Improve resizing of minibuffer windows (Bug#12419).

* window.el (window--resize-child-windows): When resizing child
windows proportionally, process them in reverse order to
preserve the "when splitting a window the new one gets the odd
line" behavior.
(window--resize-root-window-vertically): When resizing the
minibuffer window try to affect only windows at the bottom of the
frame.  (Bug#12419)

2 files changed, 47 insertions, 31 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 090a8bef4e9..283e1844a98 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,13 @@
+2012-09-25  Martin Rudalics  <rudalics@gmx.at>
+
+        * window.el (window--resize-child-windows): When resizing child
+        windows proportionally, process them in reverse order to
+        preserve the "when splitting a window the new one gets the odd
+        line" behavior.
+        (window--resize-root-window-vertically): When resizing the
+        minibuffer window try to affect only windows at the bottom of the
+        frame.  (Bug#12419)
+
 2012-09-25  Chong Yidong  <cyd@gnu.org>
 
         * subr.el (declare): Doc fix.
diff --git a/lisp/window.el b/lisp/window.el
index 87817fb8773..68f1370e9d1 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -2079,9 +2079,9 @@ preferably only resize windows adjacent to EDGE.
 Return the symbol `normalized' if new normal sizes have been
 already set by this routine."
   (let* ((first (window-child parent))
-         (sub first)
+         (last (window-last-child parent))
          (parent-total (+ (window-total-size parent horizontal) delta))
-         best-window best-value)
+         sub best-window best-value)
 
     (if (and edge (memq trail '(before after))
              (progn
@@ -2125,7 +2125,7 @@ already set by this routine."
           ;; normal sizes have been already set.
           'normalized)
       ;; Resize all windows proportionally.
-      (setq sub first)
+      (setq sub last)
       (while sub
         (cond
          ((or (window--resize-child-windows-skip-p sub)
@@ -2154,14 +2154,14 @@ already set by this routine."
                  parent-total)
               (window-normal-size sub horizontal)))))
 
-        (setq sub (window-right sub)))
+        (setq sub (window-left sub)))
 
       (cond
        ((< delta 0)
         ;; Shrink windows by delta.
         (setq best-window t)
         (while (and best-window (not (zerop delta)))
-          (setq sub first)
+          (setq sub last)
           (setq best-window nil)
           (setq best-value most-negative-fixnum)
           (while sub
@@ -2171,7 +2171,7 @@ already set by this routine."
               (setq best-window sub)
               (setq best-value (cdr (window-new-normal sub))))
 
-            (setq sub (window-right sub)))
+            (setq sub (window-left sub)))
 
           (when best-window
             (setq delta (1+ delta)))
@@ -2188,7 +2188,7 @@ already set by this routine."
         ;; Enlarge windows by delta.
         (setq best-window t)
         (while (and best-window (not (zerop delta)))
-          (setq sub first)
+          (setq sub last)
           (setq best-window nil)
           (setq best-value most-positive-fixnum)
           (while sub
@@ -2197,7 +2197,7 @@ already set by this routine."
               (setq best-window sub)
               (setq best-value (window-new-normal sub)))
 
-            (setq sub (window-right sub)))
+            (setq sub (window-left sub)))
 
           (when best-window
             (setq delta (1- delta)))
@@ -2209,7 +2209,7 @@ already set by this routine."
               (window-normal-size best-window horizontal))))))
 
       (when best-window
-        (setq sub first)
+        (setq sub last)
         (while sub
           (when (or (consp (window-new-normal sub))
                     (numberp (window-new-normal sub)))
@@ -2227,7 +2227,7 @@ already set by this routine."
                 ;; recursively even if it's size does not change.
                 (window--resize-this-window
                  sub delta horizontal ignore nil trail edge))))
-          (setq sub (window-right sub)))))))
+          (setq sub (window-left sub)))))))
 
 (defun window--resize-siblings (window delta &optional horizontal ignore trail edge)
   "Resize other windows when WINDOW is resized vertically by DELTA lines.
@@ -2406,27 +2406,33 @@ Return the number of lines that were recovered.
 This function is only called by the minibuffer window resizing
 routines.  It resizes windows proportionally and never deletes
 any windows."
-  (when (numberp delta)
-    (let (ignore)
-      (cond
-       ((< delta 0)
-        (setq delta (window-sizable window delta)))
-       ((> delta 0)
-        (unless (window-sizable window delta)
-          (setq ignore t))))
-
-      (window--resize-reset (window-frame window))
-      ;; Ideally, we would resize just the last window in a combination
-      ;; but that's not feasible for the following reason: If we grow
-      ;; the minibuffer window and the last window cannot be shrunk any
-      ;; more, we shrink another window instead.  But if we then shrink
-      ;; the minibuffer window again, the last window might get enlarged
-      ;; and the state after shrinking is not the state before growing.
-      ;; So, in practice, we'd need a history variable to record how to
-      ;; proceed.  But I'm not sure how such a variable could work with
-      ;; repeated minibuffer window growing steps.
-      (window--resize-this-window window delta nil ignore t)
-      delta)))
+  (let ((frame (window-frame window))
+        ignore)
+    (cond
+     ((not (numberp delta))
+      (setq delta 0))
+     ((zerop delta))
+     ((< delta 0)
+      (setq delta (window-sizable window delta))
+      (window--resize-reset frame)
+      ;; When shrinking the root window, emulate an edge drag in order
+      ;; to not resize other windows if we can avoid it (Bug#12419).
+      (window--resize-this-window
+       window delta nil ignore t 'before
+       (+ (window-top-line window) (window-total-size window)))
+      ;; Don't record new normal sizes to make sure that shrinking back
+      ;; proportionally works as intended.
+      (walk-window-tree
+       (lambda (window) (set-window-new-normal window 'ignore)) frame t))
+     ((> delta 0)
+      (window--resize-reset frame)
+      (unless (window-sizable window delta)
+        (setq ignore t))
+      ;; When growing the root window, resize proportionally.  This
+      ;; should give windows back their original sizes (hopefully).
+      (window--resize-this-window window delta nil ignore t)))
+     ;; Return the possibly adjusted DELTA.
+     delta))
 
 (defun adjust-window-trailing-edge (window delta &optional horizontal)
   "Move WINDOW's bottom edge by DELTA lines.