Implement bar gaps

Adds the bar subcommand `gaps <amount>|<horizontal> <vertical>|<top>
<right> <bottom> <left>` to set gaps for swaybar. Due to restrictions on
margins for a layer_surface, only the sides that are anchored to an edge
of the screen can have gaps. Since there is support for per-side outer
gaps for workspaces, those should be able to be used instead for the
last side.

5 files changed, 81 insertions, 0 deletions

diff --git a/sway/commands/bar.c b/sway/commands/bar.c
index f9ed530e..0cf94907 100644
--- a/sway/commands/bar.c
+++ b/sway/commands/bar.c
@@ -14,6 +14,7 @@ static struct cmd_handler bar_handlers[] = {
         { "colors", bar_cmd_colors },
         { "context_button", bar_cmd_context_button },
         { "font", bar_cmd_font },
+        { "gaps", bar_cmd_gaps },
         { "height", bar_cmd_height },
         { "hidden_state", bar_cmd_hidden_state },
         { "icon_theme", bar_cmd_icon_theme },
diff --git a/sway/commands/bar/gaps.c b/sway/commands/bar/gaps.c
new file mode 100644
index 00000000..f78f3742
--- /dev/null
+++ b/sway/commands/bar/gaps.c
@@ -0,0 +1,60 @@
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include "sway/commands.h"
+#include "sway/ipc-server.h"
+#include "log.h"
+
+struct cmd_results *bar_cmd_gaps(int argc, char **argv) {
+        struct cmd_results *error = NULL;
+        if ((error = checkarg(argc, "gaps", EXPECTED_AT_LEAST, 1))) {
+                return error;
+        }
+        if ((error = checkarg(argc, "gaps", EXPECTED_AT_MOST, 4))) {
+                return error;
+        }
+        if (!config->current_bar) {
+                return cmd_results_new(CMD_FAILURE, "bar gaps", "No bar defined.");
+        }
+
+        int top = 0, right = 0, bottom = 0, left = 0;
+
+        for (int i = 0; i < argc; i++) {
+                char *end;
+                int amount = strtol(argv[i], &end, 10);
+                if (strlen(end) && strcasecmp(end, "px") != 0) {
+                        return cmd_results_new(CMD_INVALID, "bar gaps",
+                                        "Expected 'bar [<bar-id>] gaps <all> | <horizonal> "
+                                        "<vertical> | <top> <right> <bottom> <left>'");
+                }
+
+                if (i == 0) {
+                        top = amount;
+                }
+                if (i == 0 || i == 1) {
+                        right = amount;
+                }
+                if (i == 0 || i == 2) {
+                        bottom = amount;
+                }
+                if (i == 0 || i == 1 || i == 3) {
+                        left = amount;
+                }
+        }
+
+        config->current_bar->gaps.top = top;
+        config->current_bar->gaps.right = right;
+        config->current_bar->gaps.bottom = bottom;
+        config->current_bar->gaps.left = left;
+
+        wlr_log(WLR_DEBUG, "Setting bar gaps to %d %d %d %d on bar: %s",
+                        config->current_bar->gaps.top, config->current_bar->gaps.right,
+                        config->current_bar->gaps.bottom, config->current_bar->gaps.left,
+                        config->current_bar->id);
+
+        if (!config->reading) {
+                ipc_event_barconfig_update(config->current_bar);
+        }
+
+        return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}
diff --git a/sway/ipc-json.c b/sway/ipc-json.c
index 40fbd3e7..fc631373 100644
--- a/sway/ipc-json.c
+++ b/sway/ipc-json.c
@@ -638,6 +638,18 @@ json_object *ipc_json_describe_bar_config(struct bar_config *bar) {
                         json_object_new_string(bar->status_command) : NULL);
         json_object_object_add(json, "font",
                         json_object_new_string((bar->font) ? bar->font : config->font));
+
+        json_object *gaps = json_object_new_object();
+        json_object_object_add(gaps, "top",
+                        json_object_new_int(bar->gaps.top));
+        json_object_object_add(gaps, "right",
+                        json_object_new_int(bar->gaps.right));
+        json_object_object_add(gaps, "bottom",
+                        json_object_new_int(bar->gaps.bottom));
+        json_object_object_add(gaps, "left",
+                        json_object_new_int(bar->gaps.left));
+        json_object_object_add(json, "gaps", gaps);
+
         if (bar->separator_symbol) {
                 json_object_object_add(json, "separator_symbol",
                                 json_object_new_string(bar->separator_symbol));
diff --git a/sway/meson.build b/sway/meson.build
index 75131891..51b40020 100644
--- a/sway/meson.build
+++ b/sway/meson.build
@@ -104,6 +104,7 @@ sway_sources = files(
         'commands/bar/colors.c',
         'commands/bar/context_button.c',
         'commands/bar/font.c',
+        'commands/bar/gaps.c',
         'commands/bar/height.c',
         'commands/bar/hidden_state.c',
         'commands/bar/icon_theme.c',
diff --git a/sway/sway-bar.5.scd b/sway/sway-bar.5.scd
index 60ee9999..a3c6af2e 100644
--- a/sway/sway-bar.5.scd
+++ b/sway/sway-bar.5.scd
@@ -61,6 +61,13 @@ Sway allows configuring swaybar in the sway configuration file.
 *binding\_mode\_indicator* yes|no
         Enable or disable binding mode indicator. Default is _yes_.
 
+*gaps* <all> | <horizontal> <vertical> | <top> <right> <bottom> <left>
+        Sets the gaps from the edge of the screen for the bar. Gaps can either be
+        set all at once, per direction, or per side. Note that only sides that
+        touch an edge of the screen can have gaps. For the side that does not
+        touch an edge of the screen, per-side outer gaps for workspaces may be of
+        use.
+
 *height* <height>
         Sets the height of the bar. Default height will match the font size.