[gtk: 2/7] gtkeventcontrollerscroll: Add scroll unit getter

[Carlos Garnacho <carlosg src gnome org>]

commit 3ab63fd03b447c3d1fccd8f22d2925bf6d10ad2f
Author: panoplie <59100-panoplie users noreply gitlab gnome org>
Date:   Mon Feb 21 16:23:24 2022 +0100

    gtkeventcontrollerscroll: Add scroll unit getter
    
    The scroll unit is accessible through
    gtk_event_controller_scroll_get_unit() after the
    "scroll" signal reception.

 gtk/gtkeventcontrollerscroll.c | 27 +++++++++++++++++++++++++++
 gtk/gtkeventcontrollerscroll.h |  3 +++
 2 files changed, 30 insertions(+)
---
diff --git a/gtk/gtkeventcontrollerscroll.c b/gtk/gtkeventcontrollerscroll.c
index 67dafb73ed..e1422e1598 100644
--- a/gtk/gtkeventcontrollerscroll.c
+++ b/gtk/gtkeventcontrollerscroll.c
@@ -85,6 +85,8 @@ struct _GtkEventControllerScroll
   double cur_dx;
   double cur_dy;
 
+  GdkScrollUnit cur_unit;
+
   guint hold_timeout_id;
   guint active : 1;
 };
@@ -365,6 +367,8 @@ gtk_event_controller_scroll_handle_event (GtkEventController *controller,
 
   g_clear_handle_id (&scroll->hold_timeout_id, g_source_remove);
 
+  scroll->cur_unit = gdk_scroll_event_get_unit (event);
+
   /* FIXME: Handle device changes */
   direction = gdk_scroll_event_get_direction (event);
   if (direction == GDK_SCROLL_SMOOTH)
@@ -497,6 +501,9 @@ gtk_event_controller_scroll_class_init (GtkEventControllerScrollClass *klass)
    * Signals that the widget should scroll by the
    * amount specified by @dx and @dy.
    *
+   * For the representation unit of the deltas, see
+   * [method@Gtk.EventControllerScroll.get_unit].
+   *
    * Returns: %TRUE if the scroll event was handled,
    *   %FALSE otherwise.
    */
@@ -614,3 +621,23 @@ gtk_event_controller_scroll_get_flags (GtkEventControllerScroll *scroll)
 
   return scroll->flags;
 }
+
+/**
+ * gtk_event_controller_scroll_get_unit:
+ * @scroll: a `GtkEventControllerScroll`.
+ *
+ * Gets the scroll unit of the last
+ * [signal@Gtk.EventControllerScroll::scroll] signal received.
+ *
+ * Returns: the scroll unit.
+ *
+ * Since: 4.8
+ */
+GdkScrollUnit
+gtk_event_controller_scroll_get_unit (GtkEventControllerScroll *scroll)
+{
+  g_return_val_if_fail (GTK_IS_EVENT_CONTROLLER_SCROLL (scroll),
+                        GDK_SCROLL_UNIT_WHEEL);
+
+  return scroll->cur_unit;
+}
diff --git a/gtk/gtkeventcontrollerscroll.h b/gtk/gtkeventcontrollerscroll.h
index 7d77097255..2be1753568 100644
--- a/gtk/gtkeventcontrollerscroll.h
+++ b/gtk/gtkeventcontrollerscroll.h
@@ -71,6 +71,9 @@ GDK_AVAILABLE_IN_ALL
 GtkEventControllerScrollFlags
                     gtk_event_controller_scroll_get_flags (GtkEventControllerScroll      *scroll);
 
+GDK_AVAILABLE_IN_4_8
+GdkScrollUnit       gtk_event_controller_scroll_get_unit (GtkEventControllerScroll       *scroll);
+
 G_END_DECLS
 
 #endif /* __GTK_EVENT_CONTROLLER_SCROLL_H__ */