CODEWITHSUNDEEP
javabufferedimage
Sam
Sam

Reputation: 93

Create A Basic Draw Program

I am trying to create a simple draw program that saves a basic drawing upon button click. I copied the draw methods from my textbook, I am just toying around. This is the buffered image I have created:

private static BufferedImage bi = new BufferedImage(500, 500,
        BufferedImage.TYPE_INT_RGB);

And this creates the paint panel:

public PaintPanel() {

    addMouseMotionListener(

    new MouseMotionAdapter() {
        public void mouseDragged(MouseEvent event) {
            if (pointCount < points.length) {
                points[pointCount] = event.getPoint();
                ++pointCount;
                repaint();
            }
        }
    });
}

public void paintComponent(Graphics g) {

    super.paintComponent(g);

    for (int i = 0; i < pointCount; i++)
        g.fillOval(points[i].x, points[i].y, 4, 4);
}

On a button click:

save.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            PaintPanel.saveImage();
            System.exit(0);
        }

I call this method:

public static void saveImage() {

    try {
        ImageIO.write(bi, "png", new File("test.png"));
    } catch (IOException ioe) {
        System.out.println("Eek");
        ioe.printStackTrace();
    }

}

But the png file that I save is just black.

Upvotes: 0

Views: 105

Answers (1)

Reimeus
Reimeus

Reputation: 159754

The BufferedImage and panel component have 2 distinct Graphics objects. Therefore it is necessary to explicitly update the Graphics object for the former:

Graphics graphics = bi.getGraphics();
for (int i = 0; i < pointCount; i++) {
    graphics.fillOval(points[i].x, points[i].y, 4, 4);
}

Upvotes: 2

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