Drawing In Java

Question

Hello I'm trying to do some drawing examples in Java using the paintComponent and the Graphics Object. I need a fixed size 'Stage' (400x300) for the drawing and the window/frame "around it".

Here is my setup:

public class MyJFrame extends JFrame{    
    public MyJFrame(){
        //setSize(new Dimension(400,300));
        setBackground(Color.green);
        Stage stage = new Stage();
        add(stage);
        
        this.pack();
        this.setResizable(false);
        this.setVisible(true);
        
        System.out.println(this.size());
        System.out.println(stage.size()); 
    }
}

public class Stage extends JPanel {
    
    public Stage(){
        setPreferredSize(new Dimension(400,300));
        //setSize(new Dimension(400,300)); 
    }
    
    @Override
    protected void paintComponent(Graphics g) {
        g.setColor(Color.BLACK);
        g.fillRect(0, 0, 400, 300); 
    }
}

Out put of the print is :

java.awt.Dimension[width=416,height=338]
java.awt.Dimension[width=400,height=300]

But the result looks like this:
enter image description here

Black part is 400x300 .. not sure from where this extra spacing comes from.
I tried several variation of setSize setPreferredSize and layouts .. but nothing really worked.

P.S any java fiddle out there?

Don't extend frame or other top level containers. Instead create & use an instance of one. — Andrew Thompson, Jul 25 '13 at 06:12

score 4 · Answer 1 · answered Jul 25 '13 at 05:21

4

//this.pack();
this.setResizable(false);
this.pack();

answered Jul 25 '13 at 05:21

camickr

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score 3 · Answer 2 · answered Jul 25 '13 at 05:24

3

Two things.

Call pack AFTER you setResizable. This is a (not commonly) known bug
Don't rely on magic numbers. You should be using known values where possible. This will make your life easier should you decide to change these values later.

For example, instead of g.fillRect(0, 0, 400, 300); you should be using g.fillRect(0, 0, getWidth(), getHeight());

answered Jul 25 '13 at 05:24

MadProgrammer

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ty, have you any source reference for this bug? The numbers in the example are fixed just to make it more strict. – d.raev Jul 25 '13 at 05:28
Mostly, this bug is from observation. Try searching the site for `setResiable` ;) – MadProgrammer Jul 25 '13 at 05:32

score 2 · Answer 3 · edited May 23 '17 at 11:49

2

In this case I think you are better off using a BufferedImage as the paint surface and simply displaying that in a JLabel. A simple (animated) example can be seen in this answer.

edited May 23 '17 at 11:49

Community

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answered Jul 25 '13 at 06:08

Andrew Thompson

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Drawing In Java

3 Answers3