support colons in SGR character attributes

Patch by Mikhail Kot <to@myrrc.dev>
With some modifications to behave more like xterm (see note below).

Example:

	printf '\033[48;2;255:0:0mtest\n'

https://invisible-island.net/xterm/ctlseqs/ctlseqs.html

Some notes:

"CSI Pm m  Character Attributes (SGR).
[...]
o   xterm allows either colons (standard) or semicolons
(legacy) to separate the subparameters (but after the
first colon, colons must be used).

README.md

@@ -1,4 +1,4 @@
-Similar to [dwm-flexipatch](https://github.com/bakkeby/dwm-flexipatch) this st 0.9 (95f22c5, 2024-03-04) project has a different take on st patching. It uses preprocessor directives to decide whether or not to include a patch during build time. Essentially this means that this build, for better or worse, contains both the patched _and_ the original code. The aim being that you can select which patches to include and the build will contain that code and nothing more.
+Similar to [dwm-flexipatch](https://github.com/bakkeby/dwm-flexipatch) this st 0.9.2 (5dbcca4, 2024-05-01) project has a different take on st patching. It uses preprocessor directives to decide whether or not to include a patch during build time. Essentially this means that this build, for better or worse, contains both the patched _and_ the original code. The aim being that you can select which patches to include and the build will contain that code and nothing more.
 
