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	st-scrollback-reflow-0.9.diff (37402B)
	---
	1 diff --git a/st.c b/st.c
	2 index 79ee9ba..5170cd4 100644
	3 --- a/st.c
	4 +++ b/st.c
	5 @@ -36,6 +36,7 @@
	6 #define STR_BUF_SIZ ESC_BUF_SIZ
	7 #define STR_ARG_SIZ ESC_ARG_SIZ
	8 #define HISTSIZE 2000
	9 +#define RESIZEBUFFER 1000
	10
	11 /* macros */
	12 #define IS_SET(flag) ((term.mode & (flag)) != 0)
	13 @@ -43,9 +44,22 @@
	14 #define ISCONTROLC1(c) (BETWEEN(c, 0x80, 0x9f))
	15 #define ISCONTROL(c) (ISCONTROLC0(c) \|\| ISCONTROLC1(c))
	16 #define ISDELIM(u) (u && wcschr(worddelimiters, u))
	17 -#define TLINE(y) ((y) < term.scr ? term.hist[((y) + term…
	18 - term.scr + HISTSIZE + 1) % HISTSIZE] : \
	19 - term.line[(y) - term.scr])
	20 +
	21 +#define TLINE(y) ( \
	22 + (y) < term.scr ? term.hist[(term.histi + (y) - term.scr + 1 + H…
	23 + : term.line[(y) - term.scr] \
	24 +)
	25 +
	26 +#define TLINEABS(y) ( \
	27 + (y) < 0 ? term.hist[(term.histi + (y) + 1 + HISTSIZE) % HISTSIZ…
	28 +)
	29 +
	30 +#define UPDATEWRAPNEXT(alt, col) do { \
	31 + if ((term.c.state & CURSOR_WRAPNEXT) && term.c.x + term.wrapcwi…
	32 + term.c.x += term.wrapcwidth[alt]; \
	33 + term.c.state &= ~CURSOR_WRAPNEXT; \
	34 + } \
	35 +} while (0);
	36
	37 enum term_mode {
	38 MODE_WRAP = 1 << 0,
	39 @@ -57,6 +71,12 @@ enum term_mode {
	40 MODE_UTF8 = 1 << 6,
	41 };
	42
	43 +enum scroll_mode {
	44 + SCROLL_RESIZE = -1,
	45 + SCROLL_NOSAVEHIST = 0,
	46 + SCROLL_SAVEHIST = 1
	47 +};
	48 +
	49 enum cursor_movement {
	50 CURSOR_SAVE,
	51 CURSOR_LOAD
	52 @@ -118,10 +138,11 @@ typedef struct {
	53 int row; /* nb row */
	54 int col; /* nb col */
	55 Line line; / screen */
	56 - Line alt; / alternate screen */
	57 Line hist[HISTSIZE]; /* history buffer */
	58 - int histi; /* history index */
	59 - int scr; /* scroll back */
	60 + int histi; /* history index */
	61 + int histf; /* nb history available */
	62 + int scr; /* scroll back */
	63 + int wrapcwidth[2]; /* used in updating WRAPNEXT when resizing…
	64 int dirty; / dirtyness of lines */
	65 TCursor c; /* cursor */
	66 int ocx; /* old cursor col */
	67 @@ -179,26 +200,37 @@ static void tprinter(char *, size_t);
	68 static void tdumpsel(void);
	69 static void tdumpline(int);
	70 static void tdump(void);
	71 -static void tclearregion(int, int, int, int);
	72 +static void tclearregion(int, int, int, int, int);
	73 static void tcursor(int);
	74 +static void tclearglyph(Glyph *, int);
	75 +static void tresetcursor(void);
	76 static void tdeletechar(int);
	77 static void tdeleteline(int);
	78 static void tinsertblank(int);
	79 static void tinsertblankline(int);
	80 -static int tlinelen(int);
	81 +static int tlinelen(Line len);
	82 +static int tiswrapped(Line line);
	83 +static char tgetglyphs(char , const Glyph , const Glyph );
	84 +static size_t tgetline(char , const Glyph );
	85 static void tmoveto(int, int);
	86 static void tmoveato(int, int);
	87 static void tnewline(int);
	88 static void tputtab(int);
	89 static void tputc(Rune);
	90 static void treset(void);
	91 -static void tscrollup(int, int, int);
	92 -static void tscrolldown(int, int, int);
	93 +static void tscrollup(int, int, int, int);
	94 +static void tscrolldown(int, int);
	95 +static void treflow(int, int);
	96 +static void rscrolldown(int);
	97 +static void tresizedef(int, int);
	98 +static void tresizealt(int, int);
	99 static void tsetattr(const int *, int);
	100 static void tsetchar(Rune, const Glyph *, int, int);
	101 static void tsetdirt(int, int);
	102 static void tsetscroll(int, int);
	103 static void tswapscreen(void);
	104 +static void tloaddefscreen(int, int);
	105 +static void tloadaltscreen(int, int);
	106 static void tsetmode(int, int, const int *, int);
	107 static int twrite(const char *, int, int);
	108 static void tfulldirt(void);
	109 @@ -212,7 +244,10 @@ static void tstrsequence(uchar);
	110 static void drawregion(int, int, int, int);
	111
	112 static void selnormalize(void);
	113 -static void selscroll(int, int);
	114 +static void selscroll(int, int, int);
	115 +static void selmove(int);
	116 +static void selremove(void);
	117 +static int regionselected(int, int, int, int);
	118 static void selsnap(int , int , int);
	119
	120 static size_t utf8decode(const char , Rune , size_t);
	121 @@ -412,17 +447,46 @@ selinit(void)
	122 }
	123
	124 int
	125 -tlinelen(int y)
	126 +tlinelen(Line line)
	127 {
	128 - int i = term.col;
	129 + int i = term.col - 1;
	130 +
	131 + for (; i >= 0 && !(line[i].mode & (ATTR_SET \| ATTR_WRAP)); i--);
	132 + return i + 1;
	133 +}
	134
	135 - if (TLINE(y)[i - 1].mode & ATTR_WRAP)
	136 - return i;
	137 +int
	138 +tiswrapped(Line line)
	139 +{
	140 + int len = tlinelen(line);
	141
	142 - while (i > 0 && TLINE(y)[i - 1].u == ' ')
	143 - --i;
	144 + return len > 0 && (line[len - 1].mode & ATTR_WRAP);
	145 +}
	146
	147 - return i;
	148 +char *
	149 +tgetglyphs(char buf, const Glyph gp, const Glyph *lgp)
	150 +{
	151 + while (gp <= lgp)
	152 + if (gp->mode & ATTR_WDUMMY) {
	153 + gp++;
	154 + } else {
	155 + buf += utf8encode((gp++)->u, buf);
	156 + }
	157 + return buf;
	158 +}
	159 +
	160 +size_t
	161 +tgetline(char buf, const Glyph fgp)
	162 +{
	163 + char *ptr;
	164 + const Glyph *lgp = &fgp[term.col - 1];
	165 +
	166 + while (lgp > fgp && !(lgp->mode & (ATTR_SET \| ATTR_WRAP)))
	167 + lgp--;
	168 + ptr = tgetglyphs(buf, fgp, lgp);
