Example usage for org.opencv.imgproc Imgproc drawContours

Introduction

In this page you can find the example usage for org.opencv.imgproc Imgproc drawContours.

Prototype

public static void drawContours(Mat image, List<MatOfPoint> contours, int contourIdx, Scalar color,
            int thickness, int lineType, Mat hierarchy, int maxLevel, Point offset) 

Source Link

Usage

From source file:qupath.opencv.processing.OpenCVTools.java

License:Open Source License

public static void labelImage(Mat matBinary, Mat matLabels, int contourType) {
    List<MatOfPoint> contours = new ArrayList<>();
    Mat hierarchy = new Mat();
    Imgproc.findContours(matBinary, contours, hierarchy, contourType, Imgproc.CHAIN_APPROX_SIMPLE);
    // It's convoluted, but drawing contours this way is *much* faster than passing the full list (which is copied by the OpenCV 2.4.9 Java code)
    List<MatOfPoint> temp = new ArrayList<>(1);
    int i = 2;/*from  w  w w. java  2 s . c  o  m*/
    int ind = 0;
    for (MatOfPoint contour : contours) {
        temp.clear();
        temp.add(contour);
        Imgproc.drawContours(matLabels, temp, 0, new Scalar(i++), -1, 8, hierarchy.col(ind), 2,
                new Point(0, 0));
        //         Imgproc.drawContours(matLabels, temp, 0, new Scalar(i++), -1);
        ind++;
    }
}

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From source file:uk.ac.horizon.artcodes.drawer.MarkerThumbnailDrawer.java

License:Open Source License

@Override
public Mat drawMarker(Marker marker, ArrayList<MatOfPoint> contours, Mat hierarchy, Rect boundingRect,
        Mat imageToDrawOn) {/*from   ww  w  . java2s.  c  om*/
    if (imageToDrawOn == null) {
        if (boundingRect == null) {
            boundingRect = Imgproc.boundingRect(contours.get(marker.markerIndex));
        }
        Mat output = new Mat(boundingRect.size(), CvType.CV_8UC4, BACKGROUND);

        Imgproc.drawContours(output, contours, marker.markerIndex, COLOR, Core.FILLED, Core.LINE_8, hierarchy,
                2, new Point(-boundingRect.tl().x, -boundingRect.tl().y));

        return output;
    } else {
        Imgproc.drawContours(imageToDrawOn, contours, marker.markerIndex, COLOR, Core.FILLED, Core.LINE_8,
                hierarchy, 2, new Point(0, 0));
        return imageToDrawOn;
    }
}

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