display: Expose a helper for retriving guest position

When running an Android VM with GL support, Android somehow enforces
support for only touch events making it difficult to work with QEMU +
Android for devolpement / demo purposes without a touch screen.

This helper is useful for being able to emulate motion / click
events as touch ones

lib/mks-display-picture-private.h

@@ -45,5 +45,9 @@ void          mks_display_picture_set_keyboard  (MksDisplayPicture *self,
 MksTouchable *mks_display_picture_get_touchable (MksDisplayPicture *self);
 void          mks_display_picture_set_touchable (MksDisplayPicture *self,
                                                  MksTouchable      *touchable);
-
+gboolean
+   mks_display_picture_event_get_guest_position (MksDisplayPicture *self,
+                                                 GdkEvent          *event,
+                                                 double            *guest_x,
+                                                 double            *guest_y);
 G_END_DECLS

lib/mks-display-picture.c

@@ -193,7 +193,7 @@ mks_display_picture_mouse_release_cb (GObject      *object,
     g_debug ("Mouse release failed: %s", error->message);
 }
 
-static gboolean
+gboolean
 mks_display_picture_event_get_guest_position (MksDisplayPicture *self,
                                               GdkEvent          *event,
                                               double            *guest_x,

lib/mks-display.c

@@ -569,3 +569,32 @@ mks_display_set_ungrab_trigger (MksDisplay         *self,
 
   MKS_EXIT;
 }
+
+/**
+ * mks_display_get_event_position_in_guest:
+ * @self: a #MksDisplay
+ * @event: A #GdkEvent
+ * @guest_x: (out): Guest's X position
+ * @guest_y: (out): Guest's Y position
+ *
+ * Retrieve the (`guest_x`, `guest_y`) position
+ * where the `event` happened.
+ * 
+ * Could be useful for implementing touch support emulation.
+ * 
+ * Returns: Whether the event has an associated position
+ */
+gboolean
+mks_display_get_event_position_in_guest (MksDisplay *self,
+                                         GdkEvent   *event,
+                                         double     *guest_x,
+                                         double     *guest_y)
+{
+  MksDisplayPrivate *priv = mks_display_get_instance_private (self);
+
+  g_return_val_if_fail (MKS_IS_DISPLAY (self), FALSE);
+  g_return_val_if_fail (GDK_IS_EVENT (event), FALSE);
+
+  return mks_display_picture_event_get_guest_position (priv->picture, event,
+                                                       guest_x, guest_y);
+}

lib/mks-display.h

@@ -58,4 +58,10 @@ gboolean            mks_display_get_auto_resize    (MksDisplay         *self);
 MKS_AVAILABLE_IN_ALL
 void                mks_display_set_auto_resize    (MksDisplay         *self,
                                                     gboolean            auto_resize);
+MKS_AVAILABLE_IN_ALL
+gboolean
+          mks_display_get_event_position_in_guest  (MksDisplay         *self,
+                                                    GdkEvent           *event,
+                                                    double             *guest_x,
+                                                    double             *guest_y);
 G_END_DECLS