[Qt-interest] QgraphicsScene: best way to manage events

[Christian Gagneraud]

Hi all,

I'm trying to implement a kind of drawing tool.
The user simply select the current tool (select, move, edit; draw 
circle, rectangle, ...) from the main toolbar, and then 
press/move/release the mouse depending on how this tool works.

I have sub-classed the scene, and I have a "Tool" base class.

As each tool will have to manage the mouse events its own way, I'm 
looking at the best way to "forward" the mouse events from the scene 
to the current tool, knowing that I would like later to be able to add 
new tools via plug-ins (so the scene have to know only about the Tool 
base class).

Should I let the tools register/unregister themselves as event filters 
to the scene, or should I forward the events to the current tool in 
the scene's event handler using postEvent()? Or are there any other 
solutions for this typical use-case?


Regards,
Chris

-- 
Christian Gagneraud,
Electronics and software engineer

TechWorks Marine Ltd
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Ireland

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