Perl SDL GUI Layout Engine

2013-09-19

As it turns out, SDLx::App only supports having one window at a time. It’s effectively a singleton. This was a problem for UAV::Pilot, because I wanted to draw the navigation output and video in seperate windows.

The fix I have now is to implement a simple layout engine, where you can specify if you want the widget to be placed at the top or bottom of the window. I didn’t want to add complications like left or right. That’s good enough for now; the video always goes on top, the nav on bottom. If you were watching the AR.Drones 720p video stream on a 720p monitor, it might be an issue, but I’m not going to worry about it for now.

Where it could be an issue is when UAV::Pilot starts implementing other types of UAVs. I’m contemplating a rover, which makes the current nav output of roll/pitch/yaw rather pointless. But it’ll still need the battery output, and maybe add throttle and steering.

That all leads into breaking the current nav output into individual widgets with a complicated layout engine, like the sort you might see in Gtk+ or KDE.

As far as I can tell, Perl has nothing like this for SDL. There’s SDLx::GUI and SDLx::Widget. Both of these are limited, and look like the respective authors have left them by the wayside. Which I totally understand. I left Gopher::Server like that.

I’m tempted to write my own, but that seems like a full project in itself. Intergrating with Gtk2 might work, but I’m not sure how well that will go with SDL. Even making Perl bindings for a C layout library seems like a full project.

For now, I can ignore the issue. Implementing just a rover won’t introduce too much redundancy.

Any takers on this one? :)