#### 15.4.7.1 Customizing Toolkit Behavior

The specific behavior of the backend toolkit may be modified using the following utility functions. Note: Not all functions apply to every graphics toolkit.

Loadable Function: [prog, args] = gnuplot_binary ()
Loadable Function: [old_prog, old_args] = gnuplot_binary (new_prog, arg1, …)

  Query or set the name of the program invoked by the plot command when the graphics toolkit is set to "gnuplot". Additional arguments to pass to the external plotting program may also be given. The default value is `"gnuplot"` with no additional arguments. See Installation.

  See also: graphics_toolkit.

Built-in Function: mode = gui_mode ()
Built-in Function: gui_mode (mode)

  Query or set the GUI mode for the current graphics toolkit. The mode argument can be one of the following strings:

  `"2d"`

    Allows panning and zooming of current axes.

  `"3d"`

    Allows rotating and zooming of current axes.

  `"none"`

    Mouse inputs have no effect.

  This function is currently implemented only for the FLTK graphics toolkit.

  See also: mouse_wheel_zoom.

Loadable Function: val = mouse_wheel_zoom ()
Loadable Function: old_val = mouse_wheel_zoom (new_val)
Loadable Function: mouse_wheel_zoom (new_val, "local")

  Query or set the mouse wheel zoom factor.

  The zoom factor is a number in the range (0,1) which is the percentage of the current axis limits that will be used when zooming. For example, if the current x-axis limits are [0, 50] and `mouse_wheel_zoom` is 0.4 (40%), then a zoom operation will change the limits by 20.

  When called from inside a function with the `"local"` option, the variable is changed locally for the function and any subroutines it calls. The original variable value is restored when exiting the function.

  This function is currently implemented only for the FLTK graphics toolkit.

  See also: gui_mode.