(mouse-avoidance-point-position): Fix compute-motion

call to use (X . Y) relative to window, not frame.
Avoid errors if window-start < point-min.

1 files changed, 15 insertions, 7 deletions

diff --git a/lisp/avoid.el b/lisp/avoid.el
index 376baf7c52a..214e5bb2757 100644
--- a/lisp/avoid.el
+++ b/lisp/avoid.el
@@ -109,18 +109,26 @@ Analogous to mouse-position."
   (let* ((w (selected-window))
          (edges (window-edges w))
          (list 
-          (compute-motion (window-start w)                     ; start pos
-                          (cons (car edges) (car (cdr edges))) ; start XY
+          (compute-motion (max (window-start w) (point-min))   ; start pos
+                          ;; window-start can be < point-min if the
+                          ;; latter has changed since the last redisplay 
+                          '(0 . 0)                             ; start XY
                           (point)                              ; stop pos
-                          (cons (nth 2 edges) (nth 3 edges))   ; stop XY: none
+                          (cons (window-width) (window-height)); stop XY: none
                           (1- (window-width))                  ; width
-                          (cons (window-hscroll w) 0) ; 0 may not be right?
+                          (cons (window-hscroll w) 0)          ; 0 may not be right?
                           (selected-window))))
     ;; compute-motion returns (pos HPOS VPOS prevhpos contin)
     ;; we want:               (frame hpos . vpos)
-    (setcar list (selected-frame))      
-    (setcdr (cdr list) (car (cdr (cdr list))))
-    list))
+    (cons (selected-frame)
+          (cons (+ (car edges)       (car (cdr list)))
+                (+ (car (cdr edges)) (car (cdr (cdr list))))))))
+
+;(defun mouse-avoidance-point-position-test ()
+;  (interactive)
+;  (message (format "point=%s mouse=%s" 
+;                  (cdr (mouse-avoidance-point-position))
+;                  (cdr (mouse-position)))))
 
 (defun mouse-avoidance-set-mouse-position (pos)
   ;; Carefully set mouse position to given position (X . Y)