[metacity] window: add a meta_window_get_titlebar_rect

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 90b36abebdf69be0abaec4015d01e46296f6f5d6
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Fri Apr 3 23:30:20 2015 +0300

    window: add a meta_window_get_titlebar_rect
    
    Based on mutter commits:
    https://git.gnome.org/browse/mutter/commit/?id=3a0af0faaebb1af75925c70ad98e73c61e57639b
    https://git.gnome.org/browse/mutter/commit/?id=ac099343dab7b5048ce242958c454c55d1924902

 src/core/constraints.c    |    4 ++--
 src/core/place.c          |   26 +++++++++-----------------
 src/core/window-private.h |    3 +++
 src/core/window.c         |   25 +++++++++++++++++++++++--
 4 files changed, 37 insertions(+), 21 deletions(-)
---
diff --git a/src/core/constraints.c b/src/core/constraints.c
index cf1b9c9..167958c 100644
--- a/src/core/constraints.c
+++ b/src/core/constraints.c
@@ -673,8 +673,8 @@ update_onscreen_requirements (MetaWindow     *window,
     {
       MetaRectangle titlebar_rect;
 
-      titlebar_rect = info->current;
-      titlebar_rect.height = info->borders->visible.top;
+      meta_window_get_titlebar_rect (window, &titlebar_rect);
+
       old = window->require_titlebar_visible;
       window->require_titlebar_visible =
         meta_rectangle_overlaps_with_region (info->usable_screen_region,
diff --git a/src/core/place.c b/src/core/place.c
index 8eb6f3a..d70cdd4 100644
--- a/src/core/place.c
+++ b/src/core/place.c
@@ -98,6 +98,7 @@ find_next_cascade (MetaWindow *window,
   GList *tmp;
   GList *sorted;
   int cascade_x, cascade_y;
+  MetaRectangle titlebar_rect;
   int x_threshold, y_threshold;
   int window_width, window_height;
   int cascade_stage;
@@ -117,16 +118,9 @@ find_next_cascade (MetaWindow *window,
    * manually cascade.
    */
 #define CASCADE_FUZZ 15
-  if (borders)
-    {
-      x_threshold = MAX (borders->visible.left, CASCADE_FUZZ);
-      y_threshold = MAX (borders->visible.top, CASCADE_FUZZ);
-    }
-  else
-    {
-      x_threshold = CASCADE_FUZZ;
-      y_threshold = CASCADE_FUZZ;
-    }
+  meta_window_get_titlebar_rect (window, &titlebar_rect);
+  x_threshold = MAX (titlebar_rect.x, CASCADE_FUZZ);
+  y_threshold = MAX (titlebar_rect.y, CASCADE_FUZZ);
 
   /* Find furthest-SE origin of all workspaces.
    * cascade_x, cascade_y are the target position
@@ -168,13 +162,11 @@ find_next_cascade (MetaWindow *window,
       if (ABS (wx - cascade_x) < x_threshold &&
           ABS (wy - cascade_y) < y_threshold)
         {
-          /* This window is "in the way", move to next cascade
-           * point. The new window frame should go at the origin
-           * of the client window we're stacking above.
-           */
-          meta_window_get_position (w, &wx, &wy);
-          cascade_x = wx;
-          cascade_y = wy;
+          meta_window_get_titlebar_rect (w, &titlebar_rect);
+
+          /* Cascade the window evenly by the titlebar height; this isn't a typo. */
+          cascade_x = wx + titlebar_rect.height;
+          cascade_y = wy + titlebar_rect.height;
 
           /* If we go off the screen, start over with a new cascade */
          if (((cascade_x + window_width) >
diff --git a/src/core/window-private.h b/src/core/window-private.h
index f76bf6e..1f201be 100644
--- a/src/core/window-private.h
+++ b/src/core/window-private.h
@@ -666,4 +666,7 @@ void meta_window_update_icon_now (MetaWindow *window);
 gboolean meta_window_can_tile_side_by_side (MetaWindow *window);
 gboolean meta_window_is_client_decorated (MetaWindow *window);
 
+void meta_window_get_titlebar_rect (MetaWindow    *window,
+                                    MetaRectangle *titlebar_rect);
+
 #endif
diff --git a/src/core/window.c b/src/core/window.c
index 3590627..128746d 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -4201,6 +4201,28 @@ meta_window_end_wireframe (MetaWindow *window)
                               window->display->grab_wireframe_last_display_height);
 }
 
+void
+meta_window_get_titlebar_rect (MetaWindow    *window,
+                               MetaRectangle *rect)
+{
+  meta_window_get_outer_rect (window, rect);
+
+  /* The returned rectangle is relative to the frame rect. */
+  rect->x = 0;
+  rect->y = 0;
+
+  if (window->frame)
+    {
+      rect->height = window->frame->child_y;
+    }
+  else
+    {
+      /* Pick an arbitrary height for a titlebar. We might want to
+       * eventually have CSD windows expose their borders to us. */
+      rect->height = 50;
+    }
+}
+
 const char*
 meta_window_get_startup_id (MetaWindow *window)
 {
@@ -6860,8 +6882,7 @@ meta_window_titlebar_is_onscreen (MetaWindow *window)
     return FALSE;
 
   /* Get the rectangle corresponding to the titlebar */
-  meta_window_get_outer_rect (window, &titlebar_rect);
-  titlebar_rect.height = window->frame->child_y;
+  meta_window_get_titlebar_rect (window, &titlebar_rect);
 
   /* Run through the spanning rectangles for the screen and see if one of
    * them overlaps with the titlebar sufficiently to consider it onscreen.