Implement title alignment

This adds support for `i3 4.16`'s ability to set the title alignment.
The command is `title_align left|center|right`.

When the title is on the right, marks are moved to the left. Otherwise,
they are on the right.

1 files changed, 30 insertions, 0 deletions

diff --git a/sway/commands/title_align.c b/sway/commands/title_align.c
new file mode 100644
index 00000000..82578186
--- /dev/null
+++ b/sway/commands/title_align.c
@@ -0,0 +1,30 @@
+#include "sway/commands.h"
+#include "sway/config.h"
+#include "sway/output.h"
+#include "sway/tree/container.h"
+#include "sway/tree/root.h"
+
+struct cmd_results *cmd_title_align(int argc, char **argv) {
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, "title_align", EXPECTED_AT_LEAST, 1))) {
+		return error;
+	}
+
+	if (strcmp(argv[0], "left") == 0) {
+		config->title_align = ALIGN_LEFT;
+	} else if (strcmp(argv[0], "center") == 0) {
+		config->title_align = ALIGN_CENTER;
+	} else if (strcmp(argv[0], "right") == 0) {
+		config->title_align = ALIGN_RIGHT;
+	} else {
+		return cmd_results_new(CMD_INVALID, "title_align",
+				"Expected 'title_align left|center|right'");
+	}
+
+	for (int i = 0; i < root->outputs->length; ++i) {
+		struct sway_output *output = root->outputs->items[i];
+		output_damage_whole(output);
+	}
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}