Description François POYER 2012-02-09 09:19:18 EST

Currently GridLayout extends AbstractLayout, while it DOES use the given hHint and wHint parameters in its #calculatePreferredSize method, result of which is cached by AbstractLayout in the #getPreferredSize method (leading to erroneous value returned by later calls).

ex: <code>
Figure container = new Figure();
GridLayout gridLayout = new GridLayout(1, true);
gridLayout.marginHeight = 0;
gridLayout.marginWidth = 0;
gridLayout.horizontalSpacing = 0;
gridLayout.verticalSpacing = 0;
container.setLayoutManager(gridLayout);
Figure child = new Figure();
GridData gridData = new GridData(SWT.FILL, SWT.CENTER, true, true);
container.add(child, gridData);

Dimension d1 = container.getPreferredSize(600, -1);
// d1.w = 600 <= OK
Dimension d2 = container.getPreferredSize(-1, -1);
// d2.w = 600 <= KO!

Figure container2 = new Figure();
GridLayout gridLayout2 = new GridLayout(1, true);
gridLayout2.marginHeight = 0;
gridLayout2.marginWidth = 0;
gridLayout2.horizontalSpacing = 0;
gridLayout2.verticalSpacing = 0;
container2.setLayoutManager(gridLayout2);
Figure child2 = new Figure();
GridData gridData2 = new GridData(SWT.FILL, SWT.CENTER, true, true);
container2.add(child2, gridData2);
Dimension d3 = container2.getPreferredSize(-1, -1);
// d3.w = 0 <= OK!
Dimension d4 = container2.getPreferredSize(600, -1);
// d4.w = 0 <= KO!
</code>

Making GridLayout extend AbstractHintLayout would fix this bug.