diff --git a/include/output.h b/include/output.h
index 0bab5db..20b8d1b 100644
--- a/include/output.h
+++ b/include/output.h
@@ -16,9 +16,9 @@
 
 #pragma once
 
-#include <wayland-client-protocol.h>
 #include <wayland-client.h>
 #include <stdint.h>
+#include <stdbool.h>
 
 struct zxdg_output_v1;
 
@@ -41,6 +41,14 @@ struct output {
 	char model[256];
 	char name[256];
 	char description[256];
+
+	bool is_dimension_changed;
+	bool is_transform_changed;
+
+	void (*on_dimension_change)(struct output*);
+	void (*on_transform_change)(struct output*);
+
+	void* userdata;
 };
 
 struct output* output_new(struct wl_output* wl_output, uint32_t id);
diff --git a/src/output.c b/src/output.c
index 72c88cb..bccf4b5 100644
--- a/src/output.c
+++ b/src/output.c
@@ -123,6 +123,9 @@ static void output_handle_geometry(void* data, struct wl_output* wl_output,
 {
 	struct output* output = data;
 
+	if (transform != (int32_t)output->transform)
+		output->is_transform_changed = true;
+
 	output->x = x;
 	output->y = y;
 	output->transform = transform;
@@ -140,12 +143,25 @@ static void output_handle_mode(void* data, struct wl_output* wl_output,
 	if (!(flags & WL_OUTPUT_MODE_CURRENT))
 		return;
 
+	if (width != (int32_t)output->width || height != (int32_t)output->height)
+		output->is_dimension_changed = true;
+
 	output->width = width;
 	output->height = height;
 }
 
 static void output_handle_done(void* data, struct wl_output* wl_output)
 {
+	struct output* output = data;
+
+	if (output->is_dimension_changed && output->on_dimension_change)
+		output->on_dimension_change(output);
+
+	if (output->is_transform_changed && output->on_transform_change)
+		output->on_transform_change(output);
+
+	output->is_dimension_changed = false;
+	output->is_transform_changed = false;
 }
 
 static void output_handle_scale(void* data, struct wl_output* wl_output,