Optionally add focused window title to the bar

Add a "window_title yes|no" bar command that displays the title of the
focused window on the bar.

include/sway/commands.h

@@ -221,6 +221,7 @@ sway_cmd bar_cmd_tray_padding;
 sway_cmd bar_cmd_unbindcode;
 sway_cmd bar_cmd_unbindsym;
 sway_cmd bar_cmd_wrap_scroll;
+sway_cmd bar_cmd_window_title;
 sway_cmd bar_cmd_workspace_buttons;
 
 sway_cmd bar_colors_cmd_active_workspace;

include/sway/config.h

@@ -271,6 +271,7 @@ struct bar_config {
 	bool strip_workspace_name;
 	bool binding_mode_indicator;
 	bool verbose;
+	bool window_title;
 	struct side_gaps gaps;
 	int status_padding;
 	int status_edge_padding;

include/swaybar/config.h

@@ -34,10 +34,12 @@ struct swaybar_config {
 	char *mode;
 	char *hidden_state;
 	char *modifier;
+	char *title;
 	bool strip_workspace_numbers;
 	bool strip_workspace_name;
 	bool binding_mode_indicator;
 	bool wrap_scroll;
+	bool window_title;
 	bool workspace_buttons;
 	list_t *bindings;
 	struct wl_list outputs; // config_output::link
@@ -51,6 +53,7 @@ struct swaybar_config {
 		int bottom;
 		int left;
 	} gaps;
+	uint64_t window_app_id;
 
 	struct {
 		uint32_t background;

sway/commands/bar.c

@@ -34,6 +34,7 @@ static struct cmd_handler bar_handlers[] = {
 	{ "tray_padding", bar_cmd_tray_padding },
 	{ "unbindcode", bar_cmd_unbindcode },
 	{ "unbindsym", bar_cmd_unbindsym },
+	{ "window_title", bar_cmd_window_title },
 	{ "workspace_buttons", bar_cmd_workspace_buttons },
 	{ "wrap_scroll", bar_cmd_wrap_scroll },
 };

sway/commands/bar/window_title.c

@@ -0,0 +1,22 @@
+#include <string.h>
+#include <strings.h>
+#include "sway/commands.h"
+#include "log.h"
+#include "util.h"
+
+struct cmd_results *bar_cmd_window_title(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "window_title", EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+	config->current_bar->window_title =
+		parse_boolean(argv[0], config->current_bar->window_title);
+	if (config->current_bar->window_title) {
+		sway_log(SWAY_DEBUG, "Enabling window title on bar: %s",
+				config->current_bar->id);
+	} else {
+		sway_log(SWAY_DEBUG, "Disabling window title on bar: %s",
+				config->current_bar->id);
+	}
+	return cmd_results_new(CMD_SUCCESS, NULL);
+}

sway/ipc-json.c

@@ -958,6 +958,8 @@ json_object *ipc_json_describe_bar_config(struct bar_config *bar) {
 			json_object_new_int(bar->status_edge_padding));
 	json_object_object_add(json, "wrap_scroll",
 			json_object_new_boolean(bar->wrap_scroll));
+	json_object_object_add(json, "window_title",
+			json_object_new_boolean(bar->window_title));
 	json_object_object_add(json, "workspace_buttons",
 			json_object_new_boolean(bar->workspace_buttons));
 	json_object_object_add(json, "strip_workspace_numbers",

sway/meson.build

@@ -137,6 +137,7 @@ sway_sources = files(
 	'commands/bar/tray_bind.c',
 	'commands/bar/tray_output.c',
 	'commands/bar/tray_padding.c',
+	'commands/bar/window_title.c',
 	'commands/bar/workspace_buttons.c',
 	'commands/bar/wrap_scroll.c',
 

sway/sway-bar.5.scd

@@ -48,6 +48,9 @@ Sway allows configuring swaybar in the sway configuration file.
 	Enables or disables wrapping when scrolling through workspaces with the
 	scroll wheel. Default is _no_.
 
+*window_title* yes|no
+	Enables or disables focused window title on the bar. Default is _no_.
+
 *workspace_buttons* yes|no
 	Enables or disables workspace buttons on the bar. Default is _yes_.
 

swaybar/ipc.c

@@ -173,6 +173,7 @@ static bool ipc_parse_config(
 		json_object_put(bar_config);
 		return false;
 	}
+	json_object *window_title;
 	json_object *markup, *mode, *hidden_state, *position, *status_command;
 	json_object *font, *gaps, *bar_height, *wrap_scroll, *workspace_buttons;
 	json_object *strip_workspace_numbers, *strip_workspace_name;
@@ -186,6 +187,7 @@ static bool ipc_parse_config(
 	json_object_object_get_ex(bar_config, "gaps", &gaps);
 	json_object_object_get_ex(bar_config, "bar_height", &bar_height);
 	json_object_object_get_ex(bar_config, "wrap_scroll", &wrap_scroll);
+	json_object_object_get_ex(bar_config, "window_title", &window_title);
 	json_object_object_get_ex(bar_config, "workspace_buttons", &workspace_buttons);
 	json_object_object_get_ex(bar_config, "strip_workspace_numbers", &strip_workspace_numbers);
 	json_object_object_get_ex(bar_config, "strip_workspace_name", &strip_workspace_name);
@@ -226,6 +228,9 @@ static bool ipc_parse_config(
 	if (wrap_scroll) {
 		config->wrap_scroll = json_object_get_boolean(wrap_scroll);
 	}
+	if (window_title) {
+		config->window_title = json_object_get_boolean(window_title);
+	}
 	if (workspace_buttons) {
 		config->workspace_buttons = json_object_get_boolean(workspace_buttons);
 	}
@@ -480,7 +485,8 @@ bool ipc_initialize(struct swaybar *bar) {
 	struct swaybar_config *config = bar->config;
 	char subscribe[128]; // suitably large buffer
 	len = snprintf(subscribe, 128,
-			"[ \"barconfig_update\" , \"bar_state_update\" %s %s ]",
+			"[ \"barconfig_update\" , \"bar_state_update\" %s %s %s ]",
+			config->window_title ? ", \"window\"" : "",
 			config->binding_mode_indicator ? ", \"mode\"" : "",
 			config->workspace_buttons ? ", \"workspace\"" : "");
 	free(ipc_single_command(bar->ipc_event_socketfd,
@@ -509,6 +515,49 @@ static bool handle_bar_state_update(struct swaybar *bar, json_object *event) {
 	return determine_bar_visibility(bar, false);
 }
 
