Add sixel patch

1 files changed, 443 insertions, 138 deletions

diff --git a/st.c b/st.c
index 8e57991..269d553 100644
--- a/st.c
+++ b/st.c
@@ -14,12 +14,15 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <termios.h>
+#include <time.h>
 #include <unistd.h>
 #include <wchar.h>
 
 #include "st.h"
 #include "win.h"
 
+#include "sixel.h"
+
 #if   defined(__linux)
  #include <pty.h>
 #elif defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
@@ -35,22 +38,27 @@
 #define ESC_ARG_SIZ   16
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
+#define STR_TERM_ST   "\033\\"
+#define STR_TERM_BEL  "\007"
 
 /* macros */
-#define IS_SET(flag)		((term.mode & (flag)) != 0)
-#define ISCONTROLC0(c)		(BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
-#define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
-#define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
-#define ISDELIM(u)		(u && wcschr(worddelimiters, u))
+#define IS_SET(flag)    ((term.mode & (flag)) != 0)
+#define ISCONTROLC0(c)  (BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
+#define ISCONTROLC1(c)  (BETWEEN(c, 0x80, 0x9f))
+#define ISCONTROL(c)    (ISCONTROLC0(c) || ISCONTROLC1(c))
+#define ISDELIM(u)      (u && wcschr(worddelimiters, u))
 
 enum term_mode {
-	MODE_WRAP        = 1 << 0,
-	MODE_INSERT      = 1 << 1,
-	MODE_ALTSCREEN   = 1 << 2,
-	MODE_CRLF        = 1 << 3,
-	MODE_ECHO        = 1 << 4,
-	MODE_PRINT       = 1 << 5,
-	MODE_UTF8        = 1 << 6,
+	MODE_WRAP         = 1 << 0,
+	MODE_INSERT       = 1 << 1,
+	MODE_ALTSCREEN    = 1 << 2,
+	MODE_CRLF         = 1 << 3,
+	MODE_ECHO         = 1 << 4,
+	MODE_PRINT        = 1 << 5,
+	MODE_UTF8         = 1 << 6,
+	MODE_SIXEL        = 1 << 7,
+	MODE_SIXEL_CUR_RT = 1 << 8,
+	MODE_SIXEL_SDM    = 1 << 9
 };
 
 enum cursor_movement {
@@ -82,16 +90,10 @@ enum escape_state {
 	ESC_STR_END    = 16, /* a final string was encountered */
 	ESC_TEST       = 32, /* Enter in test mode */
 	ESC_UTF8       = 64,
+	ESC_DCS        =128,
 };
 
 typedef struct {
-	Glyph attr; /* current char attributes */
-	int x;
-	int y;
-	char state;
-} TCursor;
-
-typedef struct {
 	int mode;
 	int type;
 	int snap;
@@ -109,27 +111,6 @@ typedef struct {
 	int alt;
 } Selection;
 
-/* Internal representation of the screen */
-typedef struct {
-	int row;      /* nb row */
-	int col;      /* nb col */
-	Line *line;   /* screen */
-	Line *alt;    /* alternate screen */
-	int *dirty;   /* dirtyness of lines */
-	TCursor c;    /* cursor */
-	int ocx;      /* old cursor col */
-	int ocy;      /* old cursor row */
-	int top;      /* top    scroll limit */
-	int bot;      /* bottom scroll limit */
-	int mode;     /* terminal mode flags */
-	int esc;      /* escape state flags */
-	char trantbl[4]; /* charset table translation */
-	int charset;  /* current charset */
-	int icharset; /* selected charset for sequence */
-	int *tabs;
-	Rune lastc;   /* last printed char outside of sequence, 0 if control */
-} Term;
-
 /* CSI Escape sequence structs */
 /* ESC '[' [[ [<priv>] <arg> [;]] <mode> [<mode>]] */
 typedef struct {
@@ -150,6 +131,7 @@ typedef struct {
 	size_t len;            /* raw string length */
 	char *args[STR_ARG_SIZ];
 	int narg;              /* nb of args */
+    char *term;            /* terminator: ST or BEL */
 } STREscape;
 
 static void execsh(char *, char **);
@@ -159,6 +141,7 @@ static void ttywriteraw(const char *, size_t);
 
 static void csidump(void);
 static void csihandle(void);
+static void dcshandle(void);
 static void csiparse(void);
 static void csireset(void);
 static void osc_color_response(int, int, int);
@@ -174,7 +157,9 @@ static void tdumpline(int);
 static void tdump(void);
 static void tclearregion(int, int, int, int);
 static void tcursor(int);
+static void tresetcursor(void);
 static void tdeletechar(int);
+static void tdeleteimages(void);
 static void tdeleteline(int);
 static void tinsertblank(int);
 static void tinsertblankline(int);
@@ -191,27 +176,24 @@ static void tsetattr(const int *, int);
 static void tsetchar(Rune, const Glyph *, int, int);
 static void tsetdirt(int, int);
 static void tsetscroll(int, int);
+static inline void tsetsixelattr(Line line, int x1, int x2);
 static void tswapscreen(void);
 static void tsetmode(int, int, const int *, int);
 static int twrite(const char *, int, int);
-static void tfulldirt(void);
 static void tcontrolcode(uchar );
 static void tdectest(char );
 static void tdefutf8(char);
 static int32_t tdefcolor(const int *, int *, int);
 static void tdeftran(char);
 static void tstrsequence(uchar);
-
-static void drawregion(int, int, int, int);
-
 static void selnormalize(void);
 static void selscroll(int, int);
 static void selsnap(int *, int *, int);
 