	169 + if (!(lgp->mode & ATTR_WRAP))
	170 + *(ptr++) = '\n';
	171 + return ptr - buf;
	172 }
	173
	174 void
	175 @@ -462,10 +526,11 @@ selextend(int col, int row, int type, int done)
	176
	177 sel.oe.x = col;
	178 sel.oe.y = row;
	179 - selnormalize();
	180 sel.type = type;
	181 + selnormalize();
	182
	183 - if (oldey != sel.oe.y \|\| oldex != sel.oe.x \|\| oldtype != sel.ty…
	184 + if (oldey != sel.oe.y \|\| oldex != sel.oe.x \|\|
	185 + oldtype != sel.type \|\| sel.mode == SEL_EMPTY)
	186 tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
	187
	188 sel.mode = done ? SEL_IDLE : SEL_READY;
	189 @@ -492,36 +557,43 @@ selnormalize(void)
	190 /* expand selection over line breaks */
	191 if (sel.type == SEL_RECTANGULAR)
	192 return;
	193 - i = tlinelen(sel.nb.y);
	194 - if (i < sel.nb.x)
	195 +
	196 + i = tlinelen(TLINE(sel.nb.y));
	197 + if (sel.nb.x > i)
	198 sel.nb.x = i;
	199 - if (tlinelen(sel.ne.y) <= sel.ne.x)
	200 - sel.ne.x = term.col - 1;
	201 + if (sel.ne.x >= tlinelen(TLINE(sel.ne.y)))
	202 + sel.ne.x = term.col - 1;
	203 }
	204
	205 int
	206 -selected(int x, int y)
	207 +regionselected(int x1, int y1, int x2, int y2)
	208 {
	209 - if (sel.mode == SEL_EMPTY \|\| sel.ob.x == -1 \|\|
	210 - sel.alt != IS_SET(MODE_ALTSCREEN))
	211 + if (sel.ob.x == -1 \|\| sel.mode == SEL_EMPTY \|\|
	212 + sel.alt != IS_SET(MODE_ALTSCREEN) \|\| sel.nb.y > y2 \|\| sel.n…
	213 return 0;
	214
	215 - if (sel.type == SEL_RECTANGULAR)
	216 - return BETWEEN(y, sel.nb.y, sel.ne.y)
	217 - && BETWEEN(x, sel.nb.x, sel.ne.x);
	218 + return (sel.type == SEL_RECTANGULAR) ? sel.nb.x <= x2 && sel.ne…
	219 + : (sel.nb.y != y2 \|\| sel.nb.x <= x2) &&
	220 + (sel.ne.y != y1 \|\| sel.ne.x >= x1);
	221 +}
	222
	223 - return BETWEEN(y, sel.nb.y, sel.ne.y)
	224 - && (y != sel.nb.y \|\| x >= sel.nb.x)
	225 - && (y != sel.ne.y \|\| x <= sel.ne.x);
	226 +int
	227 +selected(int x, int y)
	228 +{
	229 + return regionselected(x, y, x, y);
	230 }
	231
	232 void
	233 selsnap(int x, int y, int direction)
	234 {
	235 int newx, newy, xt, yt;
	236 + int rtop = 0, rbot = term.row - 1;
	237 int delim, prevdelim;
	238 const Glyph gp, prevgp;
	239
	240 + if (!IS_SET(MODE_ALTSCREEN))
	241 + rtop += -term.histf + term.scr, rbot += term.scr;
	242 +
	243 switch (sel.snap) {
	244 case SNAP_WORD:
	245 /*
	246 @@ -536,7 +608,7 @@ selsnap(int x, int y, int direction)
	247 if (!BETWEEN(newx, 0, term.col - 1)) {
	248 newy += direction;
	249 newx = (newx + term.col) % term.col;
	250 - if (!BETWEEN(newy, 0, term.row - 1))
	251 + if (!BETWEEN(newy, rtop, rbot))
	252 break;
	253
	254 if (direction > 0)
	255 @@ -547,13 +619,13 @@ selsnap(int x, int y, int direction)
	256 break;
	257 }
	258
	259 - if (newx >= tlinelen(newy))
	260 + if (newx >= tlinelen(TLINE(newy)))
	261 break;
	262
	263 gp = &TLINE(newy)[newx];
	264 delim = ISDELIM(gp->u);
	265 - if (!(gp->mode & ATTR_WDUMMY) && (delim != prev…
	266 - \|\| (delim && gp->u != prevgp->u…
	267 + if (!(gp->mode & ATTR_WDUMMY) && (delim != prev…
	268 + (delim && !(gp->u == ' ' && prevgp->u == ' …
	269 break;
	270
	271 *x = newx;
	272 @@ -570,18 +642,14 @@ selsnap(int x, int y, int direction)
	273 */
	274 *x = (direction < 0) ? 0 : term.col - 1;
	275 if (direction < 0) {
	276 - for (; y > 0; y += direction) {
	277 - if (!(TLINE(*y-1)[term.col-1].mode
	278 - & ATTR_WRAP)) {
	279 + for (; y > rtop; y -= 1) {
	280 + if (!tiswrapped(TLINE(*y-1)))
	281 break;
	282 - }
	283 }
	284 } else if (direction > 0) {
	285 - for (; y < term.row-1; y += direction) {
	286 - if (!(TLINE(*y)[term.col-1].mode
	287 - & ATTR_WRAP)) {
	288 + for (; y < rbot; y += 1) {
	289 + if (!tiswrapped(TLINE(*y)))
	290 break;
	291 - }
	292 }
	293 }
	294 break;
	295 @@ -592,40 +660,34 @@ char *
	296 getsel(void)
	297 {
	298 char str, ptr;
	299 - int y, bufsize, lastx, linelen;
	300 - const Glyph gp, last;
	301 + int y, lastx, linelen;
	302 + const Glyph gp, lgp;
	303
	304 - if (sel.ob.x == -1)
	305 + if (sel.ob.x == -1 \|\| sel.alt != IS_SET(MODE_ALTSCREEN))
	306 return NULL;
	307
	308 - bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
	309 - ptr = str = xmalloc(bufsize);
	310 + str = xmalloc((term.col + 1) * (sel.ne.y - sel.nb.y + 1) * UTF_…
	311 + ptr = str;
	312
	313 /* append every set & selected glyph to the selection */
	314 for (y = sel.nb.y; y <= sel.ne.y; y++) {
	315 - if ((linelen = tlinelen(y)) == 0) {
	316 + Line line = TLINE(y);
	317 +
	318 + if ((linelen = tlinelen(line)) == 0) {
	319 *ptr++ = '\n';
	320 continue;
	321 }
	322
	323 if (sel.type == SEL_RECTANGULAR) {
	324 - gp = &TLINE(y)[sel.nb.x];
	325 + gp = &line[sel.nb.x];
	326 lastx = sel.ne.x;
	327 } else {
	328 - gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
	329 + gp = &line[sel.nb.y == y ? sel.nb.x : 0];
	330 lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
	331 }
	332 - last = &TLINE(y)[MIN(lastx, linelen-1)];
	333 - while (last >= gp && last->u == ' ')
	334 - --last;
	335 -
	336 - for ( ; gp <= last; ++gp) {
	337 - if (gp->mode & ATTR_WDUMMY)
	338 - continue;
	339 -
	340 - ptr += utf8encode(gp->u, ptr);
	341 - }
	342 + lgp = &line[MIN(lastx, linelen-1)];
	343
	344 + ptr = tgetglyphs(ptr, gp, lgp);
	345 /*
	346 * Copy and pasting of line endings is inconsistent
	347 * in the inconsistent terminal and GUI world.
	348 @@ -636,10 +698,10 @@ getsel(void)
	349 * FIXME: Fix the computer world.
