Terminal compatibility batch

- Answer kitty keyboard protocol queries (CSI ?u -> CSI ?0u) and silently
  accept push/pop/set so clients detect the lack of support without a
  timeout, and so st stops logging them as unknown sequences.
- XTVERSION (CSI >0q) reports st(VERSION).
- DECRQM (CSI ?Ps$p / CSI Ps$p) reports the state of the common private
  and ANSI modes including 2026 (synchronized updates) and 2004.
- csiparse() now recognises the >, < and = private prefixes.
- New OSC7_OSC8_PATCH: OSC 7 stores the shell's working directory in
  term.cwd; OSC 8 hyperlinks are stored per cell and, with the
  openurlonclick patch, are clickable and take precedence over URL text
  detection.
- kitty: Unicode placeholder cells are now blitted from one cached scaled
  pixmap per virtual placement instead of rescaling every cell on every
  redraw.

kitty.c

@@ -2295,123 +2295,47 @@ kitty_find_virtual(uint32_t imgid, uint32_t plcid)
 /*
  * Blit the part of a virtual placement that corresponds to one screen cell.
  * (px, py) is the cell on screen, (row, col) the cell within the placement.
+ *
+ * The whole placement is scaled once into the placement's pixmap cache
+ * (kitty_prepare), and each cell is then a cheap XRender copy out of it.
  */
 static void
 kitty_blit_cell(KittyPlacement *p, int px, int py, int row, int col)
 {
-	KittyImage *im = p->image;
-	const unsigned char *base;
-	unsigned char *cell;
-	int cw = win.cw, ch = win.ch;
-	int fullw, fullh, sx0, sy0, x, y, i, n;
-	unsigned char *tile;
-	Pixmap pm;
-	XImage ximage;
 	Picture src, dstpic;
 	XRenderPictFormat *fmt;
 	XRenderPictureAttributes pa;
-	int bx, by;
+	int w, h, bx, by, cw = win.cw, ch = win.ch;
+	int sx, sy, cellw, cellh;
 
-	if (!im || row >= p->rows || col >= p->cols)
+	if (!p->image || row >= p->rows || col >= p->cols)
+		return;
+	if (!kitty_prepare(p, &w, &h))
 		return;
 
-	fullw = p->cols * cw;
+	sx = col * cw;
-	fullh = p->rows * ch;
+	sy = row * ch;
-	if (fullw <= 0 || fullh <= 0)
+	cellw = KMIN(cw, w - sx);
+	cellh = KMIN(ch, h - sy);
+	if (cellw <= 0 || cellh <= 0)
 		return;
 