 static size_t utf8decode(const char *, Rune *, size_t);
-static Rune utf8decodebyte(char, size_t *);
-static char utf8encodebyte(Rune, size_t);
-static size_t utf8validate(Rune *, size_t);
+static inline Rune utf8decodebyte(char, size_t *);
+static inline char utf8encodebyte(Rune, size_t);
+static inline size_t utf8validate(Rune *, size_t);
 
 static char *base64dec(const char *);
 static char base64dec_getc(const char **);
@@ -219,19 +201,20 @@ static char base64dec_getc(const char **);
 static ssize_t xwrite(int, const char *, size_t);
 
 /* Globals */
-static Term term;
 static Selection sel;
 static CSIEscape csiescseq;
 static STREscape strescseq;
 static int iofd = 1;
 static int cmdfd;
 static pid_t pid;
+sixel_state_t sixel_st;
 
 static const uchar utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
 static const uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
 static const Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
 static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};
 
+
 ssize_t
 xwrite(int fd, const char *s, size_t len)
 {
@@ -273,7 +256,6 @@ char *
 xstrdup(const char *s)
 {
 	char *p;
-
 	if ((p = strdup(s)) == NULL)
 		die("strdup: %s\n", strerror(errno));
 
@@ -283,24 +265,27 @@ xstrdup(const char *s)
 size_t
 utf8decode(const char *c, Rune *u, size_t clen)
 {
-	size_t i, j, len, type;
+	size_t i, len;
 	Rune udecoded;
 
 	*u = UTF_INVALID;
 	if (!clen)
 		return 0;
 	udecoded = utf8decodebyte(c[0], &len);
-	if (!BETWEEN(len, 1, UTF_SIZ))
+	if (!BETWEEN(len, 2, UTF_SIZ)) {
+		*u = (len == 1) ? udecoded : UTF_INVALID;
 		return 1;
-	for (i = 1, j = 1; i < clen && j < len; ++i, ++j) {
-		udecoded = (udecoded << 6) | utf8decodebyte(c[i], &type);
-		if (type != 0)
-			return j;
 	}
-	if (j < len)
+	clen = MIN(clen, len);
+	for (i = 1; i < clen; ++i) {
+		if ((c[i] & 0xC0) != 0x80)
+			return i;
+		udecoded = (udecoded << 6) | (c[i] & 0x3F);
+	}
+	if (i < len)
 		return 0;
-	*u = udecoded;
-	utf8validate(u, len);
+	*u = (!BETWEEN(udecoded, utfmin[len], utfmax[len]) || BETWEEN(udecoded, 0xD800, 0xDFFF))
+	        ? UTF_INVALID : udecoded;
 
 	return len;
 }
@@ -455,8 +440,8 @@ selextend(int col, int row, int type, int done)
 
 	sel.oe.x = col;
 	sel.oe.y = row;
-	selnormalize();
 	sel.type = type;
+	selnormalize();
 
 	if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
 		tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
@@ -485,6 +470,7 @@ selnormalize(void)
 	/* expand selection over line breaks */
 	if (sel.type == SEL_RECTANGULAR)
 		return;
+
 	i = tlinelen(sel.nb.y);
 	if (i < sel.nb.x)
 		sel.nb.x = i;
@@ -564,15 +550,15 @@ selsnap(int *x, int *y, int direction)
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if (direction < 0) {
 			for (; *y > 0; *y += direction) {
-				if (!(term.line[*y-1][term.col-1].mode
-						& ATTR_WRAP)) {
+				if (!(term.line[*y-1][term.col-1].mode & ATTR_WRAP))
+				{
 					break;
 				}
 			}
 		} else if (direction > 0) {
 			for (; *y < term.row-1; *y += direction) {
-				if (!(term.line[*y][term.col-1].mode
-						& ATTR_WRAP)) {
+				if (!(term.line[*y][term.col-1].mode & ATTR_WRAP))
+				{
 					break;
 				}
 			}
@@ -595,7 +581,8 @@ getsel(void)
 	ptr = str = xmalloc(bufsize);
 
