mesh_looptools.py

        description="Distribute vertices at constant distances along the loop",
        default=True
        )

    # space properties
    space_influence: FloatProperty(
        name="Influence",
        description="Force of the tool",
        default=100.0,
        min=0.0,
        max=100.0,
        precision=1,
        subtype='PERCENTAGE'
        )
    space_input: EnumProperty(
        name="Input",
        items=(("all", "Parallel (all)", "Also use non-selected "
                "parallel loops as input"),
            ("selected", "Selection", "Only use selected vertices as input")),
        description="Loops that are spaced",
        default='selected'
        )
    space_interpolation: EnumProperty(
        name="Interpolation",
        items=(("cubic", "Cubic", "Natural cubic spline, smooth results"),
            ("linear", "Linear", "Vertices are projected on existing edges")),
        description="Algorithm used for interpolation",
        default='cubic'
        )
    space_lock_x: BoolProperty(
        name="Lock X",
        description="Lock editing of the x-coordinate",
        default=False
        )
    space_lock_y: BoolProperty(
        name="Lock Y",
        description="Lock editing of the y-coordinate",
        default=False
        )
    space_lock_z: BoolProperty(
        name="Lock Z",
        description="Lock editing of the z-coordinate",
        default=False
        )

# draw function for integration in menus
def menu_func(self, context):
    self.layout.menu("VIEW3D_MT_edit_mesh_looptools")
    self.layout.separator()


# Add-ons Preferences Update Panel

# Define Panel classes for updating
panels = (
        VIEW3D_PT_tools_looptools,
        )


def update_panel(self, context):
    message = "LoopTools: Updating Panel locations has failed"
    try:
        for panel in panels:
            if "bl_rna" in panel.__dict__:
                bpy.utils.unregister_class(panel)

        for panel in panels:
            panel.bl_category = context.preferences.addons[__name__].preferences.category
            bpy.utils.register_class(panel)

    except Exception as e:
        print("\n[{}]\n{}\n\nError:\n{}".format(__name__, message, e))
        pass


class LoopPreferences(AddonPreferences):
    # this must match the addon name, use '__package__'
    # when defining this in a submodule of a python package.
    bl_idname = __name__

    category: StringProperty(
            name="Tab Category",
            description="Choose a name for the category of the panel",
            default="Edit",
            update=update_panel
            )

    def draw(self, context):
        layout = self.layout

        row = layout.row()
        col = row.column()
        col.label(text="Tab Category:")
        col.prop(self, "category", text="")


# define classes for registration
classes = (
    VIEW3D_MT_edit_mesh_looptools,
    VIEW3D_PT_tools_looptools,
    LoopToolsProps,
    Bridge,
    Circle,
    Curve,
    Flatten,
    GStretch,
    Relax,
    Space,
    LoopPreferences,
    RemoveGP,
)


# registering and menu integration
def register():
    for cls in classes:
        bpy.utils.register_class(cls)
    bpy.types.VIEW3D_MT_edit_mesh_context_menu.prepend(menu_func)
    bpy.types.WindowManager.looptools = PointerProperty(type=LoopToolsProps)
    update_panel(None, bpy.context)


# unregistering and removing menus
def unregister():
    for cls in reversed(classes):
        bpy.utils.unregister_class(cls)
    bpy.types.VIEW3D_MT_edit_mesh_context_menu.remove(menu_func)
    try:
        del bpy.types.WindowManager.looptools
    except Exception as e:
        print('unregister fail:\n', e)
        pass


if __name__ == "__main__":
    register()