From: Chris Hanson <org/chris-hanson/cph>
Date: Thu, 23 Sep 1993 07:06:56 +0000 (+0000)
Subject: "Clever" fix to handle case of deletion to window start causes "point
X-Git-Tag: 20090517-FFI~7814
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=a7fc3de46156de720d8cabc7184e6f5f7ccce769;p=mit-scheme.git

"Clever" fix to handle case of deletion to window start causes "point
not visible at end of redisplay" error.  This happens when the start
mark is clobbered and the new start is not near enough to the point;
for example by deleting some text, then replacing it with itself.

Also, somehow UPDATE-OUTLINES! is getting called with FORCE-REDRAW?
and the CURRENT-START-MARK both false, which shouldn't be able to
happen; compiled code deals with this by treating #f as 0.  This
change fixes this unusual case.
---

diff --git a/v7/src/edwin/bufwiu.scm b/v7/src/edwin/bufwiu.scm
index d6513567d..8b19f2f95 100644
--- a/v7/src/edwin/bufwiu.scm
+++ b/v7/src/edwin/bufwiu.scm
@@ -1,6 +1,6 @@
 ;;; -*-Scheme-*-
 ;;;
-;;;	$Id: bufwiu.scm,v 1.24 1993/01/29 23:05:40 cph Exp $
+;;;	$Id: bufwiu.scm,v 1.25 1993/09/23 07:06:56 cph Exp $
 ;;;
 ;;;	Copyright (c) 1986, 1989-93 Massachusetts Institute of Technology
 ;;;
@@ -72,12 +72,8 @@
 	      (begin
 		;; If this change affects START-MARK, invalidate it
 		;; and request a display update.
-		(if (let ((wlstart (%window-start-line-index window))
-			  (wstart (%window-start-index window)))
-		      (and (if (fix:= wlstart wstart)
-			       (fix:< start wstart)
-			       (fix:<= start wstart))
-			   (fix:<= wlstart end)))
+		(if (and (fix:<= start (%window-start-index window))
+			 (fix:<= (%window-start-line-index window) end))
 		    (begin
 		      (clear-window-start! window)
 		      (window-needs-redisplay! window)))
@@ -154,13 +150,14 @@
 	(preserve-nothing! window))
       (let ((start (%window-current-start-index window))
 	    (end (%window-current-end-index window)))
-	(cond ((and (%window-start-clip-mark window)
-		    (or (fix:< start (%window-group-start-index window))
-			(fix:< (%window-group-start-index window)
-			       (%window-start-clip-index window))
-			(fix:< (%window-group-end-index window) end)
-			(fix:< (%window-end-clip-index window)
-			       (%window-group-end-index window))))
+	(cond ((or (not start)
+		   (and (%window-start-clip-mark window)
+			(or (fix:< start (%window-group-start-index window))
+			    (fix:< (%window-group-start-index window)
+				   (%window-start-clip-index window))
+			    (fix:< (%window-group-end-index window) end)
+			    (fix:< (%window-end-clip-index window)
+				   (%window-group-end-index window)))))
 	       (preserve-nothing! window))
 	      ((and (fix:> (group-modified-tick (%window-group window))
 			   (%window-modified-tick window))