Scale 2 or more pictures using a JSlider

[Panchitopro]

Hi everybody,

I posted this message in general Java, I'am not sure if it is right or not.

I would like to know how I can display 2 or more images and then make scale in these images on the same time.

Thank you.

Francisco

I found this code here in Java Forums this is my reference:

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Hashtable;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;

public class MapScale extends JPanel {
BufferedImage image;
double scale = 1.0;

public MapScale(BufferedImage image) {
this.image = image;
}

protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATI ON,
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
double x = (getWidth() - scale*image.getWidth())/2;
double y = (getHeight() - scale*image.getHeight())/2;
AffineTransform at = AffineTransform.getTranslateInstance(x,y);
at.scale(scale, scale);
g2.drawRenderedImage(image, at);
}

public Dimension getPreferredSize() {
int w = (int)(scale*image.getWidth());
int h = (int)(scale*image.getHeight());
return new Dimension(w, h);
}

private JSlider getSlider() {
int min = 1, max = 36, inc = 5;
final JSlider slider = new JSlider(min, max, 16);
slider.setMajorTickSpacing(5);
slider.setMinorTickSpacing(1);
slider.setPaintTicks(true);
slider.setSnapToTicks(true);
slider.setLabelTable(getLabelTable(min, max, inc));
slider.setPaintLabels(true);
slider.addChangeListener(new ChangeListener() {
public void stateChanged(ChangeEvent e) {
int value = slider.getValue();
scale = (value+4)/20.0;
revalidate();
repaint();
}
});
return slider;
}

private Hashtable getLabelTable(int min, int max, int inc) {
Hashtable<Integer,JLabel> table = new Hashtable<Integer,JLabel>();
for(int j = min; j <= max; j += inc) {
String s = String.format("%.2f", (j+4)/20.0);
table.put(Integer.valueOf(j), new JLabel(s));
}
return table;
}

public static void main(String[] args) throws IOException {
String path = "images/GIRL.JPG";
BufferedImage image = ImageIO.read(new File(path));
MapScale test = new MapScale(image);
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(new JScrollPane(test));
f.getContentPane().add(test.getSlider(), "Last");
f.setSize(400,400);
f.setLocation(200,200);
f.setVisible(true);
}
}

[hardwired]

There are two general ways to do this:
1 — drawing the images in a JPanel
2 — mounting scaled images in JLabels.
Here's an example showing both ways:

Code:

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Hashtable;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;

public class MultiScale implements ChangeListener {
    BufferedImage[] images;
    ImageScalePanel imagePanel;
    JLabel[] labels;
    double scale = 1.0;

    public MultiScale(BufferedImage[] images) {
        this.images = images;
    }

    public void stateChanged(ChangeEvent e) {
        int value = ((JSlider)e.getSource()).getValue();
        scale = (value+4)/20.0;
        imagePanel.setScale(scale);
        setImages();
    }

    private JPanel getContent() {
        imagePanel = new ImageScalePanel(images);
        imagePanel.setBorder(BorderFactory.createTitledBorder("graphic"));
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.weighty = 1.0;
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        panel.add(imagePanel, gbc);
        panel.add(getLabelPanel(), gbc);
        return panel;
    }

    private JPanel getLabelPanel() {
        JPanel panel = new JPanel(new GridLayout(1,0));
        panel.setBorder(BorderFactory.createTitledBorder("labels"));
        labels = new JLabel[3];
        for(int i = 0; i < labels.length; i++) {
            labels[i] = new JLabel((ImageIcon)null, JLabel.CENTER);
            panel.add(labels[i]);
        }
        setImages();
        return panel;
    }

    private void setImages() {
        for(int i = 0; i < labels.length; i++) {
            labels[i].setIcon(new ImageIcon(getScaledImage(i)));
        }
        labels[0].getParent().validate();
    }

    private BufferedImage getScaledImage(int index) {
        int w = (int)(scale*images[index].getWidth());
        int h = (int)(scale*images[index].getHeight());
        int type = images[index].getType();
        BufferedImage image = new BufferedImage(w, h, type);
        Graphics2D g2 = image.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        g2.drawImage(images[index], 0, 0, w, h, labels[index]);
        g2.dispose();
        return image;
    }

    private JSlider getSlider() {
        int min = 1, max = 36, inc = 5;
        JSlider slider = new JSlider(min, max, 16);
        slider.setMajorTickSpacing(5);
        slider.setMinorTickSpacing(1);
        slider.setPaintTicks(true);
        slider.setSnapToTicks(true);
        slider.setLabelTable(getLabelTable(min, max, inc));
        slider.setPaintLabels(true);
        slider.addChangeListener(this);
        return slider;
    }

    private Hashtable getLabelTable(int min, int max, int inc) {
        Hashtable<Integer,JLabel> table = new Hashtable<Integer,JLabel>();
        for(int j = min; j <= max; j += inc) {
            String s = String.format("%.2f", (j+4)/20.0);
            table.put(Integer.valueOf(j), new JLabel(s));
        }
        return table;
    }

