Applying affine transform to JPanel

[Arjun Palanichamy]

Hi All
I am doing an application in which i need to scale a jpanel along with its components....for example, if i am having a jpanel of size 600x600 ,with some txtbox and buttons in it, and if i want to scale it to 300x300 with all its components visible,what shoud i do.....i heared it can be done using affine transform and i have no idea of how to use it.So please help me with some sample codes....

Thanks in advance

Arjun.

[Ulf Dittmer]

Affine transformations is something you use with graphics, not with components. You can change the size of components through their setMinimumSize/setPreferredSize/setMaximumSize methods. Of course, if there are any labels or other components that use fonts, then you will need to adjust the font size explicitly.

[Nathan Pruett]

I think you're thinking about something like making a subclass of JPanel - and inside the paint() method, have a BufferedImage that you call super.paint() on (to paint the "normal" image of the JPanel), then scale the image, and paint that on the JPanel. This would only work for the "visual" part of components, but would mess up any "interactive" parts - i.e. the button would "look" bigger, but you would still need to click where it "really" was in it's smaller size to click it.

[Arjun Palanichamy]

Hi Nathan,
You are right.I just want to see the JPanel along with all its components into a thumbnail view i.e,a scaled instance of that jpanel, and i dont want any component within that thumbnail view to perform any action like button click,etc.For example, if i am having a frame with two Jpanels , one containing several components in it and is of size 500x500,and other jpanel is empty and is of size 300x300.On clicking a button, i just want to show a thumbnail view of the first jpanel(that is ,the one containg components)in the second Jpanel.The thumbnail view may be 100x100.Please help me to do that with a sample code.

Thanks in advance
Arjun

[Nathan Pruett]

Here's some sample code I worked up that produces image thumbnails of JPanels...

Especially look at the "ScaledPanelIcon" inner class...

 
import javax.swing.*;
import java.util.Random;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImageFilter;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
 
public class FrontPanelTest {
 
    public static void main(String[] args) {
 
        Random random = new Random();
        JComponent[] panelArray = new JComponent[random.nextInt(9) + 1];
        for (int i = 0; i < panelArray.length; i++) {
            panelArray[i] = createRandomPanel("Panel " + (i + 1));
        }
 
        FrontPanel frontPanel = new FrontPanel(panelArray);
 
        JFrame f = new JFrame("FrontPanelTest");
        f.getContentPane().add(frontPanel);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(640, 480);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
 
    private static final JComponent createRandomPanel(String name) {
        JPanel panel = new JPanel();
        panel.setName(name);
        panel.setPreferredSize(new Dimension(640, 440));
        Random random = new Random();
        int numOfComponents = random.nextInt(9) + 1;
        for (int i = 0; i < numOfComponents; i++) {
            switch(random.nextInt(5)) {
                case 0: panel.add(new JLabel("label"));
                        break;
                case 1: panel.add(new JTextField("textField"));
                        break;
                case 2: panel.add(new JButton("button"));
                        break;
                case 3: panel.add(new JCheckBox("checkbox"));
                        break;
                case 4: String[] data = {"list", "value 1", "value 2"};
                        panel.add(new JList(data));
                        break;
            }
        }
        return panel;
    }
 
    private static class FrontPanel extends JPanel {
 
        private JComponent[] subComponents;
        private JComponent frontPanel;
        private JPanel cardPanel;
        private CardLayout cardLayout;
        private JButton backButton;
 
        public FrontPanel(JComponent[] subComponents) {
            this.subComponents = subComponents;
 
            frontPanel = createFrontPanel();
 
            cardPanel = new JPanel();
            cardLayout = new CardLayout();
 
            cardPanel.setLayout(cardLayout);
            cardPanel.add(frontPanel, frontPanel.getName());
            for (int i = 0; i < subComponents.length; i++) {
                cardPanel.add(subComponents[i], subComponents[i].getName());
            }
 
            cardLayout.first(cardPanel);
 
            setLayout(new BorderLayout());
            add(cardPanel, BorderLayout.CENTER);
 
            JPanel buttonPanel = new JPanel();
            backButton = new JButton("<=");
            backButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    cardLayout.first(cardPanel);
                    backButton.setEnabled(false);
                }
            });
            backButton.setEnabled(false);
            buttonPanel.add(backButton);
            add(buttonPanel, BorderLayout.SOUTH);
        }
 
        private JComponent createFrontPanel() {
            JPanel p = new JPanel();
            p.setLayout(new FlowLayout());
            p.setName("frontPanel");
 
            for (int i = 0; i < subComponents.length; i++) {
                JButton selectPanel = new JButton(new PanelSelectAction(subComponents[i]));
                p.add(selectPanel);
            }
 
            return p;
        }
 
        private class PanelSelectAction extends AbstractAction {
 
            private JComponent c;
 
            public PanelSelectAction(JComponent c) {
                super(c.getName(), new ScaledPanelIcon(c));
                this.c = c;
            }
 
            public void actionPerformed(ActionEvent e) {
                cardLayout.show(cardPanel, c.getName());
                backButton.setEnabled(true);
            }
        }
 
        private static class ScaledPanelIcon implements Icon {
 
            private int width;
            private int height;
 
            private Image image;
 
            public ScaledPanelIcon(JComponent c) {
                this(c, 100, 100);
            }
 
            public ScaledPanelIcon(JComponent c, int width, int height) {
                this.width = width;
                this.height = height;
 
                BufferedImage tempImage = new BufferedImage(c.getPreferredSize().width, c.getPreferredSize().height, BufferedImage.TYPE_INT_ARGB);
                System.out.println("image w = " + tempImage.getWidth() + " h = " + tempImage.getHeight());
                Graphics g = tempImage.getGraphics();
                JWindow tempParent = new JWindow();
                tempParent.getContentPane().add(c);
                tempParent.pack();
                try{
                    c.paint(g);
                }
                finally {
                    tempParent.remove(c);
                    tempParent.dispose();
                    g.dispose();
                }
 
                image = tempImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);
            }
 
            public int getIconHeight() {
                return height;
            }
 
            public int getIconWidth() {
                return width;
            }
 
            public void paintIcon(Component c, Graphics g, int x, int y) {
                g.drawImage(image, x, y, width, height, c);
            }
        }
    }
}

[Arjun Palanichamy]

Hi Nathan....

Your source Code Work perfectly in my application, i am very happy same time Thanks to you again.
same time i want some another help plz ,i want the import PPT file in my java swing application,i seen the your previous reply POI webpage but i canot come to clear idea.i try to convert PPT file to (.sxi) and UNziped that i got One XML file but i canot modify it my applicaton. Plz if give any simple source code ....

Thanks in Advance.
Arjun