Adding undercurl patch ref. #20

README.md

@@ -15,7 +15,7 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
 
 ### Changelog:
 
-2021-05-08 - Added blinking cursor patch
+2021-05-08 - Added blinking cursor and undercurl patches
 
 2021-05-07 - Added xresources reload patch
 
@@ -169,6 +169,9 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
    - [themed-cursor](https://st.suckless.org/patches/themed_cursor/)
       - instead of a default X cursor, use the xterm cursor from your cursor theme
 
+   - [undercurl](https://st.suckless.org/patches/undercurl/)
+      - adds support for special underlines, e.g. curly / wavy underlines
+
    - [vertcenter](https://st.suckless.org/patches/vertcenter/)
       - vertically center lines in the space available if you have set a larger chscale in config.h
 

patches.def.h

@@ -258,6 +258,20 @@
  */
 #define THEMED_CURSOR_PATCH 0
 
+/* Adds support for special underlines.
+ *
+ * Example test command:
+ *    $ echo -e "\e[4:3m\e[58:5:10munderline\e[0m"
+ *                  ^ ^     ^ ^  ^- sets terminal color 10
+ *                  | |     |  \- indicates that terminal colors should be used
+ *                  | |      \- indicates that underline color is being set
+ *                  |  \- sets underline style to curvy
+ *                   \- set underline
+ *
+ * https://st.suckless.org/patches/undercurl/
+ */
+#define UNDERCURL_PATCH 0
+
 /* Vertically center lines in the space available if you have set a larger chscale in config.h
  * https://st.suckless.org/patches/vertcenter/
  */

st.c

@@ -42,6 +42,9 @@
 #define UTF_SIZ       4
 #define ESC_BUF_SIZ   (128*UTF_SIZ)
 #define ESC_ARG_SIZ   16
+#if UNDERCURL_PATCH
+#define CAR_PER_ARG   4
+#endif // UNDERCURL_PATCH
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
 
@@ -126,6 +129,9 @@ typedef struct {
 	int arg[ESC_ARG_SIZ];
 	int narg;              /* nb of args */
 	char mode[2];
+	#if UNDERCURL_PATCH
+	int carg[ESC_ARG_SIZ][CAR_PER_ARG]; /* colon args */
+	#endif // UNDERCURL_PATCH
 } CSIEscape;
 
 /* STR Escape sequence structs */
@@ -146,6 +152,9 @@ static void ttywriteraw(const char *, size_t);
 
 static void csidump(void);
 static void csihandle(void);
+#if UNDERCURL_PATCH
+static void readcolonargs(char **, int, int[][CAR_PER_ARG]);
+#endif // UNDERCURL_PATCH
 static void csiparse(void);
 static void csireset(void);
 static int eschandle(uchar);
@@ -1286,6 +1295,30 @@ tnewline(int first_col)
 	tmoveto(first_col ? 0 : term.c.x, y);
 }
 
+#if UNDERCURL_PATCH
+void
+readcolonargs(char **p, int cursor, int params[][CAR_PER_ARG])
+{
+	int i = 0;
+	for (; i < CAR_PER_ARG; i++)
+		params[cursor][i] = -1;
+
+	if (**p != ':')
+		return;
+
+	char *np = NULL;
+	i = 0;
+
+	while (**p == ':' && i < CAR_PER_ARG) {
+		while (**p == ':')
+			(*p)++;
+		params[cursor][i] = strtol(*p, &np, 10);
+		*p = np;
+		i++;
+	}
+}
+#endif // UNDERCURL_PATCH
+
 void
 csiparse(void)
 {
@@ -1308,6 +1341,9 @@ csiparse(void)
 			v = -1;
 		csiescseq.arg[csiescseq.narg++] = v;
 		p = np;
+		#if UNDERCURL_PATCH
+		readcolonargs(&p, csiescseq.narg-1, csiescseq.carg);
+		#endif // UNDERCURL_PATCH
 		if (*p != ';' || csiescseq.narg == ESC_ARG_SIZ)
 			break;
 		p++;
@@ -1537,6 +1573,12 @@ tsetattr(int *attr, int l)
 				ATTR_STRUCK     );
 			term.c.attr.fg = defaultfg;
 			term.c.attr.bg = defaultbg;
+			#if UNDERCURL_PATCH
+			term.c.attr.ustyle = -1;
+			term.c.attr.ucolor[0] = -1;
+			term.c.attr.ucolor[1] = -1;
+			term.c.attr.ucolor[2] = -1;
+			#endif // UNDERCURL_PATCH
 			break;
 		case 1:
 			term.c.attr.mode |= ATTR_BOLD;
@@ -1548,7 +1590,18 @@ tsetattr(int *attr, int l)
 			term.c.attr.mode |= ATTR_ITALIC;
 			break;
 		case 4:
+			#if UNDERCURL_PATCH
+			term.c.attr.ustyle = csiescseq.carg[i][0];
+
+			if (term.c.attr.ustyle != 0)
 				term.c.attr.mode |= ATTR_UNDERLINE;
+			else
+				term.c.attr.mode &= ~ATTR_UNDERLINE;
+
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			#else
+			term.c.attr.mode |= ATTR_UNDERLINE;
+			#endif // UNDERCURL_PATCH
 			break;
 		case 5: /* slow blink */
 			/* FALLTHROUGH */
@@ -1607,6 +1660,20 @@ tsetattr(int *attr, int l)
 		case 49:
 			term.c.attr.bg = defaultbg;
 			break;
+		#if UNDERCURL_PATCH
+		case 58:
+			term.c.attr.ucolor[0] = csiescseq.carg[i][1];
+			term.c.attr.ucolor[1] = csiescseq.carg[i][2];
+			term.c.attr.ucolor[2] = csiescseq.carg[i][3];
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			break;
+		case 59:
+			term.c.attr.ucolor[0] = -1;
+			term.c.attr.ucolor[1] = -1;
+			term.c.attr.ucolor[2] = -1;
+			term.c.attr.mode ^= ATTR_DIRTYUNDERLINE;
+			break;
+		#endif // UNDERCURL_PATCH
 		default:
 			if (BETWEEN(attr[i], 30, 37)) {
 				#if MONOCHROME_PATCH