 For example to include the `alpha` patch then you would only need to flip this setting from 0 to 1 in [patches.h](https://github.com/bakkeby/st-flexipatch/blob/master/patches.def.h):
 ```c

config.def.h

@@ -96,7 +96,7 @@ int allowwindowops = 0;
  * near minlatency, but it waits longer for slow updates to avoid partial draw.
  * low minlatency will tear/flicker more, as it can "detect" idle too early.
  */
-static double minlatency = 8;
+static double minlatency = 2;
 static double maxlatency = 33;
 
 #if SYNC_PATCH

config.mk

@@ -1,5 +1,5 @@
 # st version
-VERSION = 0.9
+VERSION = 0.9.2
 
 # Customize below to fit your system
 

patch/externalpipe.c

@@ -42,7 +42,11 @@ externalpipe(const Arg *arg)
 	newline = 0;
 	for (n = 0; n < term.row; n++) {
 		bp = term.line[n];
+		#if REFLOW_PATCH
+		lastpos = MIN(tlinelen(TLINE(n)) + 1, term.col) - 1;
+		#else
 		lastpos = MIN(tlinelen(n) + 1, term.col) - 1;
+		#endif // REFLOW_PATCH
 		if (lastpos < 0)
 			break;
 		end = &bp[lastpos + 1];

patch/reflow.c

@@ -81,7 +81,7 @@ treflow(int col, int row)
 	int oce, nce, bot, scr;
 	int ox = 0, oy = -term.histf, nx = 0, ny = -1, len;
 	int cy = -1; /* proxy for new y coordinate of cursor */
-	int buflen, nlines, del;
+	int buflen, nlines;
 	Line *buf, bufline, line;
 	#if SIXEL_PATCH
 	ImageList *im, *next;
@@ -219,21 +219,14 @@ treflow(int col, int row)
 		}
 	}
 
-	/* expand images into new text cells or
-	 * delete images if there is text behind them */
+	/* expand images into new text cells */
 	for (im = term.images; im; im = next) {
 		next = im->next;
 		if (im->x < col) {
 			line = TLINE(im->y);
 			x2 = MIN(im->x + im->cols, col);
-			for (del = 0, x = im->x; x < x2; x++) {
-				if ((del = line[x].mode & ATTR_SET))
-					break;
-				line[x].u = ' ';
-				line[x].mode = ATTR_SIXEL;
-			}
-			if (del)
-				delete_image(im);
+			for (x = im->x; x < x2; x++)
+				line[x].mode |= ATTR_SIXEL;
 		}
 	}
 	#endif // SIXEL_PATCH

sixel.c

@@ -66,6 +66,8 @@ delete_image(ImageList *im)
 		im->next->prev = im->prev;
 	if (im->pixmap)
 		XFreePixmap(xw.dpy, (Drawable)im->pixmap);
+	if (im->clipmask)
+		XFreePixmap(xw.dpy, (Drawable)im->clipmask);
 	free(im->pixels);
 	free(im);
 }
@@ -217,6 +219,7 @@ sixel_image_deinit(sixel_image_t *image)
 
 int
 sixel_parser_init(sixel_state_t *st,
+                  int transparent,
                   sixel_color_t fgcolor, sixel_color_t bgcolor,
                   unsigned char use_private_register,
                   int cell_width, int cell_height)
@@ -232,6 +235,7 @@ sixel_parser_init(sixel_state_t *st,
 	st->attributed_pad = 1;
 	st->attributed_ph = 0;
 	st->attributed_pv = 0;
+	st->transparent = transparent;
 	st->repeat_count = 1;
 	st->color_index = 16;
 	st->grid_width = cell_width;
@@ -240,7 +244,7 @@ sixel_parser_init(sixel_state_t *st,
 	st->param = 0;
 
 	/* buffer initialization */
-	status = sixel_image_init(&st->image, 1, 1, fgcolor, bgcolor, use_private_register);
+	status = sixel_image_init(&st->image, 1, 1, fgcolor, transparent ? 0 : bgcolor, use_private_register);
 
 	return status;
 }
@@ -304,8 +308,10 @@ sixel_parser_finalize(sixel_state_t *st, ImageList **newimages, int cx, int cy,
 			im->height = MIN(h - ch * i, ch);
 			im->pixels = malloc(im->width * im->height * 4);
 			im->pixmap = NULL;
+			im->clipmask = NULL;
 			im->cw = cw;
 			im->ch = ch;
+			im->transparent = st->transparent;
 		}
 		if (!im || !im->pixels) {
 			for (im = *newimages; im; im = next) {
@@ -652,3 +658,35 @@ sixel_parser_deinit(sixel_state_t *st)
