From 03d98904f82e51c59adf31d4afcebf910160ffef Mon Sep 17 00:00:00 2001
From: yamaoka <yamaoka>
Date: Fri, 24 Sep 1999 12:39:55 +0000
Subject: [PATCH] (gnus-article-prev-page): Rewrite to realize smooth
 scrolling under XEmacs. (gnus-article-next-page):Ditto.

---
 lisp/gnus-art.el |   79 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 42 insertions(+), 37 deletions(-)

diff --git a/lisp/gnus-art.el b/lisp/gnus-art.el
index a4c6fb5..ee3b041 100644
--- a/lisp/gnus-art.el
+++ b/lisp/gnus-art.el
@@ -3701,48 +3701,53 @@ If given a numerical ARG, move forward ARG pages."
 If end of article, return non-nil.  Otherwise return nil.
 Argument LINES specifies lines to be scrolled up."
   (interactive "p")
-  (move-to-window-line -1)
-  (if (save-excursion
-	(end-of-line)
-	(and (pos-visible-in-window-p)	;Not continuation line.
-	     (eobp)))
-      ;; Nothing in this page.
-      (if (or (not gnus-page-broken)
-	      (save-excursion
-		(save-restriction
-		  (widen) (forward-line 1) (eobp)))) ;Real end-of-buffer?
-	  t				;Nothing more.
-	(gnus-narrow-to-page 1)		;Go to next page.
-	nil)
-    ;; More in this page.
-    (let ((scroll-in-place nil))
-      (condition-case ()
-	  (scroll-up lines)
-	(end-of-buffer
-	 ;; Long lines may cause an end-of-buffer error.
-	 (goto-char (point-max)))))
-    (move-to-window-line 0)
-    nil))
+  (let ((start (window-start))
+	end-of-buffer end-of-page)
+    (save-excursion
+      (move-to-window-line -1)
+      (if (<= (point) start)
+	  (progn
+	    (forward-line 2)
+	    (setq start (point)))
+	(forward-line 1)
+	(setq start nil))
+      (unless (or (cond ((eq (1+ (buffer-size)) (point))
+			 (setq end-of-buffer t))
+			((eobp)
+			 (setq end-of-page t)))
+		  (not lines))
+	(move-to-window-line lines)
+	(unless (search-backward "\n\n" nil t)
+	  (setq start (point)))))
+    (cond (end-of-buffer t)
+	  (end-of-page
+	   (gnus-narrow-to-page 1)
+	   nil)
+	  (t
+	   (if start
+	       (set-window-start (selected-window) start)
+	     (scroll-up lines))
+	   nil))))
 
 (defun gnus-article-prev-page (&optional lines)
   "Show previous page of current article.
 Argument LINES specifies lines to be scrolled down."
   (interactive "p")
-  (move-to-window-line 0)
-  (if (and gnus-page-broken
-	   (bobp)
-	   (not (save-restriction (widen) (bobp)))) ;Real beginning-of-buffer?
-      (progn
-	(gnus-narrow-to-page -1)	;Go to previous page.
-	(goto-char (point-max))
-	(recenter -1))
-    (let ((scroll-in-place nil))
-      (prog1
-	  (condition-case ()
-	      (scroll-down lines)
-	    (beginning-of-buffer
-	     (goto-char (point-min))))
-	(move-to-window-line 0)))))
+  (let (beginning-of-buffer beginning-of-page)
+    (save-excursion
+      (move-to-window-line 0)
+      (cond ((eq 1 (point))
+	     (setq beginning-of-buffer t))
+	    ((bobp)
+	     (setq beginning-of-page t))))
+    (cond (beginning-of-buffer)
+	  (beginning-of-page
+	   (gnus-narrow-to-page -1))
+	  (t
+	   (condition-case nil
+	       (scroll-down lines)
+	     (beginning-of-buffer
+	      (goto-char (point-min))))))))
 
 (defun gnus-article-refer-article ()
   "Read article specified by message-id around point."
-- 
1.7.10.4