How to draw a rectangle using OpenCV in Java?

The org.opencv.imgproc package of the Java OpenCV library contains a class named Imgproc. To draw a rectangle, you need to call the rectangle() method of this class. This method accepts the following parameters -

• A Mat object representing the image on which the rectangle is to be drawn.

• Two Point objects, representing the vertices of the rectangle to be created draw.

• A scalar object representing the color of the rectangle (BGR).

• An integer rectangle representing the thickness of the rectangle (default: 1).

Example

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.Point;
import org.opencv.core.Scalar;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
public class DrawingRectangle {
   public static void main(String args[]) {
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      //Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      //Reading the source image in to a Mat object
      Mat src = Imgcodecs.imread("D:\images\blank.jpg");
      //Drawing a Rectangle
      Point point1 = new Point(100, 100);
      Point point2 = new Point(500, 300);
      Scalar color = new Scalar(64, 64, 64);
      int thickness = 10;
      Imgproc.rectangle (src, point1, point2, color, thickness);
      //Saving and displaying the image
      Imgcodecs.imwrite("arrowed_line.jpg", src);
      HighGui.imshow("Drawing a rectangle", src);
      HighGui.waitKey();
   }
}

Output

When executed , the above program generates the following window-

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