# panel 3x

    panel(3x)                                                            panel(3x)

## NAME

           panel - panel stack extension for curses

## SYNOPSIS

           #include <panel.h>

           cc [flags] sourcefiles -lpanel -lncurses

           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 feature of depth.  Panel
           functions allow the use of stacked windows and ensure the  proper  por-
           tions  of  each  window and the curses stdscr window are hidden or dis-
           played 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 every panel.  The panel routines enable you
           to  create, move, hide, and show panels, as well as position a panel at
           any desired location in the stack.

           Panel routines are a functional layer added to  curses(3x),  make  only
           high-level curses calls, and work anywhere terminfo 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 deallo-
           cates 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 TRUE if the panel pan is in the panel stack,
           FALSE if it is not.  If the panel is a null pointer, return 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, for example if 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 COMPATIBILITY below.

### top_panel

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

## DIAGNOSTICS

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

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

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

## COMPATIBILITY

           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  is  unchanged).   The
           PANEL  data  structures  are  merely  similar.  The  programmer is cau-
           tioned not to directly use PANEL fields.

           The functions show_panel and top_panel are identical in this  implemen-
           tation,  and work equally well with displayed or hidden panels.  In the
           native 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 compat-
           ibility with native panel libraries.

## NOTE

           In your library list, libpanel.a should be  before  libncurses.a;  that
           is, you should say "-lpanel -lncurses", not the other way around (which
           would give a link-error with static libraries).

## PORTABILITY

           The panel facility was documented in SVr4.2 in Character User Interface
           Programming (UNIX SVR4.2).

           It is not part of X/Open Curses.

           A few implementations exist:

           o   Systems  based  on  SVr4  source  code, e.g., 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 was a public
               domain implementation by Warren Tucker published  in  u386mon  2.20
               (1990).

               According  to  Tucker, the SystemV 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.  This is based on the AT&T documentation.

## FILES

           panel.h interface for the panels library

           libpanel.a the panels library itself

## SEE ALSO

           curses(3x), curs_variables(3x),

           This describes ncurses version 6.2 (patch 20201107).

## AUTHOR

           Originally  written by Warren Tucker <wht@n4hgf.mt-park.ga.us>, primar-
           ily to assist in porting u386mon to systems  without  a  native  panels
           library.

           Repackaged for ncurses by Zeyd ben-Halim.

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

                                                                         panel(3x)