4 files changed, 17 insertions, 5 deletions
diff --git a/include/rootston/output.h b/include/rootston/output.h
index 81f20788..11f53d83 100644
--- a/include/rootston/output.h
+++ b/include/rootston/output.h
@@ -7,7 +7,7 @@
 
 /**
  * Damage tracking requires to keep track of previous frames' damage. To allow
- * damage tracking to work with triple buffering, an history of two frames is
+ * damage tracking to work with triple buffering, a history of two frames is
  * required.
  */
 #define ROOTS_OUTPUT_PREVIOUS_DAMAGE_LEN 2
@@ -22,7 +22,7 @@ struct roots_output {
 	struct roots_view *fullscreen_view;
 
 	struct timespec last_frame;
-	pixman_region32_t damage;
+	pixman_region32_t damage; // in ouput-local coordinates
 	bool frame_pending;
 
 	// circular queue for previous damage
diff --git a/include/wlr/types/wlr_box.h b/include/wlr/types/wlr_box.h
index 0588201c..d6cc3509 100644
--- a/include/wlr/types/wlr_box.h
+++ b/include/wlr/types/wlr_box.h
@@ -2,6 +2,7 @@
 #define WLR_TYPES_WLR_BOX_H
 
 #include <stdbool.h>
+#include <wayland-server.h>
 
 struct wlr_box {
 	int x, y;
@@ -18,8 +19,11 @@ bool wlr_box_contains_point(const struct wlr_box *box, double x, double y);
 
 bool wlr_box_empty(const struct wlr_box *box);
 
-enum wl_output_transform;
+/**
+ * Transforms a box inside a `width` x `height` box.
+ */
 void wlr_box_transform(const struct wlr_box *box,
-	enum wl_output_transform transform, struct wlr_box *dest);
+	enum wl_output_transform transform, int width, int height,
+	struct wlr_box *dest);
 
 #endif
diff --git a/include/wlr/types/wlr_output.h b/include/wlr/types/wlr_output.h
index 823c3b5e..4eefbf55 100644
--- a/include/wlr/types/wlr_output.h
+++ b/include/wlr/types/wlr_output.h
@@ -61,7 +61,8 @@ struct wlr_output {
 	enum wl_output_transform transform;
 
 	bool needs_swap;
-	pixman_region32_t damage; // damage for cursors and fullscreen surface
+	// damage for cursors and fullscreen surface, in output-local coordinates
+	pixman_region32_t damage;
 	float transform_matrix[16];
 
 	struct {
diff --git a/include/wlr/util/region.h b/include/wlr/util/region.h
index e268436b..5d2b37e1 100644
--- a/include/wlr/util/region.h
+++ b/include/wlr/util/region.h
@@ -2,6 +2,7 @@
 #define WLR_UTIL_REGION_H
 
 #include <pixman.h>
+#include <wayland-server.h>
 
 /**
  * Scales a region, ie. multiplies all its coordinates by `scale`.
@@ -12,4 +13,10 @@
 void wlr_region_scale(pixman_region32_t *dst, pixman_region32_t *src,
 	float scale);
 
+/**
+ * Applies a transform to a region inside a box of size `width` x `height`.
+ */
+void wlr_region_transform(pixman_region32_t *dst, pixman_region32_t *src,
+	enum wl_output_transform transform, int width, int height);
+
 #endif