This links together the generic MFD and the NavDisplay; it allows a fairly easy method to add a Map page to an MFD device.
----------------------
See: http://wiki.flightgear.org/Canvas_MFD_Framework
----------------------
Instantiate parameters:
1. pfd_device (instance of PFD_Device)
2. instrument display ident (e.g. mfd-map, or mfd-map-left mfd-map-right for multiple displays) - used to map to the property tree
3. layer_id: main layer in the SVG
4. nd_group_ident : group (usually within the main layer) to place the NavDisplay
5. [optional] switches - used to connect the property tree to the nav display. see the canvas nav display.
To add a canvas nav display page simply do
me.some_page = PFD_NavDisplay.new(me.PFD,"Situation", "mpcd-sit", "ID", "jtids_main");
Add generic version of a canvas MFD (based on the F-15)
It has a fairly simple class structure and hopefully is reasonably easy to understand; Thorsten's using it on the Shuttle and Hooray mentioned that it'd be a good idea to make it generic. It provides a device, that has pages and a set of buttons. The set of buttons control the page that is selected (i.e. a menu). Each page has its own set of menus. A menu defines a label and a page that is displayed. I intend to document it on the wiki once its added.