 	/* append every set & selected glyph to the selection */
-	for (y = sel.nb.y; y <= sel.ne.y; y++) {
+	for (y = sel.nb.y; y <= sel.ne.y; y++)
+	{
 		if ((linelen = tlinelen(y)) == 0) {
 			*ptr++ = '\n';
 			continue;
@@ -608,6 +595,7 @@ getsel(void)
 			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
 			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
 		}
+
 		last = &term.line[y][MIN(lastx, linelen-1)];
 		while (last >= gp && last->u == ' ')
 			--last;
@@ -628,8 +616,8 @@ getsel(void)
 		 * st.
 		 * FIXME: Fix the computer world.
 		 */
-		if ((y < sel.ne.y || lastx >= linelen) &&
-		    (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
+		if ((y < sel.ne.y || lastx >= linelen)
+		    && (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
 			*ptr++ = '\n';
 	}
 	*ptr = 0;
@@ -641,9 +629,15 @@ selclear(void)
 {
 	if (sel.ob.x == -1)
 		return;
+	selremove();
+	tsetdirt(sel.nb.y, sel.ne.y);
+}
+
+void
+selremove(void)
+{
 	sel.mode = SEL_IDLE;
 	sel.ob.x = -1;
-	tsetdirt(sel.nb.y, sel.ne.y);
 }
 
 void
@@ -697,6 +691,7 @@ execsh(char *cmd, char **args)
 	setenv("SHELL", sh, 1);
 	setenv("HOME", pw->pw_dir, 1);
 	setenv("TERM", termname, 1);
+	setenv("COLORTERM", "truecolor", 1);
 
 	signal(SIGCHLD, SIG_DFL);
 	signal(SIGHUP, SIG_DFL);
@@ -715,17 +710,16 @@ sigchld(int a)
 	int stat;
 	pid_t p;
 
-	if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
-		die("waiting for pid %hd failed: %s\n", pid, strerror(errno));
-
-	if (pid != p)
-		return;
+	while ((p = waitpid(-1, &stat, WNOHANG)) > 0) {
+		if (p == pid) {
 
-	if (WIFEXITED(stat) && WEXITSTATUS(stat))
-		die("child exited with status %d\n", WEXITSTATUS(stat));
-	else if (WIFSIGNALED(stat))
-		die("child terminated due to signal %d\n", WTERMSIG(stat));
-	_exit(0);
+			if (WIFEXITED(stat) && WEXITSTATUS(stat))
+				die("child exited with status %d\n", WEXITSTATUS(stat));
+			else if (WIFSIGNALED(stat))
+				die("child terminated due to signal %d\n", WTERMSIG(stat));
+			_exit(0);
+		}
+	}
 }
 
 void
@@ -756,6 +750,7 @@ int
 ttynew(const char *line, char *cmd, const char *out, char **args)
 {
 	int m, s;
+	struct sigaction sa;
 
 	if (out) {
 		term.mode |= MODE_PRINT;
@@ -794,7 +789,7 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 		if (ioctl(s, TIOCSCTTY, NULL) < 0)
 			die("ioctl TIOCSCTTY failed: %s\n", strerror(errno));
 		if (s > 2)
-			close(s);
+				close(s);
 #ifdef __OpenBSD__
 		if (pledge("stdio getpw proc exec", NULL) == -1)
 			die("pledge\n");
@@ -808,7 +803,10 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 #endif
 		close(s);
 		cmdfd = m;
-		signal(SIGCHLD, sigchld);
+		memset(&sa, 0, sizeof(sa));
+		sigemptyset(&sa.sa_mask);
+		sa.sa_handler = sigchld;
+		sigaction(SIGCHLD, &sa, NULL);
 		break;
 	}
 	return cmdfd;
@@ -960,6 +958,12 @@ tattrset(int attr)
 	return 0;
 }
 
+int
+tisaltscr(void)
+{
+	return IS_SET(MODE_ALTSCREEN);
+}
+
 void
 tsetdirt(int top, int bot)
 {
@@ -988,6 +992,13 @@ tsetdirtattr(int attr)
 }
 
 void
+tsetsixelattr(Line line, int x1, int x2)
+{
+	for (; x1 <= x2; x1++)
+		line[x1].mode |= ATTR_SIXEL;
+}
+
+void
 tfulldirt(void)
 {
 	tsetdirt(0, term.row-1);
@@ -1008,15 +1019,18 @@ tcursor(int mode)
 }
 
 void
+tresetcursor(void)
+{
+	term.c = (TCursor){ { .mode = ATTR_NULL, .fg = defaultfg, .bg = defaultbg },
+	                    .x = 0, .y = 0, .state = CURSOR_DEFAULT };
+}
+
+void
 treset(void)
 {
 	uint i;
 
-	term.c = (TCursor){{
-		.mode = ATTR_NULL,
-		.fg = defaultfg,
-		.bg = defaultbg
-	}, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
+	tresetcursor();
 
 	memset(term.tabs, 0, term.col * sizeof(*term.tabs));
 	for (i = tabspaces; i < term.col; i += tabspaces)
@@ -1031,6 +1045,7 @@ treset(void)
 		tmoveto(0, 0);
 		tcursor(CURSOR_SAVE);
 		tclearregion(0, 0, term.col-1, term.row-1);
+		tdeleteimages();
 		tswapscreen();
 	}
 }
@@ -1047,9 +1062,12 @@ void
 tswapscreen(void)
 {
 	Line *tmp = term.line;
+	ImageList *im = term.images;
 
 	term.line = term.alt;
 	term.alt = tmp;
+	term.images = term.images_alt;
+	term.images_alt = im;
 	term.mode ^= MODE_ALTSCREEN;
 	tfulldirt();
 }
@@ -1057,8 +1075,13 @@ tswapscreen(void)
 void
 tscrolldown(int orig, int n)
 {
+
 	int i;
 	Line temp;
+	int bot = term.bot;
+	int scr = 0;
+	int itop = orig + scr, ibot = bot + scr;
+	ImageList *im, *next;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
@@ -1071,14 +1094,29 @@ tscrolldown(int orig, int n)
 		term.line[i-n] = temp;
 	}
 
