Re: more quirks with GridBagLayout

LC's No-Spam Newsreading account <>
Tue, 27 May 2008 18:37:52 +0200
On Fri, 23 May 2008, A. Bolmarcich wrote:

On 2008-05-21, LC's No-Spam Newsreading account wrote:

In the past I succeeded in having the top panel in my applet to be
divided vertically in three areas of unequal height :

Now I want to achieve the same thing (i.e. divide vertically in three
areas of unequal height) for one of the panels of the tabbed pane, so
far unused.

       panel3a.setPreferredSize(new Dimension(MYWIDTH,50));
       panel3b.setPreferredSize(new Dimension(MYWIDTH,350));
       panel3c.setPreferredSize(new Dimension(MYWIDTH,50 ));

A basic error is that the relative gridheights of components in the
same column do not affect how the available height is distributed
among the components. The gridheight affects [...]

Ah, I see ... sort of ROWSPAN=n in HTML tables ...
.... however it worked like expected in my top panel ...

The relative weighty values determine how the available height is
distributed among the componentsi.

I thought that the weights had to be fractionary from 0.0 to 1.0,
which seems not the case in your example.

It usually helps to post an example that others can compile and run.

I thought about that, but my code was buried deep inside an applet and I
actually suspected that GridBagLayout might behave differently according
to the component it is applied ... or in an application vs an applet

Here is one that sets the height of three components in the 50/350/50
distribution that you want

Unfortunately your example does not run here (it compiles, but when it
runs - without error - nothing is displayed). I tried to take
inspiration from your code.

  static final int heights[] = {50, 350, 50};

     gbc.gridwidth = GridBagConstraints.REMAINDER;
     gbc.fill = GridBagConstraints.VERTICAL;

I had to replace VERTICAL with BOTH and add a weightx = 1.0 to achieve
more-or-less what I wanted (each area should occupy the entire width and
have the desired height.

     for (int i = 0; i < heights.length; i++) {
       gbc.weighty = heights[i];

Indeed if I use the heights of {50, 350, 50} I get something rather
close to what I wish (so thanks for the idea). The central part is
taller than in a plain GridLayout and much more legible, the bottom part
is fine, the top part is a bit too compressed.

However if I replace {50, 350, 50} with {100, 300, 50} I do not make the
top part taller at the expense of the central one ! The height of the
top part actually DECREASES. I even tried {200, 200, 50} and in that
case the top part is squeezed completely.

There should be something strange in the interpretation of the weights,
should they be normalized to be percentages of something ?

So far I achieved a nearly satisfactory look with {50, 350, 50} adding a
couple of horizontal separators to the top part.

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