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Thread: Points in a JPanel

  1. #1
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    Default Points in a JPanel

    So i am making a GUI that lets you add in vertices onto a JPanel and so far I have:

    import javax.swing.*;
     
    import java.awt.*;
    import java.util.ArrayList;
    import java.awt.Dimension;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
     
    public class Main {
     
    	static ArrayList<Vertices> Vertices = new ArrayList<Vertices>();
     
    	static JPanel panel = new JPanel();
    	static JPanel spacing = new JPanel();
    	static JButton AddVert = new JButton("Add Vertex");
    	static JButton AddEdge = new JButton("Add Edge");
    	static JButton RemVert = new JButton("Remove Vertex");
    	static JButton RemEdge = new JButton("Remove Edge");
    	static JPanel Output = new JPanel();
    	static JScrollPane Output2 = new JScrollPane();
    	static JFrame Frame = new JFrame();
     
    	private static Point points[];
     
     
    	public static void main(String[] args) {
    		JFrame Window = new JFrame("Graph");
    		//JFrame.setDefaultLookAndFeelDecorated(true);
     
    		Output.setPreferredSize(new Dimension(950,600));
    		Output2.setPreferredSize(new Dimension(200,600));
     
    		Window.setLayout(new BorderLayout(50, 10));
    		//Window.setIconImage(new ImageIcon("H:\\Graph\\img.png").getImage());
     
    	    Container pane = Window.getContentPane();
    		panel.add(AddVert);
    		panel.add(AddEdge);
    		panel.add(RemVert);
    		panel.add(RemEdge);
    		pane.add(spacing, BorderLayout.NORTH);
    		pane.add(spacing, BorderLayout.EAST);
    		pane.add(panel, BorderLayout.SOUTH);
    	    pane.add(Output2, BorderLayout.WEST);
    	    pane.add(Output, BorderLayout.CENTER);
    	    Output.add(new Vertices());
     
    	    Window.pack();
    		Window.setVisible(true);
    	}
    }

    I also have a class Vertices

    import java.awt.Color;
    import java.awt.Dimension;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.Insets;
     
    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import java.util.Random;
     
     
    public class Vertices extends JPanel {
     
    		public void paintComponent(Graphics g) {
    		      super.paintComponent(g);
     
    		      Graphics2D g2d = (Graphics2D) g;
     
    		      g2d.setColor(Color.blue);
     
    		      Dimension size = getSize();
    		      Insets insets = getInsets();
    		      int w =  size.width - insets.left - insets.right;
          		      int h =  size.height - insets.top - insets.bottom;
     
    		      Random r = new Random();
     
    		      for (int i=0; i<1000; i++) {
    		          int x = Math.abs(r.nextInt()) % w;
    		          int y = Math.abs(r.nextInt()) % h;
    		          g2d.drawLine(x, y, x, y);
    		      }
    		}
    	}

    I couldn't get it to work on its own so I am trying to make it randomly generate points around the JPanel but its doesn't seem to get it to work


  2. #2
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    Default Re: Points in a JPanel

    You're going to have to be more specific than that. What exactly do you mean when you say it doesn't work? Does it only draw a single point? Does it draw too many? Does it draw different points than what you'd expect? Does it throw an Exception? Can you see the JPanel at all?
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  3. #3
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    Default Re: Points in a JPanel

    The GUI and the JPanel work alright

    the points are the problem. The area they are drawn into is really small and when I try to change the size of the area it doesn't work at all

    So I want the points to spread out all over the JPanel

  4. #4
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    Default Re: Points in a JPanel

    I'd check your math with the insets. Trace through it with some example heights, widths, and insets and see what comes out. I'm not even sure why you're dealing with insets since your component doesn't have a border. You might want to take them out entirely until you need them.
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    Default Re: Points in a JPanel

    So at this point:

    for (int i=0; i<1000; i++) {
    		          int x = r.nextInt() % w;
    		          int y = r.nextInt() % h;
    		          g2d.drawLine(x, y, x, y);
    		      }

    What should I change for the size because I can't work out what size I would need to make it into a larger area

  6. #6
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    Default Re: Points in a JPanel

    Quote Originally Posted by Trunk Monkeey View Post
    So at this point:

    for (int i=0; i<1000; i++) {
    		          int x = r.nextInt() % w;
    		          int y = r.nextInt() % h;
    		          g2d.drawLine(x, y, x, y);
    		      }

    What should I change for the size because I can't work out what size I would need to make it into a larger area
    The problem isn't with those lines, it's with how you're calculating w and h in the first place. I'd throw some print statements in there to double-check your calculations.
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    Default Re: Points in a JPanel

    Yeah I put in some print statements and I tried just changing the numbers of h and w but it stays the same size but with less points

  8. #8
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    Default Re: Points in a JPanel

    Did the print statements make sense? Did they print out the correct width and height?

    Also, I'd recommend using fillOval() instead of drawLine() to draw a point.
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    Default Re: Points in a JPanel

    Well h and w are 10 and x and y range between like 1-10

    If I try to put a higher value for x and y nothing will come up.

  10. #10
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    Default Re: Points in a JPanel

    What are h and w supposed to represent? Height and width, right? If so, 10 x 10 is pretty small, since those values are pixels. Also, they shouldn't be fluctuating unless you're resizing your JPanel, right? Like I said, there's something off with your calculation involving insets, which I'm not sure why you're using at all.
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    Default Re: Points in a JPanel

    I got rid of the inset but whenever I make y or x larger there is nothing in the JPanel

  12. #12
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    Default Re: Points in a JPanel

    Quote Originally Posted by Trunk Monkeey View Post
    I got rid of the inset but whenever I make y or x larger there is nothing in the JPanel
    You're going to have to throw together an SSCCE that demonstrates exactly what you're doing then.
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