+	/* move images, if they are inside the scrolling region */
+	for (im = term.images; im; im = next) {
+		next = im->next;
+		if (im->y >= itop && im->y <= ibot) {
+			im->y += n;
+			if (im->y > ibot)
+				delete_image(im);
+		}
+	}
+
 	selscroll(orig, n);
 }
 
 void
 tscrollup(int orig, int n)
 {
+
 	int i;
 	Line temp;
+	int bot = term.bot;
+	int scr = 0;
+	int itop = orig + scr, ibot = bot + scr;
+	ImageList *im, *next;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
@@ -1091,6 +1129,16 @@ tscrollup(int orig, int n)
 		term.line[i+n] = temp;
 	}
 
+	/* move images, if they are inside the scrolling region */
+	for (im = term.images; im; im = next) {
+		next = im->next;
+		if (im->y >= itop && im->y <= ibot) {
+			im->y -= n;
+			if (im->y < itop)
+				delete_image(im);
+		}
+	}
+
 	selscroll(orig, -n);
 }
 
@@ -1218,6 +1266,7 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 	term.dirty[y] = 1;
 	term.line[y][x] = *attr;
 	term.line[y][x].u = u;
+
 }
 
 void
@@ -1292,10 +1341,22 @@ tinsertblankline(int n)
 }
 
 void
+tdeleteimages(void)
+{
+	ImageList *im, *next;
+
+	for (im = term.images; im; im = next) {
+		next = im->next;
+		delete_image(im);
+	}
+}
+
+void
 tdeleteline(int n)
 {
-	if (BETWEEN(term.c.y, term.top, term.bot))
+	if (BETWEEN(term.c.y, term.top, term.bot)) {
 		tscrollup(term.c.y, n);
+	}
 }
 
 int32_t
@@ -1475,7 +1536,8 @@ tsetscroll(int t, int b)
 void
 tsetmode(int priv, int set, const int *args, int narg)
 {
-	int alt; const int *lim;
+	int alt;
+	const int *lim;
 
 	for (lim = args + narg; args < lim; ++args) {
 		if (priv) {
@@ -1546,8 +1608,7 @@ tsetmode(int priv, int set, const int *args, int narg)
 					break;
 				alt = IS_SET(MODE_ALTSCREEN);
 				if (alt) {
-					tclearregion(0, 0, term.col-1,
-							term.row-1);
+					tclearregion(0, 0, term.col-1, term.row-1);
 				}
 				if (set ^ alt) /* set is always 1 or 0 */
 					tswapscreen();
@@ -1570,6 +1631,12 @@ tsetmode(int priv, int set, const int *args, int narg)
 				      and can be mistaken for other control
 				      codes. */
 				break;
+			case 80: /* DECSDM -- Sixel Display Mode */
+				MODBIT(term.mode, set, MODE_SIXEL_SDM);
+				break;
+			case 8452: /* sixel scrolling leaves cursor to right of graphic */
+				MODBIT(term.mode, set, MODE_SIXEL_CUR_RT);
+				break;
 			default:
 				fprintf(stderr,
 					"erresc: unknown private set/reset mode %d\n",
@@ -1605,8 +1672,11 @@ tsetmode(int priv, int set, const int *args, int narg)
 void
 csihandle(void)
 {
-	char buf[40];
-	int len;
+	char buffer[40];
+	int n = 0, len;
+	ImageList *im, *next;
+	int pi, pa;
+	int maxcol = term.col;
 
