window/wwscroll.c

   1 /*      $NetBSD: wwscroll.c,v 1.4 1997/11/21 08:37:48 lukem Exp $       */
   2
   3 /*
   4  * Copyright (c) 1983, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Edward Wang at The University of California, Berkeley.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  */
  38
  39 #include <sys/cdefs.h>
  40 #ifndef lint
  41 #if 0
  42 static char sccsid[] = "@(#)wwscroll.c  8.1 (Berkeley) 6/6/93";
  43 #else
  44 __RCSID("$NetBSD: wwscroll.c,v 1.4 1997/11/21 08:37:48 lukem Exp $");
  45 #endif
  46 #endif /* not lint */
  47
  48 #include "ww.h"
  49 #include "tt.h"
  50 #include "xx.h"
  51
  52 void
  53 wwscroll(w, n)
  54         struct ww *w;
  55         int n;
  56 {
  57         int dir;
  58         int top;
  59
  60         if (n == 0)
  61                 return;
  62         dir = n < 0 ? -1 : 1;
  63         top = w->ww_b.t - n;
  64         if (top > w->ww_w.t)
  65                 top = w->ww_w.t;
  66         else if (top + w->ww_b.nr < w->ww_w.b)
  67                 top = w->ww_w.b - w->ww_b.nr;
  68         n = abs(top - w->ww_b.t);
  69         if (n < w->ww_i.nr) {
  70                 while (--n >= 0) {
  71                         (void) wwscroll1(w, w->ww_i.t, w->ww_i.b, dir, 0);
  72                         w->ww_buf += dir;
  73                         w->ww_b.t -= dir;
  74                         w->ww_b.b -= dir;
  75                 }
  76         } else {
  77                 w->ww_buf -= top - w->ww_b.t;
  78                 w->ww_b.t = top;
  79                 w->ww_b.b = top + w->ww_b.nr;
  80                 wwredrawwin(w);
  81         }
  82 }
  83
  84 /*
  85  * Scroll one line, between 'row1' and 'row2', in direction 'dir'.
  86  * Don't adjust ww_scroll.
  87  * And don't redraw 'leaveit' lines.
  88  */
  89 int
  90 wwscroll1(w, row1, row2, dir, leaveit)
  91         struct ww *w;
  92         int row1, row2, dir;
  93         int leaveit;
  94 {
  95         int i;
  96         int row1x, row2x;
  97         int nvis;
  98         int nvismax;
  99         int scrolled = 0;
 100
 101         /*
 102          * See how many lines on the screen are affected.
 103          * And calculate row1x, row2x, and left at the same time.
 104          */
 105         for (i = row1; i < row2 && w->ww_nvis[i] == 0; i++)
 106                 ;
 107         if (i >= row2)                  /* can't do any fancy stuff */
 108                 goto out;
 109         row1x = i;
 110         for (i = row2 - 1; i >= row1 && w->ww_nvis[i] == 0; i--)
 111                 ;
 112         if (i <= row1x)
 113                 goto out;               /* just one line is easy */
 114         row2x = i + 1;
 115
 116         /*
 117          * See how much of this window is visible.
 118          */
 119         nvismax = wwncol * (row2x - row1x);
 120         nvis = 0;
 121         for (i = row1x; i < row2x; i++)
 122                 nvis += w->ww_nvis[i];
 123
 124         /*
 125          * If it's a good idea to scroll and the terminal can, then do it.
 126          */
 127         if (nvis < nvismax / 2)
 128                 goto no_scroll;         /* not worth it */
 129         if ((dir > 0 ? tt.tt_scroll_down == 0 : tt.tt_scroll_up == 0) ||
 130             ((tt.tt_scroll_top != row1x || tt.tt_scroll_bot != row2x - 1) &&
 131             tt.tt_setscroll == 0))
 132                 if (tt.tt_delline == 0 || tt.tt_insline == 0)
 133                         goto no_scroll;
 134         xxscroll(dir, row1x, row2x);
 135         scrolled = 1;
 136         /*
 137          * Fix up the old screen.
