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  ncurses(3NCURSES)  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(3NCURSES).   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:

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

       •   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.

       •   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

       ncurses(3NCURSES), curses_variables(3NCURSES)