-	base = kitty_frame_pixels(im, im->current_frame);
-	if (!base)
-		return;
-	base += ((size_t)p->sy * im->width + p->sx) * 4;
-
-	/* scale just this cell out of the source rect */
-	sx0 = col * cw;
-	sy0 = row * ch;
-	if (!(cell = malloc((size_t)cw * ch * 4)))
-		return;
-	for (y = 0; y < ch; y++) {
-		double fy = ((double)(sy0 + y) + 0.5) * p->sh / fullh - 0.5;
-		int y0 = (int)(fy < 0 ? 0 : fy);
-		int y1 = KMIN(y0 + 1, p->sh - 1);
-		int wy = (int)((fy - y0) * 256);
-		if (wy < 0) wy = 0;
-		if (wy > 256) wy = 256;
-		for (x = 0; x < cw; x++) {
-			double fx = ((double)(sx0 + x) + 0.5) * p->sw / fullw - 0.5;
-			int x0 = (int)(fx < 0 ? 0 : fx);
-			int x1 = KMIN(x0 + 1, p->sw - 1);
-			int wx = (int)((fx - x0) * 256);
-			const unsigned char *q00, *q01, *q10, *q11;
-			unsigned char *o = cell + ((size_t)y * cw + x) * 4;
-			int c;
-			if (wx < 0) wx = 0;
-			if (wx > 256) wx = 256;
-			q00 = base + (size_t)y0 * im->width * 4 + x0 * 4;
-			q01 = base + (size_t)y0 * im->width * 4 + x1 * 4;
-			q10 = base + (size_t)y1 * im->width * 4 + x0 * 4;
-			q11 = base + (size_t)y1 * im->width * 4 + x1 * 4;
-			for (c = 0; c < 4; c++) {
-				int t = q00[c] * (256 - wx) + q01[c] * wx;
-				int b = q10[c] * (256 - wx) + q11[c] * wx;
-				o[c] = (unsigned char)((t * (256 - wy) + b * wy) >> 16);
-			}
-		}
-	}
-
-	tile = cell;
-	n = cw * ch;
-	for (i = 0; i < n; i++) {
-		unsigned char r = tile[4*i+0], g = tile[4*i+1];
-		unsigned char b = tile[4*i+2], a = tile[4*i+3];
-		tile[4*i+0] = (unsigned char)(b * a / 255);
-		tile[4*i+1] = (unsigned char)(g * a / 255);
-		tile[4*i+2] = (unsigned char)(r * a / 255);
-		tile[4*i+3] = a;
-	}
-
-	pm = XCreatePixmap(xw.dpy, xw.win, cw, ch, 32);
-	if (!pm) {
-		free(cell);
-		return;
-	}
-	memset(&ximage, 0, sizeof ximage);
-	ximage.format = ZPixmap;
-	ximage.data = (char *)tile;
-	ximage.width = cw;
-	ximage.height = ch;
-	ximage.byte_order = LSBFirst;
-	ximage.bitmap_bit_order = MSBFirst;
-	ximage.bits_per_pixel = 32;
-	ximage.bytes_per_line = cw * 4;
-	ximage.bitmap_unit = 32;
-	ximage.bitmap_pad = 32;
-	ximage.depth = 32;
-	XInitImage(&ximage);
-	{
-		GC gc = XCreateGC(xw.dpy, pm, 0, NULL);
-		XPutImage(xw.dpy, pm, gc, &ximage, 0, 0, 0, 0, cw, ch);
-		XFreeGC(xw.dpy, gc);
-	}
-	free(cell);
-
 	kitty_border(&bx, &by);
 
 	memset(&pa, 0, sizeof pa);
 	fmt = XRenderFindStandardFormat(xw.dpy, PictStandardARGB32);
-	if (fmt) {
+	if (!fmt)
-		src = XRenderCreatePicture(xw.dpy, pm, fmt, 0, &pa);
+		return;
+	src = XRenderCreatePicture(xw.dpy, (Drawable)p->pixmap, fmt, 0, &pa);
 	fmt = XRenderFindVisualFormat(xw.dpy, xw.vis);
 	if (fmt) {
 		dstpic = XRenderCreatePicture(xw.dpy, xw.buf, fmt, 0, &pa);
-			XRenderComposite(xw.dpy, PictOpOver, src, None, dstpic, 0, 0, 0, 0,
+		XRenderComposite(xw.dpy, PictOpOver, src, None, dstpic, sx, sy, 0, 0,
-			                 bx + px * cw, by + py * ch, cw, ch);
+		                 bx + px * cw, by + py * ch, cellw, cellh);
 		XRenderFreePicture(xw.dpy, dstpic);
 	}
 	XRenderFreePicture(xw.dpy, src);
 }
-	XFreePixmap(xw.dpy, pm);
-}
 
 /* scan the visible screen for placeholder glyphs and draw their images */
 static void

patch/openurlonclick.c

@@ -61,6 +61,30 @@ clearurl(void)
 	url_y2 = -1;
 }
 
+#if OSC7_OSC8_PATCH
+/* an explicit OSC 8 hyperlink takes precedence over text detection */
+static char *
+detecthyperlink(int col, int row, int draw)
+{
+	int x1, y1, x2, y2;
+	uint32_t id = hyperlink_at(col, row, &x1, &y1, &x2, &y2);
+	const char *url;
+
+	if (!id || !(url = hyperlink_get(id)))
+		return NULL;
+	if (draw) {
+		url_x1 = x1;
+		url_x2 = x2;
+		url_y1 = y1;
+		url_y2 = y2;
+		url_maxcol = x2;
+		url_draw = 1;
+		term.dirty[y1] = 1;
+	}
+	return (char *)url;
+}
+#endif // OSC7_OSC8_PATCH
+
 #if REFLOW_PATCH
 char *
 detecturl(int col, int row, int draw)
@@ -72,11 +96,19 @@ detecturl(int col, int row, int draw)
 	int row_start = row, col_start = col;
 	int minrow = tisaltscr() ? 0 : term.scr - term.histf;
 	int maxrow = tisaltscr() ? term.row - 1 : term.scr + term.row - 1;
+	#if OSC7_OSC8_PATCH
+	char *link;
+	#endif // OSC7_OSC8_PATCH
 
