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Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!think!harvard!talcott!panda!teddy!jpn
From: jpn@teddy.UUCP
Newsgroups: net.emacs
Subject: Re: Gnu Emacs on Suns/redisplay
Message-ID: <1324@teddy.UUCP>
Date: Thu, 19-Sep-85 12:59:19 EDT
Article-I.D.: teddy.1324
Posted: Thu Sep 19 12:59:19 1985
Date-Received: Sat, 21-Sep-85 04:04:29 EDT
References: <2766@sun.uucp>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Distribution: net
Organization: GenRad, Inc., Concord, Mass.
Lines: 31

In article <2766@sun.uucp> wmb@sun.uucp (Mitch Bradley) writes:
>
>Here's a termcap entry for Sun's that improves the
>redisplay for gnu emacs (for Gosling's emacs too, if you're
>running with an rlogin instead of on the machine with the bitmap).
>The idea is that "insert line" is expensive on a bitmap, so you
>might as well just repaint the lines.  This termcap entry just
>disables the insert-character and insert-line capabilities.

NO!  This is the WRONG APPROACH.  It is much more expensive to redraw the
whole screen than to insert a line to perform a scroll-reverse.

The worst performance is seen when scrolling multiple lines: the standard
SUN termcap specifies that scrolling must be one line at a time.  If you
add the multi-line add/delete line sequences, the performance of GNU emacs,
gosling emacs (non-bitmap) and vi all improve substantially in many common
situations.

An unrelated improvement to performance might be gained by adding delays
to the insert sequences:  This would indicate to the editor that these
sequences are expensive to use, and should be avoided except when large
changes are being made.  I have not actually tried this yet.

My termcap for sun (note the addition of AL/DL/IC/DC sequences):

Mu|sun|Sun Microsystems Workstation console:\
	:li#34:co#80:cl=^L:cm=\E[%i%d;%dH:nd=\E[C:up=\E[A:\
	:ce=\E[K:cd=\E[J:so=\E[7m:se=\E[m:rs=\E[s:am:bs:km:ms:pt:\
	:kd=\E[B:kl=\E[D:ku=\E[A:kr=\E[C:kh=\E[H:\
	:al=\E[L:dl=\E[M:im=:ei=:ic=\E[@:dc=\E[P:\
	:AL=\E[%dL:DL=\E[%dM:IC=\E[%d@:DC=\E[%dP:


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