 	if (st)
 		sixel_image_deinit(&st->image);
 }
+
+Pixmap
+sixel_create_clipmask(char *pixels, int width, int height)
+{
+	char c, *clipdata, *dst;
+	int b, i, n, y, w;
+	int msb = (XBitmapBitOrder(xw.dpy) == MSBFirst);
+	sixel_color_t *src = (sixel_color_t *)pixels;
+	Pixmap clipmask;
+
+	clipdata = dst = malloc((width+7)/8 * height);
+	if (!clipdata)
+		return (Pixmap)None;
+
+	for (y = 0; y < height; y++) {
+		for (w = width; w > 0; w -= n) {
+			n = MIN(w, 8);
+			if (msb) {
+				for (b = 0x80, c = 0, i = 0; i < n; i++, b >>= 1)
+					c |= (*src++) ? b : 0;
+			} else {
+				for (b = 0x01, c = 0, i = 0; i < n; i++, b <<= 1)
+					c |= (*src++) ? b : 0;
+			}
+			*dst++ = c;
+		}
+	}
+
+	clipmask = XCreateBitmapFromData(xw.dpy, xw.win, clipdata, width, height);
+	free(clipdata);
+	return clipmask;
+}

sixel.h

@@ -39,6 +39,7 @@ typedef struct parser_context {
 	int attributed_pad;
 	int attributed_ph;
 	int attributed_pv;
+	int transparent;
 	int repeat_count;
 	int color_index;
 	int bgindex;
@@ -52,10 +53,11 @@ typedef struct parser_context {
 
 void scroll_images(int n);
 void delete_image(ImageList *im);
-int sixel_parser_init(sixel_state_t *st, sixel_color_t fgcolor, sixel_color_t bgcolor, unsigned char use_private_register, int cell_width, int cell_height);
+int sixel_parser_init(sixel_state_t *st, int transparent, sixel_color_t fgcolor, sixel_color_t bgcolor, unsigned char use_private_register, int cell_width, int cell_height);
 int sixel_parser_parse(sixel_state_t *st, const unsigned char *p, size_t len);
 int sixel_parser_set_default_color(sixel_state_t *st);
 int sixel_parser_finalize(sixel_state_t *st, ImageList **newimages, int cx, int cy, int cw, int ch);
 void sixel_parser_deinit(sixel_state_t *st);
+Pixmap sixel_create_clipmask(char *pixels, int width, int height);
 
 #endif

st.c

@@ -1498,6 +1498,7 @@ csiparse(void)
 {
 	char *p = csiescseq.buf, *np;
 	long int v;
+	int sep = ';'; /* colon or semi-colon, but not both */
 
 	csiescseq.narg = 0;
 	if (*p == '?') {
@@ -1518,7 +1519,9 @@ csiparse(void)
 		#if UNDERCURL_PATCH
 		readcolonargs(&p, csiescseq.narg-1, csiescseq.carg);
 		#endif // UNDERCURL_PATCH
-		if (*p != ';' || csiescseq.narg == ESC_ARG_SIZ)
+		if (sep == ';' && *p == ':')
+			sep = ':'; /* allow override to colon once */
+		if (*p != sep || csiescseq.narg == ESC_ARG_SIZ)
 			break;
 		p++;
 	}
@@ -2227,10 +2230,8 @@ csihandle(void)
 			/* vte does this:
 			tscrollup(0, term.row-1, term.row, SCROLL_SAVEHIST); */
 			/* alacritty does this: */
-			#if KEYBOARDSELECT_PATCH
 			for (n = term.row-1; n >= 0 && tlinelen(term.line[n]) == 0; n--)
 				;
-			#endif // KEYBOARDSELECT_PATCH
 			#if SIXEL_PATCH
 			for (im = term.images; im; im = im->next)
 				n = MAX(im->y - term.scr, n);
@@ -2716,14 +2717,18 @@ strhandle(void)
 			y1 = newimages->y;
 			x2 = x1 + newimages->cols;
 			y2 = y1 + numimages;
-			for (tail = NULL, im = term.images; im; im = next) {
-				next = im->next;
-				if (im->x >= x1 && im->x + im->cols <= x2 &&
-					im->y >= y1 && im->y <= y2) {
-					delete_image(im);
-					continue;
+			if (newimages->transparent) {
+				for (tail = term.images; tail && tail->next; tail = tail->next);
+			} else {
+				for (tail = NULL, im = term.images; im; im = next) {
+					next = im->next;
+					if (im->x >= x1 && im->x + im->cols <= x2 &&
+					    im->y >= y1 && im->y <= y2) {
+						delete_image(im);
+						continue;
+					}
+					tail = im;
 				}
-				tail = im;
 			}
 			if (tail) {
 				tail->next = newimages;
