# panel 3x 2023-12-23 ncurses 6.4 Library calls

    panel(3x)                        Library calls                       panel(3x)

## NAME

           panel - panel stack extension for curses

## SYNOPSIS

           #include <panel.h>

           PANEL *new_panel(WINDOW *win);

           int bottom_panel(PANEL *pan);
           int top_panel(PANEL *pan);
           int show_panel(PANEL *pan);
           void update_panels(void);
           int hide_panel(PANEL *pan);

           WINDOW *panel_window(const PANEL *pan);
           int replace_panel(PANEL *pan, WINDOW *window);
           int move_panel(PANEL *pan, int starty, int startx);
           int panel_hidden(const PANEL *pan);

           PANEL *panel_above(const PANEL *pan);
           PANEL *panel_below(const PANEL *pan);

           int set_panel_userptr(PANEL *pan, const void *ptr);
           const void *panel_userptr(const PANEL *pan);

           int del_panel(PANEL *pan);

           /* ncurses extensions */
           PANEL *ground_panel(SCREEN *sp);
           PANEL *ceiling_panel(SCREEN *sp);

## DESCRIPTION

           Panels  are curses(3x) windows with the added property of depth.  Panel
           functions allow the use of stacked windows and ensure that  the  proper
           portions  of  each  window  and  the curses stdscr window are hidden or
           displayed when panels are added, moved, modified, or removed.  The  set
           of  currently visible panels is the stack of panels.  The stdscr window
           is beneath all panels, and is not considered part of the stack.

           A window is associated with each panel.  The panel routines enable  you
           to  create,  move,  hide, and show panels.  You can relocate a panel to
           any desired position in the stack.

           Panel routines are a functional layer added to curses, make only  high-
           level curses calls, and work anywhere curses does.

## FUNCTIONS

### bottom_panel

           bottom_panel(pan) puts panel pan at the bottom of all panels.

### ceiling_panel

           ceiling_panel(sp) acts like panel_below(NULL) for the given SCREEN sp.

### del_panel

           del_panel(pan)   removes  the  given  panel  pan  from  the  stack  and
           deallocates the PANEL structure (but not its associated window).

### ground_panel

           ground_panel(sp) acts like panel_above(NULL) for the given SCREEN sp.

### hide_panel

           hide_panel(pan) removes the given panel pan from the  panel  stack  and
           thus  hides  it  from  view.   The  PANEL structure is not lost, merely
           removed from the stack.

### move_panel

           move_panel(pan, starty, startx) moves the given panel pan's  window  so
           that  its  upper-left  corner is at starty, startx.  It does not change
           the position of the panel in the stack.  Be sure to use this  function,
           not mvwin(3x), to move a panel window.

### new_panel

           new_panel(win)  allocates  a  PANEL  structure, associates it with win,
           places the panel on the top of the stack (causes  it  to  be  displayed
           above any other panel) and returns a pointer to the new panel.

### panel_above

           panel_above(pan)  returns  a  pointer  to  the panel above pan.  If the
           panel argument is "(PANEL *)0", it returns  a  pointer  to  the  bottom
           panel in the stack.

### panel_below

           panel_below(pan) returns a pointer to the panel just below pan.  If the
           panel argument is "(PANEL *)0", it returns a pointer to the  top  panel
           in the stack.

### panel_hidden

           panel_hidden(pan) returns FALSE if the panel pan is in the panel stack,
           and TRUE if it is not.  If the panel is a null pointer, it returns ERR.

### panel_userptr

           panel_userptr(pan) returns the user pointer for a given panel pan.

### panel_window

           panel_window(pan) returns a pointer to the window of  the  given  panel
           pan.

### replace_panel

           replace_panel(pan,  window)  replaces  the  current window of panel pan
           with window This is useful if, for example, you want to resize a panel.
           In ncurses, you can call replace_panel to resize a panel using a window
           resized with wresize(3x).  It does not change the position of the panel
           in the stack.

### set_panel_userptr

           set_panel_userptr(pan, ptr) sets the panel's user pointer.

### show_panel

           show_panel(pan)  makes  a  hidden panel visible by placing it on top of
           the panels in the panel stack.  See "PORTABILITY" below.

### top_panel

           top_panel(pan) puts the given visible panel pan on top of all panels in
           the stack.  See "PORTABILITY" below.

### update_panels

           update_panels()  refreshes  the virtual screen to reflect the relations
           between the panels in the stack, but  does  not  call  doupdate(3x)  to
           refresh the physical screen.  Use this function and not wrefresh(3x) or
           wnoutrefresh(3x).

           update_panels may be called more than once before a call  to  doupdate,
           but  doupdate  is  the  function  responsible for updating the physical
           screen.

## RETURN VALUE

           Each routine that returns a pointer returns NULL if  an  error  occurs.
           Each  routine  that  returns  an  int  value  returns OK if it executes
           successfully and ERR if not.

           Except as noted, the pan and window parameters must  be  non-null.   If
           either is null, an error is returned.

           The  move_panel  function uses mvwin(3x), and returns an error if mvwin
           returns an error.

## NOTES

           The header file panel.h itself includes the header file curses.h.

## PORTABILITY

           Reasonable care has been taken to ensure compatibility with the  native
           panel  facility  introduced  in System V; inspection of the SVr4 manual
           pages suggests the programming interface never changed.  The PANEL data
           structures  are  merely  similar.   The  programmer is cautioned not to
           directly use PANEL fields.

           The  functions  show_panel  and  top_panel  are   identical   in   this
           implementation,  and work equally well with displayed or hidden panels.
           In the System V implementation, show_panel is  intended  for  making  a
           hidden  panel  visible  (at  the  top  of  the  stack) and top_panel is
           intended for making an already-visible panel move to  the  top  of  the
           stack.   You  are  cautioned  to  use  the  correct  function to ensure
           compatibility with System V panel libraries.

## HISTORY

           A panel facility was documented in SVr4.2's  Character  User  Interface
           Programming document.

           It is not part of X/Open Curses.

           A few implementations exist:

           o   Systems  based  on  SVr4 source code, such as Solaris, provide this
               library.

           o   ncurses (since version 0.6 in 1993) and PDCurses (since version 2.2
               in  1995) provide a panel library whose common ancestor is a public
               domain implementation by Warren Tucker published  in  u386mon  2.20
               (1990).

               According  to Tucker, the System V panel library was first released
               in SVr3.2 (1988), and his implementation  helped  with  a  port  to
               SVr3.1 (1987).

               Several  developers have improved each of these; they are no longer
               the same as Tucker's implementation.

           o   NetBSD 8 (2018) has a panel library  begun  by  Valery  Ushakov  in
               2015, based on the System V documentation.

## AUTHORS

           Warren   Tucker   <wht@n4hgf.mt-park.ga.us>   originally   wrote   this
           implementation, primarily to  assist  in  porting  u386mon  to  systems
           without a native panel library.

           Zeyd ben-Halim repackaged it for ncurses.

           Juergen Pfeifer and Thomas E. Dickey revised and improved the library.

## SEE ALSO

           curses(3x), curs_variables(3x)

    ncurses 6.4                       2023-12-23                         panel(3x)