIN_APPROX_SIMPLE);
  
          Imgproc.drawContours(imageInMat, contours, -1, new Scalar(255,0,0));
  </code></pre>