@@ -2749,8 +2754,7 @@ strhandle(void)
 					line = term.line[term.c.y];
 				}
 				for (x = im->x; x < x2; x++) {
-					line[x].u = ' ';
-					line[x].mode = ATTR_SIXEL;
+					line[x].mode |= ATTR_SIXEL;
 				}
 				term.dirty[MIN(im->y, term.row-1)] = 1;
 				if (!IS_SET(MODE_SIXEL_SDM) && i < numimages-1) {
@@ -3099,7 +3103,7 @@ tcontrolcode(uchar ascii)
 void
 dcshandle(void)
 {
-	int bgcolor;
+	int bgcolor, transparent;
 	unsigned char r, g, b, a = 255;
 
 	switch (csiescseq.mode[0]) {
@@ -3121,6 +3125,7 @@ dcshandle(void)
 		break;
 	#endif // SYNC_PATCH
 	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;
@@ -3131,7 +3136,7 @@ dcshandle(void)
 				a = dc.col[defaultbg].pixel >> 24 & 255;
 		}
 		bgcolor = a << 24 | r << 16 | g << 8 | b;
-		if (sixel_parser_init(&sixel_st, (255 << 24), bgcolor, 1, win.cw, win.ch) != 0)
+		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;
@@ -3634,10 +3639,8 @@ tresize(int col, int row)
 			line = term.line[im->y];
 			#endif // SCROLLBACK_PATCH
 			x2 = MIN(im->x + im->cols, term.col);
-			for (x = im->x; x < x2; x++) {
-				line[x].u = ' ';
-				line[x].mode = ATTR_SIXEL;
-			}
+			for (x = im->x; x < x2; x++)
+				line[x].mode |= ATTR_SIXEL;
 		}
 		tswapscreen();
 	}
@@ -3694,12 +3697,10 @@ draw(void)
 	drawregion(0, 0, term.col, term.row);
 
 	#if KEYBOARDSELECT_PATCH && REFLOW_PATCH
-	if (!kbds_drawcursor()) {
-	#endif // KEYBOARDSELECT_PATCH
-
-	#if SCROLLBACK_PATCH
+	if (!kbds_drawcursor())
+	#elif REFLOW_PATCH || SCROLLBACK_PATCH
 	if (term.scr == 0)
-	#endif // SCROLLBACK_PATCH
+	#endif // SCROLLBACK_PATCH | REFLOW_PATCH | KEYBOARDSELECT_PATCH
 	#if LIGATURES_PATCH
 	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
 			term.ocx, term.ocy, term.line[term.ocy][term.ocx],
@@ -3708,9 +3709,6 @@ draw(void)
 	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
 			term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
 	#endif // LIGATURES_PATCH
-	#if KEYBOARDSELECT_PATCH && REFLOW_PATCH
-	}
-	#endif // KEYBOARDSELECT_PATCH
 	term.ocx = cx;
 	term.ocy = term.c.y;
 	xfinishdraw();

st.h

@@ -77,6 +77,7 @@ typedef struct _ImageList {
 	struct _ImageList *next, *prev;
 	unsigned char *pixels;
 	void *pixmap;
+	void *clipmask;
 	int width;
 	int height;
 	int x;
@@ -87,6 +88,7 @@ typedef struct _ImageList {
 	int cols;
 	int cw;
 	int ch;
+	int transparent;
 } ImageList;
 #endif // SIXEL_PATCH
 

x.c

@@ -325,7 +325,10 @@ zoomabs(const Arg *arg)
 	for (im = term.images; im; im = im->next) {
 		if (im->pixmap)
 			XFreePixmap(xw.dpy, (Drawable)im->pixmap);
+		if (im->clipmask)
+			XFreePixmap(xw.dpy, (Drawable)im->clipmask);
 		im->pixmap = NULL;
+		im->clipmask = NULL;
 	}
 	#endif // SIXEL_PATCH
 
@@ -1018,6 +1021,9 @@ xloadcols(void)
 	dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
 	dc.col[defaultbg].pixel &= 0x00FFFFFF;
 	dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
+	dc.col[defaultbg].color.red   *= alpha;
+	dc.col[defaultbg].color.green *= alpha;
+	dc.col[defaultbg].color.blue  *= alpha;
 	#endif // ALPHA_PATCH
 	loaded = 1;
 }
@@ -1058,6 +1064,9 @@ xsetcolorname(int x, const char *name)
 		dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
 		dc.col[defaultbg].pixel &= 0x00FFFFFF;
 		dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
+		dc.col[defaultbg].color.red   *= alpha;
+		dc.col[defaultbg].color.green *= alpha;
+		dc.col[defaultbg].color.blue  *= alpha;
 	}
 	#endif // ALPHA_PATCH
 	return 0;
@@ -2854,6 +2863,9 @@ xseticontitle(char *p)
 	XTextProperty prop;
