Add a fallback for unconverted backendswip/matthiasc/monitor

If the monitor vfuncs are not implemented in a display class,
fall back to providing a single monitor object representing
the entire screen. This is not meant to be 'good enough', it
is just to provide some implementation until the last backends
implement the monitor vfuncs. When that is the case, the
fallback should be removed.

1 files changed, 33 insertions, 0 deletions

diff --git a/gdk/gdkdisplay.c b/gdk/gdkdisplay.c
index d932b50fd9..f26dd7e9f8 100644
--- a/gdk/gdkdisplay.c
+++ b/gdk/gdkdisplay.c
@@ -33,6 +33,7 @@
 #include "gdkinternals.h"
 #include "gdkmarshalers.h"
 #include "gdkscreen.h"
+#include "gdkmonitorprivate.h"
 
 #include <math.h>
 #include <glib.h>
@@ -2520,9 +2521,38 @@ gdk_display_get_n_monitors (GdkDisplay *display)
 {
   g_return_val_if_fail (GDK_IS_DISPLAY (display), 0);
 
+  if (GDK_DISPLAY_GET_CLASS (display)->get_n_monitors == NULL)
+    return 1;
+
   return GDK_DISPLAY_GET_CLASS (display)->get_n_monitors (display);
 }
 
+static GdkMonitor *
+get_fallback_monitor (GdkDisplay *display)
+{
+  static GdkMonitor *monitor = NULL;
+  GdkScreen *screen;
+
+  if (monitor == NULL)
+    {
+      g_warning ("%s does not implement the monitor vfuncs", G_OBJECT_TYPE_NAME (display));
+      monitor = gdk_monitor_new (display);
+      gdk_monitor_set_manufacturer (monitor, "fallback");
+      gdk_monitor_set_position (monitor, 0, 0);
+      gdk_monitor_set_scale_factor (monitor, 1);
+    }
+
+  screen = gdk_display_get_default_screen (display);
+  gdk_monitor_set_size (monitor,
+                        gdk_screen_get_width (screen),
+                        gdk_screen_get_height (screen));
+  gdk_monitor_set_physical_size (monitor,
+                                 gdk_screen_get_width_mm (screen),
+                                 gdk_screen_get_height_mm (screen));
+
+  return monitor;
+}
+
 /**
  * gdk_display_get_monitor:
  * @display: a #GdkDisplay
@@ -2540,6 +2570,9 @@ gdk_display_get_monitor (GdkDisplay *display,
 {
   g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
 
+  if (GDK_DISPLAY_GET_CLASS (display)->get_monitor == NULL)
+    return get_fallback_monitor (display);
+
   return GDK_DISPLAY_GET_CLASS (display)->get_monitor (display, monitor_num);
 }