Set the size of the inner area of window

Question

I have a simple function that generates JFrame containing an image:

 //The window
 JFrame frame = new JFrame();
 //Topmost component of the window
 Container main = frame.getContentPane();
 //Turns out this is probably the simplest way to render image on screen 
 //with guaranteed 1:1 aspect ratio
 JPanel panel = new JPanel() {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, null);
    }
 };
 //Put the image drawer in the topmost window component
 main.add(panel);
 //Set window size to the image size plus some padding dimensions
 frame.setSize(image.getWidth(null)+1, image.getHeight(null)+15);

 frame.setVisible(true);

Result:

image description

I think this happens because the window dimensions include the size of the top bar and the window borders.

I also tried to set the size for JPanel and call pack() on JFrame:

 //Set the size to the panel and let JFrame size itself properly
 panel.setSize(image.getWidth(null), image.getHeight(null));
 frame.pack();

Result is even worse:

image description

So how can I precisely specify the inner window dimensions in pixels?

image description

Here's the full function code.

Well you can try inserting image in a JLabel, that may not cause this problem. — Paramvir Singh Karwal, May 01 '15 at 17:31
@ParamvirSinghKarwal I started with that. I am not sure why I am not using that solution anymore, but there was a reason I guess. — Tomáš Zato - Reinstate Monica, May 01 '15 at 17:43
The easiest way to display an image it to use a JLabel. Only do custom painting if you are manipulating the image. — camickr, May 01 '15 at 18:53
@camickr As I said just before, there was probably some problem with it, because that's what I did first. — Tomáš Zato - Reinstate Monica, May 01 '15 at 19:21
The problem is with your code, not the approach. If you have a special requirement that is not mentioned in the question then state the requirement, otherwise why reinvent the wheel? — camickr, May 01 '15 at 19:25

score 2 · Accepted Answer · edited May 23 '17 at 11:58

2

Specify the preferred size of the panel by overriding the getPreferredSize method of JPanel and calling pack() on the JFrame before making it visible

JPanel panel = new JPanel() {
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(image, 0, 0, null);
    }
    @Override
    public Dimension getPreferredSize(){
        return new Dimension(image.getWidth(), image.getHeight());
    }
};

See the answers in Use of overriding getPreferredSize() instead of using setPreferredSize() for fixed size Components on the use and effect of either this technique, or the setPreferredSize method

edited May 23 '17 at 11:58

Community

1
1

answered May 01 '15 at 17:27

copeg

8,092
17
27

Awesome! It works and is simpler than I hoped for :) – Tomáš Zato - Reinstate Monica May 01 '15 at 17:29
@TomášZato, Even simpler is to use a JLabel, since it does this for you. – camickr May 01 '15 at 18:54

Set the size of the inner area of window

1 Answers1