	350 */
	351 if ((y < sel.ne.y \|\| lastx >= linelen) &&
	352 - (!(last->mode & ATTR_WRAP) \|\| sel.type == SEL_RECTA…
	353 + (!(lgp->mode & ATTR_WRAP) \|\| sel.type == SEL_RECTAN…
	354 *ptr++ = '\n';
	355 }
	356 - *ptr = 0;
	357 + *ptr = '\0';
	358 return str;
	359 }
	360
	361 @@ -648,9 +710,15 @@ selclear(void)
	362 {
	363 if (sel.ob.x == -1)
	364 return;
	365 + selremove();
	366 + tsetdirt(sel.nb.y, sel.ne.y);
	367 +}
	368 +
	369 +void
	370 +selremove(void)
	371 +{
	372 sel.mode = SEL_IDLE;
	373 sel.ob.x = -1;
	374 - tsetdirt(sel.nb.y, sel.ne.y);
	375 }
	376
	377 void
	378 @@ -851,10 +919,8 @@ void
	379 ttywrite(const char *s, size_t n, int may_echo)
	380 {
	381 const char *next;
	382 - Arg arg = (Arg) { .i = term.scr };
	383 -
	384 - kscrolldown(&arg);
	385
	386 + kscrolldown(&((Arg){ .i = term.scr }));
	387 if (may_echo && IS_SET(MODE_ECHO))
	388 twrite(s, n, 1);
	389
	390 @@ -990,7 +1056,7 @@ tsetdirtattr(int attr)
	391 for (i = 0; i < term.row-1; i++) {
	392 for (j = 0; j < term.col-1; j++) {
	393 if (term.line[i][j].mode & attr) {
	394 - tsetdirt(i, i);
	395 + term.dirty[i] = 1;
	396 break;
	397 }
	398 }
	399 @@ -1000,7 +1066,8 @@ tsetdirtattr(int attr)
	400 void
	401 tfulldirt(void)
	402 {
	403 - tsetdirt(0, term.row-1);
	404 + for (int i = 0; i < term.row; i++)
	405 + term.dirty[i] = 1;
	406 }
	407
	408 void
	409 @@ -1017,51 +1084,116 @@ tcursor(int mode)
	410 }
	411 }
	412
	413 +void
	414 +tresetcursor(void)
	415 +{
	416 + term.c = (TCursor){ { .mode = ATTR_NULL, .fg = defaultfg, .bg =…
	417 + .x = 0, .y = 0, .state = CURSOR_DEFAULT };
	418 +}
	419 +
	420 void
	421 treset(void)
	422 {
	423 uint i;
	424 + int x, y;
	425
	426 - term.c = (TCursor){{
	427 - .mode = ATTR_NULL,
	428 - .fg = defaultfg,
	429 - .bg = defaultbg
	430 - }, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
	431 + tresetcursor();
	432
	433 memset(term.tabs, 0, term.col * sizeof(*term.tabs));
	434 for (i = tabspaces; i < term.col; i += tabspaces)
	435 term.tabs[i] = 1;
	436 term.top = 0;
	437 + term.histf = 0;
	438 + term.scr = 0;
	439 term.bot = term.row - 1;
	440 term.mode = MODE_WRAP\|MODE_UTF8;
	441 memset(term.trantbl, CS_USA, sizeof(term.trantbl));
	442 term.charset = 0;
	443
	444 + selremove();
	445 for (i = 0; i < 2; i++) {
	446 - tmoveto(0, 0);
	447 - tcursor(CURSOR_SAVE);
	448 - tclearregion(0, 0, term.col-1, term.row-1);
	449 + tcursor(CURSOR_SAVE); /* reset saved cursor */
	450 + for (y = 0; y < term.row; y++)
	451 + for (x = 0; x < term.col; x++)
	452 + tclearglyph(&term.line[y][x], 0);
	453 tswapscreen();
	454 }
	455 + tfulldirt();
	456 }
	457
	458 void
	459 tnew(int col, int row)
	460 {
	461 - term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultb…
	462 - tresize(col, row);
	463 - treset();
	464 + int i, j;
	465 +
	466 + for (i = 0; i < 2; i++) {
	467 + term.line = xmalloc(row * sizeof(Line));
	468 + for (j = 0; j < row; j++)
	469 + term.line[j] = xmalloc(col * sizeof(Glyph));
	470 + term.col = col, term.row = row;
	471 + tswapscreen();
	472 + }
	473 + term.dirty = xmalloc(row * sizeof(*term.dirty));
	474 + term.tabs = xmalloc(col * sizeof(*term.tabs));
	475 + for (i = 0; i < HISTSIZE; i++)
	476 + term.hist[i] = xmalloc(col * sizeof(Glyph));
	477 + treset();
	478 }
	479
	480 +/* handle it with care */
	481 void
	482 tswapscreen(void)
	483 {
	484 - Line *tmp = term.line;
	485 + static Line *altline;
	486 + static int altcol, altrow;
	487 + Line *tmpline = term.line;
	488 + int tmpcol = term.col, tmprow = term.row;
	489
	490 - term.line = term.alt;
	491 - term.alt = tmp;
	492 + term.line = altline;
	493 + term.col = altcol, term.row = altrow;
	494 + altline = tmpline;
	495 + altcol = tmpcol, altrow = tmprow;
	496 term.mode ^= MODE_ALTSCREEN;
	497 - tfulldirt();
	498 +}
	499 +
	500 +void
	501 +tloaddefscreen(int clear, int loadcursor)
	502 +{
	503 + int col, row, alt = IS_SET(MODE_ALTSCREEN);
	504 +
	505 + if (alt) {
	506 + if (clear)
	507 + tclearregion(0, 0, term.col-1, term.row-1, 1);
	508 + col = term.col, row = term.row;
	509 + tswapscreen();
	510 + }
	511 + if (loadcursor)
	512 + tcursor(CURSOR_LOAD);
	513 + if (alt)
	514 + tresizedef(col, row);
	515 +}
	516 +
	517 +void
	518 +tloadaltscreen(int clear, int savecursor)
	519 +{
	520 + int col, row, def = !IS_SET(MODE_ALTSCREEN);
	521 +
	522 + if (savecursor)
	523 + tcursor(CURSOR_SAVE);
	524 + if (def) {
	525 + col = term.col, row = term.row;
	526 + tswapscreen();
	527 + term.scr = 0;
	528 + tresizealt(col, row);
	529 + }
	530 + if (clear)
	531 + tclearregion(0, 0, term.col-1, term.row-1, 1);
	532 +}
	533 +
	534 +int
	535 +tisaltscreen(void)
	536 +{
	537 + return IS_SET(MODE_ALTSCREEN);
	538 }
	539
	540 void
	541 @@ -1069,17 +1201,22 @@ kscrolldown(const Arg* a)
	542 {
	543 int n = a->i;
	544
	545 - if (n < 0)
	546 - n = term.row + n;
	547 + if (!term.scr \|\| IS_SET(MODE_ALTSCREEN))
	548 + return;
	549
	550 - if (n > term.scr)
	551 - n = term.scr;
	552 + if (n < 0)
	553 + n = MAX(term.row / -n, 1);
	554
	555 - if (term.scr > 0) {
	556 + if (n <= term.scr) {
	557 term.scr -= n;
	558 - selscroll(0, -n);
	559 - tfulldirt();
	560 + } else {
	561 + n = term.scr;
	562 + term.scr = 0;
	563 }
	564 +
	565 + if (sel.ob.x != -1 && !sel.alt)
	566 + selmove(-n); /* negate change in term.scr */
	567 + tfulldirt();
	568 }
	569
	570 void
	571 @@ -1087,92 +1224,118 @@ kscrollup(const Arg* a)
	572 {
	573 int n = a->i;
