compositor: Introduce weston_output_schedule_repaint()

This lets us schedule a repaint on just the output that needs it.
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index 90ed1fd..399269d 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -230,7 +230,7 @@
 
 	if (fb == fb->output->next ||
 	    (fb == fb->output->current && !fb->output->next))
-		weston_compositor_schedule_repaint(fb->output->base.compositor);
+		weston_output_schedule_repaint(&fb->output->base);
 }
 
 static int
diff --git a/src/compositor-x11.c b/src/compositor-x11.c
index a5c1868..8cff73e 100644
--- a/src/compositor-x11.c
+++ b/src/compositor-x11.c
@@ -627,6 +627,7 @@
 	xcb_key_press_event_t *key_press, *key_release;
 	xcb_keymap_notify_event_t *keymap_notify;
 	xcb_focus_in_event_t *focus_in;
+	xcb_expose_event_t *expose;
 	xcb_atom_t atom;
 	uint32_t *k;
 	uint32_t i, set;
@@ -716,10 +717,9 @@
 			break;
 
 		case XCB_EXPOSE:
-			/* FIXME: schedule output repaint */
-			/* output = x11_compositor_find_output(c, expose->window); */
-
-			weston_compositor_schedule_repaint(&c->base);
+			expose = (xcb_expose_event_t *) event;
+			output = x11_compositor_find_output(c, expose->window);
+			weston_output_schedule_repaint(&output->base);
 			break;
 
 		case XCB_ENTER_NOTIFY:
diff --git a/src/compositor.c b/src/compositor.c
index c433c06..8aefca1 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -929,7 +929,7 @@
 
 	pixman_region32_union(&compositor->damage,
 			      &compositor->damage, &output->region);
-	weston_compositor_schedule_repaint(compositor);
+	weston_output_schedule_repaint(output);
 }
 
 static void
@@ -1175,23 +1175,21 @@
 }
 
 WL_EXPORT void
-weston_compositor_schedule_repaint(struct weston_compositor *compositor)
+weston_output_schedule_repaint(struct weston_output *output)
 {
-	struct weston_output *output;
+	struct weston_compositor *compositor = output->compositor;
 	struct wl_event_loop *loop;
 
 	if (compositor->state == WESTON_COMPOSITOR_SLEEPING)
 		return;
 
 	loop = wl_display_get_event_loop(compositor->wl_display);
-	wl_list_for_each(output, &compositor->output_list, link) {
-		output->repaint_needed = 1;
-		if (output->repaint_scheduled)
-			continue;
+	output->repaint_needed = 1;
+	if (output->repaint_scheduled)
+		return;
 
-		wl_event_loop_add_idle(loop, idle_repaint, output);
-		output->repaint_scheduled = 1;
-	}
+	wl_event_loop_add_idle(loop, idle_repaint, output);
+	output->repaint_scheduled = 1;
 
 	if (compositor->input_loop_source) {
 		wl_event_source_remove(compositor->input_loop_source);
@@ -1200,6 +1198,15 @@
 }
 
 WL_EXPORT void
+weston_compositor_schedule_repaint(struct weston_compositor *compositor)
+{
+	struct weston_output *output;
+
+	wl_list_for_each(output, &compositor->output_list, link)
+		weston_output_schedule_repaint(output);
+}
+
+WL_EXPORT void
 weston_compositor_fade(struct weston_compositor *compositor, float tint)
 {
 	struct weston_output *output;
diff --git a/src/compositor.h b/src/compositor.h
index b437d59..ed09157 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -519,6 +519,8 @@
 void
 weston_output_finish_frame(struct weston_output *output, int msecs);
 void
+weston_output_schedule_repaint(struct weston_output *output);
+void
 weston_output_damage(struct weston_output *output);
 void
 weston_compositor_schedule_repaint(struct weston_compositor *compositor);
diff --git a/src/screenshooter.c b/src/screenshooter.c
index 542425e..aa8d0c0 100644
--- a/src/screenshooter.c
+++ b/src/screenshooter.c
@@ -165,7 +165,7 @@
 
 	l->listener.notify = screenshooter_frame_notify;
 	wl_signal_add(&output->frame_signal, &l->listener);
-	weston_compositor_schedule_repaint(output->compositor);
+	weston_output_schedule_repaint(output);
 }
 
 struct screenshooter_interface screenshooter_implementation = {