[Chameleon] How is ROI saved to session?

[Yahya Mohammad]

Hi all,

I'm developing a widget called ROIBoundingBoxTool that should pop up a box 
like the BoundingBoxPopup widget and add a rectangular ROI at the entered 
coordinates. I need this functionality in my application in order to make 
more precise selections than using the mouse. So far I've managed to get it 
to work without refreshing the page when the entered coords are within the 
current extent.

Now if the coords are beyond the extent I believe I should write to 
$_SESSION['ROIRENDERER'] and refresh the page with an extent somewhat bigger 
than the selected ROI. Is this a correct approach? If so, is there an 
existing mechanism to do this? I looked at the existing ROI widgets' code but 
haven't yet been able to figure out how the ROI selection data gets into the 
$_SESSION variable.

Thanks,
Yahya Mohammad