panel(3X)

NAME
panel - manage overlapping curses windows

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 ERR if mvwin returns ERR.

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
curses(3X), curs_variables(3X)