 	/* clear previously underlined url */
 	if (draw)
 		clearurl();
 
+	#if OSC7_OSC8_PATCH
+	if ((link = detecthyperlink(col, row, draw)))
+		return link;
+	#endif // OSC7_OSC8_PATCH
+
 	url_maxcol = 0;
 	line = TLINE(row);
 
@@ -143,6 +175,9 @@ char *
 detecturl(int col, int row, int draw)
 {
 	static char url[2048];
+	#if OSC7_OSC8_PATCH
+	char *link;
+	#endif // OSC7_OSC8_PATCH
 	int x1, y1, x2, y2, wrapped;
 	int row_start = row;
 	int col_start = col;
@@ -162,6 +197,11 @@ detecturl(int col, int row, int draw)
 	if (draw)
 		clearurl();
 
+	#if OSC7_OSC8_PATCH
+	if ((link = detecthyperlink(col, row, draw)))
+		return link;
+	#endif // OSC7_OSC8_PATCH
+
 	if (!isvalidurlchar(TLINEURL(row)[col].u))
 		return NULL;
 

patch/reflow.c

@@ -68,6 +68,9 @@ tclearglyph(Glyph *gp, int usecurattr)
 	#if KITTY_GRAPHICS_PATCH
 	gp->kitty = 0;
 	#endif // KITTY_GRAPHICS_PATCH
+	#if OSC7_OSC8_PATCH
+	gp->link = 0;
+	#endif // OSC7_OSC8_PATCH
 }
 
 #if SIXEL_PATCH

patches.def.h

@@ -357,6 +357,14 @@
  */
 #define KITTY_GRAPHICS_PATCH 0
 
+/* This patch adds support for OSC 7 (current working directory reporting) and
+ * OSC 8 (hyperlinks). Shells and programs can mark ranges of text as links to
+ * arbitrary URLs; with the openurlonclick patch these become clickable and
+ * take precedence over URL text detection. The working directory reported by
+ * the shell is stored in term.cwd for use by e.g. new window shortcuts.
+ */
+#define OSC7_OSC8_PATCH 0
+
 /* This patch adds SIXEL graphics support for st.
  * Note that patch/sixel.c/sixel_hls.c come from mintty, licensed under GPL.
  * Known issues:

patches.h

@@ -357,6 +357,14 @@
  */
 #define KITTY_GRAPHICS_PATCH 1
 
+/* This patch adds support for OSC 7 (current working directory reporting) and
+ * OSC 8 (hyperlinks). Shells and programs can mark ranges of text as links to
+ * arbitrary URLs; with the openurlonclick patch these become clickable and
+ * take precedence over URL text detection. The working directory reported by
+ * the shell is stored in term.cwd for use by e.g. new window shortcuts.
+ */
+#define OSC7_OSC8_PATCH 1
+
 /* This patch adds SIXEL graphics support for st.
  * Note that patch/sixel.c/sixel_hls.c come from mintty, licensed under GPL.
  * Known issues:

st.c

@@ -143,6 +143,7 @@ typedef struct {
 	char buf[ESC_BUF_SIZ]; /* raw string */
 	size_t len;            /* raw string length */
 	char priv;
+	char prefix;           /* '>', '<' or '=' private prefix */
 	int arg[ESC_ARG_SIZ];
 	int narg;              /* nb of args */
 	char mode[2];
@@ -226,6 +227,7 @@ static void tsetdirt(int, int);
 static void tsetscroll(int, int);
 static void tswapscreen(void);
 static void tsetmode(int, int, const int *, int);
+static int tmodestatus(int, int);
 static int twrite(const char *, int, int);
 static void tcontrolcode(uchar );
 static void tdectest(char );
@@ -270,6 +272,115 @@ static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF
 
