diff --git a/src/render.c b/src/render.c
index e7d599e..ac3320e 100644
--- a/src/render.c
+++ b/src/render.c
@@ -443,7 +443,7 @@ static void paint_root(session_t *ps, const region_t *reg_paint) {
 	             ps->root_tile_paint.pict);
 }
 
-static xcb_image_t *make_shadow(session_t *ps, double opacity, int width, int height) {
+xcb_image_t *make_shadow(session_t *ps, double opacity, int width, int height) {
 	xcb_image_t *ximage;
 	int ylimit, xlimit;
 	int swidth = width + ps->cgsize;
diff --git a/src/render.h b/src/render.h
index eca135e..e5fc25f 100644
--- a/src/render.h
+++ b/src/render.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include <xcb/render.h>
+#include <xcb/xcb_image.h>
 #include "region.h"
 
 typedef struct _glx_texture glx_texture_t;
@@ -34,3 +35,5 @@ void free_root_tile(session_t *ps);
 
 bool init_render(session_t *ps);
 void deinit_render(session_t *ps);
+
+xcb_image_t *make_shadow(session_t *ps, double opacity, int width, int height);
diff --git a/src/win.c b/src/win.c
index 84466ca..5129baf 100644
--- a/src/win.c
+++ b/src/win.c
@@ -117,6 +117,8 @@ void win_get_region_noframe_local(win *w, region_t *res) {
     pixman_region32_init_rect(res, x, y, width, height);
 }
 
+gen_by_val(win_get_region_noframe_local)
+
 /**
  * Add a window to damaged area.
  *
@@ -1130,6 +1132,8 @@ void win_extents(win *w, region_t *res) {
       w->g.y + w->shadow_dy, w->shadow_width, w->shadow_height);
 }
 
+gen_by_val(win_extents)
+
 /**
  * Update the out-dated bounding shape of a window.
  *
diff --git a/src/win.h b/src/win.h
index 07e2d19..cb02da0 100644
--- a/src/win.h
+++ b/src/win.h
@@ -115,7 +115,8 @@ struct win {
   bool need_configure;
   /// Queued <code>ConfigureNotify</code> when the window is unmapped.
   xcb_configure_notify_event_t queue_configure;
-  /// The region of screen that will be obscured when windows above is painted.
+  /// The region of screen that will be obscured when windows above is painted,
+  /// in global coordinates.
   /// We use this to reduce the pixels that needed to be paint when painting
   /// this window and anything underneath. Depends on window frame
   /// opacity state, window geometry, window mapped/unmapped state,
@@ -303,12 +304,14 @@ void win_update_focused(session_t *ps, win *w);
 // XXX was win_border_size
 void win_update_bounding_shape(session_t *ps, win *w);
 /**
- * Get a rectangular region a window (and possibly its shadow) occupies.
+ * Get a rectangular region in global coordinates a window (and possibly
+ * its shadow) occupies.
  *
  * Note w->shadow and shadow geometry must be correct before calling this
  * function.
  */
 void win_extents(win *w, region_t *res);
+region_t win_extents_by_val(win *w);
 /**
  * Add a window to damaged area.
  *
@@ -322,6 +325,7 @@ void add_damage_from_win(session_t *ps, win *w);
  * Return region in global coordinates.
  */
 void win_get_region_noframe_local(win *w, region_t *);
+region_t win_get_region_noframe_local_by_val(win *w);
 /**
  * Retrieve frame extents from a window.
  */