[clutter] evdev: use libinput's new merged scroll events

[Emmanuele Bassi <ebassi src gnome org>]

commit ede13b11d72a310e535f9a6f0b7e3f774f5529dc
Author: Peter Hutterer <peter hutterer who-t net>
Date:   Fri Jan 16 01:03:52 2015 +0100

    evdev: use libinput's new merged scroll events
    
    libinput's API changed from separate scroll events for vert/horiz scrolling to
    a single event that contains both axes if they changed.
    
    Updated by Armin K. to use the discrete axis value for wheel events as done
    in Weston.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=742829

 clutter/evdev/clutter-device-manager-evdev.c |   40 +++++++++++++++++--------
 configure.ac                                 |    2 +-
 2 files changed, 28 insertions(+), 14 deletions(-)
---
diff --git a/clutter/evdev/clutter-device-manager-evdev.c b/clutter/evdev/clutter-device-manager-evdev.c
index 7b48481..2b3828a 100644
--- a/clutter/evdev/clutter-device-manager-evdev.c
+++ b/clutter/evdev/clutter-device-manager-evdev.c
@@ -1191,29 +1191,43 @@ process_device_event (ClutterDeviceManagerEvdev *manager_evdev,
 
     case LIBINPUT_EVENT_POINTER_AXIS:
       {
-        gdouble value, dx = 0.0, dy = 0.0;
+        gdouble dx = 0.0, dy = 0.0;
         guint32 time;
+        gboolean wheel = FALSE;
         enum libinput_pointer_axis axis;
+        enum libinput_pointer_axis_source source;
         struct libinput_event_pointer *axis_event =
           libinput_event_get_pointer_event (event);
+
         device = libinput_device_get_user_data (libinput_device);
 
         time = libinput_event_pointer_get_time (axis_event);
-        value = libinput_event_pointer_get_axis_value (axis_event);
-        axis = libinput_event_pointer_get_axis (axis_event);
+        source = libinput_event_pointer_get_axis_source (axis_event);
 
-        switch (axis)
-          {
-          case LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL:
-            dx = 0;
-            dy = value;
-            break;
+        /* libinput < 0.8 sent wheel click events with value 10. Since 0.8
+           the value is the angle of the click in degrees. To keep
+           backwards-compat with existing clients, we just send multiples of
+           the click count. */
+
+        if (source == LIBINPUT_POINTER_AXIS_SOURCE_WHEEL)
+            wheel = TRUE;
 
-          case LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL:
-            dx = value;
-            dy = 0;
-            break;
+        axis = LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL;
+        if (libinput_event_pointer_has_axis (axis_event, axis))
+          {
+            if (wheel)
+              dy = 10 * libinput_event_pointer_get_axis_value_discrete (axis_event, axis);
+            else
+              dy = libinput_event_pointer_get_axis_value (axis_event, axis);
+          }
 
+        axis = LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL;
+        if (libinput_event_pointer_has_axis (axis_event, axis))
+          {
+            if (wheel)
+              dx = 10 * libinput_event_pointer_get_axis_value_discrete (axis_event, axis);
+            else
+              dx = libinput_event_pointer_get_axis_value (axis_event, axis);
           }
 
         notify_scroll (device, time, dx, dy);
diff --git a/configure.ac b/configure.ac
index 0a9a580..2a47744 100644
--- a/configure.ac
+++ b/configure.ac
@@ -146,7 +146,7 @@ m4_define([uprof_req_version],          [0.3])
 m4_define([gtk_doc_req_version],        [1.20])
 m4_define([xcomposite_req_version],     [0.4])
 m4_define([gdk_req_version],            [3.3.18])
-m4_define([libinput_req_version],       [0.4.0])
+m4_define([libinput_req_version],       [0.8.0])
 m4_define([libudev_req_version],        [136])
 
 AC_SUBST([GLIB_REQ_VERSION],       [glib_req_version])