True color (24-bit) terminal support for tmux-1.9a and tmux-2.0

tmux-24.diff

This diff is a modified version of a diff written by Arnis Lapsa.

[ The original can be found here: https://gist.github.com/ArnisL/6156593 ]

This diff adds support to tmux for 24-bit color CSI SRG sequences. This
allows terminal based programs that take advantage of it (e.g., vim or
emacs with https://gist.github.com/choppsv1/73d51cedd3e8ec72e1c1 patch)
to display 16 million colors while running in tmux.

The primary change I made was to support ":" as a delimeter as well
as the older ";" delimeter. The ":" delimiter is defined by ITU T.416
which is apparently the correct way to do this; however, many early
implementations of 24 bit support in terminal applications used ";"
so both are supported. Additionally I updated the diff to apply cleanly
to 1.9a as well as the current tmux git head.

diff -ur tmux-1.9a/colour.c tmux-1.9a-24bit/colour.c
--- tmux-1.9a/colour.c	2014-02-22 15:48:37.000000000 -0500
+++ tmux-1.9a-24bit/colour.c	2014-09-13 21:26:15.000000000 -0400
@@ -29,12 +29,6 @@
  * of the 256 colour palette.
  */
 
-/* An RGB colour. */
-struct colour_rgb {
-	u_char	r;
-	u_char	g;
-	u_char	b;
-};
 
 /* 256 colour RGB table, generated on first use. */
 struct colour_rgb *colour_rgb_256;
diff -ur tmux-1.9a/input.c tmux-1.9a-24bit/input.c
--- tmux-1.9a/input.c	2014-02-22 15:48:37.000000000 -0500
+++ tmux-1.9a-24bit/input.c	2014-09-13 21:26:15.000000000 -0400
@@ -447,8 +447,7 @@
 	{ 0x1c, 0x1f, input_c0_dispatch,  NULL },
 	{ 0x20, 0x2f, input_intermediate, &input_state_csi_intermediate },
 	{ 0x30, 0x39, input_parameter,	  &input_state_csi_parameter },
-	{ 0x3a, 0x3a, NULL,		  &input_state_csi_ignore },
-	{ 0x3b, 0x3b, input_parameter,	  &input_state_csi_parameter },
+	{ 0x3a, 0x3b, input_parameter,	  &input_state_csi_parameter },
 	{ 0x3c, 0x3f, input_intermediate, &input_state_csi_parameter },
 	{ 0x40, 0x7e, input_csi_dispatch, &input_state_ground },
 	{ 0x7f, 0xff, NULL,		  NULL },
@@ -465,8 +464,7 @@
 	{ 0x1c, 0x1f, input_c0_dispatch,  NULL },
 	{ 0x20, 0x2f, input_intermediate, &input_state_csi_intermediate },
 	{ 0x30, 0x39, input_parameter,	  NULL },
-	{ 0x3a, 0x3a, NULL,		  &input_state_csi_ignore },
-	{ 0x3b, 0x3b, input_parameter,	  NULL },
+	{ 0x3a, 0x3b, input_parameter,	  NULL },
 	{ 0x3c, 0x3f, NULL,		  &input_state_csi_ignore },
 	{ 0x40, 0x7e, input_csi_dispatch, &input_state_ground },
 	{ 0x7f, 0xff, NULL,		  NULL },
@@ -817,7 +815,7 @@
 		return (0);
 
 	ptr = ictx->param_buf;
-	while ((out = strsep(&ptr, ";")) != NULL) {
+	while ((out = strsep(&ptr, ":;")) != NULL) {
 		if (*out == '\0')
 			n = -1;
 		else {
@@ -1506,7 +1504,26 @@
 
