Add new surface.map_transient() request to map a surface relative to another

compositor/compositor.c

@@ -472,6 +472,26 @@ surface_map_toplevel(struct wl_client *client,
 	es->mapped = 1;
 }
 
+static void
+surface_map_transient(struct wl_client *client,
+		      struct wl_surface *surface, struct wl_surface *parent,
+		      int x, int y, uint32_t flags)
+{
+	struct wlsc_surface *es = (struct wlsc_surface *) surface;
+	struct wlsc_surface *pes = (struct wlsc_surface *) parent;
+
+	if (es->mapped)
+		return;
+
+	es->x = pes->x + x;
+	es->y = pes->y + y;
+
+	wlsc_surface_update_matrix(es);
+	wl_list_insert(&es->compositor->surface_list, &es->link);
+	wlsc_compositor_schedule_repaint(es->compositor);
+	es->mapped = 1;
+}
+
 static void
 surface_damage(struct wl_client *client,
 	       struct wl_surface *surface,
@@ -487,6 +507,7 @@ const static struct wl_surface_interface surface_interface = {
 	surface_destroy,
 	surface_attach,
 	surface_map_toplevel,
+	surface_map_transient,
 	surface_damage
 };
 

protocol/wayland.xml

@@ -341,6 +341,21 @@
     <!-- Make the surface visible as a toplevel window. -->
     <request name="map_toplevel"/>
 
+    <!-- Map the surface relative to an existing surface. The x and y
+         arguments specify the locations of the upper left corner of
+         the surface relative to the upper left corner of the parent
+         surface.  The flags argument controls overflow/clipping
+         behaviour when the surface would intersect a screen edge,
+         panel or such.  And possibly whether the offset only
+         determines the initial position or if the surface is locked
+         to that relative position during moves. -->
+    <request name="map_transient">
+      <arg name="parent" type="object" interface="surface"/>
+      <arg name="x" type="int"/>
+      <arg name="y" type="int"/>
+      <arg name="flags" type="uint"/>
+    </request>
+
     <!-- Notify the server that the attached buffer's contents have
          changed, and request a redraw. The arguments allow you to
          damage only a part of the surface, but the server may ignore