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curs_overlay 3x 2025-01-18 ncurses 6.5 Library calls

curs_overlay(3x)                 Library calls                curs_overlay(3x)

NAME

       overlay,  overwrite,  copywin  -  overlay curses windows and manipulate
       them

SYNOPSIS

       #include <curses.h>

       int overlay(const WINDOW *srcwin, WINDOW *dstwin);
       int overwrite(const WINDOW *srcwin, WINDOW *dstwin);
       int copywin(const WINDOW *srcwin, WINDOW *dstwin, int sminrow,
             int smincol, int dminrow, int dmincol, int dmaxrow,
             int dmaxcol, int overlay);

DESCRIPTION

overlay, overwrite

       The overlay and overwrite routines overlay srcwin  on  top  of  dstwin.
       scrwin and dstwin are not required to be the same size; only text where
       the two windows overlap is copied.  The difference is that  overlay  is
       non-destructive   (blanks   are   not   copied)  whereas  overwrite  is
       destructive.

copywin

       The copywin routine provides a finer granularity of  control  over  the
       overlay  and  overwrite  routines.   As  in  the  prefresh  routine,  a
       rectangle is specified in the destination  window,  (dminrow,  dmincol)
       and  (dmaxrow,  dmaxcol),  and the upper-left-corner coordinates of the
       source window, (sminrow, smincol).  If the argument  overlay  is  true,
       then copying is non-destructive, as in overlay.

RETURN VALUE

       These functions return OK on success and ERR on failure.

       In ncurses, they return ERR if

       o   either of the window pointers are null, or

       o   any part of the window would be placed off-screen.

NOTES

       overlay and overwrite may be implemented as macros.

PORTABILITY

       X/Open Curses Issue 4 describes these functions.  It specifies no error
       conditions for them.  It adds const qualifiers to  the  arguments.   It
       further  specifies  their  behavior  in the presence of characters with
       multibyte renditions (not yet supported in this implementation).

       SVr4 describes a successful return value  only  as  "an  integer  value
       other than ERR".