Smooth Scaling of Image in java

Question

I created a button that extends Jbutton, I added to the button image but this not render smooth the image. I try getScaledInstance But it's not working

This is orginal image:

That's how it really presents the picture:

public class Button extends JButton {
private Image image;


public Button(Image image) {
    this.image = image;
}

public Image getImage() {
    return image;
}

public void setImage(Image image) {
    this.image = image;
}

public void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.drawImage(image, 0, 0, getWidth(), getHeight(), null);
}

Edit:

I understood why it not rendered smooth the image. I had to change the drawImage to g.drawImage(image, 0, 0, null);

I run the code, sometimes it shows me the pictures and sometimes it shows me empty squares And that shows me errors in the console.

And only I move them with the mouse the pictures appear

Answer 1

Try the following. It is pretty self explanatory.

public class CircleDisplay extends JPanel {

    final static int height = 500;
    final static int width = 500;
    Image img = null;
    JFrame frame = new JFrame();

    public static void main(String[] args) {
        new CircleDisplay();
    }

    public CircleDisplay() {
        Image img = null;
        try {
            img = ImageIO
                    .read(new File("f:yellowCircle.png"));
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
        frame.setDefaultCloseOperation(
                JFrame.EXIT_ON_CLOSE);
        frame.add(this);
        img = 
                img.getScaledInstance(50, 50,
                        Image.SCALE_SMOOTH);
        Button b = new Button(img);
        b.setPreferredSize(new Dimension(50,50));

        add(b);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
}

class Button extends JButton {
    Image img;
    public Button(Image img) {
        this.img = img;
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        g.drawImage(img,0,0,null);
    }
}

Answer 2

I don't understand why it needs to be so complicated.
I suggest simply creating an ImageIcon and setting the JButton icon.
Sample code:

javax.swing.ImageIcon imgIco = new javax.swing.ImageIcon("path-to-icon-file");
javax.swing.JButton button2 = new javax.swing.JButton(imgIco);
button2.setPreferredSize(new java.awt.Dimension(imgIco.getIconWidth(), imgIco.getIconHeight()));

The last line of the above code ensures that the JButton size is the same as the icon size, since you implied that this is what you want in your comment to the other answer.