[gtk/gtk-3-24: 1/3] GDK W32: send both smooth and discrete scrolling events

[LRN <ruslanizhb src gnome org>]

commit db2c9a6ec8f856abd1a7c7c74d65371d68c609cc
Author: Руслан Ижбулатов <lrn1986 gmail com>
Date:   Wed Sep 12 06:55:49 2018 +0000

    GDK W32: send both smooth and discrete scrolling events
    
    Commit 359df028be7b1dae76a1abb9bad8a3b86a648765 changed the
    code to send GDK_SCROLL_SMOOTH with deltas instead of
    GDK_SCROLL_(UP|DOWN|LEFT|RIGHT). Change it again, to send
    both the GDK_SCROLL_SMOOTH and the GDK_SCROLL_(UP|DOWN|LEFT|RIGHT)
    event separately (with the discrete event marked as emulated),
    as this is what other backends (such as wayland) do.

 gdk/win32/gdkevents-win32.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
index beaac53f49..8b2d2f7ec9 100644
--- a/gdk/win32/gdkevents-win32.c
+++ b/gdk/win32/gdkevents-win32.c
@@ -3109,6 +3109,20 @@ gdk_event_translate (MSG  *msg,
       gdk_event_set_device (event, device_manager_win32->core_pointer);
       gdk_event_set_source_device (event, device_manager_win32->system_pointer);
       gdk_event_set_seat (event, gdk_device_get_seat (device_manager_win32->core_pointer));
+      gdk_event_set_pointer_emulated (event, FALSE);
+
+      _gdk_win32_append_event (gdk_event_copy (event));
+
+      /* Append the discrete version too */
+      if (msg->message == WM_MOUSEWHEEL)
+       event->scroll.direction = (((short) HIWORD (msg->wParam)) > 0) ?
+         GDK_SCROLL_UP : GDK_SCROLL_DOWN;
+      else if (msg->message == WM_MOUSEHWHEEL)
+       event->scroll.direction = (((short) HIWORD (msg->wParam)) > 0) ?
+         GDK_SCROLL_RIGHT : GDK_SCROLL_LEFT;
+      event->scroll.delta_x = 0;
+      event->scroll.delta_y = 0;
+      gdk_event_set_pointer_emulated (event, TRUE);
 
       _gdk_win32_append_event (event);