Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site yetti.UUCP Path: utzoo!mnetor!yetti!mike From: mike@yetti.UUCP (Mike Clarkson ) Newsgroups: comp.emacs Subject: Re: flow control by termcap Message-ID: <493@yetti.UUCP> Date: Tue, 7-Jul-87 02:59:47 EDT Article-I.D.: yetti.493 Posted: Tue Jul 7 02:59:47 1987 Date-Received: Thu, 9-Jul-87 00:37:26 EDT Reply-To: mike@yetti.UUCP (Mike Clarkson ) Organization: York University Computer Science Lines: 58 In article <492@yetti.UUCP> oz@yetti.UUCP (Ozan Yigit) writes: In article <491@yetti.UUCP> mike@yetti.UUCP (Mike Clarkson ) writes: > >Take for example the much maligned, and ever present vt100. In >the current Emacs distribution, the scroll region capabilities (sr: sf:) >are disabled. Does this mean that in all of these years someone hasn't >figured out a way of making vt100's use scroll regions? >You've got to admit that it *is* an important functional requirement >for an Emacs. > For a *proper* implementation of Scroll regions along with the true Goslings Dynamic Programming Algorithm for optimal screen updates, see MicroEmacs (V30 / vt100) or MicroGnuEmacs (Termcap). It works very well indeed. You missed the point entirely. It's not the GNU Emacs algorithm that's faulty, it's the termcap distributed with GNU Emacs that has the scroll regions disabled. I'm quite confident in RMS' ability to implement a *proper* algorithm for screen updates. In article <8707061437.AA06719@ucbvax.Berkeley.EDU> John Robinson writes: >> Does anyone have a good termcap entry for a vt100 >> in Smooth Scroll mode? You have to be kidding. If it could, emacs should take the vt100 out of smooth-scroll. Certianly the fastest update will generally be to repaint the entire screen than to wait for the scroll to happen. Since emacs finds the fastest update, an accurate termcap would appear to be broken because you would never see the scroll happen. So you would have to remove all forms of screen update, including clear-screen, and force it to use scrolling regions. But then it will doubtless decide your terminal is too dumb to run emacs. It would probably be right. Maybe at 9600 baud, but it's not true at slow speeds. If you are yanking 3 or 4 lines at 1200 baud, scroll regions are indeed much faster. Moreover, the main reason for having a smooth scroll at low speeds is that it is much easier on the eyes than jump scroll. I work a lot with Gnu on a vt100 at 1200/2400 baud, and jump-mode plus no-scroll-region is horrible. Emacs will find the fastest way to update the screen *only* if it has an accurate termcap, and I would rather have Emacs figure it out than accept your certainty that the fastest way to update will be to repaint the entire screen. So my question remains - does anyone have a good vt100 entry for smooth scroll mode? -- Mike Clarkson, ...!allegra \ BITNET: mike@YUYETTI or CRESS, York University, ...!decvax \ SYMALG@YUSOL 4700 Keele Street, ...!ihnp4 > !utzoo!yetti!mike North York, Ontario, ...!linus / CANADA M3J 1P3. ...!watmath / Phone: +1 (416) 736-2100 x 7767 "...the most inevitable business communications system on the planet." - ROLM magazine advertisement which planet?