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(3NCURSES), 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(3NCURSES)  to  refresh  the  physical  screen.   Use  this  function  and  not
       wrefresh(3NCURSES) or wnoutrefresh(3NCURSES).

       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(3NCURSES), 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)