Allow tiled windows to be resized horizontally

Determine whether the user is initiating a resize action on a tiled
window. If the user is trying to grab the window for resizing
horizontally from the edge that's farther away from the screen edge,
allow the resize to occur. Otherwise maintain the current tile geometry.

Also modified the window hints to allow resizing from the window menu.

Fixes #250

1 files changed, 31 insertions, 2 deletions

diff --git a/src/core/constraints.c b/src/core/constraints.c
index 69263a51..783449d3 100644
--- a/src/core/constraints.c
+++ b/src/core/constraints.c
@@ -876,6 +876,7 @@ constrain_tiling (MetaWindow         *window,
   gboolean hminbad, vminbad;
   gboolean horiz_equal, vert_equal;
   gboolean constraint_already_satisfied;
+  gboolean allow_resize = FALSE;
 
   if (priority > PRIORITY_TILING)
     return TRUE;
@@ -908,9 +909,37 @@ constrain_tiling (MetaWindow         *window,
   if (check_only || constraint_already_satisfied)
     return constraint_already_satisfied;
 
+  /* Allow the user to resize horizontally when tiled */
+  if (info->is_user_action)
+    {
+      /* Only allow resizing from the window side farther from the screen edge */
+      switch (info->resize_gravity)
+        {
+        case NorthEastGravity:
+        case EastGravity:
+        case SouthEastGravity:
+          if (window->tile_mode == META_TILE_RIGHT)
+            allow_resize = TRUE;
+          break;
+        case NorthWestGravity:
+        case WestGravity:
+        case SouthWestGravity:
+          if (window->tile_mode == META_TILE_LEFT)
+            allow_resize = TRUE;
+          break;
+        }
+
+      /* Maintain current tile size for all other user-initiated alternatives */
+      target_size.x = info->orig.x;
+      target_size.width = info->orig.width;
+    }
+
   /*** Enforce constraint ***/
-  info->current.x      = target_size.x;
-  info->current.width  = target_size.width;
+  if (!allow_resize)
+    {
+      info->current.x      = target_size.x;
+      info->current.width  = target_size.width;
+    }
   info->current.y      = target_size.y;
   info->current.height = target_size.height;