Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!mks
From: mks@cbmvax.commodore.com (Michael Sinz - CATS)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Scrolling with the copper (in a text editor)
Message-ID: <10820@cbmvax.commodore.com>
Date: 12 Apr 90 13:25:59 GMT
References: <1656@eklektik.UUCP>
Reply-To: mks@cbmvax (Michael Sinz - CATS)
Organization: Commodore, West Chester, PA
Lines: 51

In article <1656@eklektik.UUCP> danbabcock@eklektik.UUCP (/dev/tty000) writes:
>Jonathan Abbey (jonabbey@ccwf.cc.utexas.edu) wrote in message ID
><27737@ut-emx.UUCP>:
>
>> Good advice at the last, but how do you intend for him to use the copper?
>
>Consider writing out a new line of text at the bottom of the screen and
>scrolling. Most editors just rewrite the entire screen from the ASCII
>buffer, or else use the blitter to copy the bitmap to itself, offset one
>line, and write out the new line to replace the last line in the bitmap.
>
>However, the most efficient approach is to use the copper to simulate a
>circular buffer-type display, much like the VIDC in the Archimedes.
>In this scheme, the new line is placed where line 1 used to be, and the
>copper list is adjusted so that line 1 (in memory) is displayed at the
>bottom of the screen. Only one line (i.e. 640 bytes) in the bitmap needs
>to be rewritten, and no memory needs to be physically moved. No "extra"
>memory is required, besides the few words needed for the copper list.
>(please note that when I say "line" I mean a line of text, not a line
>of the bitmap)
>
>Admittedly, using such a copper list could result in intuition menus
>popping up in unusual areas of the screen, so it might be neccesary to
>write custom menu code.

I find that the editors I am using scroll faster than I can even try to see
let alone read.  It seems that everyone is looking at the wrong place
where editors need help.

Editors need to work WITH the system, not against it.
Editors need to have ZERO bugs.
Editors need to have GOOD ARexx ports.
Editors need to have ZERO bugs.  (Can't say this enough)
Editors need to use the ClipBoard device.
Editors need to have ZERO bugs.  (An EDITOR should NEVER crash my machine!)
Editors need to have multiple tasks for multiple files.
Editors need to habe ZERO bugs.  (A buggy editor is worthless)
Editors need to be able to reconfigure the keyboard easily.
Editors need to have ZERO bugs.  (I used them a lot and can not with bugs)
Editors need to have features that help in editing (column cut/paste, etc)
Editors need to have ZERO bugs.  (They should work in ANY version of the OS)
Editors need to have features that help in coding (folds, simple syntax, etc)
Editors need to have ZERO bugs.  (This is very important!)

/----------------------------------------------------------------------\
|      /// Michael Sinz -- CATS/Amiga Software Engineer                |
|     ///  PHONE 215-431-9422  UUCP ( uunet | rutgers ) !cbmvax!mks    |
|    ///                                                               |
|\\\///          "I don't think so," said Ren'e Descartes.             |
| \XX/                    Just then, he vanished.                      |
\----------------------------------------------------------------------/