Add `gaps <type> <scope> toggle <px>` command

Add a subcommand for `gaps` that allows to toggle gaps at
runtime. This functionality is part of i3-gaps since [1]
but is missing in sway.

[1] https://github.com/Airblader/i3/pull/264

2 files changed, 11 insertions, 5 deletions

diff --git a/sway/commands/gaps.c b/sway/commands/gaps.c
index 021df843..1deeb56e 100644
--- a/sway/commands/gaps.c
+++ b/sway/commands/gaps.c
@@ -11,7 +11,8 @@
 enum gaps_op {
         GAPS_OP_SET,
         GAPS_OP_ADD,
-        GAPS_OP_SUBTRACT
+        GAPS_OP_SUBTRACT,
+        GAPS_OP_TOGGLE
 };
 
 struct gaps_data {
@@ -102,6 +103,9 @@ static void apply_gaps_op(int *prop, enum gaps_op op, int amount) {
         case GAPS_OP_SUBTRACT:
                 *prop -= amount;
                 break;
+        case GAPS_OP_TOGGLE:
+                *prop = *prop ? 0 : amount;
+                break;
         }
 }
 
@@ -133,9 +137,9 @@ static void configure_gaps(struct sway_workspace *ws, void *_data) {
 }
 
 // gaps inner|outer|horizontal|vertical|top|right|bottom|left current|all
-// set|plus|minus <px>
+// set|plus|minus|toggle <px>
 static const char expected_runtime[] = "'gaps inner|outer|horizontal|vertical|"
-        "top|right|bottom|left current|all set|plus|minus <px>'";
+        "top|right|bottom|left current|all set|plus|minus|toggle <px>'";
 static struct cmd_results *gaps_set_runtime(int argc, char **argv) {
         struct cmd_results *error = checkarg(argc, "gaps", EXPECTED_EQUAL_TO, 4);
         if (error) {
@@ -180,6 +184,8 @@ static struct cmd_results *gaps_set_runtime(int argc, char **argv) {
                 data.operation = GAPS_OP_ADD;
         } else if (strcasecmp(argv[2], "minus") == 0) {
                 data.operation = GAPS_OP_SUBTRACT;
+        } else if (strcasecmp(argv[2], "toggle") == 0) {
+                data.operation = GAPS_OP_TOGGLE;
         } else {
                 return cmd_results_new(CMD_INVALID, "Expected %s", expected_runtime);
         }
@@ -200,7 +206,7 @@ static struct cmd_results *gaps_set_runtime(int argc, char **argv) {
 }
 
 // gaps inner|outer|<dir>|<side> <px> - sets defaults for workspaces
-// gaps inner|outer|<dir>|<side> current|all set|plus|minus <px> - runtime only
+// gaps inner|outer|<dir>|<side> current|all set|plus|minus|toggle <px> - runtime only
 // <dir> = horizontal|vertical
 // <side> = top|right|bottom|left
 struct cmd_results *cmd_gaps(int argc, char **argv) {
diff --git a/sway/sway.5.scd b/sway/sway.5.scd
index 02592b5f..8958c7e3 100644
--- a/sway/sway.5.scd
+++ b/sway/sway.5.scd
@@ -155,7 +155,7 @@ They are expected to be used with *bindsym* or at runtime through *swaymsg*(1).
         is specified, the view will be fullscreen across all outputs.
 
 *gaps* inner|outer|horizontal|vertical|top|right|bottom|left all|current
-set|plus|minus <amount>
+set|plus|minus|toggle <amount>
         Changes the _inner_ or _outer_ gaps for either _all_ workspaces or the
         _current_ workspace. _outer_ gaps can be altered per side with _top_,
         _right_, _bottom_, and _left_ or per direction with _horizontal_ and