From: Chris Hanson <org/chris-hanson/cph>
Date: Wed, 18 Aug 1993 23:57:38 +0000 (+0000)
Subject: Fix instance of "point not visible at end of redisplay" error that
X-Git-Tag: 20090517-FFI~8052
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=1bda466f2193841bdf4fc2b3f866a8a5985e03b4;p=mit-scheme.git

Fix instance of "point not visible at end of redisplay" error that
Matt Birkholz pointed out.  Change code that generates this error to
conditionally force the point to be visible; this results in more
robust behavior.
---

diff --git a/v7/src/edwin/bufwin.scm b/v7/src/edwin/bufwin.scm
index 889f7d403..a6849e78d 100644
--- a/v7/src/edwin/bufwin.scm
+++ b/v7/src/edwin/bufwin.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;	$Id: bufwin.scm,v 1.300 1993/01/16 05:15:30 cph Exp $
+;;;	$Id: bufwin.scm,v 1.301 1993/08/18 23:57:38 cph Exp $
 ;;;
 ;;;	Copyright (c) 1986, 1989-93 Massachusetts Institute of Technology
 ;;;
@@ -966,7 +966,8 @@ This number is a percentage, where 0 is the window's top and 100 the bottom."
 	     (let ((mask (set-interrupt-enables! interrupt-mask/gc-ok)))
 	       (%set-window-point-index!
 		window
-		(or (predict-index window start y-start 0 point-y)
+		(or (predict-index window start y-start
+				   (vector-ref cws 4) point-y)
 		    (%window-group-end-index window)))
 	       (set-window-start! window cws)
 	       (set-interrupt-enables! mask)
@@ -1198,9 +1199,23 @@ If this is zero, point is always centered after it moves off screen."
 
 (define (update-cursor! window)
   (let ((xy (buffer-window/point-coordinates window)))
-    (if (not (and (fix:<= 0 (car xy))
-		  (fix:< (car xy) (window-x-size window))
-		  (fix:<= 0 (cdr xy))
-		  (fix:< (cdr xy) (window-y-size window))))
-	(error "point not visible at end of redisplay"))
-    (set-inferior-position! (%window-cursor-inferior window) xy)))
\ No newline at end of file
+    (if (and (fix:<= 0 (car xy))
+	     (fix:< (car xy) (window-x-size window))
+	     (fix:<= 0 (cdr xy))
+	     (fix:< (cdr xy) (window-y-size window)))
+	(set-inferior-position! (%window-cursor-inferior window) xy)
+	(begin
+	  (if point-not-visible-error?
+	      (error "point not visible at end of redisplay"))
+	  (%set-window-point-index!
+	   window
+	   (or (predict-index window
+			      (%window-start-line-index window)
+			      (%window-start-line-y window)
+			      (%window-start-partial window)
+			      0)
+	       (%window-group-end-index window)))
+	  (update-cursor! window)))))
+
+(define point-not-visible-error?
+  #f)
\ No newline at end of file