[mutter/gnome-3-12] boxes: Ignore struts that don't attach to the side they claim

[Florian Müllner <fmuellner src gnome org>]

commit e1841f722d2d4881d812c1f4a96261bccb37744b
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jun 6 07:58:20 2014 +0200

    boxes: Ignore struts that don't attach to the side they claim
    
    Like the _NET_WM_STRUT/_NET_WM_STRUT_PARTIAL client properties,
    _NET_WORKAREA is defined in terms of screen geometry rather than
    taking individual monitors into account. However we do want to
    allow system chrome to be attached to a monitor edge rather than
    a screen edges under some circumstances. As not all clients can
    be assumed to deal gracefully with the resulting workarea, use
    those "struts" only internally for constraining windows, but
    ignore them when exporting _NET_WORKAREA.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=730527

 src/core/boxes.c |   29 ++++++++++++++++++++++++++---
 1 files changed, 26 insertions(+), 3 deletions(-)
---
diff --git a/src/core/boxes.c b/src/core/boxes.c
index 7f916cb..4f7fe26 100644
--- a/src/core/boxes.c
+++ b/src/core/boxes.c
@@ -546,6 +546,26 @@ compare_rect_areas (gconstpointer a, gconstpointer b)
   return b_area - a_area; /* positive ret value denotes b > a, ... */
 }
 
+/* ... and another helper for get_minimal_spanning_set_for_region()... */
+static gboolean
+check_strut_align (MetaStrut *strut, const MetaRectangle *rect)
+{
+  /* Check whether @strut actually aligns to the side of @rect it claims */
+  switch (strut->side)
+    {
+    case META_SIDE_TOP:
+      return BOX_TOP (strut->rect) <= BOX_TOP (*rect);
+    case META_SIDE_BOTTOM:
+      return BOX_BOTTOM (strut->rect) >= BOX_BOTTOM (*rect);
+    case META_SIDE_LEFT:
+      return BOX_LEFT (strut->rect) <= BOX_LEFT (*rect);
+    case META_SIDE_RIGHT:
+      return BOX_RIGHT (strut->rect) >= BOX_RIGHT (*rect);
+    default:
+      return FALSE;
+    }
+}
+
 /**
  * meta_rectangle_get_minimal_spanning_set_for_region:
  * @basic_rect: Input rectangle
@@ -629,8 +649,9 @@ meta_rectangle_get_minimal_spanning_set_for_region (
 
   for (strut_iter = all_struts; strut_iter; strut_iter = strut_iter->next)
     {
-      GList *rect_iter; 
-      MetaRectangle *strut_rect = &((MetaStrut*)strut_iter->data)->rect;
+      GList *rect_iter;
+      MetaStrut *strut = (MetaStrut*)strut_iter->data;
+      MetaRectangle *strut_rect = &strut->rect;
 
       tmp_list = ret;
       ret = NULL;
@@ -638,7 +659,9 @@ meta_rectangle_get_minimal_spanning_set_for_region (
       while (rect_iter)
         {
           MetaRectangle *rect = (MetaRectangle*) rect_iter->data;
-          if (!meta_rectangle_overlap (rect, strut_rect))
+
+          if (!meta_rectangle_overlap (strut_rect, rect) ||
+              !check_strut_align (strut, basic_rect))
             ret = g_list_prepend (ret, rect);
           else
             {