dave@oldcolo.UUCP (Dave Hughes) (03/09/89)
In a response to an Amiga graphics-gurus complaint about the
treatment by Byte of Amiga's (since muted), I suggested that if
Amiga programmers would just develop an encoder (drawing program)
and decoder (terminal and display program) using the NAPLPS
standard, they wouldn't have to worry about Byte - or any other
magazine - being the only showcase for their computer art. That
they could display it online and bypass print publications as
the only practical distribution media.
I have since had a number of e-mail questions about NAPLPS -
what it is it and where can one find more information about the
standard. I will here oblige in open postings, for a number of
reasons. I joined this newsgroup to find out if there is more
expertise out there in NewsNet land on the NAPLPS standard. And
whether there is or not, to see if there were a few graphics
hackers out there interested in helping develop some public
domain stuff - particularly low end encoder/decoders based on it.
Or those who could simply make useful comments and approaches to
the aim of gaining more acceptance for the standard among
telecommunicators.
For after 6 years of acquaintance with NAPLPS, and watching
others compete in the marketplace, I am convinced it still is:
(1)the most universal standard for the encoding and display
of animated graphics and text for the widest range of target
machines - from the lowest end AppleIIs, through Amigas, Ataris,
IBM PCs and MacIntoshes to CAD/CAM.
(2)is, because of its quite compressed code nature, the most
suited to generalized telecommunicated graphics.
And some recent decisions by some pretty big companies
(IBM/Sears, Bell Canada) tells me that no other standard yet is
as useful when it gets down to the mass market, the general
business market, and general educational purposes.
So, for those who don't know what it is, let me start there.
NAPLPS stands for the North American Presentation Level
Protocol Syntax. A joint ANSI Standard (X3.110-1983) and the
Canadian Standards Association (T500-1983). One can get the
complete 158 page standard from ANSI, 1430 Broadway, NY, NY
10018. It cost about $25 a few years ago. Last telephone number I
had was 212-354-3300.
The standard was most comprehensively described in a series
of 4 Byte articles Feb thru May, 1983 by Jim Fleming and William
Frezza.
And there was another very useful article - together with a
Tutorial program in C for the key subroutines in NAPLPS, by David
McCune in the July and August Microsystems Journal.
NAPLPS is a standard for encoding visual information in a
compact form.
Its chief characteristics are:
(1) it deals with the 6th or 'Presentation Level' of the 7
level ISO model.
(2) it uses primitives - line, arc, point, polygon,
rectangle, as well as colors, textures, blink.
(3) It is compact because it is not a bit map which travels
over the phone line, but a set of instructions for the 'decoder'
program in the target machine to draw the graphics and textual
routines within the limits (resolution, colors) of that machine.
Thus a Naplps 'frame' can range from a few hundred bytes to tens
of K, but with 1-5K being fully adequate for lots of complete
displays. And a graphic drawn on a Sun Workstation can be
displayed on an Apple IIc, and visa versa.
(4) it is 'terminal independent' using ratios rather than
absolute locations.
(5) It is extensible, since it uses a series of 'tables'
which are invoked. The standard default tables are ASCII, PDI
(Picture Definition Instructions), SUP TXT, MACRO, MOSAIC and
DRCS (Dynamically Redefinable Character Set). Other tables could
be added - such as sound.
(6) By supporting Macros, it can further decrease the
demands on telecommunications, by storing , temporarily or
permanently, macros representing graphics subroutines which can
be called to the screen by even fewer transmitted bytes.
It also has been a bust in the Videotext marketplace. For a
perfectly understandable set of reasons which have little to do
with the standard itself.
Which I will comment on in the next article.
Classic_-_Concepts@cup.portal.com (03/15/89)
I thought I would add some information to the previous post on basic
NAPLPS facts. I don't have a technical knowledge of NAPLPS, as I turned my
interests to other formats, but there may be applications where it's viable.
A few years ago (1985, I think), I coordinated a project in which I taught
artists to use NAPLPS drawing tools and then encouraged them (as if artists
need encouragement) to create graphics for an 'electronic online gallery'.
Initially the drawing was clumsy and the equipment was running at 1200
baud, but some practise and a series of 'ah hahs' on the part of all involved
resulted in a lot of fine graphics and mini-animations. The tools may differ
now, but this is what I observed at the time:
1. NAPLPS graphics displayed in the same order the elements were drawn.
Thus, at low baud rates, you actually 'see' how the graphic was
created. This is irritating until you realize you can
capitalize on it by planning the image carefully. By selectively
and sequentially drawing and erasing, an animation gradually evolves
into the final drawing. Unfortunately, if you made an error, the
error and its subsequent correction also displayed.
2. The artists involved quickly adapted to the limitations of the
file display and drawing tools and incorporated the characteristics
3. The format uses object priorities, in that a circle drawn over a
square obscures the square, but if you erase the circle, the full
square remains, or the circle can be 'pushed' behind the square.
4. Drawing with NAPLPS tools at that time was extremely clumsy and
unintuitive compared to bitmap graphics tools I have since used.
If they have not improved, then graphics creation is slow, particularly
with keyboard rather than digitizer (mouse, stylus, etc.) input.
If there are people interested in this format, personally,
I would prefer drawing with existing drawing packages and then converting
to NAPLPS rather than using a NAPLPS drawing package (unless they've improved)
graphics. In fact, DXF files probably share some similarities with NAPLPS
and are much easier to create.
LadyHawke@cup.portal.comdave@oldcolo.UUCP (Dave Hughes) (03/20/89)
In the previsou LadyHawk made some interesting observations
about Naplps as it was in 1985. Quite valid.
1. That the tools to draw it with were crude. That has been
changed a lot. PLP DRAW by Voila in Canada is a VGA drawing
tool, which can be done with a mouse very rapidly, with lots
of easy click-on choices, and, more importantly, editing
commands. I watched two young boys pick up the mouse and
imnmediately start drawing and editing by just following the
screen commands, windows, menus.
2. But it is also true that converting from another format
with a good drawing interface could make life easy. There
have been produced by several Canadian firms translation
programs - one of which can take a Targa board image, and
resolve it into a naplps frame at 1/30th the filesize of
the original.
3. I find that the characteristic of dynamic 'drawing' of the
frame as it displays is part of the charm of Naplps. So
much so I use it to create my 'Word Dance' visual speech
literary works - in which ascii characters presented anywhere
on the screen, in whatever size, color, and duration -
presents the pieces as if they are being spoken, as in
a play. No more of this dull Gutenburg 'Upper-left-to-lower
Right' static screens for me.
4. As a result of the above it is possible to create
dynamic texts, in which the page is framed, or a drawing
displays on part of the screen, while the words display,
wait, scroll, or disappear to be replaced by another
phrase until the piece is done. And the text can have been
prepared in advance, in ascii, by a word processor, to be
'inloaded' to the naplps frame-file, after the characteristics
have been set.
5. Errors can and are deleted from the buffer in any drawing
programs I have seen.
--
Dave Hughes Old Colorado City Communications
hplabs!hp-lsd!oldcolo!dave
"It is better to light one screen than cursor the darkness"
Bill Robinsondave@oldcolo.UUCP (Dave Hughes) (03/20/89)
One company which makes a Targa to Naplps conversion
is Imatex Communications of Montreal, Canada
--
Dave Hughes Old Colorado City Communications
hplabs!hp-lsd!oldcolo!dave
"It is better to light one screen than cursor the darkness"
Bill Robinson