如何始终在前台显示 Sirius Label

Question

For the context, I'm working with Capella, an Eclipse RCP application based on Sirius (hence, EMF, GMF and draw2d). This application is used for MBSE, that basically means diagram representations for industrial systems.

I'm developping an add-on (viewpoint) to display custom labels next to diagram elements. These diagram elements are, to put it simply, boxes inside boxes. My problem is that usually the label text is larger than the space between a box and its container, so the label gets hidden. What I need is these labels to always be in foreground. As I'm more used to web development, what I'm looking for would be the equivalent of the z-index CSS property.

Currently I have no idea of how to achieve this, I'm using a custom .odesign that allows me to control some rendering options, like labels text, the color of some elements or to add decoration, but I dont think its the way to go for my problem. Maybe I should use a custom EditPart or a custom StyleConfiguration (I already used these components for other projects) but I have no clue where to start for this issue.

Any leads will be greatly appreciated.

Answer 1

We recently did this kind of changes to keep some labels in Sirius Sequence diagrams always on top: the combined fragments are placed behind the lifelines (z order) but we wanted to keep the labels of the CombinedFragments visible event their bounds intersects Lifelines, Executions or States).

This has been handled in Bug 564239 for Sirius 6.3.2 (used in Capella 1.4.1). You could find some hints the bugzilla (Gerrits and commits can be retrieved from the See also section).

In Sirius Sequence diagram , we use org.eclipse.sirius.diagram.sequence.ui.tool.internal.layout.SequenceZOrderingRefresher to control the z-order of CombinedFragments : all the figures that composes them comes from some expressions in the odesign, and synchronization with the Capella model for exemple.

But in your case you want to control only the label, so it must not be dealt on the edit par level, but on the figure one. The "overlay" layer and figure lead might be a good one.

Do not forget another thing: in GMF/GEF, the labels of an element is displayed/shown/rendered/visible if it fits to the visible area of the parent container: in the case of a node in a container with scrollbar, the visible are will impact the visibility of the sub nodes (extended to their border nodes, edges, labels, ...)

Regards

Maxime