How to add borders to an image using Java OpenCV library?

Java Object Oriented Programming Programming

You can add borders to a given image using the copyMakeBorder() method, this method accepts the following parameters −

Two Mat objects representing the source and destination images.
An object of the class Mat representing the destination (output) image.
Four integer variables representing the lengths of the borders in all the 4 directions of the image.
An integer variable representing the type of the border that is to be used.

Example

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javafx.application.Application;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.image.ImageView;
import javafx.scene.image.WritableImage;
import javafx.stage.Stage;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
public class AddingBorders extends Application {
   public void start(Stage stage) throws IOException {
      //Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      String file ="D:\\Images\\cat.jpg";
      Mat src = Imgcodecs.imread(file);
      //Creating an empty matrices to store the destination image.
      Mat dst = new Mat(src.rows(), src.cols(), src.type());
      //Adding borders
      Core.copyMakeBorder(src, dst, 20, 20, 20, 20, Core.BORDER_CONSTANT);
      //Converting matrix to JavaFX writable image
      Image img = HighGui.toBufferedImage(dst);
      WritableImage writableImage= SwingFXUtils.toFXImage((BufferedImage) img, null);
      //Setting the image view
      ImageView imageView = new ImageView(writableImage);
      imageView.setX(10);
      imageView.setY(10);
      imageView.setFitWidth(575);
      imageView.setPreserveRatio(true);
      //Setting the Scene object
      Group root = new Group(imageView);
      Scene scene = new Scene(root, 595, 400);
      stage.setTitle("Adding Borders");
      stage.setScene(scene);
      stage.show();
   }
   public static void main(String args[]) {
      launch(args);
   }
}

Input Image

Output

On executing, the above program generates the following windows −

Krishna Kasyap

Published on 13-Apr-2020 11:20:56

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