 	DEFAULT(p, opt_title);
 
+	if (p[0] == '\0')
+		p = opt_title;
+
 	if (Xutf8TextListToTextProperty(xw.dpy, &p, 1, XUTF8StringStyle,
 			&prop) != Success)
 		return;
@@ -2873,7 +2885,7 @@ xsettitle(char *p, int pop)
 		titlestack[tstki] = NULL;
 		tstki = (tstki - 1 + TITLESTACKSIZE) % TITLESTACKSIZE;
 		p = titlestack[tstki] ? titlestack[tstki] : opt_title;
-	} else if (p) {
+	} else if (p && p[0] != '\0') {
 		titlestack[tstki] = xstrdup(p);
 	} else {
 		titlestack[tstki] = NULL;
@@ -2913,6 +2925,9 @@ xsettitle(char *p)
 	XTextProperty prop;
 	DEFAULT(p, opt_title);
 
+	if (p[0] == '\0')
+		p = opt_title;
+
 	if (Xutf8TextListToTextProperty(xw.dpy, &p, 1, XUTF8StringStyle,
 			&prop) != Success)
 		return;
@@ -3126,7 +3141,7 @@ xfinishdraw(void)
 	XGCValues gcvalues;
 	GC gc;
 	int width, height;
-	int x, x2, del;
+	int x, x2, del, destx, desty;
 	Line line;
 	#endif // SIXEL_PATCH
 
@@ -3139,8 +3154,8 @@ xfinishdraw(void)
 			continue;
 
 		/* scale the image */
-		width = im->width * win.cw / im->cw;
-		height = im->height * win.ch / im->ch;
+		width = MAX(im->width * win.cw / im->cw, 1);
+		height = MAX(im->height * win.ch / im->ch, 1);
 		if (!im->pixmap) {
 			im->pixmap = (void *)XCreatePixmap(xw.dpy, xw.win, width, height,
 				#if ALPHA_PATCH
@@ -3149,6 +3164,8 @@ xfinishdraw(void)
 				DefaultDepth(xw.dpy, xw.scr)
 				#endif // ALPHA_PATCH
 			);
+			if (!im->pixmap)
+				continue;
 			if (win.cw == im->cw && win.ch == im->ch) {
 				XImage ximage = {
 					.format = ZPixmap,
@@ -3169,12 +3186,15 @@ xfinishdraw(void)
 					#endif // ALPHA_PATCH
 				};
 				XPutImage(xw.dpy, (Drawable)im->pixmap, dc.gc, &ximage, 0, 0, 0, 0, width, height);
+				if (im->transparent)
+					im->clipmask = (void *)sixel_create_clipmask((char *)im->pixels, width, height);
 			} else {
 				origin = imlib_create_image_using_data(im->width, im->height, (DATA32 *)im->pixels);
 				if (!origin)
 					continue;
 				imlib_context_set_image(origin);
 				imlib_image_set_has_alpha(1);
+				imlib_context_set_anti_alias(im->transparent ? 0 : 1); /* anti-aliasing messes up the clip mask */
 				scaled = imlib_create_cropped_scaled_image(0, 0, im->width, im->height, width, height);
 				imlib_free_image_and_decache();
 				if (!scaled)
@@ -3200,6 +3220,8 @@ xfinishdraw(void)
 					#endif // ALPHA_PATCH
 				};
 				XPutImage(xw.dpy, (Drawable)im->pixmap, dc.gc, &ximage, 0, 0, 0, 0, width, height);
+				if (im->transparent)
+					im->clipmask = (void *)sixel_create_clipmask((char *)imlib_image_get_data_for_reading_only(), width, height);
 				imlib_free_image_and_decache();
 			}
 		}
@@ -3228,12 +3250,17 @@ xfinishdraw(void)
 		gcvalues.graphics_exposures = False;
 		gc = XCreateGC(xw.dpy, xw.win, GCGraphicsExposures, &gcvalues);
 		#if ANYSIZE_PATCH
-		XCopyArea(xw.dpy, (Drawable)im->pixmap, xw.buf, gc, 0, 0,
-			width, height, win.hborderpx + im->x * win.cw, win.vborderpx + im->y * win.ch);
+		destx = win.hborderpx + im->x * win.cw;
+		desty = win.vborderpx + im->y * win.ch;
 		#else
-		XCopyArea(xw.dpy, (Drawable)im->pixmap, xw.buf, gc, 0, 0,
-			width, height, borderpx + im->x * win.cw, borderpx + im->y * win.ch);
+		destx = borderpx + im->x * win.cw;
+		desty = borderpx + im->y * win.ch;
 		#endif // ANYSIZE_PATCH
+		if (im->clipmask) {
+			XSetClipMask(xw.dpy, gc, (Drawable)im->clipmask);
+			XSetClipOrigin(xw.dpy, gc, destx, desty);
+		}
+		XCopyArea(xw.dpy, (Drawable)im->pixmap, xw.buf, gc, 0, 0, width, height, destx, desty);
 		XFreeGC(xw.dpy, gc);
 	}
 	#endif // SIXEL_PATCH