 	switch (csiescseq.mode[0]) {
 	default:
@@ -1704,19 +1774,30 @@ csihandle(void)
 	case 'J': /* ED -- Clear screen */
 		switch (csiescseq.arg[0]) {
 		case 0: /* below */
-			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
-			if (term.c.y < term.row-1) {
-				tclearregion(0, term.c.y+1, term.col-1,
-						term.row-1);
-			}
+			tclearregion(term.c.x, term.c.y, maxcol-1, term.c.y);
+			if (term.c.y < term.row-1)
+				tclearregion(0, term.c.y+1, maxcol-1, term.row-1);
 			break;
 		case 1: /* above */
 			if (term.c.y > 0)
-				tclearregion(0, 0, term.col-1, term.c.y-1);
+				tclearregion(0, 0, maxcol-1, term.c.y-1);
 			tclearregion(0, term.c.y, term.c.x, term.c.y);
 			break;
-		case 2: /* all */
-			tclearregion(0, 0, term.col-1, term.row-1);
+		case 2: /* screen */
+
+			tclearregion(0, 0, maxcol-1, term.row-1);
+			tdeleteimages();
+			break;
+		case 3: /* scrollback */
+			for (im = term.images; im; im = next) {
+				next = im->next;
+				if (im->y < 0)
+					delete_image(im);
+			}
+			break;
+		case 6: /* sixels */
+			tdeleteimages();
+			tfulldirt();
 			break;
 		default:
 			goto unknown;
@@ -1725,19 +1806,43 @@ csihandle(void)
 	case 'K': /* EL -- Clear line */
 		switch (csiescseq.arg[0]) {
 		case 0: /* right */
-			tclearregion(term.c.x, term.c.y, term.col-1,
-					term.c.y);
+			tclearregion(term.c.x, term.c.y, maxcol-1, term.c.y);
 			break;
 		case 1: /* left */
 			tclearregion(0, term.c.y, term.c.x, term.c.y);
 			break;
 		case 2: /* all */
-			tclearregion(0, term.c.y, term.col-1, term.c.y);
+			tclearregion(0, term.c.y, maxcol-1, term.c.y);
 			break;
 		}
 		break;
-	case 'S': /* SU -- Scroll <n> line up */
-		if (csiescseq.priv) break;
+	case 'S': /* SU -- Scroll <n> line up ; XTSMGRAPHICS */
+		if (csiescseq.priv) {
+			if (csiescseq.narg > 1) {
+				/* XTSMGRAPHICS */
+				pi = csiescseq.arg[0];
+				pa = csiescseq.arg[1];
+				if (pi == 1 && (pa == 1 || pa == 2 || pa == 4)) {
+					/* number of sixel color registers */
+					/* (read, reset and read the maximum value give the same response) */
+					n = snprintf(buffer, sizeof buffer, "\033[?1;0;%dS", DECSIXEL_PALETTE_MAX);
+					ttywrite(buffer, n, 1);
+					break;
+				} else if (pi == 2 && (pa == 1 || pa == 2 || pa == 4)) {
+					/* sixel graphics geometry (in pixels) */
+					/* (read, reset and read the maximum value give the same response) */
+					n = snprintf(buffer, sizeof buffer, "\033[?2;0;%d;%dS",
+					             MIN(term.col * win.cw, DECSIXEL_WIDTH_MAX),
+					             MIN(term.row * win.ch, DECSIXEL_HEIGHT_MAX));
+					ttywrite(buffer, n, 1);
+					break;
+				}
+				/* the number of color registers and sixel geometry can't be changed */
+				n = snprintf(buffer, sizeof buffer, "\033[?%d;3;0S", pi); /* failure */
+				ttywrite(buffer, n, 1);
+			}
+			goto unknown;
+		}
 		DEFAULT(csiescseq.arg[0], 1);
 		tscrollup(term.top, csiescseq.arg[0]);
 		break;
@@ -1785,9 +1890,9 @@ csihandle(void)
 			ttywrite("\033[0n", sizeof("\033[0n") - 1, 0);
 			break;
 		case 6: /* Report Cursor Position (CPR) "<row>;<column>R" */
-			len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
+			len = snprintf(buffer, sizeof(buffer), "\033[%i;%iR",
 			               term.c.y+1, term.c.x+1);
-			ttywrite(buf, len, 0);
+			ttywrite(buffer, len, 0);
 			break;
 		default:
 			goto unknown;
@@ -1806,6 +1911,27 @@ csihandle(void)
 	case 's': /* DECSC -- Save cursor position (ANSI.SYS) */
 		tcursor(CURSOR_SAVE);
 		break;
+	case 't': /* title stack operations ; XTWINOPS */
+		switch (csiescseq.arg[0]) {
+		case 14: /* text area size in pixels */
+			if (csiescseq.narg > 1)
+				goto unknown;
+			n = snprintf(buffer, sizeof buffer, "\033[4;%d;%dt",
+			             term.row * win.ch, term.col * win.cw);
+			ttywrite(buffer, n, 1);
+			break;
+		case 16: /* character cell size in pixels */
+			n = snprintf(buffer, sizeof buffer, "\033[6;%d;%dt", win.ch, win.cw);
+			ttywrite(buffer, n, 1);
+			break;
+		case 18: /* size of the text area in characters */
+			n = snprintf(buffer, sizeof buffer, "\033[8;%d;%dt", term.row, term.col);
+			ttywrite(buffer, n, 1);
+			break;
+		default:
+			goto unknown;
+		}
+		break;
 	case 'u': /* DECRC -- Restore cursor position (ANSI.SYS) */
 		if (csiescseq.priv) {
 			goto unknown;
@@ -1870,8 +1996,8 @@ osc_color_response(int num, int index, int is_osc4)
 		return;
 	}
 
