Rotating buffered image

[Ravi Kumar]

Below is a simple program to rotate an buffered Image which is not working.

I'm create a small rectangle and rotating the entire graphic, which int urn should rotate the rectangle as well.
I'm lost, as to why it is not writing the rotated image. It writes the image which is not rotated.

I would appreciate any suggestions.

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class RotateImage {
	public static void main(String args[]) throws IOException {

			BufferedImage bi = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
			Graphics2D g2d = bi.createGraphics();
			g2d.setColor(Color.green);
			g2d.fillRect(50, 50, 30, 30);
			g2d.rotate(Math.toRadians(45));

			RenderedImage ri = bi;
                      	ImageIO.write(ri, "BMP", new File("/rotateimg.BMP"));

	}
}

[Ulf Dittmer]

Have you tried doing the rotation before the drawing?

[Ravi Kumar]

Thanks for the quick response...It works !

How can i preserve the entire image. As the rotated image is big, the 90% of rectangle is out the the frame.
Is it okay if i create another bufferedImage of double the size and copy it ?

[Rob Spoor]

Instead of doubling the size you should calculate the new width (and height!) using Math.cos, Math.sin and/or Math.tan. Although in this case it's a square that's rotated by 45 degrees so that makes the diagonal the width and height, and the diagonal is the width times the square root of 2 (1.4something; use Math.sqrt(2)).

[Ravi Kumar]

Thank you for the idea. I will try that.