VDisplayPanel - displays a panel in the dialog window.
  VDisplayPanel(num_of_cmds, cmds)
  int num_of_cmds;
  PanelCmdInfo *cmds;
  VDisplayPanel displays a panel in the dialog window. VDisplayPanel checks
if the dialog window is in front of the image window; if so, VDisplayPanel
displays the panel with the specified commands in the dialog window, else
VDisplayPanel stores the panel in a pixmap. Each command can have a maximum 
of MAX_PANEL_CHARS (defined in 3DVIEWNIX.PAR) characters. If the command is 
longer than MAX_PANEL_CHARS, it is truncated to MAX_PANEL_CHARS. A command 
can be a switch or a button. If the command type is 0, it is a button and it 
just displays a command name in the panel item area. If the command type is 1,
then the command is a switch. For a switch, both the command name and the 
default switch value are displayed in the panel item area. The commands are 
displayed two per row and are grouped by number. Each group occupies a 
consecutive set of rows. Even and odd groups are displayed in different
  typedef struct {
        short  group;           /*the group number*/
        Char30 cmd;             /*the name of command*/
        short  type;            /*0 - button type; 1 - switch type.*/
        short  num_of_switches; /*the number of switches per command*/
        Char30 *switches;	/*the names of the switches*/
        short  switch_item_displayed; /*the switch item to be displayed*/
  } PanelCmdInfo;
Return Value
  0 - work successfully.
  1 - memory allocation error.
  215 - cannot display panel when scale is on in the panel area.
  242 - panel height is out of the dialog window boundary.
  248 - panel is already on.
  254 - panel command has been truncated.
  258 - pixmap is NULL and image window is in front of the dialog window.
  num_of_cmds - specifies the number of commands to be displayed in the panel.
  cmds - an array of PanelCmdInfo structure that contains command name, 
	command type, number of items for switches, and the content of 
Side Effects
Entry Conditions
  VCreateColormap should be called earlier,else VDisplayPanel prints an
error message to the standard error stream, produces a core dump file and
exits from the current process.
Related Functions
VSelectPanelItem, VErasePanel, VGetPanelInformation, VChangePanelItem.