master a05baff: Fix incorrect GTK menus on HiDPI monitors with scaling factor > 1

[Robert Pluim]

branch: master
commit a05bafffdcb88df74408a8402cafc9829407c1e5
Author: Tobias Bading <address@hidden>
Commit: Robert Pluim <address@hidden>

    Fix incorrect GTK menus on HiDPI monitors with scaling factor > 1
    
    This should fix Bug#31223, Bug#28106, Bug#23672 as well as Ubuntu bug
    https://bugs.launchpad.net/ubuntu/+source/emacs25/+bug/1695228
    
    Also fixes the formerly unscaled Y value returned by
    frame-monitor-workarea (and display-monitor-attributes-list).
    
    For details on why some GTK menus were empty please see thread
    https://lists.gnu.org/archive/html/emacs-devel/2019-11/msg01061.html
    
    * src/gtkutil.c (menubar_map_cb, xg_update_frame_menubar): Scale up
    req.height so that the menu bar's height is in device pixels as
    expected.
    (xg_event_is_for_menubar): Scale down rec.x and rec.y so that
    gtk_widget_intersect() works as intended.
    * src/xfns.c (Fx_display_monitor_attributes_list): Scale work.x and
    work.y up to be in device pixels.
    
    Copyright-paperwork-exempt: yes
---
 src/gtkutil.c | 8 +++++---
 src/xfns.c    | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/gtkutil.c b/src/gtkutil.c
index cf5c31a..7e6db57 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -3471,6 +3471,7 @@ menubar_map_cb (GtkWidget *w, gpointer user_data)
   GtkRequisition req;
   struct frame *f = user_data;
   gtk_widget_get_preferred_size (w, NULL, &req);
+  req.height *= xg_get_scale (f);
   if (FRAME_MENUBAR_HEIGHT (f) != req.height)
     {
       FRAME_MENUBAR_HEIGHT (f) = req.height;
@@ -3502,7 +3503,7 @@ xg_update_frame_menubar (struct frame *f)
   g_signal_connect (x->menubar_widget, "map", G_CALLBACK (menubar_map_cb), f);
   gtk_widget_show_all (x->menubar_widget);
   gtk_widget_get_preferred_size (x->menubar_widget, NULL, &req);
-
+  req.height *= xg_get_scale (f);
   if (FRAME_MENUBAR_HEIGHT (f) != req.height)
     {
       FRAME_MENUBAR_HEIGHT (f) = req.height;
@@ -3568,8 +3569,9 @@ xg_event_is_for_menubar (struct frame *f, const XEvent 
*event)
 
   list = gtk_container_get_children (GTK_CONTAINER (x->menubar_widget));
   if (! list) return 0;
-  rec.x = event->xbutton.x;
-  rec.y = event->xbutton.y;
+  int scale = xg_get_scale (f);
+  rec.x = event->xbutton.x / scale;
+  rec.y = event->xbutton.y / scale;
   rec.width = 1;
   rec.height = 1;
 
diff --git a/src/xfns.c b/src/xfns.c
index b1b4070..47aa196 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -5093,6 +5093,8 @@ Internal use only, use `display-monitor-attributes-list' 
instead.  */)
 #endif
       rec.width *= scale;
       rec.height *= scale;
+      work.x *= scale;
+      work.y *= scale;
       work.width *= scale;
       work.height *= scale;