Customize the Accelerator GUI

The Accelerator GUI is implemented in Tcl/Tk. By editing the file, the appearance can be customized and extra elements can be added. The customization file is gui.tcl, which located in the server configuration directory (normally $VOVDIR/../../vnc/vnc.swd/gui.tcl).

In the following example, a button is added at the bottom of the GUI, which is only available when the GUI is started with environment variable SIMPLEDEMO set.
# This is a fragment of vnc.swd/gui.tcl
# to demonstrate the customizability of the NC GUI.
if [info exists env(SIMPLEDEMO)] {
    button .demo -text "Simple Customization Demo" -command {
        puts "You can run any command you want."
    pack .demo -side bottom -fill x -expand 0
To test and verify the customization, use the following command:
% env SIMPLEDEMO=1 nc gui &