Thread: Resizable image?

Hello,

I have an image with a standard size, what I'm trying to do is I want to be able to resize the image manually after opening it, i.e. click one of the corners and drag it to the wished size. When I try to resize it the way I mentioned I'm able to resize the frame but not the image, I don't know how to resize both the frame and the panel (or the label). Any ideas?

Thanks.

Originally Posted by KevinWorkman

You might have to do some custom painting. Recommended reading: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)

Thanks Kevin,

And do you know how I can just fix the frame to the image? because something I don't like is that every time I click and drag the frame the image stays the same but not the frame, the frame gets kind of shifted? you know what I mean?

This might be uncomfortable for new users who for some reason want to resize the image, they would normally click one of the corners, drag it, and then realize that the frame is getting resized but not the image. So resizing the frame back to the image's size is a bit annoying.

well if your image is inside your resizable frame, I would suggest to try giving your frame the BorderLayout, then add your image to the center area.
(do a search on BorderLayout for cut and paste code to do this, its barely more complex then a standard add.)
then INSIDE YOUR FRAME RESIZING, you need to revalidate() and or repaint().
you may need to revalidate and or repaint the frame too, never quite sure what the GUI wants with these,
but in some combination I can always find a solution for them to update immediately.

post code if its more complex then this solution and ill try to help,
Jonathan

Thanks Jonathan, the repaint() part didn't work for me but I'm pretty sure I did it wrong, please check it out and let me know:

package resize2;
 
import java.awt.BorderLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
 
public class Resize2 extends JFrame {
 
    private JLabel label;
    private JPanel panel;
 
    public Resize2() {
        super("Sensor");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocation(250, 230);
        setLayout(new BorderLayout());
 
        label = new JLabel(new ImageIcon("rotation.jpg"));
        panel = new JPanel();
 
        add(panel);
        panel.add(label, BorderLayout.CENTER);
 
        repaint();
        panel.repaint();
 
        pack();
        setVisible(true);
    }
 
    public static void main (String args []){
        new Resize2();
    }
}

Thanks a lot.

My experience is if you tell the image to be added inside a boarderlayout/Center it has demands on the object for resizing, and will demand it to be a certain size, so rethinking it, you would need to use border layout for the frame and everything else that is between the frame and the image. because they would all need to get the message of the Frame demanding a resize.

so for example. if you add a image to a jlabel and a jlabel to a jpanel and a jpanel to a jframe, and have the jframe, jpanel, jlabel all use borderlayout
and add the image the label and the jpanel to the CENTER region of their respective containers.

when you resize the frame it tells the jpanel to follow suit, if the jpanel doesnt have any special layout, it will just take on this burden itself, but if it too uses borderlayout/Center region, it will tell its components they have to meet the size it ends up with, and so on and so forth. it seems like a lot of overhead, but it is more intuitive then having your image communicate directly with the jframe and resize based on this communication.

also using borderlayout might not be the most lean overhead method of using this technique, there are probably a few simple methods that will force objects inside a container to obey, but borderlayour center region does this naturally, so i offered it as a quick fix.

hopefully this is the solution!
Jon.

It seems behavior I witnessed in my program earlier this week is due to something else, the SSCCE using only layout managers failed to resize the image
sorry for the rabbit chase knightmetal!

public class SSCCELayoutResizeTest {
 
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setLayout(new BorderLayout());
        frame.setTitle("ResizeTest");
        frame.setSize(500, 500);
 
        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());
 
        JLabel label = new JLabel();
        //label.setLayout(new BorderLayout());
 
        ImageIcon image = new ImageIcon("picture.png"); //size of picture is 80x80 Pixels
 
        label.setIcon(image);
        panel.add(label, BorderLayout.CENTER);
        frame.add(panel, BorderLayout.CENTER);
 
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
    }
}