Draw message as one format, allowing prompts and messages to occupy only

a portion of the status bar, overlaying the normal status content rather
than replacing the entire line. A new message-format option now controls
the entire message (like status-format). From Conor Taylor in GitHub
issue 4861.

options-table.c

@@ -724,13 +724,24 @@ const struct options_table_entry options_table[] = {
 	{ .name = "message-command-style",
 	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "bg=black,fg=yellow",
+	  .default_str = "bg=black,fg=yellow,fill=black",
 	  .flags = OPTIONS_TABLE_IS_STYLE,
 	  .separator = ",",
 	  .text = "Style of the command prompt when in command mode, if "
 		  "'mode-keys' is set to 'vi'."
 	},
 
+	{ .name = "message-format",
+	  .type = OPTIONS_TABLE_STRING,
+	  .scope = OPTIONS_TABLE_SESSION,
+	  .default_str = "#[#{?#{command_prompt},"
+		  "#{E:message-command-style},"
+		  "#{E:message-style}}]"
+		  "#{message}",
+	  .text = "Format string for the prompt and message area. "
+		  "The '#{message}' placeholder is replaced with the content."
+	},
+
 	{ .name = "message-line",
 	  .type = OPTIONS_TABLE_CHOICE,
 	  .scope = OPTIONS_TABLE_SESSION,
@@ -742,10 +753,13 @@ const struct options_table_entry options_table[] = {
 	{ .name = "message-style",
 	  .type = OPTIONS_TABLE_STRING,
 	  .scope = OPTIONS_TABLE_SESSION,
-	  .default_str = "bg=yellow,fg=black",
+	  .default_str = "bg=yellow,fg=black,fill=yellow",
 	  .flags = OPTIONS_TABLE_IS_STYLE,
 	  .separator = ",",
-	  .text = "Style of messages and the command prompt."
+	  .text = "Style of messages and the command prompt. "
+		  "A 'fill' attribute controls background clearing and "
+		  "a 'width' attribute (fixed or percentage) constrains "
+		  "the prompt area width."
 	},
 
 	{ .name = "mouse",

status.c

@@ -551,6 +551,71 @@ status_message_callback(__unused int fd, __unused short event, void *data)
 	status_message_clear(c);
 }
 
+/*
+ * Calculate prompt/message area geometry from the style's width and align
+ * directives: x offset and available width within the status line.
+ */
+static void
+status_prompt_area(struct client *c, u_int *area_x, u_int *area_w)
+{
+	struct session		*s = c->session;
+	struct style		*sy;
+	u_int			 w;
+
+	/* Get width from message-style's width directive. */
+	sy = options_string_to_style(s->options, "message-style", NULL);
+	if (sy != NULL && sy->width >= 0) {
+		if (sy->width_percentage)
+			w = (c->tty.sx * (u_int)sy->width) / 100;
+		else
+			w = (u_int)sy->width;
+	} else
+		w = c->tty.sx;
+	if (w == 0 || w > c->tty.sx)
+		w = c->tty.sx;
+
+	/* Get horizontal position from message-style's align directive. */
+	if (sy != NULL) {
+		switch (sy->align) {
+		case STYLE_ALIGN_CENTRE:
+		case STYLE_ALIGN_ABSOLUTE_CENTRE:
+			*area_x = (c->tty.sx - w) / 2;
+			break;
+		case STYLE_ALIGN_RIGHT:
+			*area_x = c->tty.sx - w;
+			break;
+		default:
+			*area_x = 0;
+			break;
+		}
+	} else
+		*area_x = 0;
+
+	*area_w = w;
+}
+
+/* Escape # characters in a string so format_draw treats them as literal. */
+static char *
+status_prompt_escape(const char *s)
+{
+	const char	*cp;
+	char		*out, *p;
+	size_t		 n = 0;
+
+	for (cp = s; *cp != '\0'; cp++) {
+		if (*cp == '#')
+			n++;
+	}
+	p = out = xmalloc(strlen(s) + n + 1);
+	for (cp = s; *cp != '\0'; cp++) {
+		if (*cp == '#')
+			*p++ = '#';
+		*p++ = *cp;
+	}
+	*p = '\0';
+	return (out);
+}
+
 /* Draw client message on status line of present else on last line. */
 int
 status_message_redraw(struct client *c)
@@ -559,10 +624,12 @@ status_message_redraw(struct client *c)
 	struct screen_write_ctx	 ctx;
 	struct session		*s = c->session;
 	struct screen		 old_screen;
-	size_t			 len;
-	u_int			 lines, offset, messageline;
+	u_int			 lines, messageline;
+	u_int			 ax, aw;
 	struct grid_cell	 gc;
 	struct format_tree	*ft;
+	const char		*msgfmt;
+	char			*expanded, *msg;
 
