Create Image from Jframe

Question

I created a pie chart using JFrame and swings. But I want to convert the pie chart into the image and save in desktop/local path. But not having idea how to create image using JFrame Pie.

package test;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;

class Main1 {
  double value;
  Color color;


  public Main1(double value, Color color) {
    this.value = value;
    this.color = color;
  }
}

class MyComponent extends JComponent {
    Main1[] slices = { new Main1(1, Color.black), new Main1(1, Color.green),
      new Main1(1, Color.yellow), new Main1(1, Color.red) };

  MyComponent() {

  }
  public void paint(Graphics g) {
    drawPie((Graphics2D) g, getBounds(), slices);
  }

  void drawPie(Graphics2D g, Rectangle area, Main1[] slices) {
    double total = 0.0D;
    for (int i = 0; i < slices.length; i++) {
      total += slices[i].value;
    }

    double curValue = 0.0D;
    int startAngle = 0;
    for (int i = 0; i < slices.length; i++) {
      startAngle = (int) (curValue * 360 / total);
      int arcAngle = (int) (slices[i].value * 360 / total);

      g.setColor(slices[i].color);
      g.fillArc(area.x, area.y, area.width, area.height, startAngle, arcAngle);
      curValue += slices[i].value;
    }
  }
}

public class Main2 {
     public JPanel contentPane;
  public static void main(String[] argv) {
    JFrame frame = new JFrame();
    frame.getContentPane().add(new MyComponent());
    frame.setSize(300, 200);
    frame.setVisible(true);   
  }

}

Answer 1

The basic logic for creating an Image of a Swing component is:

Dimension d = component.getSize();
BufferedImage image = new BufferedImage(d.width, d.height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = image.createGraphics();
component.print( g2d );
g2d.dispose();
ImageIO.write(image, ".jpg", new File(...));

You can also check out the Screen Image class for convenience methods that paint the entire frame, a component on the frame or a rectangle of a component on the frame.

Note the above suggestion assumes you do the custom painting correctly which means you:

1. extend JPanel
2. override paintComponent(...), not paint(...)
3. invoke super.paintComponent(...)

If you want to extend JComponent then you need to:

1. override paintComponent(...);
2. fill the background of your component first before invoking the drawPie(...) method

Answer 2

But I want to convert the pie chart into the image

Create a BufferedImage and paint to it

BufferedImage bi = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = bi.createGraphics();
new MyComponent().drawPie(g2d, new Rectangle(0, 0, 200, 200), slices);
g2d.dispose();

and save in desktop/local path

Use ImageIO

ImageIO.write(bi, "jpg", new File("the/path/andName.jpg"));