bug#31223: [PATCH] Fix empty/incorrect GTK menus on HiDPI monitors with window scaling factor > 1

[Robert Pluim]

>>>>> On Tue, 17 Dec 2019 15:43:50 +0100, Robert Pluim <rpluim@gmail.com> said:
    Robert> diff --git a/src/xfns.c b/src/xfns.c
    Robert> index 47aa19607f..51a46bd6db 100644
    Robert> --- a/src/xfns.c
    Robert> +++ b/src/xfns.c
    Robert> @@ -5091,6 +5091,8 @@ DEFUN ("x-display-monitor-attributes-list", 
Fx_display_monitor_attributes_list,
    Robert>  #elif defined HAVE_GTK3
    Robert>        scale = gdk_screen_get_monitor_scale_factor (gscreen, i);
    Robert>  #endif
    Robert> +      rec.x *= scale;
    Robert> +      rec.y *= scale;
    Robert>        rec.width *= scale;
    Robert>        rec.height *= scale;
    Robert>        work.x *= scale;

Eli, is this OK for emacs-27? It will only affect
display-monitor-attributes-list for people using GTK on multiple
monitors where one is HiDPI.

Robert