OpenCV - Rotation

Quiz

You can perform rotation operation on an image using the warpAffine() method of the imgproc class. Following is the syntax of this method −

Imgproc.warpAffine(src, dst, rotationMatrix, size);

This method accepts the following parameters −

src − A Mat object representing the source (input image) for this operation.
dst − A Mat object representing the destination (output image) for this operation.
rotationMatrix − A Mat object representing the rotation matrix.
size − A variable of the type integer representing the size of the output image.

Example

The following program demonstrates how to rotate an image.

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.Point;
import org.opencv.core.Size;

import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

public class Rotation {
   public static void main(String args[]) {
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );

      // Reading the Image from the file and storing it in to a Matrix object
      String file ="E:/OpenCV/chap24/transform_input.jpg";
      Mat src="/?originalUrl=https%3A%2F%2Fdev.tutorialspoint.com%2FImgcodecs.imread(file)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520an%2520empty%2520matrix%2520to%2520store%2520the%2520result%2520%2520%2520%2520%2520%2520Mat%2520dst%2520%3D%2520new%2520Mat()%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520a%2520Point%2520object%2520%2520%2520%2520%2520%2520Point%2520point%2520%3D%2520new%2520Point(300%2C%2520200)%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520the%2520transformation%2520matrix%2520M%2520%2520%2520%2520%2520%2520Mat%2520rotationMatrix%2520%3D%2520Imgproc.getRotationMatrix2D(point%2C%252030%2C%25201)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520the%2520object%2520of%2520the%2520class%2520Size%2520%2520%2520%2520%2520%2520Size%2520size%2520%3D%2520new%2520Size(src.cols()%2C%2520src.cols())%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Rotating%2520the%2520given%2520image%2520%2520%2520%2520%2520%2520Imgproc.warpAffine(src%2C%2520dst%2C%2520rotationMatrix%2C%2520size)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Writing%2520the%2520image%2520%2520%2520%2520%2520%2520Imgcodecs.imwrite("E:/OpenCV/chap24/rotate_output.jpg", dst);

      System.out.println("Image Processed");
   }
}

Assume that following is the input image transform_input.jpg specified in the above program.

Output

On executing the program, you will get the following output −

Image Processed

If you open the specified path, you can observe the output image as follows −

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