	574
	575 + if (!term.histf \|\| IS_SET(MODE_ALTSCREEN))
	576 + return;
	577 +
	578 if (n < 0)
	579 - n = term.row + n;
	580 + n = MAX(term.row / -n, 1);
	581
	582 - if (term.scr <= HISTSIZE-n) {
	583 + if (term.scr + n <= term.histf) {
	584 term.scr += n;
	585 - selscroll(0, n);
	586 - tfulldirt();
	587 + } else {
	588 + n = term.histf - term.scr;
	589 + term.scr = term.histf;
	590 }
	591 +
	592 + if (sel.ob.x != -1 && !sel.alt)
	593 + selmove(n); /* negate change in term.scr */
	594 + tfulldirt();
	595 }
	596
	597 void
	598 -tscrolldown(int orig, int n, int copyhist)
	599 +tscrolldown(int top, int n)
	600 {
	601 - int i;
	602 + int i, bot = term.bot;
	603 Line temp;
	604
	605 - LIMIT(n, 0, term.bot-orig+1);
	606 - if (copyhist) {
	607 - term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
	608 - temp = term.hist[term.histi];
	609 - term.hist[term.histi] = term.line[term.bot];
	610 - term.line[term.bot] = temp;
	611 - }
	612 -
	613 + if (n <= 0)
	614 + return;
	615 + n = MIN(n, bot-top+1);
	616
	617 - tsetdirt(orig, term.bot-n);
	618 - tclearregion(0, term.bot-n+1, term.col-1, term.bot);
	619 + tsetdirt(top, bot-n);
	620 + tclearregion(0, bot-n+1, term.col-1, bot, 1);
	621
	622 - for (i = term.bot; i >= orig+n; i--) {
	623 + for (i = bot; i >= top+n; i--) {
	624 temp = term.line[i];
	625 term.line[i] = term.line[i-n];
	626 term.line[i-n] = temp;
	627 }
	628
	629 - if (term.scr == 0)
	630 - selscroll(orig, n);
	631 + if (sel.ob.x != -1 && sel.alt == IS_SET(MODE_ALTSCREEN))
	632 + selscroll(top, bot, n);
	633 }
	634
	635 void
	636 -tscrollup(int orig, int n, int copyhist)
	637 +tscrollup(int top, int bot, int n, int mode)
	638 {
	639 - int i;
	640 + int i, j, s;
	641 + int alt = IS_SET(MODE_ALTSCREEN);
	642 + int savehist = !alt && top == 0 && mode != SCROLL_NOSAVEHIST;
	643 Line temp;
	644
	645 - LIMIT(n, 0, term.bot-orig+1);
	646 -
	647 - if (copyhist) {
	648 - term.histi = (term.histi + 1) % HISTSIZE;
	649 - temp = term.hist[term.histi];
	650 - term.hist[term.histi] = term.line[orig];
	651 - term.line[orig] = temp;
	652 + if (n <= 0)
	653 + return;
	654 + n = MIN(n, bot-top+1);
	655 +
	656 + if (savehist) {
	657 + for (i = 0; i < n; i++) {
	658 + term.histi = (term.histi + 1) % HISTSIZE;
	659 + temp = term.hist[term.histi];
	660 + for (j = 0; j < term.col; j++)
	661 + tclearglyph(&temp[j], 1);
	662 + term.hist[term.histi] = term.line[i];
	663 + term.line[i] = temp;
	664 + }
	665 + term.histf = MIN(term.histf + n, HISTSIZE);
	666 + s = n;
	667 + if (term.scr) {
	668 + j = term.scr;
	669 + term.scr = MIN(j + n, HISTSIZE);
	670 + s = j + n - term.scr;
	671 + }
	672 + if (mode != SCROLL_RESIZE)
	673 + tfulldirt();
	674 + } else {
	675 + tclearregion(0, top, term.col-1, top+n-1, 1);
	676 + tsetdirt(top+n, bot);
	677 }
	678
	679 - if (term.scr > 0 && term.scr < HISTSIZE)
	680 - term.scr = MIN(term.scr + n, HISTSIZE-1);
	681 -
	682 - tclearregion(0, orig, term.col-1, orig+n-1);
	683 - tsetdirt(orig+n, term.bot);
	684 -
	685 - for (i = orig; i <= term.bot-n; i++) {
	686 + for (i = top; i <= bot-n; i++) {
	687 temp = term.line[i];
	688 term.line[i] = term.line[i+n];
	689 term.line[i+n] = temp;
	690 }
	691
	692 - if (term.scr == 0)
	693 - selscroll(orig, -n);
	694 + if (sel.ob.x != -1 && sel.alt == alt) {
	695 + if (!savehist) {
	696 + selscroll(top, bot, -n);
	697 + } else if (s > 0) {
	698 + selmove(-s);
	699 + if (-term.scr + sel.nb.y < -term.histf)
	700 + selremove();
	701 + }
	702 + }
	703 }
	704
	705 void
	706 -selscroll(int orig, int n)
	707 +selmove(int n)
	708 {
	709 - if (sel.ob.x == -1)
	710 - return;
	711 + sel.ob.y += n, sel.nb.y += n;
	712 + sel.oe.y += n, sel.ne.y += n;
	713 +}
	714 +
	715 +void
	716 +selscroll(int top, int bot, int n)
	717 +{
	718 + /* turn absolute coordinates into relative */
	719 + top += term.scr, bot += term.scr;
	720
	721 - if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig…
	722 + if (BETWEEN(sel.nb.y, top, bot) != BETWEEN(sel.ne.y, top, bot))…
	723 selclear();
	724 - } else if (BETWEEN(sel.nb.y, orig, term.bot)) {
	725 - sel.ob.y += n;
	726 - sel.oe.y += n;
	727 - if (sel.ob.y < term.top \|\| sel.ob.y > term.bot \|\|
	728 - sel.oe.y < term.top \|\| sel.oe.y > term.bot) {
	729 + } else if (BETWEEN(sel.nb.y, top, bot)) {
	730 + selmove(n);
	731 + if (sel.nb.y < top \|\| sel.ne.y > bot)
	732 selclear();
	733 - } else {
	734 - selnormalize();
	735 - }
	736 }
	737 }
	738
	739 @@ -1182,7 +1345,7 @@ tnewline(int first_col)
	740 int y = term.c.y;
	741
	742 if (y == term.bot) {
	743 - tscrollup(term.top, 1, 1);
	744 + tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIST);
	745 } else {
	746 y++;
	747 }
	748 @@ -1272,89 +1435,93 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
	749 } else if (term.line[y][x].mode & ATTR_WDUMMY) {
	750 term.line[y][x-1].u = ' ';
	751 term.line[y][x-1].mode &= ~ATTR_WIDE;
	752 - }
	753 + }
	754
	755 term.dirty[y] = 1;
	756 term.line[y][x] = *attr;
	757 term.line[y][x].u = u;
	758 + term.line[y][x].mode \|= ATTR_SET;
	759 }
	760
	761 void
	762 -tclearregion(int x1, int y1, int x2, int y2)
	763 +tclearglyph(Glyph *gp, int usecurattr)
	764 {
	765 - int x, y, temp;
	766 - Glyph *gp;
	767 + if (usecurattr) {
	768 + gp->fg = term.c.attr.fg;
	769 + gp->bg = term.c.attr.bg;
	770 + } else {
	771 + gp->fg = defaultfg;
	772 + gp->bg = defaultbg;
	773 + }
	774 + gp->mode = ATTR_NULL;
