Name: jk109818 Date: 05/15/2003


FULL PRODUCT VERSION :
java version "1.4.1_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1_01-b01)
Java HotSpot(TM) Client VM (build 1.4.1_01-b01, mixed mode)

FULL OS VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
BoxLayout lays out incorrectly if any of the subcomponents return a very large preferred size. The behaviour is caused by a rounding error in SizeRequirements.compressedTile(). In the example code below it will cause the total height of the subcomponents to be visibly larger that the height of their enclosing container.

I am not sure how other layout managers handle extreme preferred sizes but I feel that BoxLayout ought to behave more sensibly.

The obvious workaround: avoid very large values for preferred size (if staying a factor 1000 below Integer.MAX_VALUE things seem to work all right).



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile and run the Test class

EXPECTED VERSUS ACTUAL BEHAVIOR :
Sum of child component heights = parent component height
Sum of child component heights > parent component height

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javax.swing.*;
import java.awt.*;

public class Test {
    public static void main(String[] args) {
        JFrame frame = new JFrame();
        JPanel panel = new JPanel();
        panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
        {
            JPanel child = new JPanel();
            child.setBackground(Color.BLUE);
            child.setBorder(BorderFactory.createTitledBorder("LibertM- "));
            panel.add(child);
        }
        {
            JPanel child = new JPanel();
            child.setBackground(Color.WHITE);
            child.setBorder(BorderFactory.createTitledBorder("EgalitM- "));

            // set very large preferred and maximum sizes
            int large = Integer.MAX_VALUE;
            child.setPreferredSize(new Dimension(large, large));
            child.setMaximumSize(new Dimension(large, large));

            panel.add(child);
        }
        {
            JPanel child = new JPanel();
            child.setBackground(Color.RED);
            child.setBorder(BorderFactory.createTitledBorder("FraternitM- "));
            panel.add(child);
        }

        frame.getContentPane().add(panel);
        frame.setBounds(100,100,200,200);
        frame.setVisible(true);
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Do not use values larger than one million pixels in any direction when specifying "space greedy" components.
(Review ID: 182833)
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