[clutter/clutter-1.20] Fix scaling of pointer axis vectors

[Emmanuele Bassi <ebassi src gnome org>]

commit 7ed92c845fbaf145e0afe9182ba564898fd734e9
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Jan 5 16:03:59 2014 +0100

    Fix scaling of pointer axis vectors
    
    The vector of libinput and Wayland pointer axis events are in pointer
    motion coordinate space. To convert to clutter's internal representation
    the vectors need to be scaled to Xi2 scroll steps.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=723560

 clutter/evdev/clutter-device-manager-evdev.c   |    6 +++++-
 clutter/wayland/clutter-input-device-wayland.c |    9 +++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/clutter/evdev/clutter-device-manager-evdev.c b/clutter/evdev/clutter-device-manager-evdev.c
index 17d2ac8..9065fdc 100644
--- a/clutter/evdev/clutter-device-manager-evdev.c
+++ b/clutter/evdev/clutter-device-manager-evdev.c
@@ -442,7 +442,7 @@ notify_scroll (ClutterInputDevice *input_device,
   ClutterStage *stage;
   ClutterEvent *event = NULL;
   ClutterPoint point;
-  const gdouble scroll_factor = 10.0f;
+  gdouble scroll_factor;
 
   /* We can drop the event on the floor if no stage has been
    * associated with the device yet. */
@@ -460,7 +460,11 @@ notify_scroll (ClutterInputDevice *input_device,
   event->scroll.device = seat->core_pointer;
   _clutter_xkb_translate_state (event, seat->xkb, seat->button_state);
 
+  /* libinput pointer axis events are in pointer motion coordinate space.
+   * To convert to Xi2 discrete step coordinate space, multiply the factor
+   * 1/10. */
   event->scroll.direction = CLUTTER_SCROLL_SMOOTH;
+  scroll_factor = 1.0 / 10.0;
   clutter_event_set_scroll_delta (event,
                                   scroll_factor * dx,
                                   scroll_factor * dy);
diff --git a/clutter/wayland/clutter-input-device-wayland.c b/clutter/wayland/clutter-input-device-wayland.c
index a3c9c19..7bfb615 100644
--- a/clutter/wayland/clutter-input-device-wayland.c
+++ b/clutter/wayland/clutter-input-device-wayland.c
@@ -167,6 +167,7 @@ clutter_wayland_handle_axis (void *data,
   ClutterStageCogl          *stage_cogl;
   ClutterEvent              *event;
   gdouble                    delta_x, delta_y;
+  gdouble                    delta_factor;
 
   if (!device->pointer_focus)
     return;
@@ -179,15 +180,19 @@ clutter_wayland_handle_axis (void *data,
   event->scroll.x = device->x;
   event->scroll.y = device->y;
 
+  /* Wayland pointer axis events are in pointer motion coordinate space.
+   * To convert to Xi2 discrete step coordinate space, multiply the factor
+   * 1/10. */
+  delta_factor = 1.0 / 10.0;
   if (axis == WL_POINTER_AXIS_HORIZONTAL_SCROLL)
     {
-      delta_x = -wl_fixed_to_double(value) * 23;
+      delta_x = wl_fixed_to_double (value) * delta_factor;
       delta_y = 0;
     }
   else
     {
       delta_x = 0;
-      delta_y = -wl_fixed_to_double(value) * 23; /* XXX: based on my bcm5794 */
+      delta_y = wl_fixed_to_double (value) * delta_factor;
     }
   clutter_event_set_scroll_delta (event, delta_x, delta_y);