	775 + gp->u = ' ';
	776 +}
	777
	778 - if (x1 > x2)
	779 - temp = x1, x1 = x2, x2 = temp;
	780 - if (y1 > y2)
	781 - temp = y1, y1 = y2, y2 = temp;
	782 +void
	783 +tclearregion(int x1, int y1, int x2, int y2, int usecurattr)
	784 +{
	785 + int x, y;
	786
	787 - LIMIT(x1, 0, term.col-1);
	788 - LIMIT(x2, 0, term.col-1);
	789 - LIMIT(y1, 0, term.row-1);
	790 - LIMIT(y2, 0, term.row-1);
	791 + /* regionselected() takes relative coordinates */
	792 + if (regionselected(x1+term.scr, y1+term.scr, x2+term.scr, y2+te…
	793 + selremove();
	794
	795 for (y = y1; y <= y2; y++) {
	796 term.dirty[y] = 1;
	797 - for (x = x1; x <= x2; x++) {
	798 - gp = &term.line[y][x];
	799 - if (selected(x, y))
	800 - selclear();
	801 - gp->fg = term.c.attr.fg;
	802 - gp->bg = term.c.attr.bg;
	803 - gp->mode = 0;
	804 - gp->u = ' ';
	805 - }
	806 + for (x = x1; x <= x2; x++)
	807 + tclearglyph(&term.line[y][x], usecurattr);
	808 }
	809 }
	810
	811 void
	812 tdeletechar(int n)
	813 {
	814 - int dst, src, size;
	815 - Glyph *line;
	816 -
	817 - LIMIT(n, 0, term.col - term.c.x);
	818 + int src, dst, size;
	819 + Line line;
	820
	821 + if (n <= 0)
	822 + return;
	823 dst = term.c.x;
	824 - src = term.c.x + n;
	825 + src = MIN(term.c.x + n, term.col);
	826 size = term.col - src;
	827 - line = term.line[term.c.y];
	828 -
	829 - memmove(&line[dst], &line[src], size * sizeof(Glyph));
	830 - tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
	831 + if (size > 0) { /* otherwise src would point beyond the array
	832 + https://stackoverflow.com/questions/29844298…
	833 + line = term.line[term.c.y];
	834 + memmove(&line[dst], &line[src], size * sizeof(Glyph));
	835 + }
	836 + tclearregion(dst + size, term.c.y, term.col - 1, term.c.y, 1);
	837 }
	838
	839 void
	840 tinsertblank(int n)
	841 {
	842 - int dst, src, size;
	843 - Glyph *line;
	844 -
	845 - LIMIT(n, 0, term.col - term.c.x);
	846 + int src, dst, size;
	847 + Line line;
	848
	849 - dst = term.c.x + n;
	850 + if (n <= 0)
	851 + return;
	852 + dst = MIN(term.c.x + n, term.col);
	853 src = term.c.x;
	854 size = term.col - dst;
	855 - line = term.line[term.c.y];
	856 -
	857 - memmove(&line[dst], &line[src], size * sizeof(Glyph));
	858 - tclearregion(src, term.c.y, dst - 1, term.c.y);
	859 + if (size > 0) { /* otherwise dst would point beyond the array */
	860 + line = term.line[term.c.y];
	861 + memmove(&line[dst], &line[src], size * sizeof(Glyph));
	862 + }
	863 + tclearregion(src, term.c.y, dst - 1, term.c.y, 1);
	864 }
	865
	866 void
	867 tinsertblankline(int n)
	868 {
	869 if (BETWEEN(term.c.y, term.top, term.bot))
	870 - tscrolldown(term.c.y, n, 0);
	871 + tscrolldown(term.c.y, n);
	872 }
	873
	874 void
	875 tdeleteline(int n)
	876 {
	877 if (BETWEEN(term.c.y, term.top, term.bot))
	878 - tscrollup(term.c.y, n, 0);
	879 + tscrollup(term.c.y, term.bot, n, SCROLL_NOSAVEHIST);
	880 }
	881
	882 int32_t
	883 @@ -1528,7 +1695,7 @@ tsetscroll(int t, int b)
	884 void
	885 tsetmode(int priv, int set, const int *args, int narg)
	886 {
	887 - int alt; const int *lim;
	888 + const int *lim;
	889
	890 for (lim = args + narg; args < lim; ++args) {
	891 if (priv) {
	892 @@ -1589,25 +1756,18 @@ tsetmode(int priv, int set, const int *args, int…
	893 xsetmode(set, MODE_8BIT);
	894 break;
	895 case 1049: /* swap screen & set/restore cursor …
	896 - if (!allowaltscreen)
	897 - break;
	898 - tcursor((set) ? CURSOR_SAVE : CURSOR_LO…
	899 - /* FALLTHROUGH */
	900 case 47: /* swap screen */
	901 - case 1047:
	902 + case 1047: /* swap screen, clearing alternate s…
	903 if (!allowaltscreen)
	904 break;
	905 - alt = IS_SET(MODE_ALTSCREEN);
	906 - if (alt) {
	907 - tclearregion(0, 0, term.col-1,
	908 - term.row-1);
	909 - }
	910 - if (set ^ alt) /* set is always 1 or 0 …
	911 - tswapscreen();
	912 - if (*args != 1049)
	913 - break;
	914 - /* FALLTHROUGH */
	915 + if (set)
	916 + tloadaltscreen(args == 1049, …
	917 + else
	918 + tloaddefscreen(args == 1047, …
	919 + break;
	920 case 1048:
	921 + if (!allowaltscreen)
	922 + break;
	923 tcursor((set) ? CURSOR_SAVE : CURSOR_LO…
	924 break;
	925 case 2004: /* 2004: bracketed paste mode */
	926 @@ -1659,7 +1819,7 @@ void
	927 csihandle(void)
	928 {
	929 char buf[40];
	930 - int len;
	931 + int n, x;
	932
	933 switch (csiescseq.mode[0]) {
	934 default:
	935 @@ -1757,20 +1917,30 @@ csihandle(void)
	936 case 'J': /* ED -- Clear screen */
	937 switch (csiescseq.arg[0]) {
	938 case 0: /* below */
	939 - tclearregion(term.c.x, term.c.y, term.col-1, te…
	940 + tclearregion(term.c.x, term.c.y, term.col-1, te…
	941 if (term.c.y < term.row-1) {
	942 - tclearregion(0, term.c.y+1, term.col-1,
	943 - term.row-1);
	944 + tclearregion(0, term.c.y+1, term.col-1,…
	945 }
	946 break;
	947 case 1: /* above */
	948 - if (term.c.y > 1)
	949 - tclearregion(0, 0, term.col-1, term.c.y…
	950 - tclearregion(0, term.c.y, term.c.x, term.c.y);
	951 + if (term.c.y >= 1)
	952 + tclearregion(0, 0, term.col-1, term.c.y…
	953 + tclearregion(0, term.c.y, term.c.x, term.c.y, 1…
	954 break;
	955 case 2: /* all */
	956 - tclearregion(0, 0, term.col-1, term.row-1);
	957 - break;
	958 + if (IS_SET(MODE_ALTSCREEN)) {
	959 + tclearregion(0, 0, term.col-1, term.row-1, 1);
	960 + break;
	961 + }
	962 + /* vte does this:
	963 + tscrollup(0, term.row-1, term.row, SCROLL_SAVEH…
	964 +
	965 + /* alacritty does this: */
	966 + for (n = term.row-1; n >= 0 && tlinelen(term.li…