 		if (n == 38 || n == 48) {
 			i++;
-			if (input_get(ictx, i, 0, -1) != 5)
+			m=input_get(ictx, i, 0, -1);
+			if (m == 2){ // 24bit?
+				u_char r, g, b;
+				r = input_get(ictx, i+1, 0, -1);
+				g = input_get(ictx, i+2, 0, -1);
+				b = input_get(ictx, i+3, 0, -1);
+				struct colour_rgb rgb = {.r=r, .g=g, .b=b};
+				if (n == 38){
+					gc->flags &= ~GRID_FLAG_FG256;
+					gc->flags |= GRID_FLAG_FG24;
+					gc->fg_rgb = rgb;
+				} else if (n == 48){
+					gc->flags &= ~GRID_FLAG_BG256;
+					gc->flags |= GRID_FLAG_BG24;
+					gc->bg_rgb = rgb;
+				}
+				break;
+			}
+
+			if (m != 5)
 				continue;
 
 			i++;
@@ -1514,18 +1531,22 @@
 			if (m == -1) {
 				if (n == 38) {
 					gc->flags &= ~GRID_FLAG_FG256;
+					gc->flags &= ~GRID_FLAG_FG24;
 					gc->fg = 8;
 				} else if (n == 48) {
 					gc->flags &= ~GRID_FLAG_BG256;
+					gc->flags &= ~GRID_FLAG_BG24;
 					gc->bg = 8;
 				}
 
 			} else {
 				if (n == 38) {
 					gc->flags |= GRID_FLAG_FG256;
+					gc->flags &= ~GRID_FLAG_FG24;
 					gc->fg = m;
 				} else if (n == 48) {
 					gc->flags |= GRID_FLAG_BG256;
+					gc->flags &= ~GRID_FLAG_BG24;
 					gc->bg = m;
 				}
 			}
@@ -1584,10 +1605,12 @@
 		case 36:
 		case 37:
 			gc->flags &= ~GRID_FLAG_FG256;
+			gc->flags &= ~GRID_FLAG_FG24;
 			gc->fg = n - 30;
 			break;
 		case 39:
 			gc->flags &= ~GRID_FLAG_FG256;
+			gc->flags &= ~GRID_FLAG_FG24;
 			gc->fg = 8;
 			break;
 		case 40:
@@ -1599,10 +1622,12 @@
 		case 46:
 		case 47:
 			gc->flags &= ~GRID_FLAG_BG256;
+			gc->flags &= ~GRID_FLAG_BG24;
 			gc->bg = n - 40;
 			break;
 		case 49:
 			gc->flags &= ~GRID_FLAG_BG256;
+			gc->flags &= ~GRID_FLAG_BG24;
 			gc->bg = 8;
 			break;
 		case 90:
@@ -1625,6 +1650,7 @@
 		case 106:
 		case 107:
 			gc->flags &= ~GRID_FLAG_BG256;
+			gc->flags &= ~GRID_FLAG_BG24;
 			gc->bg = n - 10;
 			break;
 		}
diff -ur tmux-1.9a/tmux.h tmux-1.9a-24bit/tmux.h
--- tmux-1.9a/tmux.h	2014-02-22 15:48:37.000000000 -0500
+++ tmux-1.9a-24bit/tmux.h	2014-09-13 21:26:15.000000000 -0400
@@ -675,10 +675,19 @@
 #define GRID_FLAG_FG256 0x1
 #define GRID_FLAG_BG256 0x2
 #define GRID_FLAG_PADDING 0x4
+#define GRID_FLAG_FG24 0x8
+#define GRID_FLAG_BG24 0x10
 
 /* Grid line flags. */
 #define GRID_LINE_WRAPPED 0x1
 
+/* An RGB colour. */
+struct colour_rgb {
+	u_char	r;
+	u_char	g;
+	u_char	b;
+};
+
 /* Grid cell data. */
 struct grid_cell {
 	u_char	attr;
@@ -688,6 +697,8 @@
 
 	u_char	xstate; /* top 4 bits width, bottom 4 bits size */
 	u_char	xdata[UTF8_SIZE];
+	struct colour_rgb fg_rgb;
+	struct colour_rgb bg_rgb;
 } __packed;
 
