Back to index

tetex-bin  3.0
Functions
lib_scroll.c File Reference
#include <curses.priv.h>

Go to the source code of this file.

Functions

 _nc_scroll_window (WINDOW *win, int const n, NCURSES_SIZE_T const top, NCURSES_SIZE_T const bottom, NCURSES_CH_T blank)
 wscrl (WINDOW *win, int n)

Function Documentation

_nc_scroll_window ( WINDOW win,
int const  n,
NCURSES_SIZE_T const  top,
NCURSES_SIZE_T const  bottom,
NCURSES_CH_T  blank 
)

Definition at line 49 of file lib_scroll.c.

{
    int limit;
    int line;
    int j;
    size_t to_copy = (size_t) (sizeof(NCURSES_CH_T) * (win->_maxx + 1));

    TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top, bottom));

    if (top < 0
       || bottom < top
       || bottom > win->_maxy) {
       TR(TRACE_MOVE, ("nothing to scroll"));
       return;
    }

    /*
     * This used to do a line-text pointer-shuffle instead of text copies.
     * That (a) doesn't work when the window is derived and doesn't have
     * its own storage, (b) doesn't save you a lot on modern machines
     * anyway.  Your typical memcpy implementations are coded in
     * assembler using a tight BLT loop; for the size of copies we're
     * talking here, the total execution time is dominated by the one-time
     * setup cost.  So there is no point in trying to be excessively
     * clever -- esr.
     */

    /* shift n lines downwards */
    if (n < 0) {
       limit = top - n;
       for (line = bottom; line >= limit && line >= 0; line--) {
           TR(TRACE_MOVE, ("...copying %d to %d", line + n, line));
           memcpy(win->_line[line].text,
                 win->_line[line + n].text,
                 to_copy);
           if_USE_SCROLL_HINTS(win->_line[line].oldindex =
                            win->_line[line + n].oldindex);
       }
       for (line = top; line < limit && line <= win->_maxy; line++) {
           TR(TRACE_MOVE, ("...filling %d", line));
           for (j = 0; j <= win->_maxx; j++)
              win->_line[line].text[j] = blank;
           if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
       }
    }

    /* shift n lines upwards */
    if (n > 0) {
       limit = bottom - n;
       for (line = top; line <= limit && line <= win->_maxy; line++) {
           memcpy(win->_line[line].text,
                 win->_line[line + n].text,
                 to_copy);
           if_USE_SCROLL_HINTS(win->_line[line].oldindex =
                            win->_line[line + n].oldindex);
       }
       for (line = bottom; line > limit && line >= 0; line--) {
           for (j = 0; j <= win->_maxx; j++)
              win->_line[line].text[j] = blank;
           if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX);
       }
    }
    touchline(win, top, bottom - top + 1);
}

Here is the call graph for this function:

Here is the caller graph for this function:

wscrl ( WINDOW win,
int  n 
)

Definition at line 116 of file lib_scroll.c.

{
    T((T_CALLED("wscrl(%p,%d)"), win, n));

    if (!win || !win->_scroll) {
       TR(TRACE_MOVE, ("...scrollok is false"));
       returnCode(ERR);
    }

    if (n != 0) {
       _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd);
       _nc_synchook(win);
    }
    returnCode(OK);
}

Here is the call graph for this function:

Here is the caller graph for this function: