lib: use mouse-set from peer to update local position

We may need to tweak this for relative mouse positions if we find we dont
get reliable information from the peer. But this is a start, which I see
we get back from Qemu at least when we're in -enable-kvm mode.

lib/mks-display.c

@@ -44,6 +44,7 @@ typedef struct
   gulong invalidate_contents_handler;
   gulong invalidate_size_handler;
   gulong notify_cursor_handler;
+  gulong mouse_set_handler;
 
   /* Tracking the last known positions of mouse events so that we may
    * do something "reasonable" if the pointer is not absolute.
@@ -133,6 +134,21 @@ mks_display_notify_cursor_cb (MksDisplay   *self,
   gtk_widget_set_cursor (GTK_WIDGET (self), cursor);
 }
 
+static void
+mks_display_mouse_set_cb (MksDisplay   *self,
+                          int           x,
+                          int           y,
+                          MksPaintable *paintable)
+{
+  MksDisplayPrivate *priv = mks_display_get_instance_private (self);
+
+  g_assert (MKS_IS_DISPLAY (self));
+  g_assert (MKS_IS_PAINTABLE (paintable));
+
+  priv->last_mouse_x = x;
+  priv->last_mouse_y = y;
+}
+
 static void
 mks_display_set_paintable (MksDisplay   *self,
                            GdkPaintable *paintable)
@@ -150,6 +166,7 @@ mks_display_set_paintable (MksDisplay   *self,
       g_clear_signal_handler (&priv->invalidate_contents_handler, priv->paintable);
       g_clear_signal_handler (&priv->invalidate_size_handler, priv->paintable);
       g_clear_signal_handler (&priv->notify_cursor_handler, priv->paintable);
+      g_clear_signal_handler (&priv->mouse_set_handler, priv->paintable);
       g_clear_object (&priv->paintable);
     }
 
@@ -174,6 +191,12 @@ mks_display_set_paintable (MksDisplay   *self,
                                  G_CALLBACK (mks_display_notify_cursor_cb),
                                  self,
                                  G_CONNECT_SWAPPED);
+      priv->notify_cursor_handler =
+        g_signal_connect_object (paintable,
+                                 "mouse-set",
+                                 G_CALLBACK (mks_display_mouse_set_cb),
+                                 self,
+                                 G_CONNECT_SWAPPED);
     }
 
   g_object_notify_by_pspec (G_OBJECT (self), properties [PROP_PAINTABLE]);
@@ -388,11 +411,8 @@ mks_display_legacy_event_cb (MksDisplay               *self,
             if (gdk_event_get_axis (event, GDK_AXIS_X, &x) &&
                 gdk_event_get_axis (event, GDK_AXIS_Y, &y))
               {
-                double delta_x = floor (x - priv->last_mouse_x) / area.size.width * guest_width;
+                double delta_x = priv->last_mouse_x - (x / area.size.width) * guest_width;
-                double delta_y = floor (y - priv->last_mouse_y) / area.size.height * guest_height;
+                double delta_y = priv->last_mouse_y - (y / area.size.height) * guest_height;
-
-                priv->last_mouse_x = x;
-                priv->last_mouse_y = y;
 
                 mks_mouse_move_by (mouse,
                                    delta_x,

lib/mks-paintable-private.h

@@ -33,5 +33,8 @@ GdkPaintable *_mks_paintable_new        (GCancellable  *cancellable,
                                            int           *peer_fd,
                                            GError       **error);
 GdkCursor    *_mks_paintable_get_cursor   (MksPaintable  *self);
+void          _mks_paintable_get_position (MksPaintable  *self,
+                                           int           *x,
+                                           int           *y);
 
 G_END_DECLS

lib/mks-paintable.c

@@ -32,6 +32,8 @@
 #include "mks-paintable-private.h"
 #include "mks-qemu.h"
 
+#include "mks-marshal.h"
+
 struct _MksPaintable
 {
   GObject          parent_instance;
@@ -40,6 +42,8 @@ struct _MksPaintable
   GDBusConnection *connection;
   GdkPaintable    *child;
   GdkCursor       *cursor;
+  int              mouse_x;
+  int              mouse_y;
 };
 
 enum {
@@ -49,7 +53,13 @@ enum {
   N_PROPS
 };
 
+enum {
+  MOUSE_SET,
+  N_SIGNALS
+};
+
 static GParamSpec *properties [N_PROPS];
+static guint signals [N_SIGNALS];
 
 static cairo_format_t
 _pixman_format_to_cairo_format (guint pixman_format)
@@ -198,6 +208,18 @@ mks_paintable_class_init (MksPaintableClass *klass)
                          (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 
   g_object_class_install_properties (object_class, N_PROPS, properties);
+
+  signals [MOUSE_SET] =
+    g_signal_new ("mouse-set",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  _mks_marshal_VOID__INT_INT,
+                  G_TYPE_NONE, 2, G_TYPE_INT, G_TYPE_INT);
+  g_signal_set_va_marshaller (signals [MOUSE_SET],
+                              G_TYPE_FROM_CLASS (klass),
+                              _mks_marshal_VOID__INT_INTv);
 }
 
 static void
@@ -563,8 +585,13 @@ mks_paintable_listener_mouse_set (MksPaintable          *self,
   g_assert (G_IS_DBUS_METHOD_INVOCATION (invocation));
   g_assert (MKS_QEMU_IS_LISTENER (listener));
 
+  self->mouse_x = x;
+  self->mouse_y = y;
+
   mks_qemu_listener_complete_mouse_set (listener, invocation);
 
+  g_signal_emit (self, signals[MOUSE_SET], 0, x, y);
+
   return TRUE;
 }