Drawing HiDPI component to BufferedImage

[Hendrik Schreiber]

On Jan 24, 2014, at 14:31, Sergey Bylokhov <Sergey.Bylokhov at oracle.com> wrote:

> You can draw the component to the VolatileImage. or you can create double size bufferedimage and set scale on its graphics to 2.

Drawing to a VolatileImage created via

GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice()
                .getDefaultConfiguration().createCompatibleVolatileImage(100, 100);

seems to do the trick.

However, your other suggestion (double size bufferedimage), does not work. Is this intended or a bug?

Thanks!

-hendrik



Here's a simple demo class. I'd expect both checkboxes to render in the same quality, but they don't using a BufferedImage.

import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;

public class RenderHiDPI {

    public static void main(String[] args) {
        final JFrame frame = new JFrame();
        final JLabel label = new JLabel();
        frame.getContentPane().setLayout(new FlowLayout());
        final JCheckBox hiDPICheckBox = new JCheckBox("Hi DPI");
        hiDPICheckBox.setFocusable(false);
        frame.getContentPane().add(hiDPICheckBox);
        frame.getContentPane().add(label);
        final JCheckBox checkBox = new JCheckBox("Lo DPI");
        checkBox.setSize(new Dimension(100, 100));
        final BufferedImage image = new BufferedImage(200, 200, BufferedImage.TYPE_INT_ARGB);
        final Graphics g = image.getGraphics();
        ((Graphics2D)g).scale(2f, 2f);
        checkBox.paint(g);
        g.dispose();
        label.setIcon(new Icon(){
            @Override
            public void paintIcon(final Component c, final Graphics g, final int x, final int y) {
                final Graphics2D graphics = (Graphics2D)g.create();
                graphics.scale(0.5f, 0.5f);
                graphics.drawImage(image, x, y, c);
            }

            @Override
            public int getIconWidth() {
                return 100;
            }

            @Override
            public int getIconHeight() {
                return 100;
            }
        });

        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                frame.setBounds(100, 100, 100, 100);
                frame.setVisible(true);
            }
        });
    }
}