 #include "patch/st_include.h"
 
+#if OSC7_OSC8_PATCH
+/*
+ * OSC 8 hyperlinks. Each distinct (id, url) pair gets a numeric handle that
+ * is stored in Glyph.link. Links with an explicit id= parameter are shared
+ * between all cells using that id, so a link split across lines still counts
+ * as one link.
+ */
+typedef struct {
+	char *id;    /* the id= parameter, or NULL */
+	char *url;
+} Hyperlink;
+
+static Hyperlink *hyperlinks;   /* index 0 is unused (0 == no link) */
+static uint32_t nhyperlinks, hyperlinkcap;
+static uint32_t curlink;        /* link applied to newly printed cells */
+
+static uint32_t
+hyperlink_add(const char *id, const char *url)
+{
+	uint32_t i;
+	Hyperlink *h;
+
+	if (!url || !*url)
+		return 0;
+
+	/* reuse an existing entry for the same id and url */
+	for (i = 1; i < nhyperlinks; i++) {
+		h = &hyperlinks[i];
+		if (!strcmp(h->url, url) &&
+		    ((!id && !h->id) || (id && h->id && !strcmp(id, h->id))))
+			return i;
+	}
+
+	if (nhyperlinks + 1 > hyperlinkcap) {
+		uint32_t ncap = hyperlinkcap ? hyperlinkcap * 2 : 64;
+		hyperlinks = xrealloc(hyperlinks, ncap * sizeof *hyperlinks);
+		if (!nhyperlinks) {
+			hyperlinks[0].id = hyperlinks[0].url = NULL;
+			nhyperlinks = 1;
+		}
+		hyperlinkcap = ncap;
+	}
+	h = &hyperlinks[nhyperlinks];
+	h->id = (id && *id) ? xstrdup(id) : NULL;
+	h->url = xstrdup(url);
+	return nhyperlinks++;
+}
+
+const char *
+hyperlink_get(uint32_t id)
+{
+	if (id == 0 || id >= nhyperlinks)
+		return NULL;
+	return hyperlinks[id].url;
+}
+
+/* handle "OSC 8 ; params ; url": params is a ':'-separated key=value list */
+static void
+hyperlink_osc(const char *params, const char *url)
+{
+	char idbuf[256], *id = NULL;
+	const char *p = params;
+
+	while (p && *p) {
+		const char *end = strchr(p, ':');
+		size_t n = end ? (size_t)(end - p) : strlen(p);
+		if (n > 3 && !strncmp(p, "id=", 3)) {
+			n = MIN(n - 3, sizeof idbuf - 1);
+			memcpy(idbuf, p + 3, n);
+			idbuf[n] = '\0';
+			id = idbuf;
+		}
+		p = end ? end + 1 : NULL;
+	}
+	curlink = hyperlink_add(id, url);
+}
+
+/*
+ * Find the extent of the link at (col, row) on the visible screen. Returns
+ * the link handle, or 0 if the cell is not part of a link. The returned
+ * rectangle covers the contiguous run on this row; use hyperlink_get() for
+ * the url.
+ */
+uint32_t
+hyperlink_at(int col, int row, int *x1, int *y1, int *x2, int *y2)
+{
+	Line line;
+	uint32_t id;
+	int x;
+
+	if (row < 0 || row >= term.row || col < 0 || col >= term.col)
+		return 0;
+	#if REFLOW_PATCH || SCROLLBACK_PATCH
+	line = TLINE(row);
+	#else
+	line = term.line[row];
+	#endif
+	if (!(id = line[col].link))
+		return 0;
+	for (x = col; x > 0 && line[x-1].link == id; x--);
+	*x1 = x;
+	for (x = col; x < term.col-1 && line[x+1].link == id; x++);
+	*x2 = x;
+	*y1 = *y2 = row;
+	return id;
+}
+#endif // OSC7_OSC8_PATCH
+
+
 ssize_t
 xwrite(int fd, const char *s, size_t len)
 {
@@ -1204,6 +1315,9 @@ treset(void)
 	term.top = 0;
 	term.bot = term.row - 1;
 	term.mode = MODE_WRAP|MODE_UTF8;
+	#if OSC7_OSC8_PATCH
+	curlink = 0;
+	#endif // OSC7_OSC8_PATCH
 	memset(term.trantbl, CS_USA, sizeof(term.trantbl));
 	term.charset = 0;
 	#if REFLOW_PATCH
@@ -1508,9 +1622,13 @@ csiparse(void)
 	int sep = ';'; /* colon or semi-colon, but not both */
 
