Re: balance-windows again

[storm@cua.dk (Kim F. Storm)]

Lennart Borgman <lennart.borgman.073@student.lu.se> writes:

>>>Is there any possibility that access to the window split tree from
>>>elisp could be implemented in Emacs?
>>
> A tree where the nodes are the splits and the leaves are the windows.
>

The following patch adds a window-split-tree function which returns a simple
tree presentation of the window split.  You can use window-edges on the
elements of the tree to get the dimensions (and build your representation).



Index: window.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/window.c,v
retrieving revision 1.516
diff -c -r1.516 window.c
*** window.c	18 Sep 2005 16:28:53 -0000	1.516
--- window.c	27 Sep 2005 22:54:40 -0000
***************
*** 6225,6230 ****
--- 6226,6312 ----
    return unbind_to (count, val);
  }

+
+ \f
+ /***********************************************************************
+ 			    Window Split Tree
+  ***********************************************************************/
+
+ static Lisp_Object
+ window_split_tree (w)
+      struct window *w;
+ {
+   Lisp_Object tail = Qnil;
+   Lisp_Object result = Qnil;
+
+   while (w)
+     {
+       Lisp_Object wn;
+
+       XSETWINDOW (wn, w);
+       if (!NILP (w->hchild))
+ 	wn = Fcons (Qnil, Fcons (wn, window_split_tree (XWINDOW (w->hchild))));
+       else if (!NILP (w->vchild))
+ 	wn = Fcons (Qt, Fcons (wn, window_split_tree (XWINDOW (w->vchild))));
+
+       if (NILP (result))
+ 	{
+ 	  result = tail = Fcons (wn, Qnil);
+ 	}
+       else
+ 	{
+ 	  XSETCDR (tail, Fcons (wn, Qnil));
+ 	  tail = XCDR (tail);
+ 	}
+
+       w = NILP (w->next) ? 0 : XWINDOW (w->next);
+     }
+
+   return result;
+ }
+
+
+
+ DEFUN ("window-split-tree", Fwindow_split_tree, Swindow_split_tree,
+        0, 1, 0,
+        doc: /* Return the window split tree for frame FRAME.
+
+ The return value is a list of the form (ROOT MINI), where ROOT
+ represents the window split tree of the frame's root window, and MINI
+ is the frame's minibuffer window.
+
+ If the root window is not split, ROOT is the root window itself.
+ Otherwise, ROOT is a list (DIR W W1 W2 ...) where DIR is nil for a
+ horisontal split, and t for a vertical split, W is the container
+ window for the window split, and the rest of the elements are the
+ subwindows in the split.  Each of the subwindows may again be a window
+ or a list of subwindows, and so on.
+
+ The container windows are not live windows (see `window-live-p'), but
+ you can use `window-edges' and `window-inside-edges' on the container
+ windows to get the combined size of a sub-tree of the full window
+ split.
+
+ If FRAME is nil or omitted, return information on the currently
+ selected frame.  */)
+      (frame)
+      Lisp_Object frame;
+ {
+   Lisp_Object alist;
+   FRAME_PTR f;
+
+   if (NILP (frame))
+     frame = selected_frame;
+
+   CHECK_FRAME (frame);
+   f = XFRAME (frame);
+
+   if (!FRAME_LIVE_P (f))
+     return Qnil;
+
+   return window_split_tree (XWINDOW (FRAME_ROOT_WINDOW (f)));
+ }
+
  \f
  /***********************************************************************
  			    Marginal Areas
***************
*** 7031,7036 ****
--- 7113,7119 ----
    defsubr (&Sset_window_configuration);
    defsubr (&Scurrent_window_configuration);
    defsubr (&Ssave_window_excursion);
+   defsubr (&Swindow_split_tree);
    defsubr (&Sset_window_margins);
    defsubr (&Swindow_margins);
    defsubr (&Sset_window_fringes);
>

--
Kim F. Storm <storm@cua.dk> http://www.cua.dk