Creates a marking menu for switching between cameras (Maya script)

camera_marking_menu.py

'''
Creates a marking menu for switching between cameras
Marking menu opens on Shift+MMB
Lists all cameras in a group named "Cameras"
Menu items will look through the selected camera
Menu item labels are created dynamically to match the order and names of your cameras

Marking menu code based on this blog post: http://bindpose.com/custom-marking-menu-maya-python/
'''
import maya.cmds as mc

MENU_NAME = "markingMenu"

class markingMenu():
    '''The main class, which encapsulates everything we need to build and rebuild our marking menu. All
    that is done in the constructor, so all we need to do in order to build/update our marking menu is
    to initialize this class.'''

    def __init__(self):
        self._removeOld()
        self._build()

    def _build(self):
        '''Creates the marking menu context and calls the _buildMarkingMenu() method to populate it with all items.'''
        # Trigger on Shift+MMB
        menu = mc.popupMenu(MENU_NAME, mm=1, b=2, aob=1, ctl=0, alt=0, sh=1, p="viewPanes", pmo=1, pmc=self._buildMarkingMenu)

    def _removeOld(self):
        '''Checks if there is a marking menu with the given name and if so deletes it to prepare for creating a new one.
        We do this in order to be able to easily update our marking menus.'''
        if mc.popupMenu(MENU_NAME, ex=1):
            mc.deleteUI(MENU_NAME)
            
    def _get_cameras_in_group(self, group_name):
        group_members = mc.listRelatives(group_name, children=True)
        
        # Filter out cameras
        cameras = []
        if group_members:
            for member in group_members:
                shapes = mc.listRelatives(member, shapes=True)
                if shapes and mc.objectType(shapes[0]) == 'camera':
                    cameras.append(member)
        return cameras

    def _buildMarkingMenu(self, menu, parent):
        '''This is where all the elements of the marking menu are built.'''
        mc.menuItem(p=menu, label="persp", radialPosition="N", command="mc.lookThru('persp')")
        
        cameras = self._get_cameras_in_group("Cameras")
    
        if not cameras:
            mc.warning('No cameras found in the group: {}'.format(group_name))
            return
        
        # Create marking menu and dynamically add camera names
        radialPositions = ['NW', 'NE', 'W', 'E', 'SW', 'S', 'SE']
        for i, camera in enumerate(cameras):
            kwargs = {
                "p": menu,
                "label": camera,
                "command": f"mc.lookThru('{camera}')"
            }
            
            # Only set radial position for the first 7 cameras
            # Following cameras will end up in the list menu below the radial options
            if i < len(radialPositions):
                kwargs["radialPosition"] = radialPositions[i]
                
            mc.menuItem(**kwargs)

        # Rebuild
        # mc.menuItem(p=menu, l="Rebuild Marking Menu", c=rebuildMarkingMenu)

markingMenu()