 	if (c->tty.sx == 0 || c->tty.sy == 0)
 		return (0);
@@ -577,26 +644,36 @@ status_message_redraw(struct client *c)
 	if (messageline > lines - 1)
 		messageline = lines - 1;
 
-	len = screen_write_strlen("%s", c->message_string);
-	if (len > c->tty.sx)
-		len = c->tty.sx;
+	status_prompt_area(c, &ax, &aw);
 
 	ft = format_create_defaults(NULL, c, NULL, NULL, NULL);
-	style_apply(&gc, s->options, "message-style", ft);
+	memcpy(&gc, &grid_default_cell, sizeof gc);
+
+	/*
+	 * Set #{message} in the format tree. If styles should be ignored in
+	 * the message content, escape # characters so format_draw treats them
+	 * as literal text.
+	 */
+	if (c->message_ignore_styles) {
+		msg = status_prompt_escape(c->message_string);
+		format_add(ft, "message", "%s", msg);
+		free(msg);
+	} else
+		format_add(ft, "message", "%s", c->message_string);
+	format_add(ft, "command_prompt", "%d", 0);
+
+	msgfmt = options_get_string(s->options, "message-format");
+	expanded = format_expand_time(ft, msgfmt);
 	format_free(ft);
 
 	screen_write_start(&ctx, sl->active);
 	screen_write_fast_copy(&ctx, &sl->screen, 0, 0, c->tty.sx, lines);
-	screen_write_cursormove(&ctx, 0, messageline, 0);
-	for (offset = 0; offset < c->tty.sx; offset++)
-		screen_write_putc(&ctx, &gc, ' ');
-	screen_write_cursormove(&ctx, 0, messageline, 0);
-	if (c->message_ignore_styles)
-		screen_write_nputs(&ctx, len, &gc, "%s", c->message_string);
-	else
-		format_draw(&ctx, &gc, c->tty.sx, c->message_string, NULL, 0);
+	screen_write_cursormove(&ctx, ax, messageline, 0);
+	format_draw(&ctx, &gc, aw, expanded, NULL, 0);
 	screen_write_stop(&ctx);
 
+	free(expanded);
+
 	if (grid_compare(sl->active->grid, old_screen.grid) == 0) {
 		screen_free(&old_screen);
 		return (0);
@@ -789,9 +866,10 @@ status_prompt_redraw(struct client *c)
 	struct screen		 old_screen;
 	u_int			 i, lines, offset, left, start, width, n;
 	u_int			 pcursor, pwidth, promptline;
+	u_int			 ax, aw;
 	struct grid_cell	 gc;
-	struct format_tree	*ft = c->prompt_formats;
-	char			*prompt, *tmp;
+	const char		*msgfmt;
+	char			*expanded, *prompt, *tmp;
 
 	if (c->tty.sx == 0 || c->tty.sy == 0)
 		return (0);
@@ -816,29 +894,40 @@ status_prompt_redraw(struct client *c)
 		promptline = lines - 1;
 
 	if (c->prompt_mode == PROMPT_COMMAND)
-		style_apply(&gc, s->options, "message-command-style", ft);
+		style_apply(&gc, s->options, "message-command-style", NULL);
 	else
-		style_apply(&gc, s->options, "message-style", ft);
+		style_apply(&gc, s->options, "message-style", NULL);
+
+	status_prompt_area(c, &ax, &aw);
 
