1 /* @(#)wwscroll.c 8.1 (Berkeley) 6/6/93 */
2 /* $NetBSD: wwscroll.c,v 1.7 2003/08/07 11:17:44 agc Exp $ */
3
4 /*
5 * Copyright (c) 1983, 1993
6 * The Regents of the University of California. All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Edward Wang at The University of California, Berkeley.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <stdlib.h>
37
38 #include "ww.h"
39 #include "tt.h"
40 #include "xx.h"
41
42 void
wwscroll(struct ww * w,int n)43 wwscroll(struct ww *w, int n)
44 {
45 int dir;
46 int top;
47
48 if (n == 0)
49 return;
50 dir = n < 0 ? -1 : 1;
51 top = w->ww_b.t - n;
52 if (top > w->ww_w.t)
53 top = w->ww_w.t;
54 else if (top + w->ww_b.nr < w->ww_w.b)
55 top = w->ww_w.b - w->ww_b.nr;
56 n = abs(top - w->ww_b.t);
57 if (n < w->ww_i.nr) {
58 while (--n >= 0) {
59 (void) wwscroll1(w, w->ww_i.t, w->ww_i.b, dir, 0);
60 w->ww_buf += dir;
61 w->ww_b.t -= dir;
62 w->ww_b.b -= dir;
63 }
64 } else {
65 w->ww_buf -= top - w->ww_b.t;
66 w->ww_b.t = top;
67 w->ww_b.b = top + w->ww_b.nr;
68 wwredrawwin(w);
69 }
70 }
71
72 /*
73 * Scroll one line, between 'row1' and 'row2', in direction 'dir'.
74 * Don't adjust ww_scroll.
75 * And don't redraw 'leaveit' lines.
76 */
77 int
wwscroll1(struct ww * w,int row1,int row2,int dir,int leaveit)78 wwscroll1(struct ww *w, int row1, int row2, int dir, int leaveit)
79 {
80 int i;
81 int row1x, row2x;
82 int nvis;
83 int nvismax;
84 int scrolled = 0;
85
86 /*
87 * See how many lines on the screen are affected.
88 * And calculate row1x, row2x, and left at the same time.
89 */
90 for (i = row1; i < row2 && w->ww_nvis[i] == 0; i++)
91 ;
92 if (i >= row2) /* can't do any fancy stuff */
93 goto out;
94 row1x = i;
95 for (i = row2 - 1; i >= row1 && w->ww_nvis[i] == 0; i--)
96 ;
97 if (i <= row1x)
98 goto out; /* just one line is easy */
99 row2x = i + 1;
100
101 /*
102 * See how much of this window is visible.
103 */
104 nvismax = wwncol * (row2x - row1x);
105 nvis = 0;
106 for (i = row1x; i < row2x; i++)
107 nvis += w->ww_nvis[i];
108
109 /*
110 * If it's a good idea to scroll and the terminal can, then do it.
111 */
112 if (nvis < nvismax / 2)
113 goto no_scroll; /* not worth it */
114 if ((dir > 0 ? tt.tt_scroll_down == 0 : tt.tt_scroll_up == 0) ||
115 ((tt.tt_scroll_top != row1x || tt.tt_scroll_bot != row2x - 1) &&
116 tt.tt_setscroll == 0))
117 if (tt.tt_delline == 0 || tt.tt_insline == 0)
118 goto no_scroll;
119 xxscroll(dir, row1x, row2x);
120 scrolled = 1;
121 /*
122 * Fix up the old screen.
123 */
124 {
125 union ww_char *tmp;
126 union ww_char **cpp, **cqq;
127
128 if (dir > 0) {
129 cpp = &wwos[row1x];
130 cqq = cpp + 1;
131 tmp = *cpp;
132 for (i = row2x - row1x; --i > 0;)
133 *cpp++ = *cqq++;
134 *cpp = tmp;
135 } else {
136 cpp = &wwos[row2x];
137 cqq = cpp - 1;
138 tmp = *cqq;
139 for (i = row2x - row1x; --i > 0;)
140 *--cpp = *--cqq;
141 *cqq = tmp;
142 }
143 for (i = wwncol; --i >= 0;)
144 tmp++->c_w = ' ';
145 }
146
147 no_scroll:
148 /*
149 * Fix the new screen.
150 */
151 if (nvis == nvismax) {
152 /*
153 * Can shift whole lines.
154 */
155 if (dir > 0) {
156 {
157 union ww_char *tmp;
158 union ww_char **cpp, **cqq;
159
160 cpp = &wwns[row1x];
161 cqq = cpp + 1;
162 tmp = *cpp;
163 for (i = row2x - row1x; --i > 0;)
164 *cpp++ = *cqq++;
165 *cpp = tmp;
166 }
167 if (scrolled) {
168 char *p, *q;
169
170 p = &wwtouched[row1x];
171 q = p + 1;
172 for (i = row2x - row1x; --i > 0;)
173 *p++ = *q++;
174 *p |= WWU_TOUCHED;
175 } else {
176 char *p;
177
178 p = &wwtouched[row1x];
179 for (i = row2x - row1x; --i >= 0;)
180 *p++ |= WWU_TOUCHED;
181 }
182 wwredrawwin1(w, row1, row1x, dir);
183 wwredrawwin1(w, row2x - 1, row2 - leaveit, dir);
184 } else {
185 {
186 union ww_char *tmp;
187 union ww_char **cpp, **cqq;
188
189 cpp = &wwns[row2x];
190 cqq = cpp - 1;
191 tmp = *cqq;
192 for (i = row2x - row1x; --i > 0;)
193 *--cpp = *--cqq;
194 *cqq = tmp;
195 }
196 if (scrolled) {
197 char *p, *q;
198
199 p = &wwtouched[row2x];
200 q = p - 1;
201 for (i = row2x - row1x; --i > 0;)
202 *--p = *--q;
203 *q |= WWU_TOUCHED;
204 } else {
205 char *p;
206
207 p = &wwtouched[row1x];
208 for (i = row2x - row1x; --i >= 0;)
209 *p++ |= WWU_TOUCHED;
210 }
211 wwredrawwin1(w, row1 + leaveit, row1x + 1, dir);
212 wwredrawwin1(w, row2x, row2, dir);
213 }
214 } else {
215 if (scrolled) {
216 char *p;
217
218 p = &wwtouched[row1x];
219 for (i = row2x - row1x; --i >= 0;)
220 *p++ |= WWU_TOUCHED;
221 }
222 out:
223 if (dir > 0)
224 wwredrawwin1(w, row1, row2 - leaveit, dir);
225 else
226 wwredrawwin1(w, row1 + leaveit, row2, dir);
227 }
228 return scrolled;
229 }
230