    public static void main(String[] args) throws IOException {
        String prefix = "images/geek/geek";
        String ext = ".gif";
        String[] ids = { "-c---", "--g--", "---h-" };
        BufferedImage[] images = new BufferedImage[ids.length];
        for(int i = 0; i < images.length; i++) {
            String path = prefix + ids[i] + ext;
            images[i] = ImageIO.read(new File(path));
        }
        MultiScale test = new MultiScale(images);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new JScrollPane(test.getContent()));
        f.getContentPane().add(test.getSlider(), "Last");
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

class ImageScalePanel extends JPanel {
    BufferedImage[] images;
    double scale = 1.0;
    int totalWidth;

    public ImageScalePanel(BufferedImage[] images) {
        this.images = images;
        for(int i = 0; i < images.length; i++)
            totalWidth += images[i].getWidth();
    }

    public void setScale(double scale) {
        this.scale = scale;
        revalidate();
        repaint();
    }

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        double x = getInsets().left;
        double y = getInsets().top;
        for(int i = 0; i < images.length; i++) {
            AffineTransform at = AffineTransform.getTranslateInstance(x,y);
            at.scale(scale, scale);
            g2.drawRenderedImage(images[i], at);
            x += scale*images[i].getWidth();
        }
    }

    public Dimension getPreferredSize() {
        Insets insets = getInsets();
        int vi = insets.top + insets.bottom;
        int hi = insets.left + insets.right;
        int w = (int)(scale*totalWidth) + hi;
        int h = (int)(scale*images[0].getHeight()) + vi;
        return new Dimension(w, h);
    }
}

Images from Using Swing Components Examples, down low.

[Panchitopro]

Morning,

I checked the code and I took the images from the project CheckBoxDemo (Using Swing Components: Examples (The Java™ Tutorials > Creating a GUI with JFC/Swing > Using Swing Components)) and it works.

Just I would like to comment that I found 3 things when I put the code in Eclipse:

1. in this part I had an error:
...
Hashtable<Integer,JLabel> table = new Hashtable<Integer,JLabel>();
...
It display a Syntax error, parameterized types are only available if source level is 5.0.

I just changed by:
Hashtable table = new Hashtable();

2. In this line:
...
String s = String.format("%.2f", (j+4)/20.0);
...
and the message in Eclipse said:
The method format(String, Object[]) in the type String is not applicable for the arguments (String, double)

Here I wrote String s = "x"; instead.

I don't understand why method "format" does not work.


3. It has appeared a warning message in Eclipse when I tryed to do a debug, something about deprecated functions, and Eclipse gave me 3 options (Continue, Cancel and Restart), I chose Restart and now it works correctly. I tryed to put the original code in a new project to see the text message but I couldn't do it, this is rare. Anyway.

Thank you very much hardwired.

Now I would like to know how can I put an image with a dimension 2400 x 1800 like a thumbnail into this project. I will check that, however if you can help me with a reference please, I will apprecite it.

Thank you again.

Panchitopro

[hardwired]

parameterized types are only available if source level is 5.0
Generics was introduced in j2se 1.5. You can check the version of java at the prompt with >java -version
The method format(String, Object[]) in the type String is not applicable for the arguments (String, double)
The String.format method was also new in j2se 1.5
Looks like your ide might have a format method used for writing out arrays.

Code:

import java.awt.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;

public class Thumbnail {
    private JLabel getContent(BufferedImage image) {
        BufferedImage thumb = scaleImage(image);
        ImageIcon icon = new ImageIcon(thumb);
        JLabel label = new JLabel(icon, JLabel.CENTER);
        return label;
    }

    private BufferedImage scaleImage(BufferedImage src) {
        int w = 75;   // thumbnail
        int h = 100;  // dimensions
        int type = BufferedImage.TYPE_INT_RGB;
        BufferedImage dst = new BufferedImage(w, h, type);
        Graphics2D g2 = dst.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
        g2.setBackground(UIManager.getColor("Panel.background"));
        g2.clearRect(0,0,w,h);
        double xScale = (double)w/src.getWidth();
        double yScale = (double)h/src.getHeight();
        double scale = Math.min(xScale, yScale);    // fit
                       //Math.max(xScale, yScale);  // fill
        double x = (w - scale*src.getWidth())/2;
        double y = (h - scale*src.getHeight())/2;
        AffineTransform at = AffineTransform.getTranslateInstance(x,y);
        at.scale(scale, scale);
        g2.drawRenderedImage(src, at);
        g2.dispose();
        return dst;
    }

    public static void main(String[] args) throws IOException {
        String path = "http://imgsrc.hubblesite.org/hu/db/" +
                      "1999/12/images/a/formats/full_jpg.jpg";
        URL url = new URL(path);
        URLConnection uc = url.openConnection();
        uc.connect();
        InputStream is = uc.getInputStream();
        BufferedImage image = ImageIO.read(is);
        System.out.printf("imageWidth = %d  imageHeight = %d%n",
                           image.getWidth(), image.getHeight());
        is.close();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new Thumbnail().getContent(image));
        f.setSize(300,175);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}