 /* Grid line. */
diff -ur tmux-1.9a/tty.c tmux-1.9a-24bit/tty.c
--- tmux-1.9a/tty.c	2014-02-22 15:48:37.000000000 -0500
+++ tmux-1.9a-24bit/tty.c	2014-09-13 21:26:15.000000000 -0400
@@ -35,6 +35,7 @@
 void	tty_error_callback(struct bufferevent *, short, void *);
 
 int	tty_try_256(struct tty *, u_char, const char *);
+int	tty_try_24(struct tty *, struct colour_rgb, const char *);
 
 void	tty_colours(struct tty *, const struct grid_cell *);
 void	tty_check_fg(struct tty *, struct grid_cell *);
@@ -1378,14 +1379,23 @@
 
 void
 tty_colours(struct tty *tty, const struct grid_cell *gc)
-{
+{	
 	struct grid_cell	*tc = &tty->cell;
 	u_char			 fg = gc->fg, bg = gc->bg, flags = gc->flags;
 	int			 have_ax, fg_default, bg_default;
 
 	/* No changes? Nothing is necessary. */
 	if (fg == tc->fg && bg == tc->bg &&
-	    ((flags ^ tc->flags) & (GRID_FLAG_FG256|GRID_FLAG_BG256)) == 0)
+	    tc->fg_rgb.r == gc->fg_rgb.r &&
+	    tc->fg_rgb.g == gc->fg_rgb.g &&
+	    tc->fg_rgb.b == gc->fg_rgb.b &&
+
+	    tc->bg_rgb.r == gc->bg_rgb.r &&
+	    tc->bg_rgb.g == gc->bg_rgb.g &&
+	    tc->bg_rgb.b == gc->bg_rgb.b &&
+	    ((flags ^ tc->flags) & (GRID_FLAG_FG256|GRID_FLAG_BG256|GRID_FLAG_FG24|GRID_FLAG_BG24)) == 0
+	    
+	    )
 		return;
 
 	/*
@@ -1394,8 +1404,8 @@
 	 * case if only one is default need to fall onward to set the other
 	 * colour.
 	 */
-	fg_default = (fg == 8 && !(flags & GRID_FLAG_FG256));
-	bg_default = (bg == 8 && !(flags & GRID_FLAG_BG256));
+	fg_default = (fg == 8 && !(flags & GRID_FLAG_FG256) && !(flags & GRID_FLAG_FG24));
+	bg_default = (bg == 8 && !(flags & GRID_FLAG_BG256) && !(flags & GRID_FLAG_BG24));
 	if (fg_default || bg_default) {
 		/*
 		 * If don't have AX but do have op, send sgr0 (op can't
@@ -1409,39 +1419,49 @@
 			tty_reset(tty);
 		else {
 			if (fg_default &&
-			    (tc->fg != 8 || tc->flags & GRID_FLAG_FG256)) {
+			    (tc->fg != 8 || tc->flags & GRID_FLAG_FG256 || tc->flags & GRID_FLAG_FG24)) {
 				if (have_ax)
 					tty_puts(tty, "\033[39m");
 				else if (tc->fg != 7 ||
-				    tc->flags & GRID_FLAG_FG256)
+				    tc->flags & GRID_FLAG_FG256 ||
+				    tc->flags & GRID_FLAG_FG24)
 					tty_putcode1(tty, TTYC_SETAF, 7);
 				tc->fg = 8;
 				tc->flags &= ~GRID_FLAG_FG256;
+				tc->flags &= ~GRID_FLAG_FG24;
 			}
 			if (bg_default &&
-			    (tc->bg != 8 || tc->flags & GRID_FLAG_BG256)) {
+			    (tc->bg != 8 || tc->flags & GRID_FLAG_BG256 || tc->flags & GRID_FLAG_BG24)) {
 				if (have_ax)
 					tty_puts(tty, "\033[49m");
 				else if (tc->bg != 0 ||
-				    tc->flags & GRID_FLAG_BG256)
+				    tc->flags & GRID_FLAG_BG256 ||
+				    tc->flags & GRID_FLAG_BG24)
 					tty_putcode1(tty, TTYC_SETAB, 0);
 				tc->bg = 8;
 				tc->flags &= ~GRID_FLAG_BG256;
+				tc->flags &= ~GRID_FLAG_BG24;
 			}
 		}
 	}
 
