diff --git a/src/region.h b/src/region.h
index a056c80..bda66e2 100644
--- a/src/region.h
+++ b/src/region.h
@@ -47,3 +47,54 @@ static inline rect_t *from_x_rects(int nrects, const xcb_rectangle_t *rects) {
 	}
 	return ret;
 }
+
+/**
+ * Resize a region.
+ */
+static inline void _resize_region(const region_t *region, region_t *output, int dx,
+		int dy) {
+	if (!region || !output) {
+		return;
+	}
+	if (!dx && !dy) {
+		if (region != output) {
+			pixman_region32_copy(output, (region_t *)region);
+		}
+		return;
+	}
+	// Loop through all rectangles
+	int nrects;
+	int nnewrects = 0;
+	const rect_t *rects = pixman_region32_rectangles((region_t *)region, &nrects);
+	auto newrects = ccalloc(nrects, rect_t);
+	for (int i = 0; i < nrects; i++) {
+		int x1 = rects[i].x1 - dx;
+		int y1 = rects[i].y1 - dy;
+		int x2 = rects[i].x2 + dx;
+		int y2 = rects[i].y2 + dy;
+		int wid = x2 - x1;
+		int hei = y2 - y1;
+		if (wid <= 0 || hei <= 0) {
+			continue;
+		}
+		newrects[nnewrects] =
+		    (rect_t){.x1 = x1, .x2 = x2, .y1 = y1, .y2 = y2};
+		++nnewrects;
+	}
+
+	pixman_region32_fini(output);
+	pixman_region32_init_rects(output, newrects, nnewrects);
+
+	free(newrects);
+}
+
+static inline region_t resize_region(const region_t *region, int dx, int dy) {
+	region_t ret;
+	pixman_region32_init(&ret);
+	_resize_region(region, &ret, dx, dy);
+	return ret;
+}
+
+static inline void resize_region_in_place(region_t *region, int dx, int dy) {
+	return _resize_region(region, region, dx, dy);
+}
diff --git a/src/render.c b/src/render.c
index b4fa733..d64ed27 100644
--- a/src/render.c
+++ b/src/render.c
@@ -740,37 +740,6 @@ win_blur_background(session_t *ps, struct managed_win *w, xcb_render_picture_t t
 	}
 }
 
-/**
- * Resize a region.
- */
-static inline void resize_region(region_t *region, short mod) {
-	if (!mod || !region)
-		return;
-	// Loop through all rectangles
-	int nrects;
-	int nnewrects = 0;
-	pixman_box32_t *rects = pixman_region32_rectangles(region, &nrects);
-	auto newrects = ccalloc(nrects, pixman_box32_t);
-	for (int i = 0; i < nrects; i++) {
-		int x1 = rects[i].x1 - mod;
-		int y1 = rects[i].y1 - mod;
-		int x2 = rects[i].x2 + mod;
-		int y2 = rects[i].y2 + mod;
-		int wid = x2 - x1;
-		int hei = y2 - y1;
-		if (wid <= 0 || hei <= 0)
-			continue;
-		newrects[nnewrects] =
-		    (pixman_box32_t){.x1 = x1, .x2 = x2, .y1 = y1, .y2 = y2};
-		++nnewrects;
-	}
-
-	pixman_region32_fini(region);
-	pixman_region32_init_rects(region, newrects, nnewrects);
-
-	free(newrects);
-}
-
 /// paint all windows
 /// region = ??
 /// region_real = the damage region
@@ -807,7 +776,7 @@ void paint_all(session_t *ps, struct managed_win *t, bool ignore_damage) {
 #endif
 
 	if (ps->o.resize_damage > 0) {
-		resize_region(&region, (short)ps->o.resize_damage);
+		resize_region_in_place(&region, ps->o.resize_damage, ps->o.resize_damage);
 	}
 
 	// Remove the damaged area out of screen