focal_length_menu.py

"""
Creates a marking menu to switch the active camera between a list of focal lengths
Opens on Cmd+Shift+MMB
"""

import maya.cmds as mc

MENU_NAME = "focalLengthMarkingMenu"

class FocalLengthMarkingMenu:
    def __init__(self):
        self._remove_old_menu()
        self._create_menu()

    def _remove_old_menu(self):
        if mc.popupMenu(MENU_NAME, exists=True):
            mc.deleteUI(MENU_NAME)

    def _create_menu(self):
        mc.popupMenu(
            MENU_NAME,
            markingMenu=True,
            button=2,  # MMB
            clt=True,
            parent="viewPanes",
            postMenuCommand=self._build_menu_content
        )

    def _build_menu_content(self, menu, parent):
        focal_lengths = [
            (25, "N"), 
            (35, "W"),
            (50, "E"), 
            (70, "S")
        ]

        for fl, position in focal_lengths:
            mc.menuItem(
                parent=menu,
                label=f"{fl}mm",
                radialPosition=position,
                command=lambda _, fl=fl: self._set_focal_length(fl)
            )

    def _set_focal_length(self, focal_length):
        current_panel = mc.getPanel(withFocus=True)
        if mc.getPanel(typeOf=current_panel) == "modelPanel":
            camera = mc.modelPanel(current_panel, query=True, camera=True)
            mc.setAttr(f"{camera}.focalLength", focal_length)

# Create the marking menu
FocalLengthMarkingMenu()