-	n = snprintf(buf, sizeof buf, "\033]%s%d;rgb:%02x%02x/%02x%02x/%02x%02x\007",
-	             is_osc4 ? "4;" : "", num, r, r, g, g, b, b);
+	n = snprintf(buf, sizeof buf, "\033]%s%d;rgb:%02x%02x/%02x%02x/%02x%02x%s",
+	             is_osc4 ? "4;" : "", num, r, r, g, g, b, b, strescseq.term);
 	if (n < 0 || n >= sizeof(buf)) {
 		fprintf(stderr, "error: %s while printing %s response\n",
 		        n < 0 ? "snprintf failed" : "truncation occurred",
@@ -1891,6 +2017,11 @@ strhandle(void)
 		{ defaultbg, "background" },
 		{ defaultcs, "cursor" }
 	};
+	ImageList *im, *newimages, *next, *tail = NULL;
+	int i, x1, y1, x2, y2, y, numimages;
+	int cx, cy;
+	Line line;
+	int scr = 0;
 
 	term.esc &= ~(ESC_STR_END|ESC_STR);
 	strparse();
@@ -1924,6 +2055,8 @@ strhandle(void)
 				}
 			}
 			return;
+		case 8: /* Clear Hyperlinks */
+			return;
 		case 10: /* set dynamic VT100 text foreground color */
 		case 11: /* set dynamic VT100 text background color */
 		case 12: /* set dynamic text cursor color */
@@ -1986,6 +2119,95 @@ strhandle(void)
 		xsettitle(strescseq.args[0]);
 		return;
 	case 'P': /* DCS -- Device Control String */
+		if (IS_SET(MODE_SIXEL)) {
+			term.mode &= ~MODE_SIXEL;
+			if (!sixel_st.image.data) {
+				sixel_parser_deinit(&sixel_st);
+				return;
+			}
+			cx = IS_SET(MODE_SIXEL_SDM) ? 0 : term.c.x;
+			cy = IS_SET(MODE_SIXEL_SDM) ? 0 : term.c.y;
+			if ((numimages = sixel_parser_finalize(&sixel_st, &newimages,
+					cx, cy + scr, win.cw, win.ch)) <= 0) {
+				sixel_parser_deinit(&sixel_st);
+				perror("sixel_parser_finalize() failed");
+				return;
+			}
+			sixel_parser_deinit(&sixel_st);
+			x1 = newimages->x;
+			y1 = newimages->y;
+			x2 = x1 + newimages->cols;
+			y2 = y1 + numimages;
+			/* Delete the old images that are covered by the new image(s). We also need
+			 * to check if they have already been deleted before adding the new ones. */
+			if (term.images) {
+				char transparent[numimages];
+				for (i = 0, im = newimages; im; im = im->next, i++) {
+					transparent[i] = im->transparent;
+				}
+				for (im = term.images; im; im = next) {
+					next = im->next;
+					if (im->y >= y1 && im->y < y2) {
+						y = im->y - scr;
+						if (y >= 0 && y < term.row && term.dirty[y]) {
+							line = term.line[y];
+							j = MIN(im->x + im->cols, term.col);
+							for (i = im->x; i < j; i++) {
+								if (line[i].mode & ATTR_SIXEL)
+									break;
+							}
+							if (i == j) {
+								delete_image(im);
+								continue;
+							}
+						}
+						if (im->x >= x1 && im->x + im->cols <= x2 && !transparent[im->y - y1]) {
+							delete_image(im);
+							continue;
+						}
+					}
+					tail = im;
+				}
+			}
+			if (tail) {
+				tail->next = newimages;
+				newimages->prev = tail;
+			} else {
+				term.images = newimages;
+			}
+			x2 = MIN(x2, term.col) - 1;
+			if (IS_SET(MODE_SIXEL_SDM)) {
+				/* Sixel display mode: put the sixel in the upper left corner of
+				 * the screen, disable scrolling (the sixel will be truncated if
+				 * it is too long) and do not change the cursor position. */
+				for (i = 0, im = newimages; im; im = next, i++) {
+					next = im->next;
+					if (i >= term.row) {
+						delete_image(im);
+						continue;
+					}
+					im->y = i + scr;
+					tsetsixelattr(term.line[i], x1, x2);
+					term.dirty[MIN(im->y, term.row-1)] = 1;
+				}
+			} else {
+				for (i = 0, im = newimages; im; im = next, i++) {
+					next = im->next;
+					im->y = term.c.y + scr;
+					tsetsixelattr(term.line[term.c.y], x1, x2);
+					term.dirty[MIN(im->y, term.row-1)] = 1;
+					if (i < numimages-1) {
+						im->next = NULL;
+						tnewline(0);
+						im->next = next;
+					}
+				}
+				/* if mode 8452 is set, sixel scrolling leaves cursor to right of graphic */
+				if (IS_SET(MODE_SIXEL_CUR_RT))
+					term.c.x = MIN(term.c.x + newimages->cols, term.col-1);
+			}
+		}
+		return;
 	case '_': /* APC -- Application Program Command */
 	case '^': /* PM -- Privacy Message */
 		return;
@@ -2007,6 +2229,16 @@ strparse(void)
 	if (*p == '\0')
 		return;
 
