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AWT Background Problem

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posted 13 years ago

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When I first bring up the web page, I get the wrong background color (it's actually the foreground color - black - instead, although that might be coincidence). Refreshing the page makes the background of the applet area the same color as the HTML page background. Then, when I go to another tab and return, the background of the applet area is whatever was in that area on the page of the last tab that I visited. I actually wouldn't mind if the background in the applet area was transparent right to the background of the HTML page, but only the HTML page in which is resides - not wherever I was before ...

Correlation does not prove causality.

Roger F. Gay

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posted 13 years ago

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The problem occurred using Firefox, but was not repeatable in Opera. So, I'm guessing it's a Firefox bug. Anyone concur ? Disagree?

Correlation does not prove causality.

Michael Dunn

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posted 13 years ago

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> Anyone concur ? Disagree?

to concur/disagree you would need to post the 'exact' code/steps that reproduces the problem.

lines in the code like this

.....

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Roger F. Gay

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posted 13 years ago

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import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;

/* 
 * This is like the FontDemo applet in volume 1, except that it 
 * uses the Java 2D APIs to define and render the graphics and text.
 */

public class Rooms extends JApplet {

final static Color bg = Color.white;
    final static Color fg = Color.black;
    final static Color red = Color.red;
    final static Color white = Color.white;

final static BasicStroke stroke = new BasicStroke(2.0f);
    final static BasicStroke wideStroke = new BasicStroke(8.0f);

Dimension totalSize;

public void init() {
        //Initialize drawing colors
        setBackground(bg);
        setForeground(fg);
    }

public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        Dimension d = getSize();
        int gridWidth = d.width / 6;
        int gridHeight = d.height / 2;

Color fg3D = Color.lightGray;

g2.setPaint(fg3D);
        g2.draw3DRect(0, 0, d.width - 1, d.height - 1, true);
        g2.draw3DRect(3, 3, d.width - 7, d.height - 7, false);
        g2.setPaint(fg);

int x = 5;
        int y = 7;
        int rectWidth = gridWidth - 2*x;
        int rectHeight = gridHeight - y - 5;

// draw Line2D.Double
        g2.draw(new Line2D.Double(x, y+rectHeight-1, x + rectWidth, y));
        x += gridWidth;

// draw Rectangle2D.Double
        g2.setStroke(stroke);
        g2.draw(new Rectangle2D.Double(x, y, rectWidth, rectHeight));
        x += gridWidth;

// draw Arc2D.Double       
        g2.setStroke(wideStroke);
        g2.draw(new Arc2D.Double(x, y, rectWidth, rectHeight, 90, 
                                 135, Arc2D.OPEN));
        x += gridWidth;

// NEW ROW
        x = 5;
        y += gridHeight;

// fill Ellipse2D.Double
        GradientPaint redtowhite = new GradientPaint(x,y,red,x+rectWidth, y,white);
        g2.setPaint(redtowhite);
        g2.fill (new Ellipse2D.Double(x, y, rectWidth, rectHeight));
        g2.setPaint(fg);
        x += gridWidth;

}

public static void main(String s[]) {
        JFrame f = new JFrame("Rooms");
        f.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });
        JApplet applet = new Rooms();
        f.getContentPane().add("Center", applet);
        applet.init();
        f.pack();
        f.setSize(new Dimension(550,100));
        f.setVisible(true);
    }

}

Correlation does not prove causality.

Maneesh Godbole

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posted 13 years ago

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1) You extend JApplet. In such scenarios (where you use Swing components) it is recommended to override paintComponent() for custom painting
2) In the init() you are invoking setBack/Foreground(). Later on you are also calling g2.fill. What exactly are you trying to do here?
3) Your class has a main method? Who is supposed to be invoking that?
4) Your main method creates a JFrame and you add an applet instance to it? What exactly are you trying to do here?

Recommended reading: http://java.sun.com/docs/books/tutorial/uiswing/components/applet.html

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Michael Dunn

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posted 13 years ago