 	/* Set the foreground colour. */
-	if (!fg_default && (fg != tc->fg ||
-	    ((flags & GRID_FLAG_FG256) != (tc->flags & GRID_FLAG_FG256))))
+	if (!fg_default && (fg != tc->fg || ((flags & GRID_FLAG_FG256) != (tc->flags & GRID_FLAG_FG256)) || 
+	    (
+		    ( tc->fg_rgb.r!=gc->fg_rgb.r || tc->fg_rgb.g!=gc->fg_rgb.g || tc->fg_rgb.b!=gc->fg_rgb.b ) ||
+		    ((flags & GRID_FLAG_FG24) != (tc->flags & GRID_FLAG_FG24))
+	    )))
 		tty_colours_fg(tty, gc);
 
 	/*
 	 * Set the background colour. This must come after the foreground as
 	 * tty_colour_fg() can call tty_reset().
 	 */
-	if (!bg_default && (bg != tc->bg ||
-	    ((flags & GRID_FLAG_BG256) != (tc->flags & GRID_FLAG_BG256))))
+	if (!bg_default && (bg != tc->bg || ((flags & GRID_FLAG_BG256) != (tc->flags & GRID_FLAG_BG256)) || 
+	    (
+		    ( tc->bg_rgb.r!=gc->bg_rgb.r || tc->bg_rgb.g!=gc->bg_rgb.g || tc->bg_rgb.b!=gc->bg_rgb.b ) ||
+		    ((flags & GRID_FLAG_BG24) != (tc->flags & GRID_FLAG_BG24))
+	    )))
 		tty_colours_bg(tty, gc);
 }
 
@@ -1451,7 +1471,7 @@
 	u_int	colours;
 
 	/* Is this a 256-colour colour? */
-	if (gc->flags & GRID_FLAG_FG256) {
+	if (gc->flags & GRID_FLAG_FG256 && !(gc->flags & GRID_FLAG_BG24)) {
 		/* And not a 256 colour mode? */
 		if (!(tty->term->flags & TERM_256COLOURS) &&
 		    !(tty->term_flags & TERM_256COLOURS)) {
@@ -1480,7 +1500,7 @@
 	u_int	colours;
 
 	/* Is this a 256-colour colour? */
-	if (gc->flags & GRID_FLAG_BG256) {
+	if (gc->flags & GRID_FLAG_BG256 && !(gc->flags & GRID_FLAG_BG24)) {
 		/*
 		 * And not a 256 colour mode? Translate to 16-colour
 		 * palette. Bold background doesn't exist portably, so just
@@ -1509,15 +1529,29 @@
 tty_colours_fg(struct tty *tty, const struct grid_cell *gc)
 {
 	struct grid_cell	*tc = &tty->cell;
+	struct colour_rgb	 rgb= gc->fg_rgb;
 	u_char			 fg = gc->fg;
 	char			 s[32];
 
+	tc->flags &= ~GRID_FLAG_FG256;
+	tc->flags &= ~GRID_FLAG_FG24;
+
+	/* Is this a 24-colour colour? */
+	if (gc->flags & GRID_FLAG_FG24) {
+//log_debug("trying to output 24bit fg");
+		if (tty_try_24(tty, rgb, "38") == 0){
+			tc->fg_rgb = rgb;
+			tc->flags |= gc->flags & GRID_FLAG_FG24;
+		}
+		return;
+	}
+
 	/* Is this a 256-colour colour? */
 	if (gc->flags & GRID_FLAG_FG256) {
-		/* Try as 256 colours. */
-		if (tty_try_256(tty, fg, "38") == 0)
-			goto save_fg;
-		/* Else already handled by tty_check_fg. */
+		if (tty_try_256(tty, fg, "38") == 0){
+			tc->fg = fg;
+			tc->flags |= gc->flags & GRID_FLAG_FG256;
+		}
 		return;
 	}
 