 	tmp = utf8_tocstr(c->prompt_buffer);
 	format_add(c->prompt_formats, "prompt-input", "%s", tmp);
 	prompt = format_expand_time(c->prompt_formats, c->prompt_string);
-	free (tmp);
+	free(tmp);
+
+	/*
+	 * Set #{message} to the prompt string and expand message-format.
+	 * format_draw handles fill, alignment, and decorations in one call.
+	 */
+	format_add(c->prompt_formats, "message", "%s", prompt);
+	format_add(c->prompt_formats, "command_prompt", "%d",
+	    c->prompt_mode == PROMPT_COMMAND);
+	msgfmt = options_get_string(s->options, "message-format");
+	expanded = format_expand_time(c->prompt_formats, msgfmt);
 
 	start = format_width(prompt);
-	if (start > c->tty.sx)
-		start = c->tty.sx;
+	if (start > aw)
+		start = aw;
 
 	screen_write_start(&ctx, sl->active);
 	screen_write_fast_copy(&ctx, &sl->screen, 0, 0, c->tty.sx, lines);
-	screen_write_cursormove(&ctx, 0, promptline, 0);
-	for (offset = 0; offset < c->tty.sx; offset++)
-		screen_write_putc(&ctx, &gc, ' ');
-	screen_write_cursormove(&ctx, 0, promptline, 0);
-	format_draw(&ctx, &gc, start, prompt, NULL, 0);
-	screen_write_cursormove(&ctx, start, promptline, 0);
+	screen_write_cursormove(&ctx, ax, promptline, 0);
+	format_draw(&ctx, &gc, aw, expanded, NULL, 0);
+	screen_write_cursormove(&ctx, ax + start, promptline, 0);
 
-	left = c->tty.sx - start;
+	free(expanded);
+
+	left = aw - start;
 	if (left == 0)
 		goto finished;
 
@@ -857,7 +946,7 @@ status_prompt_redraw(struct client *c)
 		offset = 0;
 	if (pwidth > left)
 		pwidth = left;
-	c->prompt_cursor = start + pcursor - offset;
+	c->prompt_cursor = ax + start + pcursor - offset;
 
 	width = 0;
 	for (i = 0; c->prompt_buffer[i].size != 0; i++) {
@@ -1831,7 +1920,7 @@ status_prompt_complete_list_menu(struct client *c, char **list, u_int size,
 	struct menu_item		 item;
 	struct status_prompt_menu	*spm;
 	u_int				 lines = status_line_size(c), height, i;
-	u_int				 py;
+	u_int				 py, ax, aw;
 
 	if (size <= 1)
 		return (0);
@@ -1859,11 +1948,13 @@ status_prompt_complete_list_menu(struct client *c, char **list, u_int size,
 		menu_add_item(menu, &item, NULL, c, NULL);
 	}
 
+	status_prompt_area(c, &ax, &aw);
 	if (options_get_number(c->session->options, "status-position") == 0)
 		py = lines;
 	else
 		py = c->tty.sy - 3 - height;
 	offset += utf8_cstrwidth(c->prompt_string);
+	offset += ax;
 	if (offset > 2)
 		offset -= 2;
 	else
@@ -1890,7 +1981,7 @@ status_prompt_complete_window_menu(struct client *c, struct session *s,
 	struct winlink			 *wl;
 	char				**list = NULL, *tmp;
 	u_int				  lines = status_line_size(c), height;
-	u_int				  py, size = 0, i;
+	u_int				  py, size = 0, i, ax, aw;
 
 	if (c->tty.sy - lines < 3)
 		return (NULL);
@@ -1955,11 +2046,13 @@ status_prompt_complete_window_menu(struct client *c, struct session *s,
 	spm->size = size;
 	spm->list = list;
 
+	status_prompt_area(c, &ax, &aw);
 	if (options_get_number(c->session->options, "status-position") == 0)
 		py = lines;
 	else
 		py = c->tty.sy - 3 - height;
 	offset += utf8_cstrwidth(c->prompt_string);
+	offset += ax;
 	if (offset > 2)
 		offset -= 2;
 	else

