[PATCH v3 2/2] ui/gtk: a new array param monitor to specify the target displays

[Dongwon Kim <dongwon.kim@intel.com>]

New integer array parameter, 'monitor' is for specifying the target
monitors where individual GTK windows are placed upon launching.

Monitor numbers in the array are associated with virtual consoles
in the order of [VC0, VC1, VC2 ... VCn].

Every GTK window containing each VC will be placed in the region
of corresponding monitors.

Usage: -display gtk,monitor.<id of VC>=<target monitor>,..
       ex)-display gtk,monitor.0=1,monitor.1=0

v3: - Revised commit message
    - Rewrote desription of the new parameter (Markus Armbruster)
    - Replaced unnecessary 'for' loop with 'if' condition
      (Markus Armbruster)

Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
 qapi/ui.json    |  9 ++++++++-
 qemu-options.hx |  3 ++-
 ui/gtk.c        | 31 +++++++++++++++++++++++++++++--
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/qapi/ui.json b/qapi/ui.json
index 413371d5e8..7b4c098bb4 100644
--- a/qapi/ui.json
+++ b/qapi/ui.json
@@ -1195,12 +1195,19 @@
 #               assuming the guest will resize the display to match
 #               the window size then.  Otherwise it defaults to "off".
 #               Since 3.1
+# @monitor:     Array of numbers, each of which represents physical
+#               monitor where GTK window containing a given VC will be
+#               placed. Each monitor number in the array will be
+#               associated with a virtual-console starting from VC0.
+#
+#               since 7.1
 #
 # Since: 2.12
 ##
 { 'struct'  : 'DisplayGTK',
   'data'    : { '*grab-on-hover' : 'bool',
-                '*zoom-to-fit'   : 'bool'  } }
+                '*zoom-to-fit'   : 'bool',
+                '*monitor'       : ['uint16']  } }
 
 ##
 # @DisplayEGLHeadless:
diff --git a/qemu-options.hx b/qemu-options.hx
index 377d22fbd8..aabdfb0636 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1938,7 +1938,8 @@ DEF("display", HAS_ARG, QEMU_OPTION_display,
 #endif
 #if defined(CONFIG_GTK)
     "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n"
-    "            [,show-cursor=on|off][,window-close=on|off]\n"
+    "            [,monitor.<id of VC>=<monitor number>][,show-cursor=on|off]"
+    "            [,window-close=on|off]\n"
 #endif
 #if defined(CONFIG_VNC)
     "-display vnc=<display>[,<optargs>]\n"
diff --git a/ui/gtk.c b/ui/gtk.c
index e6878c3209..935176e614 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -2316,6 +2316,10 @@ static void gtk_display_init(DisplayState *ds, DisplayOptions *opts)
     GtkDisplayState *s = g_malloc0(sizeof(*s));
     GdkDisplay *window_display;
     GtkIconTheme *theme;
+    GtkWidget *win;
+    GdkRectangle dest;
+    uint16List *mon;
+    int n_mon;
     int i;
     char *dir;
 
@@ -2393,10 +2397,33 @@ static void gtk_display_init(DisplayState *ds, DisplayOptions *opts)
             gtk_menu_item_activate(GTK_MENU_ITEM(s->untabify_item));
         }
     }
-    if (opts->has_full_screen &&
-        opts->full_screen) {
+
+    if (opts->u.gtk.has_monitor) {
+        i = 0;
+        n_mon = gdk_display_get_n_monitors(window_display);
+        for (mon = opts->u.gtk.monitor; mon; mon = mon->next) {
+            if (mon->value < n_mon && i < s->nb_vcs) {
+                win = s->vc[i].window ? s->vc[i].window : s->window;
+                if (opts->has_full_screen && opts->full_screen) {
+                    gtk_window_fullscreen_on_monitor(
+                        GTK_WINDOW(win),
+                        gdk_display_get_default_screen(window_display),
+                        mon->value);
+                } else {
+                    gdk_monitor_get_geometry(
+                        gdk_display_get_monitor(window_display, mon->value),
+                        &dest);
+                    gtk_window_move(GTK_WINDOW(win),
+                                    dest.x, dest.y);
+                }
+                i++;
+            }
+        }
+    } else if (opts->has_full_screen &&
+               opts->full_screen) {
         gtk_menu_item_activate(GTK_MENU_ITEM(s->full_screen_item));
     }
+
     if (opts->u.gtk.has_grab_on_hover &&
         opts->u.gtk.grab_on_hover) {
         gtk_menu_item_activate(GTK_MENU_ITEM(s->grab_on_hover_item));
-- 
2.20.1