 	csiescseq.narg = 0;
+	csiescseq.prefix = '\0';
 	if (*p == '?') {
 		csiescseq.priv = 1;
 		p++;
+	} else if (*p == '>' || *p == '<' || *p == '=') {
+		csiescseq.prefix = *p;
+		p++;
 	}
 
 	csiescseq.buf[csiescseq.len] = '\0';
@@ -1610,6 +1728,10 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 		term.line[y][x].mode |= ATTR_BOXDRAW;
 	#endif // BOXDRAW_PATCH
 
+	#if OSC7_OSC8_PATCH
+	term.line[y][x].link = curlink;
+	#endif // OSC7_OSC8_PATCH
+
 	#if KITTY_GRAPHICS_PATCH
 	term.line[y][x].kitty = 0;
 	if (u == KITTY_PLACEHOLDER)
@@ -1951,6 +2073,49 @@ tsetscroll(int t, int b)
 	term.bot = b;
 }
 
+/* DECRQM: report the state of a mode */
+static int
+tmodestatus(int priv, int mode)
+{
+	int wm = win.mode;
+
+	if (priv) {
+		switch (mode) {
+		case 1:    return (wm & MODE_APPCURSOR) ? 1 : 2;
+		case 6:    return (term.c.state & CURSOR_ORIGIN) ? 1 : 2;
+		case 7:    return IS_SET(MODE_WRAP) ? 1 : 2;
+		case 12:   return 0;
+		case 25:   return (wm & MODE_HIDE) ? 2 : 1;
+		case 47:
+		case 1047:
+		case 1049: return IS_SET(MODE_ALTSCREEN) ? 1 : 2;
+		case 9:    return (wm & MODE_MOUSEX10) ? 1 : 2;
+		case 1000: return (wm & MODE_MOUSEBTN) ? 1 : 2;
+		case 1002: return (wm & MODE_MOUSEMOTION) ? 1 : 2;
+		case 1003: return (wm & MODE_MOUSEMANY) ? 1 : 2;
+		case 1004: return (wm & MODE_FOCUS) ? 1 : 2;
+		case 1006: return (wm & MODE_MOUSESGR) ? 1 : 2;
+		case 1034: return (wm & MODE_8BIT) ? 1 : 2;
+		case 2004: return (wm & MODE_BRCKTPASTE) ? 1 : 2;
+		#if SYNC_PATCH
+		case 2026: return su ? 1 : 2;
+		#endif // SYNC_PATCH
+		#if SIXEL_PATCH
+		case 80:   return IS_SET(MODE_SIXEL_SDM) ? 1 : 2;
+		case 8452: return IS_SET(MODE_SIXEL_CUR_RT) ? 1 : 2;
+		#endif // SIXEL_PATCH
+		}
+		return 0;
+	}
+	switch (mode) {
+	case 2:  return 4; /* KAM, always reset */
+	case 4:  return IS_SET(MODE_INSERT) ? 1 : 2;
+	case 12: return IS_SET(MODE_ECHO) ? 2 : 1;
+	case 20: return IS_SET(MODE_CRLF) ? 1 : 2;
+	}
+	return 0;
+}
+
 void
 tsetmode(int priv, int set, const int *args, int narg)
 {
@@ -2535,9 +2700,47 @@ csihandle(void)
 		}
 		break;
 	#endif // CSI_22_23_PATCH | SIXEL_PATCH
-	case 'u': /* DECRC -- Restore cursor position (ANSI.SYS) */
+	case 'u':
+		if (csiescseq.priv) {
+			/* CSI ? u -- kitty keyboard protocol: query flags. We do not
+			 * implement the protocol, so answer with no flags set. */
+			ttywrite("\033[?0u", 5, 0);
+			break;
+		}
+		if (csiescseq.prefix == '>' || csiescseq.prefix == '<' ||
+		    csiescseq.prefix == '=') {
+			/* CSI > flags u (push), CSI < flags u (pop), CSI = flags ; mode u
+			 * (set): kitty keyboard protocol, silently ignored. */
+			break;
+		}
