Implement side-by-side tiling

Patch by Florian Müllner for Metacity
https://bugzilla.gnome.org/show_bug.cgi?id=607694

When dragging a window over a screen edge and dropping it there,
maximize it vertically and scale it horizontally to cover the
corresponding half of the current monitor.

Whenever a "hot area" which triggers this behavior is entered, an
indication of window's target size is displayed after a short delay
to avoid distraction when moving a window between monitors.

1 files changed, 64 insertions, 2 deletions

diff --git a/src/core/screen.c b/src/core/screen.c
index e8fce40a..eefe58f2 100644
--- a/src/core/screen.c
+++ b/src/core/screen.c
@@ -582,7 +582,10 @@ meta_screen_new (MetaDisplay *display,
                             screen->xscreen);
 
   screen->tab_popup = NULL;
-  
+  screen->tile_preview = NULL;
+
+  screen->tile_preview_timeout_id = 0;
+
   screen->stack = meta_stack_new (screen);
 
   meta_prefs_add_listener (prefs_changed_callback, screen);
@@ -691,7 +694,13 @@ meta_screen_free (MetaScreen *screen,
   
   if (screen->xinerama_infos)
     g_free (screen->xinerama_infos);
-  
+
+  if (screen->tile_preview_timeout_id)
+    g_source_remove (screen->tile_preview_timeout_id);
+
+  if (screen->tile_preview)
+    meta_tile_preview_free (screen->tile_preview);
+
   g_free (screen->screen_name);
   g_free (screen);
 
@@ -1451,6 +1460,59 @@ meta_screen_ensure_workspace_popup (MetaScreen *screen)
   /* don't show tab popup, since proper space isn't selected yet */
 }
 
+static gboolean
+meta_screen_tile_preview_update_timeout (gpointer data)
+{
+  MetaScreen *screen = data;
+  MetaWindow *window = screen->display->grab_window;
+  gboolean composited = screen->display->compositor != NULL;
+
+  screen->tile_preview_timeout_id = 0;
+
+  if (!screen->tile_preview)
+    screen->tile_preview = meta_tile_preview_new (screen->number,
+                                                  composited);
+
+  if (window
+      && !META_WINDOW_TILED (window)
+      && window->tile_mode != META_TILE_NONE)
+    {
+      MetaRectangle tile_rect;
+
+      meta_window_get_current_tile_area (window, &tile_rect);
+      meta_tile_preview_show (screen->tile_preview, &tile_rect);
+    }
+  else
+    meta_tile_preview_hide (screen->tile_preview);
+
+  return FALSE;
+}
+
+#define TILE_PREVIEW_TIMEOUT_MS 200
+
+void
+meta_screen_tile_preview_update (MetaScreen *screen,
+                                 gboolean    delay)
+{
+  if (delay)
+    {
+      if (screen->tile_preview_timeout_id > 0)
+        return;
+
+      screen->tile_preview_timeout_id =
+        g_timeout_add (TILE_PREVIEW_TIMEOUT_MS,
+                       meta_screen_tile_preview_update_timeout,
+                       screen);
+    }
+  else
+    {
+      if (screen->tile_preview_timeout_id > 0)
+        g_source_remove (screen->tile_preview_timeout_id);
+
+      meta_screen_tile_preview_update_timeout ((gpointer)screen);
+    }
+}
+
 MetaWindow*
 meta_screen_get_mouse_window (MetaScreen  *screen,
                               MetaWindow  *not_this_one)