Re: Drawing line on ImageIcon on panel after getting data

From:

Lew <lew@lewscanon.com>

Newsgroups:

comp.lang.java.help

Date:

Thu, 01 Nov 2007 22:54:16 -0400

Message-ID:

<9_qdnXOMbbXEDLfanZ2dnUVZ_hudnZ2d@comcast.com>

bH wrote:

On Oct 25, 11:13 pm, "Andrew Thompson" <u32984@uwe> wrote:

bH wrote:

..

public class IconMapShoScale extends JPanel{

This example might have been an SSCCE except for:
a) line wrap, which had to be fixed before it compiled
b) lack of images locally.

For the first, you might try <http://www.physci.org/twc.jnlp>
This little tool shows the width of the source/text pasted
in the text area. I recommned limiting it to '62 chars' for
usenet posts.

For the second, try obtaining images that are small (in bytes),
but large enough (in width/height) to show the problem,
directly off the net. If you have a site of your own, upload
some examples to use, otherwise the code might get them
off another site.

Here is one image search..
<http://images.google.com.au/images?q=+filetype:jpg&as_st=y&svnum=10&h...

That search locates images that are 'small' in width/height.

As to the technical side of the problem, I suspect it is
non-optimal to create an ImageIcon. I would tend to use
a JPanel, override paintComponent and draw the Image
directly (Graphics.drawImage()). Once the points are
obtained, it is a simple matter to Graphics.drawLine()
(obviously, draw the lines *after* the image itself is drawn).

--
Andrew Thompsonhttp://www.athompson.info/andrew/

Message posted viahttp://www.javakb.com

Hi Andrew,

Thanks for the text width checker.
Taking your suggestions and making revisions using your suggestions,
This is supplied below.
bH

import javax.swing.*;
import java.awt.*;
import javax.swing.border.BevelBorder;
import java.awt.event.*;
import java.net.*;

/* Notes for use....
* Map scale enter number to be used; i.e. 600
* Click points requried
* [0] Click point Map Location of City 1
* [1] Click point Map Location of City 2
* [3] Click on the point Scale Chart at the 0 Minimum Value
* [4] Click on the point Scale Chart at the Maximum Value
*/

public class IconMapShoScaleImgs extends JFrame{

Probably better to have a JFrame than to be one, but no matter ...

[snip]
    pack() ;
    setLocationRelativeTo(null) ;
    setVisible(true);
  }

Shouldn't all this be happening on the EDT?

  public static void main(String[] args) {

    IconMapShoScaleImgs IconMapShoScaleImgs1 = new
IconMapShoScaleImgs();
  }
}

Wise writers on matters Java advise not to run everything from the
constructor. Bad Things can happen. Constructors are for construction - you
have a JFrame running in an incompletely-constructed object. Strangely, you
didn't in your first post.

Summary:
- Run Swing / AWT actions on the EDT.
- Constructors should only construct.
- Prefer composition to inheritance. (Joshua Bloch, /Effective Java/)

--
Lew