(line-move-1): Rename from line-move.

(line-move): New function that adjusts vscroll for partially
visible rows, and calls line-move-1 otherwise.

1 files changed, 22 insertions, 1 deletions

diff --git a/lisp/simple.el b/lisp/simple.el
index fbcb776c7dc..e2476577fe3 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3179,10 +3179,31 @@ Outline mode sets this."
       (or (memq prop buffer-invisibility-spec)
           (assq prop buffer-invisibility-spec)))))
 
+;; Perform vertical scrolling of tall images if necessary.
+(defun line-move (arg &optional noerror to-end)
+  (if auto-window-vscroll
+      (let ((forward (> arg 0))
+            (pvis (pos-visible-in-window-p (window-start) nil t)))
+        (if (and pvis (null (nth 2 pvis))
+                 (> (nth (if forward 4 3) pvis) 0))
+            (set-window-vscroll nil
+                                (if forward
+                                    (+ (window-vscroll nil t)
+                                       (min (nth 4 pvis)
+                                            (* (frame-char-height) arg)))
+                                  (max 0
+                                       (- (window-vscroll nil t)
+                                          (min (nth 3 pvis)
+                                               (* (frame-char-height) (- arg))))))
+                                t)
+          (set-window-vscroll nil 0)
+          (line-move-1 arg noerror to-end)))
+    (line-move-1 arg noerror to-end)))
+
 ;; This is the guts of next-line and previous-line.
 ;; Arg says how many lines to move.
 ;; The value is t if we can move the specified number of lines.
-(defun line-move (arg &optional noerror to-end)
+(defun line-move-1 (arg &optional noerror to-end)
   ;; Don't run any point-motion hooks, and disregard intangibility,
   ;; for intermediate positions.
   (let ((inhibit-point-motion-hooks t)