Add support for manually setting subpixel hinting on outputs.

Many laptop screens report unknown subpixel order. Allow users to manually set subpixel hinting to work around this.

Addresses https://github.com/swaywm/sway/issues/3163

2 files changed, 37 insertions, 0 deletions

diff --git a/sway/commands/output.c b/sway/commands/output.c
index 40dbf3ca..44e28512 100644
--- a/sway/commands/output.c
+++ b/sway/commands/output.c
@@ -18,6 +18,7 @@ static struct cmd_handler output_handlers[] = {
 	{ "res", output_cmd_mode },
 	{ "resolution", output_cmd_mode },
 	{ "scale", output_cmd_scale },
+	{ "subpixel", output_cmd_subpixel },
 	{ "transform", output_cmd_transform },
 };
 
diff --git a/sway/commands/output/subpixel.c b/sway/commands/output/subpixel.c
new file mode 100644
index 00000000..63191ee6
--- /dev/null
+++ b/sway/commands/output/subpixel.c
@@ -0,0 +1,36 @@
+#include <string.h>
+#include "log.h"
+#include "sway/commands.h"
+#include "sway/config.h"
+#include "sway/output.h"
+
+struct cmd_results *output_cmd_subpixel(int argc, char **argv) {
+	if (!config->handler_context.output_config) {
+		return cmd_results_new(CMD_FAILURE, "Missing output config");
+	}
+	if (!argc) {
+		return cmd_results_new(CMD_INVALID, "Missing subpixel argument.");
+	}
+	enum wl_output_subpixel subpixel;
+
+	if (strcmp(*argv, "rgb") == 0) {
+		subpixel = WL_OUTPUT_SUBPIXEL_HORIZONTAL_RGB;
+	} else if (strcmp(*argv, "bgr") == 0) {
+		subpixel = WL_OUTPUT_SUBPIXEL_HORIZONTAL_BGR;
+	} else if (strcmp(*argv, "vrgb") == 0) {
+		subpixel = WL_OUTPUT_SUBPIXEL_VERTICAL_RGB;
+	} else if (strcmp(*argv, "vbgr") == 0) {
+		subpixel = WL_OUTPUT_SUBPIXEL_VERTICAL_BGR;
+	} else if (strcmp(*argv, "none") == 0) {
+		subpixel = WL_OUTPUT_SUBPIXEL_NONE;
+	} else {
+		return cmd_results_new(CMD_INVALID, "Invalid output subpixel.");
+	}
+
+	struct output_config *oc = config->handler_context.output_config;
+	config->handler_context.leftovers.argc = argc - 1;
+	config->handler_context.leftovers.argv = argv + 1;
+
+	oc->subpixel = subpixel;
+	return NULL;
+}