st.h

@@ -59,6 +59,9 @@ enum glyph_attribute {
 	ATTR_SIXEL      = 1 << 13,
 	#endif // SIXEL_PATCH
 	ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
+	#if UNDERCURL_PATCH
+	ATTR_DIRTYUNDERLINE = 1 << 15,
+	#endif // UNDERCURL_PATCH
 };
 
 #if SIXEL_PATCH
@@ -115,6 +118,10 @@ typedef struct {
 	ushort mode;      /* attribute flags */
 	uint32_t fg;      /* foreground  */
 	uint32_t bg;      /* background  */
+	#if UNDERCURL_PATCH
+	int ustyle;	      /* underline style */
+	int ucolor[3];    /* underline color */
+	#endif // UNDERCURL_PATCH
 } Glyph;
 
 typedef Glyph *Line;

st.info

@@ -1,4 +1,5 @@
 st-mono| simpleterm monocolor,
+	Su,
 	acsc=+C\,D-A.B0E``aaffgghFiGjjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
 	am,
 	bce,

x.c

@@ -1713,7 +1713,100 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 
 	/* Render underline and strikethrough. */
 	if (base.mode & ATTR_UNDERLINE) {
+		#if UNDERCURL_PATCH
+		// Underline Color
+		int wlw = 1; // Wave Line Width
+		int linecolor;
+		if ((base.ucolor[0] >= 0) &&
+			!(base.mode & ATTR_BLINK && win.mode & MODE_BLINK) &&
+			!(base.mode & ATTR_INVISIBLE)
+		) {
+			// Special color for underline
+			// Index
+			if (base.ucolor[1] < 0) {
+				linecolor = dc.col[base.ucolor[0]].pixel;
+			}
+			// RGB
+			else {
+				XColor lcolor;
+				lcolor.red = base.ucolor[0] * 257;
+				lcolor.green = base.ucolor[1] * 257;
+				lcolor.blue = base.ucolor[2] * 257;
+				lcolor.flags = DoRed | DoGreen | DoBlue;
+				XAllocColor(xw.dpy, xw.cmap, &lcolor);
+				linecolor = lcolor.pixel;
+			}
+		} else {
+			// Foreground color for underline
+			linecolor = fg->pixel;
+		}
+
+		XGCValues ugcv = {
+			.foreground = linecolor,
+			.line_width = wlw,
+			.line_style = LineSolid,
+			.cap_style = CapNotLast
+		};
+
+		GC ugc = XCreateGC(xw.dpy, XftDrawDrawable(xw.draw),
+			GCForeground | GCLineWidth | GCLineStyle | GCCapStyle,
+			&ugcv);
+
+		// Underline Style
+		if (base.ustyle != 3) {
+			//XftDrawRect(xw.draw, fg, winx, winy + dc.font.ascent + 1, width, 1);
+			XFillRectangle(xw.dpy, XftDrawDrawable(xw.draw), ugc, winx,
+				winy + dc.font.ascent + 1, width, wlw);
+		} else if (base.ustyle == 3) {
+			int ww = win.cw;//width;
+			int wh = dc.font.descent - wlw/2 - 1;//r.height/7;
+			int wx = winx;
+			int wy = winy + win.ch - dc.font.descent;
 			#if VERTCENTER_PATCH
+			wy += win.cyo;
+			#endif // VERTCENTER_PATCH
+
+			// Draw waves
+			int narcs = charlen * 2 + 1;
+			XArc *arcs = xmalloc(sizeof(XArc) * narcs);
+
+			int i = 0;
+			for (i = 0; i < charlen-1; i++) {
+				arcs[i*2] = (XArc) {
+					.x = wx + win.cw * i + ww / 4,
+					.y = wy,
+					.width = win.cw / 2,
+					.height = wh,
+					.angle1 = 0,
+					.angle2 = 180 * 64
+				};
+				arcs[i*2+1] = (XArc) {
+					.x = wx + win.cw * i + ww * 0.75,
+					.y = wy,
+					.width = win.cw/2,
+					.height = wh,
+					.angle1 = 180 * 64,
+					.angle2 = 180 * 64
+				};
+			}
+			// Last wave
+			arcs[i*2] = (XArc) {wx + ww * i + ww / 4, wy, ww / 2, wh,
+			0, 180 * 64 };
+			// Last wave tail
+			arcs[i*2+1] = (XArc) {wx + ww * i + ww * 0.75, wy, ceil(ww / 2.),
+			wh, 180 * 64, 90 * 64};
+			// First wave tail
+			i++;
+			arcs[i*2] = (XArc) {wx - ww/4 - 1, wy, ceil(ww / 2.), wh, 270 * 64,
+			90 * 64 };
+
+			XDrawArcs(xw.dpy, XftDrawDrawable(xw.draw), ugc, arcs, narcs);
+
+			free(arcs);
+		}
+
+		XFreeGC(xw.dpy, ugc);
+		#elif VERTCENTER_PATCH
 		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + dc.font.ascent + 1,
 				width, 1);
 		#else