	967 + if (n >= 0)
	968 + tscrollup(0, term.row-1, n+1, SCROLL_SA…
	969 + tscrollup(0, term.row-1, term.row-n-1, SCROLL_N…
	970 + break;
	971 default:
	972 goto unknown;
	973 }
	974 @@ -1778,24 +1948,24 @@ csihandle(void)
	975 case 'K': /* EL -- Clear line */
	976 switch (csiescseq.arg[0]) {
	977 case 0: /* right */
	978 - tclearregion(term.c.x, term.c.y, term.col-1,
	979 - term.c.y);
	980 + tclearregion(term.c.x, term.c.y, term.col-1, te…
	981 break;
	982 case 1: /* left */
	983 - tclearregion(0, term.c.y, term.c.x, term.c.y);
	984 + tclearregion(0, term.c.y, term.c.x, term.c.y, 1…
	985 break;
	986 case 2: /* all */
	987 - tclearregion(0, term.c.y, term.col-1, term.c.y);
	988 + tclearregion(0, term.c.y, term.col-1, term.c.y,…
	989 break;
	990 }
	991 break;
	992 case 'S': /* SU -- Scroll <n> line up */
	993 DEFAULT(csiescseq.arg[0], 1);
	994 - tscrollup(term.top, csiescseq.arg[0], 0);
	995 + /* xterm, urxvt, alacritty save this in history */
	996 + tscrollup(term.top, term.bot, csiescseq.arg[0], SCROLL_…
	997 break;
	998 case 'T': /* SD -- Scroll <n> line down */
	999 DEFAULT(csiescseq.arg[0], 1);
	1000 - tscrolldown(term.top, csiescseq.arg[0], 0);
	1001 + tscrolldown(term.top, csiescseq.arg[0]);
	1002 break;
	1003 case 'L': /* IL -- Insert <n> blank lines */
	1004 DEFAULT(csiescseq.arg[0], 1);
	1005 @@ -1809,9 +1979,11 @@ csihandle(void)
	1006 tdeleteline(csiescseq.arg[0]);
	1007 break;
	1008 case 'X': /* ECH -- Erase <n> char */
	1009 + if (csiescseq.arg[0] < 0)
	1010 + return;
	1011 DEFAULT(csiescseq.arg[0], 1);
	1012 - tclearregion(term.c.x, term.c.y,
	1013 - term.c.x + csiescseq.arg[0] - 1, term.c…
	1014 + x = MIN(term.c.x + csiescseq.arg[0], term.col) - 1;
	1015 + tclearregion(term.c.x, term.c.y, x, term.c.y, 1);
	1016 break;
	1017 case 'P': /* DCH -- Delete <n> char */
	1018 DEFAULT(csiescseq.arg[0], 1);
	1019 @@ -1833,9 +2005,9 @@ csihandle(void)
	1020 break;
	1021 case 'n': /* DSR – Device Status Report (cursor position) */
	1022 if (csiescseq.arg[0] == 6) {
	1023 - len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
	1024 + n = snprintf(buf, sizeof(buf), "\033[%i;%iR",
	1025 term.c.y+1, term.c.x+1);
	1026 - ttywrite(buf, len, 0);
	1027 + ttywrite(buf, n, 0);
	1028 }
	1029 break;
	1030 case 'r': /* DECSTBM -- Set Scrolling Region */
	1031 @@ -2128,16 +2300,8 @@ tdumpsel(void)
	1032 void
	1033 tdumpline(int n)
	1034 {
	1035 - char buf[UTF_SIZ];
	1036 - const Glyph bp, end;
	1037 -
	1038 - bp = &term.line[n][0];
	1039 - end = &bp[MIN(tlinelen(n), term.col) - 1];
	1040 - if (bp != end \|\| bp->u != ' ') {
	1041 - for ( ; bp <= end; ++bp)
	1042 - tprinter(buf, utf8encode(bp->u, buf));
	1043 - }
	1044 - tprinter("\n", 1);
	1045 + char str[(term.col + 1) * UTF_SIZ];
	1046 + tprinter(str, tgetline(str, &term.line[n][0]));
	1047 }
	1048
	1049 void
	1050 @@ -2358,7 +2522,7 @@ eschandle(uchar ascii)
	1051 return 0;
	1052 case 'D': /* IND -- Linefeed */
	1053 if (term.c.y == term.bot) {
	1054 - tscrollup(term.top, 1, 1);
	1055 + tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIS…
	1056 } else {
	1057 tmoveto(term.c.x, term.c.y+1);
	1058 }
	1059 @@ -2371,7 +2535,7 @@ eschandle(uchar ascii)
	1060 break;
	1061 case 'M': /* RI -- Reverse index */
	1062 if (term.c.y == term.top) {
	1063 - tscrolldown(term.top, 1, 1);
	1064 + tscrolldown(term.top, 1);
	1065 } else {
	1066 tmoveto(term.c.x, term.c.y-1);
	1067 }
	1068 @@ -2511,7 +2675,8 @@ check_control_code:
	1069 */
	1070 return;
	1071 }
	1072 - if (selected(term.c.x, term.c.y))
	1073 + /* selected() takes relative coordinates */
	1074 + if (selected(term.c.x + term.scr, term.c.y + term.scr))
	1075 selclear();
	1076
	1077 gp = &term.line[term.c.y][term.c.x];
	1078 @@ -2546,6 +2711,7 @@ check_control_code:
	1079 if (term.c.x+width < term.col) {
	1080 tmoveto(term.c.x+width, term.c.y);
	1081 } else {
	1082 + term.wrapcwidth[IS_SET(MODE_ALTSCREEN)] = width;
	1083 term.c.state \|= CURSOR_WRAPNEXT;
	1084 }
	1085 }
	1086 @@ -2583,93 +2749,275 @@ twrite(const char *buf, int buflen, int show_ct…
	1087 }
	1088
	1089 void
	1090 -tresize(int col, int row)
	1091 +treflow(int col, int row)
	1092 {
	1093 int i, j;
	1094 - int minrow = MIN(row, term.row);
	1095 - int mincol = MIN(col, term.col);
	1096 - int *bp;
	1097 - TCursor c;
	1098 -
	1099 - if (col < 1 \|\| row < 1) {
	1100 - fprintf(stderr,
	1101 - "tresize: error resizing to %dx%d\n", col, row);
	1102 - return;
	1103 + int oce, nce, bot, scr;
	1104 + int ox = 0, oy = -term.histf, nx = 0, ny = -1, len;
	1105 + int cy = -1; /* proxy for new y coordinate of cursor */
	1106 + int nlines;
	1107 + Line *buf, line;
	1108 +
	1109 + /* y coordinate of cursor line end */
	1110 + for (oce = term.c.y; oce < term.row - 1 &&
	1111 + tiswrapped(term.line[oce]); oce++);
	1112 +
	1113 + nlines = term.histf + oce + 1;
	1114 + if (col < term.col) {
	1115 + /* each line can take this many lines after reflow */
	1116 + j = (term.col + col - 1) / col;
	1117 + nlines = j * nlines;
	1118 + if (nlines > HISTSIZE + RESIZEBUFFER + row) {
	1119 + nlines = HISTSIZE + RESIZEBUFFER + row;
	1120 + oy = -(nlines / j - oce - 1);
	1121 + }
	1122 }
	1123 + buf = xmalloc(nlines * sizeof(Line));
	1124 + do {
	1125 + if (!nx)
	1126 + buf[++ny] = xmalloc(col * sizeof(Glyph));
	1127 + if (!ox) {
	1128 + line = TLINEABS(oy);
	1129 + len = tlinelen(line);
	1130 + }
	1131 + if (oy == term.c.y) {
