From 5c1f718e74110bf08901bd76bc4106d0f044289f Mon Sep 17 00:00:00 2001
From: Laurent Napias <tamplan@free.fr>
Date: Tue, 18 Jun 2019 18:52:09 +0200
Subject: Add scroll interface tabs with mouse wheel

---
 mate-volume-control/gvc-mixer-dialog.c | 75 ++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/mate-volume-control/gvc-mixer-dialog.c b/mate-volume-control/gvc-mixer-dialog.c
index e191bfc..f100e5a 100644
--- a/mate-volume-control/gvc-mixer-dialog.c
+++ b/mate-volume-control/gvc-mixer-dialog.c
@@ -131,6 +131,10 @@ static void bar_set_stream_control      (GvcMixerDialog         *dialog,
                                          GtkWidget              *bar,
                                          MateMixerStreamControl *control);
 
+static gboolean dialog_page_scroll_event_cb (GtkWidget          *widget,
+                                             GdkEventScroll     *event,
+                                             GtkWindow          *window);
+
 G_DEFINE_TYPE (GvcMixerDialog, gvc_mixer_dialog, GTK_TYPE_DIALOG)
 
 static MateMixerSwitch *
@@ -1924,6 +1928,13 @@ gvc_mixer_dialog_constructor (GType                  type,
                             self->priv->output_bar, TRUE, TRUE, 12);
 
         self->priv->notebook = gtk_notebook_new ();
+
+        gtk_widget_add_events (self->priv->notebook, GDK_SCROLL_MASK);
+        g_signal_connect (self->priv->notebook,
+                          "scroll-event",
+                          G_CALLBACK (dialog_page_scroll_event_cb),
+                          self);
+
         gtk_box_pack_start (GTK_BOX (main_vbox),
                             self->priv->notebook,
                             TRUE, TRUE, 0);
@@ -2366,3 +2377,67 @@ gvc_mixer_dialog_set_page (GvcMixerDialog *self, const gchar *page)
 
         return TRUE;
 }
+
+static gboolean
+dialog_page_scroll_event_cb (GtkWidget      *widget,
+                             GdkEventScroll *event,
+                             GtkWindow      *window)
+{
+        GtkNotebook *notebook = GTK_NOTEBOOK (widget);
+        GtkWidget *child, *event_widget, *action_widget;
+
+        child = gtk_notebook_get_nth_page (notebook, gtk_notebook_get_current_page (notebook));
+        if (child == NULL)
+                return FALSE;
+
+        event_widget = gtk_get_event_widget ((GdkEvent *) event);
+
+        /* Ignore scroll events from the content of the page */
+        if (event_widget == NULL ||
+            event_widget == child ||
+            gtk_widget_is_ancestor (event_widget, child))
+                return FALSE;
+
+        /* And also from the action widgets */
+        action_widget = gtk_notebook_get_action_widget (notebook, GTK_PACK_START);
+        if (event_widget == action_widget ||
+            (action_widget != NULL && gtk_widget_is_ancestor (event_widget, action_widget)))
+                return FALSE;
+        action_widget = gtk_notebook_get_action_widget (notebook, GTK_PACK_END);
+        if (event_widget == action_widget ||
+            (action_widget != NULL && gtk_widget_is_ancestor (event_widget, action_widget)))
+                return FALSE;
+
+        switch (event->direction) {
+
+                case GDK_SCROLL_RIGHT:
+                case GDK_SCROLL_DOWN:
+                        gtk_notebook_next_page (notebook);
+                        break;
+                case GDK_SCROLL_LEFT:
+                case GDK_SCROLL_UP:
+                        gtk_notebook_prev_page (notebook);
+                        break;
+
+                case GDK_SCROLL_SMOOTH:
+                        switch (gtk_notebook_get_tab_pos (notebook)) {
+                            case GTK_POS_LEFT:
+                            case GTK_POS_RIGHT:
+                                    if (event->delta_y > 0)
+                                        gtk_notebook_next_page (notebook);
+                                    else if (event->delta_y < 0)
+                                        gtk_notebook_prev_page (notebook);
+                                    break;
+                            case GTK_POS_TOP:
+                            case GTK_POS_BOTTOM:
+                                    if (event->delta_x > 0)
+                                        gtk_notebook_next_page (notebook);
+                                    else if (event->delta_x < 0)
+                                        gtk_notebook_prev_page (notebook);
+                                    break;
+                        }
+                        break;
+        }
+
+        return TRUE;
+}
-- 
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