+	/* preserve semicolons in window titles, icon names and OSC 7 sequences */
+	if (strescseq.type == ']' && (
+		p[0] <= '2'
+	) && p[1] == ';') {
+		strescseq.args[strescseq.narg++] = p;
+		strescseq.args[strescseq.narg++] = p + 2;
+		p[1] = '\0';
+		return;
+	}
+
 	while (strescseq.narg < STR_ARG_SIZ) {
 		strescseq.args[strescseq.narg++] = p;
 		while ((c = *p) != ';' && c != '\0')
@@ -2041,7 +2273,7 @@ strdump(void)
 			fprintf(stderr, "(%02x)", c);
 		}
 	}
-	fprintf(stderr, "ESC\\\n");
+	fprintf(stderr, (strescseq.term[0] == 0x1b) ? "ESC\\\n" : "BEL\n");
 }
 
 void
@@ -2179,9 +2411,12 @@ tdectest(char c)
 void
 tstrsequence(uchar c)
 {
+	strreset();
+
 	switch (c) {
 	case 0x90:   /* DCS -- Device Control String */
 		c = 'P';
+		term.esc |= ESC_DCS;
 		break;
 	case 0x9f:   /* APC -- Application Program Command */
 		c = '_';
@@ -2193,7 +2428,6 @@ tstrsequence(uchar c)
 		c = ']';
 		break;
 	}
-	strreset();
 	strescseq.type = c;
 	term.esc |= ESC_STR;
 }
@@ -2220,6 +2454,7 @@ tcontrolcode(uchar ascii)
 	case '\a':   /* BEL */
 		if (term.esc & ESC_STR_END) {
 			/* backwards compatibility to xterm */
+			strescseq.term = STR_TERM_BEL;
 			strhandle();
 		} else {
 			xbell();
@@ -2295,6 +2530,38 @@ tcontrolcode(uchar ascii)
 	term.esc &= ~(ESC_STR_END|ESC_STR);
 }
 
+void
+dcshandle(void)
+{
+	int bgcolor, transparent;
+	unsigned char r, g, b, a = 255;
+
+	switch (csiescseq.mode[0]) {
+	default:
+	unknown:
+		fprintf(stderr, "erresc: unknown csi ");
+		csidump();
+		/* die(""); */
+		break;
+	case 'q': /* DECSIXEL */
+		transparent = (csiescseq.narg >= 2 && csiescseq.arg[1] == 1);
+		if (IS_TRUECOL(term.c.attr.bg)) {
+			r = term.c.attr.bg >> 16 & 255;
+			g = term.c.attr.bg >> 8 & 255;
+			b = term.c.attr.bg >> 0 & 255;
+		} else {
+			xgetcolor(term.c.attr.bg, &r, &g, &b);
+			if (term.c.attr.bg == defaultbg)
+				a = dc.col[defaultbg].pixel >> 24 & 255;
+		}
+		bgcolor = a << 24 | r << 16 | g << 8 | b;
+		if (sixel_parser_init(&sixel_st, transparent, (255 << 24), bgcolor, 1, win.cw, win.ch) != 0)
+			perror("sixel_parser_init() failed");
+		term.mode |= MODE_SIXEL;
+		break;
+	}
+}
+
 /*
  * returns 1 when the sequence is finished and it hasn't to read
  * more characters for this sequence, otherwise 0
@@ -2313,6 +2580,7 @@ eschandle(uchar ascii)
 		term.esc |= ESC_UTF8;
 		return 0;
 	case 'P': /* DCS -- Device Control String */
+		term.esc |= ESC_DCS;
 	case '_': /* APC -- Application Program Command */
 	case '^': /* PM -- Privacy Message */
 	case ']': /* OSC -- Operating System Command */
@@ -2372,8 +2640,10 @@ eschandle(uchar ascii)
 		tcursor(CURSOR_LOAD);
 		break;
 	case '\\': /* ST -- String Terminator */
-		if (term.esc & ESC_STR_END)
+		if (term.esc & ESC_STR_END) {
+			strescseq.term = STR_TERM_ST;
 			strhandle();
+		}
 		break;
 	default:
 		fprintf(stderr, "erresc: unknown sequence ESC 0x%02X '%c'\n",
@@ -2392,7 +2662,8 @@ tputc(Rune u)
 	Glyph *gp;
 
 	control = ISCONTROL(u);
-	if (u < 127 || !IS_SET(MODE_UTF8)) {
+	if (u < 127 || !IS_SET(MODE_UTF8))
+	{
 		c[0] = u;
 		width = len = 1;
 	} else {
@@ -2413,11 +2684,14 @@ tputc(Rune u)
 	if (term.esc & ESC_STR) {
 		if (u == '\a' || u == 030 || u == 032 || u == 033 ||
 		   ISCONTROLC1(u)) {
-			term.esc &= ~(ESC_START|ESC_STR);
+			term.esc &= ~(ESC_START|ESC_STR|ESC_DCS);
 			term.esc |= ESC_STR_END;
 			goto check_control_code;
 		}
 