 138          */
 139         {
 140                 union ww_char *tmp;
 141                 union ww_char **cpp, **cqq;
 142
 143                 if (dir > 0) {
 144                         cpp = &wwos[row1x];
 145                         cqq = cpp + 1;
 146                         tmp = *cpp;
 147                         for (i = row2x - row1x; --i > 0;)
 148                                 *cpp++ = *cqq++;
 149                         *cpp = tmp;
 150                 } else {
 151                         cpp = &wwos[row2x];
 152                         cqq = cpp - 1;
 153                         tmp = *cqq;
 154                         for (i = row2x - row1x; --i > 0;)
 155                                 *--cpp = *--cqq;
 156                         *cqq = tmp;
 157                 }
 158                 for (i = wwncol; --i >= 0;)
 159                         tmp++->c_w = ' ';
 160         }
 161
 162 no_scroll:
 163         /*
 164          * Fix the new screen.
 165          */
 166         if (nvis == nvismax) {
 167                 /*
 168                  * Can shift whole lines.
 169                  */
 170                 if (dir > 0) {
 171                         {
 172                                 union ww_char *tmp;
 173                                 union ww_char **cpp, **cqq;
 174
 175                                 cpp = &wwns[row1x];
 176                                 cqq = cpp + 1;
 177                                 tmp = *cpp;
 178                                 for (i = row2x - row1x; --i > 0;)
 179                                         *cpp++ = *cqq++;
 180                                 *cpp = tmp;
 181                         }
 182                         if (scrolled) {
 183                                 char *p, *q;
 184
 185                                 p = &wwtouched[row1x];
 186                                 q = p + 1;
 187                                 for (i = row2x - row1x; --i > 0;)
 188                                         *p++ = *q++;
 189                                 *p |= WWU_TOUCHED;
 190                         } else {
 191                                 char *p;
 192
 193                                 p = &wwtouched[row1x];
 194                                 for (i = row2x - row1x; --i >= 0;)
 195                                         *p++ |= WWU_TOUCHED;
 196                         }
 197                         wwredrawwin1(w, row1, row1x, dir);
 198                         wwredrawwin1(w, row2x - 1, row2 - leaveit, dir);
 199                 } else {
 200                         {
 201                                 union ww_char *tmp;
 202                                 union ww_char **cpp, **cqq;
 203
 204                                 cpp = &wwns[row2x];
 205                                 cqq = cpp - 1;
 206                                 tmp = *cqq;
 207                                 for (i = row2x - row1x; --i > 0;)
 208                                         *--cpp = *--cqq;
 209                                 *cqq = tmp;
 210                         }
 211                         if (scrolled) {
 212                                 char *p, *q;
 213
 214                                 p = &wwtouched[row2x];
 215                                 q = p - 1;
 216                                 for (i = row2x - row1x; --i > 0;)
 217                                         *--p = *--q;
 218                                 *q |= WWU_TOUCHED;
 219                         } else {
 220                                 char *p;
 221
 222                                 p = &wwtouched[row1x];
 223                                 for (i = row2x - row1x; --i >= 0;)
 224                                         *p++ |= WWU_TOUCHED;
 225                         }
 226                         wwredrawwin1(w, row1 + leaveit, row1x + 1, dir);
 227                         wwredrawwin1(w, row2x, row2, dir);
 228                 }
 229         } else {
 230                 if (scrolled) {
 231                         char *p;
 232
 233                         p = &wwtouched[row1x];
 234                         for (i = row2x - row1x; --i >= 0;)
 235                                 *p++ |= WWU_TOUCHED;
 236                 }
 237 out:
 238                 if (dir > 0)
 239                         wwredrawwin1(w, row1, row2 - leaveit, dir);
 240                 else
 241                         wwredrawwin1(w, row1 + leaveit, row2, dir);
 242         }
 243         return scrolled;
 244 }