[gnome-flashback/wip/segeiger/gnome-3-18-inputmethods] Positioning for popup window

[Sebastian Geiger <segeiger src gnome org>]

commit d723be60bbb76a225f0873a94a86e1b48ea0a077
Author: Sebastian Geiger <sbastig gmx net>
Date:   Wed Jan 13 13:36:12 2016 +0100

    Positioning for popup window

 .../libinput-sources/gf-candidate-popup.c          |   40 ++++++++++++++++++--
 1 files changed, 36 insertions(+), 4 deletions(-)
---
diff --git a/gnome-flashback/libinput-sources/gf-candidate-popup.c 
b/gnome-flashback/libinput-sources/gf-candidate-popup.c
index 7bd0735..48cb7a6 100644
--- a/gnome-flashback/libinput-sources/gf-candidate-popup.c
+++ b/gnome-flashback/libinput-sources/gf-candidate-popup.c
@@ -20,13 +20,11 @@
 /* _XOPEN_SOURCE macro needed for floor function from math library */
 #define _XOPEN_SOURCE 600
 
-#include "math.h"
+#include <math.h>
 
 #include "gf-candidate-popup.h"
 #include "gf-candidate-area.h"
 
-#include "gtk/gtk.h"
-
 struct _GfCandidatePopup
 {
   GObject           parent;
@@ -73,7 +71,41 @@ set_cursor_location_cb (IBusPanelService *service,
                         gint              h,
                         gpointer          user_data)
 {
-  g_message ("set_cursor_location_cb");
+  GfCandidatePopup *popup;
+  gint height, width;
+  GdkScreen *screen;
+  GdkWindow *window;
+  GdkRectangle rectangle;
+  int monitor;
+
+  /* We want to position the candidate window as close as possible to the
+   * cursor. But we do not want it to extend outside the screen area.
+   * If placing the candidate area below the cursor would cause parts of the
+   * window to extend outside the screen, then we will place it above the
+   * cursor instead. */
+
+  g_message ("set_cursor_location_cb： (x: %d, y: %d, w: %d, h: %d)", x, y, w, h);
+
+  popup = GF_CANDIDATE_POPUP (user_data);
+
+  gtk_window_get_size (GTK_WINDOW (popup->window), &height, &width);
+
+  window = gtk_widget_get_window (popup->window);
+  screen = gdk_window_get_screen (window);
+  monitor = gdk_screen_get_monitor_at_window (screen, window);
+  gdk_screen_get_monitor_geometry (screen, monitor, &rectangle);
+
+  if (x + width > rectangle.width)
+    {
+      x = x - height - h;
+    }
+
+  if (y + height > rectangle.height)
+    {
+      y = y - width - h;
+    }
+
+  gtk_window_move (GTK_WINDOW (popup->window), x, y);
 }
 
 static void