+		if (term.esc & ESC_DCS)
+			goto check_control_code;
+
 		if (strescseq.len+len >= strescseq.siz) {
 			/*
 			 * Here is a bug in terminals. If the user never sends
@@ -2471,6 +2745,15 @@ check_control_code:
 				csihandle();
 			}
 			return;
+		} else if (term.esc & ESC_DCS) {
+			csiescseq.buf[csiescseq.len++] = u;
+			if (BETWEEN(u, 0x40, 0x7E)
+					|| csiescseq.len >= \
+					sizeof(csiescseq.buf)-1) {
+				csiparse();
+				dcshandle();
+			}
+			return;
 		} else if (term.esc & ESC_UTF8) {
 			tdefutf8(u);
 		} else if (term.esc & ESC_ALTCHARSET) {
@@ -2489,6 +2772,7 @@ check_control_code:
 		 */
 		return;
 	}
+
 	if (selected(term.c.x, term.c.y))
 		selclear();
 
@@ -2541,7 +2825,11 @@ twrite(const char *buf, int buflen, int show_ctrl)
 	int n;
 
 	for (n = 0; n < buflen; n += charsize) {
-		if (IS_SET(MODE_UTF8)) {
+		if (IS_SET(MODE_SIXEL) && sixel_st.state != PS_ESC) {
+			charsize = sixel_parser_parse(&sixel_st, (const unsigned char*)buf + n, buflen - n);
+			continue;
+		} else if (IS_SET(MODE_UTF8))
+		{
 			/* process a complete utf8 char */
 			charsize = utf8decode(buf + n, &u, buflen - n);
 			if (charsize == 0)
@@ -2568,11 +2856,13 @@ twrite(const char *buf, int buflen, int show_ctrl)
 void
 tresize(int col, int row)
 {
-	int i;
+	int i, j;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
 	int *bp;
-	TCursor c;
+	int x2;
+	Line line;
+	ImageList *im, *next;
 
 	if (col < 1 || row < 1) {
 		fprintf(stderr,
@@ -2580,23 +2870,19 @@ tresize(int col, int row)
 		return;
 	}
 
-	/*
-	 * slide screen to keep cursor where we expect it -
-	 * tscrollup would work here, but we can optimize to
-	 * memmove because we're freeing the earlier lines
-	 */
-	for (i = 0; i <= term.c.y - row; i++) {
-		free(term.line[i]);
-		free(term.alt[i]);
-	}
-	/* ensure that both src and dst are not NULL */
-	if (i > 0) {
-		memmove(term.line, term.line + i, row * sizeof(Line));
-		memmove(term.alt, term.alt + i, row * sizeof(Line));
-	}
-	for (i += row; i < term.row; i++) {
-		free(term.line[i]);
-		free(term.alt[i]);
+	/* scroll both screens independently */
+	if (row < term.row) {
+		tcursor(CURSOR_SAVE);
+		tsetscroll(0, term.row - 1);
+		for (i = 0; i < 2; i++) {
+			if (term.c.y >= row) {
+				tscrollup(0, term.c.y - row + 1);
+			}
+			for (j = row; j < term.row; j++)
+				free(term.line[j]);
+			tswapscreen();
+			tcursor(CURSOR_LOAD);
+		}
 	}
 
 	/* resize to new height */
@@ -2616,25 +2902,27 @@ tresize(int col, int row)
 		term.line[i] = xmalloc(col * sizeof(Glyph));
 		term.alt[i] = xmalloc(col * sizeof(Glyph));
 	}
-	if (col > term.col) {
+	if (col > term.col)
+	{
 		bp = term.tabs + term.col;
-
 		memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
+
 		while (--bp > term.tabs && !*bp)
 			/* nothing */ ;
 		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
 			*bp = 1;
 	}
+
 	/* update terminal size */
 	term.col = col;
 	term.row = row;
+
 	/* reset scrolling region */
 	tsetscroll(0, row-1);
-	/* make use of the LIMIT in tmoveto */
-	tmoveto(term.c.x, term.c.y);
 	/* Clearing both screens (it makes dirty all lines) */
-	c = term.c;
 	for (i = 0; i < 2; i++) {
+		tmoveto(term.c.x, term.c.y);  /* make use of the LIMIT in tmoveto */
+		tcursor(CURSOR_SAVE);
 		if (mincol < col && 0 < minrow) {
 			tclearregion(mincol, 0, col - 1, minrow - 1);
 		}
@@ -2644,7 +2932,22 @@ tresize(int col, int row)
 		tswapscreen();
 		tcursor(CURSOR_LOAD);
 	}
-	term.c = c;
+
+	/* expand images into new text cells */
+	for (i = 0; i < 2; i++) {
+		for (im = term.images; im; im = next) {
+			next = im->next;
+			if (im->y < 0 || im->y >= term.row) {
+				delete_image(im);
+				continue;
+			}
+			line = term.line[im->y];
+			x2 = MIN(im->x + im->cols, col) - 1;
+			if (mincol < col && x2 >= mincol && im->x < col)
+				tsetsixelattr(line, MAX(im->x, mincol), x2);
+		}
+		tswapscreen();
+	}
 }
 
 void
@@ -2667,6 +2970,7 @@ drawregion(int x1, int y1, int x2, int y2)
 	}
 }
 
+
 void
 draw(void)
 {
@@ -2684,6 +2988,7 @@ draw(void)
 		cx--;
 
 	drawregion(0, 0, term.col, term.row);
+
 	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
 			term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
 	term.ocx = cx;