Skip any drawing activities if VC is invisible because it can't be finished.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Dongwon Kim <dongwon.kim@intel.com>
---
 ui/gtk-egl.c     | 4 ++++
 ui/gtk-gl-area.c | 4 ++++
 ui/gtk.c         | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index 8eae2b4b1f..63bfad1f06 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -148,6 +148,10 @@ void gd_egl_refresh(DisplayChangeListener *dcl)
     gd_update_monitor_refresh_rate(
             vc, vc->window ? vc->window : vc->gfx.drawing_area);
 
+    if (!vc->gfx.visible) {
+        return;
+    }
+
     if (!vc->gfx.esurface) {
         gd_egl_init(vc);
         if (!vc->gfx.esurface) {
diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 8228cc9f3f..8d01addb3b 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -123,6 +123,10 @@ void gd_gl_area_refresh(DisplayChangeListener *dcl)
 
     gd_update_monitor_refresh_rate(vc, vc->window ? vc->window : vc->gfx.drawing_area);
 
+    if (!vc->gfx.visible) {
+        return;
+    }
+
     if (!vc->gfx.gls) {
         if (!gtk_widget_get_realized(vc->gfx.drawing_area)) {
             return;
diff --git a/ui/gtk.c b/ui/gtk.c
index e4ef1f7173..0bc35b64e0 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -847,6 +847,10 @@ static gboolean gd_draw_event(GtkWidget *widget, cairo_t *cr, void *opaque)
 
 #if defined(CONFIG_OPENGL)
     if (vc->gfx.gls) {
+        if (!vc->gfx.visible) {
+            return TRUE;
+        }
+
         if (gtk_use_gl_area) {
             /* invoke render callback please */
             return FALSE;
-- 
2.34.1