+		/* DECRC -- Restore cursor position (ANSI.SYS) */
 		tcursor(CURSOR_LOAD);
 		break;
+	case 'q':
+		if (csiescseq.prefix == '>') {
+			/* XTVERSION -- CSI > Ps q: report terminal name and version */
+			n = snprintf(buffer, sizeof(buffer), "\033P>|st(%s)\033\\", VERSION);
+			ttywrite(buffer, n, 0);
+			break;
+		}
+		goto unknown;
+	case '$':
+		switch (csiescseq.mode[1]) {
+		case 'p': /* DECRQM -- request mode */
+			/*
+			 * Reply: CSI ? Pd ; Ps $ y   (ANSI: CSI Pd ; Ps $ y)
+			 * Ps: 0 not recognized, 1 set, 2 reset,
+			 *     3 permanently set, 4 permanently reset
+			 */
+			n = snprintf(buffer, sizeof(buffer), "\033[%s%d;%d$y",
+			             csiescseq.priv ? "?" : "", csiescseq.arg[0],
+			             tmodestatus(csiescseq.priv, csiescseq.arg[0]));
+			ttywrite(buffer, n, 0);
+			break;
+		default:
+			goto unknown;
+		}
+		break;
 	case ' ':
 		switch (csiescseq.mode[1]) {
 		case 'q': /* DECSCUSR -- Set Cursor Style */
@@ -2678,8 +2881,29 @@ strhandle(void)
 				}
 			}
 			return;
+		#if OSC7_OSC8_PATCH
+		case 7: /* current working directory: file://host/path */
+			if (narg > 1) {
+				p = strescseq.args[1];
+				if (!strncmp(p, "file://", 7)) {
+					/* skip the host part */
+					p += 7;
+					p = strchr(p, '/');
+				}
+				free(term.cwd);
+				term.cwd = (p && *p == '/') ? xstrdup(p) : NULL;
+			}
+			return;
+		case 8: /* hyperlink: OSC 8 ; params ; url */
+			if (narg > 2 && strescseq.args[2][0])
+				hyperlink_osc(strescseq.args[1], strescseq.args[2]);
+			else
+				curlink = 0;
+			return;
+		#else
 		case 8: /* Clear Hyperlinks */
 			return;
+		#endif // OSC7_OSC8_PATCH
 		case 10:
 		case 11:
 		case 12:

st.h

@@ -150,6 +150,9 @@ typedef struct {
 	#if KITTY_GRAPHICS_PATCH
 	uint32_t kitty;   /* kitty Unicode placeholder row/column/msb */
 	#endif // KITTY_GRAPHICS_PATCH
+	#if OSC7_OSC8_PATCH
+	uint32_t link;    /* OSC 8 hyperlink id, 0 == none */
+	#endif // OSC7_OSC8_PATCH
 } Glyph;
 
 typedef Glyph *Line;
@@ -208,6 +211,9 @@ typedef struct {
 	ImageList *images_alt; /* sixel images for alternate screen */
 	#endif // SIXEL_PATCH
 	Rune lastc;   /* last printed char outside of sequence, 0 if control */
+	#if OSC7_OSC8_PATCH
+	char *cwd;    /* working directory reported via OSC 7, or NULL */
+	#endif // OSC7_OSC8_PATCH
 } Term;
 
 typedef union {
@@ -376,6 +382,11 @@ char *getsel(void);
 
 size_t utf8encode(Rune, char *);
 
+#if OSC7_OSC8_PATCH
+const char *hyperlink_get(uint32_t id);
+uint32_t hyperlink_at(int col, int row, int *x1, int *y1, int *x2, int *y2);
+#endif // OSC7_OSC8_PATCH
+
 void *xmalloc(size_t);
 void *xrealloc(void *, size_t);
 char *xstrdup(const char *);