[balsa/gtk4: 65/311] popup-widgets: Center the popup when shift-F10

[Peter Bloomfield <peterb src gnome org>]

commit a0fec780fcf6e4f68fe0fdec71ac3929d0609692
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Mon Jun 22 19:28:50 2020 -0400

    popup-widgets: Center the popup when shift-F10
    
    Center the popup on its widget when it is invoked through the keyboard
    shift-F10 combination.

 libbalsa/libbalsa.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/libbalsa/libbalsa.c b/libbalsa/libbalsa.c
index b28e398df..1cfbd0b70 100644
--- a/libbalsa/libbalsa.c
+++ b/libbalsa/libbalsa.c
@@ -811,10 +811,10 @@ libbalsa_popup_widget_popup(GtkWidget      *popup_widget,
         GtkPopover *popover = GTK_POPOVER(popup_widget);
         GtkWidget *relative_to = gtk_popover_get_relative_to(popover);
         gdouble x, y;
+        GdkRectangle rectangle;
 
         if (event != NULL &&
             gdk_event_get_coords(event, &x, &y)) {
-            GdkRectangle rectangle;
 
             if (GTK_IS_TREE_VIEW(relative_to)) {
                 gtk_tree_view_convert_bin_window_to_widget_coords(GTK_TREE_VIEW(relative_to),
@@ -838,9 +838,15 @@ libbalsa_popup_widget_popup(GtkWidget      *popup_widget,
                 rectangle.width = 0;
                 rectangle.height = 0;
             }
-            gtk_popover_set_pointing_to(popover, &rectangle);
+        } else {
+            gtk_widget_get_allocation(relative_to, (GtkAllocation *) &rectangle);
+            rectangle.x += rectangle.width / 2;
+            rectangle.width = 0;
+            rectangle.y += rectangle.height / 2;
+            rectangle.height = 0;
         }
 
+        gtk_popover_set_pointing_to(popover, &rectangle);
         gtk_popover_popup(popover);
     } else {
         GtkMenu *menu = GTK_MENU(popup_widget);