Widget Layouting

This examples shows GammaRay's capabilities in analyzing widget layouting issues.

Problem

The widget layouting example application shows a complex dialog window that cannot be resized as small as one would expect.

Investigation

GammaRay supports several approaches of analyzing widget layouting issues. All of them revolve around the Widget Inspector.

In-app widget picking

You can select the widget occupying a specific screen pixel by clicking on the area you are interested in the target applicationi while holding Ctrl+Shift. This will select the top-most QWidget occupying this space.

This is particularly useful for identifying the "owner" of seemingly empty space. In our example this can be used to identify the QLabel on the lower left that has an unnecessarily high minimum size set.

Property inspection

For the selected QWidget or QLayout instance you can look at and edit many layouting-relevant properties in the Properties view on the right. Tweaking these values at runtime avoids lengthy recompile and restart cycles just to verify a specific change.

In our example, we can change the minimum size of the offending QLabel in the lower left to something more reasonable and immediately verify that the window resizing has improved.

Bisection layouting problems

A useful approach for identifying more complicated layouting issues is bisecting them, that is, take our parts of the UI and verify if the problem persists. You can do this at runtime with GammaRay too, without needing to recompile or restart the target application, by setting the relevant QWidget sub-tree to invisible in the Properties view.

In our example, we can use this to exclude the QGroupBox instances at the right side as a possible source for the window resizing issue. Hiding one of them makes it a lot more apparent that the actual source of the problem is the QLabel on the lower left.

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