+static bool handle_title_update(struct swaybar *bar,
+		json_object *json_window_event) {
+	json_object *json_container;
+	json_object_object_get_ex(json_window_event, "container",
+		&json_container);
+	struct swaybar_config *config = bar->config;
+
+	json_object *json_change;
+	json_object_object_get_ex(json_window_event, "change", &json_change);
+	const char *change = json_object_get_string(json_change);
+	if (strcmp(change, "close") == 0) {
+		json_object *json_id;
+		json_object_object_get_ex(json_container, "id", &json_id);
+		uint64_t app_id = json_object_get_int64(json_id);
+		if (config->window_app_id == app_id) {
+			// The focused window was closed so remove the title
+			config->window_app_id = 0;
+			if (config->title) {
+				free(config->title);
+			}
+			config->title = NULL;
+		}
+		return true;
+	}
+
+	json_object *json_focused;
+	json_object_object_get_ex(json_container, "focused", &json_focused);
+	if (json_object_get_boolean(json_focused)) {
+		json_object *json_name;
+		json_object_object_get_ex(json_container, "name", &json_name);
+		if (config->title) {
+			free(config->title);
+		}
+		config->title = strdup(json_object_get_string(json_name));
+		json_object *json_id;
+		json_object_object_get_ex(json_container, "id", &json_id);
+		config->window_app_id = json_object_get_int64(json_id);
+		return true;
+	}
+
+	return false;
+}
+
 static bool handle_barconfig_update(struct swaybar *bar,
 		json_object *json_config) {
 	json_object *json_id;
@@ -576,6 +625,9 @@ bool handle_ipc_readable(struct swaybar *bar) {
 
 	bool bar_is_dirty = true;
 	switch (resp->type) {
+	case IPC_EVENT_WINDOW:
+		bar_is_dirty = handle_title_update(bar, result);
+		break;
 	case IPC_EVENT_WORKSPACE:
 		bar_is_dirty = ipc_get_workspaces(bar);
 		break;

swaybar/render.c

@@ -536,6 +536,45 @@ static uint32_t render_binding_mode_indicator(cairo_t *cairo,
 	return output->height;
 }
 
+static uint32_t render_window_title(cairo_t *cairo,
+		struct swaybar_output *output, double x) {
+	const char *title = output->bar->config->title;
+	if (!title) {
+		return 0;
+	}
+
+	struct swaybar_config *config = output->bar->config;
+	int text_width, text_height;
+	get_text_size(cairo, config->font, &text_width, &text_height, NULL,
+			output->scale, output->bar->mode_pango_markup,
+			"%s", title);
+
+	int ws_vertical_padding = WS_VERTICAL_PADDING * output->scale;
+	int ws_horizontal_padding = WS_HORIZONTAL_PADDING * output->scale;
+	int border_width = BORDER_WIDTH * output->scale;
+
+	uint32_t ideal_height = text_height + ws_vertical_padding * 2
+		+ border_width * 2;
+	uint32_t ideal_surface_height = ideal_height / output->scale;
+	if (!output->bar->config->height &&
+			output->height < ideal_surface_height) {
+		return ideal_surface_height;
+	}
+	uint32_t width = text_width + ws_horizontal_padding * 2 + border_width * 2;
+
+	uint32_t height = output->height * output->scale;
+	cairo_set_source_u32(cairo, config->colors.background);
+	cairo_rectangle(cairo, x, 0, width, height);
+	cairo_fill(cairo);
+
+	double text_y = height / 2.0 - text_height / 2.0;
+	cairo_set_source_u32(cairo, config->colors.statusline);
+	cairo_move_to(cairo, x + width / 2 - text_width / 2, (int)floor(text_y));
+	pango_printf(cairo, config->font, output->scale,
+			output->bar->mode_pango_markup, "%s", title);
+	return output->height;
+}
+
 static enum hotspot_event_handling workspace_hotspot_callback(
 		struct swaybar_output *output, struct swaybar_hotspot *hotspot,
 		int x, int y, uint32_t button, void *data) {
@@ -660,6 +699,11 @@ static uint32_t render_to_cairo(cairo_t *cairo, struct swaybar_output *output) {
 		max_height = h > max_height ? h : max_height;
 	}
 
+	if (config->window_title) {
+		uint32_t h = render_window_title(cairo, output, x);
+		max_height = h > max_height ? h : max_height;
+	}
+
 	return max_height > output->height ? max_height : output->height;
 }