lib/curses/winscrol.c

   1 /****************************************************************/
   2 /* Scroll() routine of the PCcurses package                     */
   3 /*                                                              */
   4 /****************************************************************/
   5 /* This version of curses is based on ncurses, a curses version */
   6 /* Originally written by Pavel Curtis at Cornell University.    */
   7 /* I have made substantial changes to make it run on IBM PC's,  */
   8 /* And therefore consider myself free to make it public domain. */
   9 /*              Bjorn Larsson (...mcvax!enea!infovax!bl)        */
  10 /****************************************************************/
  11 /* 1.0: Release:                                        870515  */
  12 /****************************************************************/
  13 /* Modified to run under the MINIX operating system by Don Cope */
  14 /* These changes are also released into the public domain.      */
  15 /*                                                      900906  */
  16 /****************************************************************/
  17
  18 #include <curses.h>
  19 #include "curspriv.h"
  20
  21 /****************************************************************/
  22 /* Scroll() scrolls the scrolling region of 'win', but only if  */
  23 /* Scrolling is allowed and if the cursor is inside the scrol-  */
  24 /* Ling region.                                                 */
  25 /****************************************************************/
  26
  27 void scroll(win)
  28 WINDOW *win;
  29 {
  30   int i;
  31   int *ptr;
  32   int *temp;
  33   static int blank;
  34
  35   blank = ' ' | (win->_attrs & ATR_MSK);
  36   if ((!win->_scroll)           /* check if window scrolls */
  37       ||(win->_cury < win->_regtop)     /* and cursor in region */
  38       ||(win->_cury > win->_regbottom)
  39         )
  40         return;
  41
  42   temp = win->_line[win->_regtop];
  43   for (i = win->_regtop; i < win->_regbottom; i++) {
  44         win->_line[i] = win->_line[i + 1];      /* re-arrange line pointers */
  45         win->_minchng[i] = 0;
  46         win->_maxchng[i] = win->_maxx;
  47   }
  48   for (ptr = temp; ptr - temp <= win->_maxx; ptr++)
  49         *ptr = blank;           /* make a blank line */
  50   win->_line[win->_regbottom] = temp;
  51   if (win->_cury > win->_regtop)/* if not on top line */
  52         win->_cury--;           /* cursor scrolls too */
  53   win->_minchng[win->_regbottom] = 0;
  54   win->_maxchng[win->_regbottom] = win->_maxx;
  55 }                               /* scroll */