init:
    python:

        # A dict of 5-tuples mapping button labels to image buttons.
        config.image_buttons = { }

        # A dict mapping label to image.
        config.image_labels = { }

        # Maps from button or label to additional properties.
        config.button_properties = { }
        config.button_text_properties = { }
        config.label_properties = { }

        def _button_factory(label,
                            type=None,
                            selected=None,
                            disabled=False,
                            clicked=None,
                            properties={},
                            index=None,
                            **props):
            """
            This function is called to create the various buttons used
            in the game menu. By overriding this function, one can
            (for example) replace the default textbuttons with image buttons.
            When it is called, it's expected to add a button to the screen.

            @param label: The label of this button, before translation. 

            @param type: The type of the button. One of "mm" (main menu),
            "gm_nav" (game menu), "file_picker_nav", "yesno", or "prefs".

            @param selected: True if the button is selected, False if not,
            or None if it doesn't matter.

            @param disabled: True if the button is disabled, False if not.

            @param clicked: A function that should be executed when the
            button is clicked.

            @param properties: Addtional layout properties.
            """

            props.update(properties)
            props.update(config.button_properties.get(label, { }))
            
            if disabled:
                clicked = None

            if selected and not disabled:
                role = "selected_"
            else:
                role = ""

                
            if label in config.image_buttons:
                
                (idle, hover, sel_idle, sel_hover, disabled) = config.image_buttons[label]

                ui.imagebutton(idle,
                               hover,
                               disabled,
                               hover,
                               sel_idle,
                               sel_hover,
                               disabled,
                               sel_hover,
                               clicked=clicked,
                               style=style.image_button[label],
                               role=role,
                               **props)
                
                return

            button_style = type + "_button"
            text_style = type + "_button_text"

            if index is None:
                index = label
            
            button_style = getattr(style, button_style)[index]
            text_style = getattr(style, text_style)[index]
            
            ui.button(style=button_style, clicked=clicked, role=role, **props)
            ui.text(_(label), style=text_style, **config.button_text_properties.get(label, { }))
            
        def _label_factory(label, type, properties={}, **props):
            """
            This function is called to create a new label. It can be
            overridden by the user to change how these labels are created.

            @param label: The label of the box.

            @param type: "prefs" or "yesno". (perhaps more by now.)

            @param properties: This may contain position properties.
            """

            props.update(properties)
            props.update(config.label_properties.get(label, { }))

            if label in config.image_labels:
                ui.image(config.image_labels[label], **props)
                return

            style = getattr(store.style, type + "_label")[label]
            
            ui.text(_(label), style=style, **props)
