Re: ctor: this.setLayout(

From:

"John B. Matthews" <john.b..matthews@THRWHITE.remove-dii-this>

Newsgroups:

comp.lang.java.gui

Date:

Wed, 27 Apr 2011 15:50:45 GMT

Message-ID:

<nospam-376A9C.04130515112008@feeder.motzarella.org>

To: comp.lang.java.gui
In article <nospam-06C9C0.07380714112008@feeder.motzarella.org>,
"John B. Matthews" <nospam@nospam.invalid> wrote:

In article
<a037f2e0-dc88-4004-8204-11818ad7d8d7@r36g2000prf.googlegroups.com>,
lbrtchx@gmail.com wrote:

[...]

I think I still have a chicken-or-egg first kind of problem with my
code and I see as one of the differences between your example and my
toy code, that you are employing an actual JLabel as canvas. Is there
anything more graphically convenient that could be used as canvas?

JLabel? We don't need no stinking JLabel! :-)

Sadly, I have stumbled into hubris. Again. One disadvantage of raw
drawing is how easy it is to get the geometry wrong. I made another try
below.

A more flexible approach is to implement the Icon interface in a
JComponent, e.g. JPanel or JLabel. This makes it somewhat easier to mix
components in a layout, as the x and y offsets are parameters to the
paintIcon() method. Here is an example:

<http://sites.google.com/site/drjohnbmatthews/composite>

I see at least one rendering implementation extends JPanel.

<http://www.exmpl.de/projects/mathml/math.html>

[Some knowledge of German required.]

<code>
class UrlPane extends JPanel {
    private final Font font = new Font("Serif", Font.BOLD, 24);
    private final String label = "\u2615 " + name;

    public UrlPane() {
        this.setBackground(Color.lightGray);
        this.setPreferredSize(new Dimension(0, 250));
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2D = (Graphics2D) g;

        int inset = 30;
        int h = this.getHeight() - inset;
        int w = h * 1618 / 1000;
        int x = (this.getWidth() - w) / 2;
        int y = inset / 2;

        // __ circle
        Ellipse2D ellipse = new Ellipse2D.Double(x, y, w, h);
        g2D.draw(ellipse);

        // __ square
        g2D.drawRect(x, y, w, h);

        // __ title
        g.setFont(font);
        int x2 = this.getWidth() / 2;
        int y2 = this.getHeight() / 2;
        int w2 = g.getFontMetrics().stringWidth(label) / 2;
        int h2 = g.getFontMetrics().getDescent();
        g.drawString(label, x2 - w2, y2 + h2);
    }
}
</code>

--
John B. Matthews
trashgod at gmail dot com
http://home.roadrunner.com/~jbmatthews/

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