diff --git a/redo/area_darwin.go b/redo/area_darwin.go
index 509c05d..ad82777 100644
--- a/redo/area_darwin.go
+++ b/redo/area_darwin.go
@@ -35,6 +35,20 @@ func (a *area) SetSize(width, height int) {
 	C.moveControl(a._id, 0, 0, C.intptr_t(a.width), C.intptr_t(a.height))
 }
 
+func (a *area) Repaint(r image.Rectangle) {
+	var s C.struct_xrect
+
+	r = image.Rect(0, 0, a.width, a.height).Intersect(r)
+	if r.Empty() {
+		return
+	}
+	s.x = C.intptr_t(r.Min.X)
+	s.y = C.intptr_t(r.Min.Y)
+	s.width = C.intptr_t(r.Dx())
+	s.height = C.intptr_t(r.Dy())
+	C.areaRepaint(a._id, s)
+}
+
 func (a *area) RepaintAll() {
 	C.areaRepaintAll(a._id)
 }
diff --git a/redo/area_darwin.m b/redo/area_darwin.m
index d76f3a1..b3d095e 100644
--- a/redo/area_darwin.m
+++ b/redo/area_darwin.m
@@ -188,6 +188,17 @@ uintptr_t keyCode(id e)
 	return (uintptr_t) ([toNSEvent(e) keyCode]);
 }
 
+void areaRepaint(id view, struct xrect r)
+{
+	NSRect s;
+
+	s.origin.x = (CGFloat) r.x;
+	s.origin.y = (CGFloat) r.y;
+	s.size.width = (CGFloat) r.width;
+	s.size.height = (CGFloat) r.height;
+	[toNSView(view) displayRect:s];
+}
+
 void areaRepaintAll(id view)
 {
 	[toNSView(view) display];
diff --git a/redo/objc_darwin.h b/redo/objc_darwin.h
index d4a58d0..826334c 100644
--- a/redo/objc_darwin.h
+++ b/redo/objc_darwin.h
@@ -125,6 +125,7 @@ extern intptr_t buttonNumber(id);
 extern intptr_t clickCount(id);
 extern uintptr_t pressedMouseButtons(void);
 extern uintptr_t keyCode(id);
+extern void areaRepaint(id, struct xrect);
 extern void areaRepaintAll(id);
 
 /* common_darwin.m */