	1132 + if (!ox)
	1133 + len = MAX(len, term.c.x + 1);
	1134 + /* update cursor */
	1135 + if (cy < 0 && term.c.x - ox < col - nx) {
	1136 + term.c.x = nx + term.c.x - ox, cy = ny;
	1137 + UPDATEWRAPNEXT(0, col);
	1138 + }
	1139 + }
	1140 + /* get reflowed lines in buf */
	1141 + if (col - nx > len - ox) {
	1142 + memcpy(&buf[ny][nx], &line[ox], (len-ox) * size…
	1143 + nx += len - ox;
	1144 + if (len == 0 \|\| !(line[len - 1].mode & ATTR_WRA…
	1145 + for (j = nx; j < col; j++)
	1146 + tclearglyph(&buf[ny][j], 0);
	1147 + nx = 0;
	1148 + } else if (nx > 0) {
	1149 + buf[ny][nx - 1].mode &= ~ATTR_WRAP;
	1150 + }
	1151 + ox = 0, oy++;
	1152 + } else if (col - nx == len - ox) {
	1153 + memcpy(&buf[ny][nx], &line[ox], (col-nx) * size…
	1154 + ox = 0, oy++, nx = 0;
	1155 + } else/* if (col - nx < len - ox) */ {
	1156 + memcpy(&buf[ny][nx], &line[ox], (col-nx) * size…
	1157 + ox += col - nx;
	1158 + buf[ny][col - 1].mode \|= ATTR_WRAP;
	1159 + nx = 0;
	1160 + }
	1161 + } while (oy <= oce);
	1162 + if (nx)
	1163 + for (j = nx; j < col; j++)
	1164 + tclearglyph(&buf[ny][j], 0);
	1165
	1166 - /*
	1167 - * slide screen to keep cursor where we expect it -
	1168 - * tscrollup would work here, but we can optimize to
	1169 - * memmove because we're freeing the earlier lines
	1170 - */
	1171 - for (i = 0; i <= term.c.y - row; i++) {
	1172 + /* free extra lines */
	1173 + for (i = row; i < term.row; i++)
	1174 free(term.line[i]);
	1175 - free(term.alt[i]);
	1176 + /* resize to new height */
	1177 + term.line = xrealloc(term.line, row * sizeof(Line));
	1178 +
	1179 + bot = MIN(ny, row - 1);
	1180 + scr = MAX(row - term.row, 0);
	1181 + /* update y coordinate of cursor line end */
	1182 + nce = MIN(oce + scr, bot);
	1183 + /* update cursor y coordinate */
	1184 + term.c.y = nce - (ny - cy);
	1185 + if (term.c.y < 0) {
	1186 + j = nce, nce = MIN(nce + -term.c.y, bot);
	1187 + term.c.y += nce - j;
	1188 + while (term.c.y < 0) {
	1189 + free(buf[ny--]);
	1190 + term.c.y++;
	1191 + }
	1192 }
	1193 - /* ensure that both src and dst are not NULL */
	1194 - if (i > 0) {
	1195 - memmove(term.line, term.line + i, row * sizeof(Line));
	1196 - memmove(term.alt, term.alt + i, row * sizeof(Line));
	1197 + /* allocate new rows */
	1198 + for (i = row - 1; i > nce; i--) {
	1199 + term.line[i] = xmalloc(col * sizeof(Glyph));
	1200 + for (j = 0; j < col; j++)
	1201 + tclearglyph(&term.line[i][j], 0);
	1202 }
	1203 - for (i += row; i < term.row; i++) {
	1204 + /* fill visible area */
	1205 + for (/i = nce /; i >= term.row; i--, ny--)
	1206 + term.line[i] = buf[ny];
	1207 + for (/i = term.row - 1 /; i >= 0; i--, ny--) {
	1208 free(term.line[i]);
	1209 - free(term.alt[i]);
	1210 + term.line[i] = buf[ny];
	1211 + }
	1212 + /* fill lines in history buffer and update term.histf */
	1213 + for (/i = -1 /; ny >= 0 && i >= -HISTSIZE; i--, ny--) {
	1214 + j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
	1215 + free(term.hist[j]);
	1216 + term.hist[j] = buf[ny];
	1217 + }
	1218 + term.histf = -i - 1;
	1219 + term.scr = MIN(term.scr, term.histf);
	1220 + /* resize rest of the history lines */
	1221 + for (/i = -term.histf - 1 /; i >= -HISTSIZE; i--) {
	1222 + j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
	1223 + term.hist[j] = xrealloc(term.hist[j], col * sizeof(Glyp…
	1224 }
	1225 + free(buf);
	1226 +}
	1227
	1228 - /* resize to new height */
	1229 - term.line = xrealloc(term.line, row * sizeof(Line));
	1230 - term.alt = xrealloc(term.alt, row * sizeof(Line));
	1231 - term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
	1232 - term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
	1233 +void
	1234 +rscrolldown(int n)
	1235 +{
	1236 + int i;
	1237 + Line temp;
	1238
	1239 - for (i = 0; i < HISTSIZE; i++) {
	1240 - term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyp…
	1241 - for (j = mincol; j < col; j++) {
	1242 - term.hist[i][j] = term.c.attr;
	1243 - term.hist[i][j].u = ' ';
	1244 - }
	1245 - }
	1246 + /* can never be true as of now
	1247 + if (IS_SET(MODE_ALTSCREEN))
	1248 + return; */
	1249
	1250 - /* resize each row to new width, zero-pad if needed */
	1251 - for (i = 0; i < minrow; i++) {
	1252 - term.line[i] = xrealloc(term.line[i], col * sizeof(Glyp…
	1253 - term.alt[i] = xrealloc(term.alt[i], col * sizeof(Glyp…
	1254 - }
	1255 + if ((n = MIN(n, term.histf)) <= 0)
	1256 + return;
	1257
	1258 - /* allocate any new rows */
	1259 - for (/* i = minrow */; i < row; i++) {
	1260 - term.line[i] = xmalloc(col * sizeof(Glyph));
	1261 - term.alt[i] = xmalloc(col * sizeof(Glyph));
	1262 + for (i = term.c.y + n; i >= n; i--) {
	1263 + temp = term.line[i];
	1264 + term.line[i] = term.line[i-n];
	1265 + term.line[i-n] = temp;
	1266 }
	1267 + for (/i = n - 1 /; i >= 0; i--) {
	1268 + temp = term.line[i];
	1269 + term.line[i] = term.hist[term.histi];
	1270 + term.hist[term.histi] = temp;
	1271 + term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
	1272 + }
	1273 + term.c.y += n;
	1274 + term.histf -= n;
	1275 + if ((i = term.scr - n) >= 0) {
	1276 + term.scr = i;
	1277 + } else {
	1278 + term.scr = 0;
	1279 + if (sel.ob.x != -1 && !sel.alt)
	1280 + selmove(-i);
	1281 + }
	1282 +}
	1283 +
	1284 +void
	1285 +tresize(int col, int row)
	1286 +{
	1287 + int *bp;
	1288 +
	1289 + /* col and row are always MAX(_, 1)
	1290 + if (col < 1 \|\| row < 1) {
