Prevent Zest 2.0 GraphViewer from executing the layout algorithm with refresh

Question

Since updating Zest from 1.4 to 2.0 I have a problem with the layout algorithms.

In 1.4 the layout algorithm was executed only by invoking applyLayout. It was possible to set the layout, execute it and after that change the Graph and refresh the GraphViewer without executing it again.

In 2.0 every refresh, necessary to update the Viewer after the Graph changed, causes an execution of the layout algorithm. Therefore adding a new Node results in changing every position of every Node in the GraphViewer.

That is not acceptable for my use case. Is there a possibility to prevent the GraphViewer from executing the LayoutAlgorithm with refresh?

What I need is to layout the Graph in the Viewer only when the "layout" button is clicked. There should not be any automatic layouting.

I thought of unsetting the LayoutAlgorithm after invocation, so that there is no algorithm during later refreshs, but that seems not possible, too. Calling setLayoutAlgorithm with null as argument on the GraphViewer results in a NullPointerException.

Is there any possibility to get the "old behavior" of Zest GraphViewers with 2.0?

Thank you!

Kristina

score 1 · Answer 1 · answered Sep 20 '12 at 08:46

1

The Graph widget has a public void setDynamicLayout(boolean enabled) method, that according the Javadoc might just do the trick you need.

To get the widget from the GraphViewer, use GraphViewer#getGraphControl method.

answered Sep 20 '12 at 08:46

Zoltán Ujhelyi

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I tried that already, but it doesn not work. This property doesn't seem to interfere with the refresh method. – Kristina Sep 20 '12 at 10:55
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Then sadly, I think, this option is missing. Maybe you should open a ticket for it in the Eclipse Bugzilla. – Zoltán Ujhelyi Sep 20 '12 at 13:53

Prevent Zest 2.0 GraphViewer from executing the layout algorithm with refresh

1 Answers1