@@ -1525,32 +1559,41 @@
 	if (fg >= 90 && fg <= 97) {
 		xsnprintf(s, sizeof s, "\033[%dm", fg);
 		tty_puts(tty, s);
-		goto save_fg;
+		tc->fg = fg;
+		return;
 	}
 
 	/* Otherwise set the foreground colour. */
 	tty_putcode1(tty, TTYC_SETAF, fg);
-
-save_fg:
-	/* Save the new values in the terminal current cell. */
 	tc->fg = fg;
-	tc->flags &= ~GRID_FLAG_FG256;
-	tc->flags |= gc->flags & GRID_FLAG_FG256;
 }
 
 void
 tty_colours_bg(struct tty *tty, const struct grid_cell *gc)
 {
 	struct grid_cell	*tc = &tty->cell;
+	struct colour_rgb	 rgb= gc->bg_rgb;
 	u_char			 bg = gc->bg;
 	char			 s[32];
 
+	tc->flags &= ~GRID_FLAG_BG256;
+	tc->flags &= ~GRID_FLAG_BG24;
+
+	/* Is this a 24-colour colour? */
+	if (gc->flags & GRID_FLAG_BG24) {
+		if (tty_try_24(tty, rgb, "48") == 0){
+			tc->bg_rgb = rgb;
+			tc->flags |= gc->flags & GRID_FLAG_BG24;
+		}
+		return;
+	}
+
 	/* Is this a 256-colour colour? */
 	if (gc->flags & GRID_FLAG_BG256) {
-		/* Try as 256 colours. */
-		if (tty_try_256(tty, bg, "48") == 0)
-			goto save_bg;
-		/* Else already handled by tty_check_bg. */
+		if (tty_try_256(tty, bg, "48") == 0){
+			tc->bg = bg;
+			tc->flags |= gc->flags & GRID_FLAG_BG256;
+		}
 		return;
 	}
 
@@ -1560,20 +1603,16 @@
 		if (tty_term_number(tty->term, TTYC_COLORS) >= 16) {
 			xsnprintf(s, sizeof s, "\033[%dm", bg + 10);
 			tty_puts(tty, s);
-			goto save_bg;
+			tc->bg = bg;
 		}
 		bg -= 90;
+		return;
 		/* no such thing as a bold background */
 	}
 
 	/* Otherwise set the background colour. */
 	tty_putcode1(tty, TTYC_SETAB, bg);
-
-save_bg:
-	/* Save the new values in the terminal current cell. */
 	tc->bg = bg;
-	tc->flags &= ~GRID_FLAG_BG256;
-	tc->flags |= gc->flags & GRID_FLAG_BG256;
 }
 
 int
@@ -1606,6 +1645,23 @@
 	return (-1);
 }
 
+
+int
+tty_try_24(struct tty *tty, struct colour_rgb rgb, const char *type)
+{
+	char	s[32];
+
+	//if (!(tty->term->flags & TERM_256COLOURS) &&
+	//    !(tty->term_flags & TERM_256COLOURS))
+	//	return (-1);
+
+	//xsnprintf(s, sizeof s, "\033[%s;5;%hhum", type, colour);
+	xsnprintf(s, sizeof s, "\033[%s;2;%hhu;%hhu;%hhum", type, rgb.r, rgb.g, rgb.b);
+//log_debug("24bit output: %s",s);
+	tty_puts(tty, s);
+	return (0);
+}
+
 void
 tty_bell(struct tty *tty)
 {

@michaelslec here is the changed section in my brew formula. I put it right before def install:

  option "with-truecolor", "Build with truecolor patch enabled"
  patch do
    url "https://gist.githubusercontent.com/choppsv1/dd00858d4f7f356ce2cf/raw/75b073e85f3d539ed24907f1615d9e0fa3e303f4/tmux-24.diff"
    sha1 "101aa54529adf8aa22216c3f35d55fc837c246e8"
  end if build.with? "truecolor"

Then run brew install tmux --with-truecolor. I haven't used linuxbrew so I'm not sure if you need to change those steps at all. Hope it helps!

@choppsv1
Compatible tmux HEAD.

https://gist.github.com/zchee/9f6f2ca17acf49e04088