	1291 + fprintf(stderr, "tresize: error resizing to %dx%d\n", c…
	1292 + return;
	1293 + } */
	1294 +
	1295 + term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
	1296 + term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
	1297 if (col > term.col) {
	1298 bp = term.tabs + term.col;
	1299 -
	1300 memset(bp, 0, sizeof(term.tabs) (col - term.col));
	1301 while (--bp > term.tabs && !*bp)
	1302 /* nothing */ ;
	1303 for (bp += tabspaces; bp < term.tabs + col; bp += tabsp…
	1304 *bp = 1;
	1305 }
	1306 - /* update terminal size */
	1307 - term.col = col;
	1308 - term.row = row;
	1309 - /* reset scrolling region */
	1310 - tsetscroll(0, row-1);
	1311 - /* make use of the LIMIT in tmoveto */
	1312 - tmoveto(term.c.x, term.c.y);
	1313 - /* Clearing both screens (it makes dirty all lines) */
	1314 - c = term.c;
	1315 - for (i = 0; i < 2; i++) {
	1316 - if (mincol < col && 0 < minrow) {
	1317 - tclearregion(mincol, 0, col - 1, minrow - 1);
	1318 +
	1319 + if (IS_SET(MODE_ALTSCREEN))
	1320 + tresizealt(col, row);
	1321 + else
	1322 + tresizedef(col, row);
	1323 +}
	1324 +
	1325 +void
	1326 +tresizedef(int col, int row)
	1327 +{
	1328 + int i, j;
	1329 +
	1330 + /* return if dimensions haven't changed */
	1331 + if (term.col == col && term.row == row) {
	1332 + tfulldirt();
	1333 + return;
	1334 + }
	1335 + if (col != term.col) {
	1336 + if (!sel.alt)
	1337 + selremove();
	1338 + treflow(col, row);
	1339 + } else {
	1340 + /* slide screen up if otherwise cursor would get out of…
	1341 + if (term.c.y >= row) {
	1342 + tscrollup(0, term.row - 1, term.c.y - row + 1, …
	1343 + term.c.y = row - 1;
	1344 }
	1345 - if (0 < col && minrow < row) {
	1346 - tclearregion(0, minrow, col - 1, row - 1);
	1347 + for (i = row; i < term.row; i++)
	1348 + free(term.line[i]);
	1349 +
	1350 + /* resize to new height */
	1351 + term.line = xrealloc(term.line, row * sizeof(Line));
	1352 + /* allocate any new rows */
	1353 + for (i = term.row; i < row; i++) {
	1354 + term.line[i] = xmalloc(col * sizeof(Glyph));
	1355 + for (j = 0; j < col; j++)
	1356 + tclearglyph(&term.line[i][j], 0);
	1357 }
	1358 - tswapscreen();
	1359 - tcursor(CURSOR_LOAD);
	1360 + /* scroll down as much as height has increased */
	1361 + rscrolldown(row - term.row);
	1362 + }
	1363 + /* update terminal size */
	1364 + term.col = col, term.row = row;
	1365 + /* reset scrolling region */
	1366 + term.top = 0, term.bot = row - 1;
	1367 + /* dirty all lines */
	1368 + tfulldirt();
	1369 +}
	1370 +
	1371 +void
	1372 +tresizealt(int col, int row)
	1373 +{
	1374 + int i, j;
	1375 +
	1376 + /* return if dimensions haven't changed */
	1377 + if (term.col == col && term.row == row) {
	1378 + tfulldirt();
	1379 + return;
	1380 }
	1381 - term.c = c;
	1382 + if (sel.alt)
	1383 + selremove();
	1384 + /* slide screen up if otherwise cursor would get out of the scr…
	1385 + for (i = 0; i <= term.c.y - row; i++)
	1386 + free(term.line[i]);
	1387 + if (i > 0) {
	1388 + /* ensure that both src and dst are not NULL */
	1389 + memmove(term.line, term.line + i, row * sizeof(Line));
	1390 + term.c.y = row - 1;
	1391 + }
	1392 + for (i += row; i < term.row; i++)
	1393 + free(term.line[i]);
	1394 + /* resize to new height */
	1395 + term.line = xrealloc(term.line, row * sizeof(Line));
	1396 + /* resize to new width */
	1397 + for (i = 0; i < MIN(row, term.row); i++) {
	1398 + term.line[i] = xrealloc(term.line[i], col * sizeof(Glyp…
	1399 + for (j = term.col; j < col; j++)
	1400 + tclearglyph(&term.line[i][j], 0);
	1401 + }
	1402 + /* allocate any new rows */
	1403 + for (/i = MIN(row, term.row) /; i < row; i++) {
	1404 + term.line[i] = xmalloc(col * sizeof(Glyph));
	1405 + for (j = 0; j < col; j++)
	1406 + tclearglyph(&term.line[i][j], 0);
	1407 + }
	1408 + /* update cursor */
	1409 + if (term.c.x >= col) {
	1410 + term.c.state &= ~CURSOR_WRAPNEXT;
	1411 + term.c.x = col - 1;
	1412 + } else {
	1413 + UPDATEWRAPNEXT(1, col);
	1414 + }
	1415 + /* update terminal size */
	1416 + term.col = col, term.row = row;
	1417 + /* reset scrolling region */
	1418 + term.top = 0, term.bot = row - 1;
	1419 + /* dirty all lines */
	1420 + tfulldirt();
	1421 }
	1422
	1423 void
	1424 diff --git a/st.h b/st.h
	1425 index 818a6f8..514ec08 100644
	1426 --- a/st.h
	1427 +++ b/st.h
	1428 @@ -22,17 +22,19 @@
	1429
	1430 enum glyph_attribute {
	1431 ATTR_NULL = 0,
	1432 - ATTR_BOLD = 1 << 0,
	1433 - ATTR_FAINT = 1 << 1,
	1434 - ATTR_ITALIC = 1 << 2,
	1435 - ATTR_UNDERLINE = 1 << 3,
	1436 - ATTR_BLINK = 1 << 4,
	1437 - ATTR_REVERSE = 1 << 5,
	1438 - ATTR_INVISIBLE = 1 << 6,
	1439 - ATTR_STRUCK = 1 << 7,
	1440 - ATTR_WRAP = 1 << 8,
	1441 - ATTR_WIDE = 1 << 9,
	1442 - ATTR_WDUMMY = 1 << 10,
	1443 + ATTR_SET = 1 << 0,
	1444 + ATTR_BOLD = 1 << 1,
	1445 + ATTR_FAINT = 1 << 2,
	1446 + ATTR_ITALIC = 1 << 3,
	1447 + ATTR_UNDERLINE = 1 << 4,
	1448 + ATTR_BLINK = 1 << 5,
	1449 + ATTR_REVERSE = 1 << 6,
	1450 + ATTR_INVISIBLE = 1 << 7,
	1451 + ATTR_STRUCK = 1 << 8,
	1452 + ATTR_WRAP = 1 << 9,
	1453 + ATTR_WIDE = 1 << 10,
	1454 + ATTR_WDUMMY = 1 << 11,
	1455 + ATTR_SELECTED = 1 << 12,
	1456 ATTR_BOLD_FAINT = ATTR_BOLD \| ATTR_FAINT,
	1457 };
	1458
	1459 @@ -90,6 +92,7 @@ void toggleprinter(const Arg *);
	1460
	1461 int tattrset(int);
	1462 void tnew(int, int);
	1463 +int tisaltscreen(void);
	1464 void tresize(int, int);
	1465 void tsetdirtattr(int);
	1466 void ttyhangup(void);