style.c

@@ -39,7 +39,7 @@ static struct style style_default = {
 
 	STYLE_RANGE_NONE, 0, "",
 
-	STYLE_WIDTH_DEFAULT, STYLE_PAD_DEFAULT,
+	STYLE_WIDTH_DEFAULT, 0, STYLE_PAD_DEFAULT,
 
 	STYLE_DEFAULT_BASE
 };
@@ -226,10 +226,20 @@ style_parse(struct style *sy, const struct grid_cell *base, const char *in)
 				sy->gc.attr &= ~value;
 			}
 		} else if (end > 6 && strncasecmp(tmp, "width=", 6) == 0) {
-			n = strtonum(tmp + 6, 0, UINT_MAX, &errstr);
-			if (errstr != NULL)
-				goto error;
-			sy->width = (int)n;
+			if (end > 7 && tmp[end - 1] == '%') {
+				tmp[end - 1] = '\0';
+				n = strtonum(tmp + 6, 0, 100, &errstr);
+				if (errstr != NULL)
+					goto error;
+				sy->width = (int)n;
+				sy->width_percentage = 1;
+			} else {
+				n = strtonum(tmp + 6, 0, UINT_MAX, &errstr);
+				if (errstr != NULL)
+					goto error;
+				sy->width = (int)n;
+				sy->width_percentage = 0;
+			}
 		} else if (end > 4 && strncasecmp(tmp, "pad=", 4) == 0) {
 			n = strtonum(tmp + 4, 0, UINT_MAX, &errstr);
 			if (errstr != NULL)
@@ -343,13 +353,17 @@ style_tostring(struct style *sy)
 		comma = ",";
 	}
 	if (gc->attr != 0) {
-		xsnprintf(s + off, sizeof s - off, "%s%s", comma,
+		off += xsnprintf(s + off, sizeof s - off, "%s%s", comma,
 		    attributes_tostring(gc->attr));
 		comma = ",";
 	}
 	if (sy->width >= 0) {
-		xsnprintf(s + off, sizeof s - off, "%swidth=%u", comma,
-		    sy->width);
+		if (sy->width_percentage)
+			off += xsnprintf(s + off, sizeof s - off,
+			    "%swidth=%u%%", comma, sy->width);
+		else
+			off += xsnprintf(s + off, sizeof s - off,
+			    "%swidth=%u", comma, sy->width);
 		comma = ",";
 	}
 	if (sy->pad >= 0) {

tmux.1

@@ -4745,6 +4745,23 @@ For how to specify
 see the
 .Sx STYLES
 section.
+.It Ic message-format Ar string
+Set the format string for the prompt and message area.
+The special placeholder
+.Ql #{message}
+expands to the interactive prompt or message text and
+.Ql #{command_prompt}
+is set to 1 when the prompt is in command mode (vi).
+Style directives like
+.Ic fill ,
+.Ic align ,
+and
+.Ic width
+may be used in the format string.
+The default uses a conditional to select between
+.Ic message-style
+and
+.Ic message-command-style .
 .It Xo Ic message-line
 .Op Ic 0 | 1 | 2 | 3 | 4
 .Xc
@@ -4752,6 +4769,23 @@ Set line on which status line messages and the command prompt are shown.
 .It Ic message-style Ar style
 Set status line message style.
 This is used for messages and for the command prompt.
+The message is drawn on top of the existing status line.
+A
+.Ic width
+attribute (a fixed number of columns or a percentage such as
+.Ql 50% )
+constrains the prompt area width and an
+.Ic align
+attribute
+.Pq Ic left , centre , right
+sets its horizontal position.
+When the width is less than the full terminal width, the normal status
+bar content remains visible around the prompt area.
+The
+.Ic fill
+attribute is used by the default
+.Ic message-format
+to clear the background.
 For how to specify
 .Ar style ,
 see the
@@ -6522,6 +6556,11 @@ is the terminal alternate character set.
 Align text to the left, centre or right of the available space if appropriate.
 .It Ic fill=colour
 Fill the available space with a background colour if appropriate.
+.It Ic width=N
+Set the width of the styled area.
+.Ar N
+may be a column count or a percentage (for example
+.Ql 50% ) .
 .It Xo Ic list=on ,
 .Ic list=focus ,
 .Ic list=left-marker ,

tmux.h

@@ -911,6 +911,7 @@ struct style {
 	char			range_string[16];
 
 	int			width;
+	int			width_percentage;
 	int			pad;
 
 	enum style_default_type	default_type;