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1993-01-11
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Viewtek 1.03b - Another Picture/Animation Viewer
Written by Thomas Krehbiel
January 1993
INTRODUCTION
~~~~~~~~~~~~
Some of you may remember an ILBM/ANIM viewer program I wrote a while
back called "TIV". Some would say that "Viewtek" is TIV 2.0, but I
consider it a totally different and much improved program (no part of TIV
is in Viewtek; it is all rewritten from scratch). (If you're using TIV
now under 2.0 I *strongly* suggest you dump it in favor of Viewtek.)
Viewtek was written with a few objectives in mind. I wanted a program
that first and foremost was totally 2.0 (and 3.0) compatible. I wanted it
to take advantage of 3.0 and the AGA chips wherever possible. I wanted it
to show ANIMs as good or better than TIV did, with support for any and all
display modes. I also wanted to be able to render decent (if not
spectacular) representations of 24-bit ILBMs, GIFs, and JPEGs. And I
wanted to keep the program internally modular enough to support 3rd party
display devices fairly easily.
The result you have before you.
FEATURES
~~~~~~~~
o Requires Workbench 2.04 or greater.
o Shows most ILBM's (including 24-bit ILBM's).
o Shows most Compuserve GIF format images.
o Shows most JFIF format JPEG images.
o Shows most ANIM Op-5 format animations, with support for
different palettes for each frame.
o Supports SHAM, CTBL, and PCHG images.
o Full support of ECS/AGA display modes (ie. show 256 color GIF's
directly, show 800x600xHAM animations, etc.).
o Supports viewing contents of clipboard.
o Iconifies to a Workbench AppIcon.
o Includes a version written for GVP's Impact Vision 24, to support
true 24-bit display.
o And even includes a stripped-down version that doesn't show GIF's
or JPEG's for those who don't need it.
DISTRIBUTION
~~~~~~~~~~~~
Viewtek is being distributed as Freeware. It may be freely distributed
to any bulletin board service, network, or public domain collection, so
long as no fees (beyond reasonable media fees) are charged for such
distribution. I'm not asking for donations on this one, but feel free to
drop me a note (preferably e-mail) or something if you want.
Note, however, that Viewtek is NOT public domain. The author retains
all rights to the program.
OOPS!
~~~~~
Previous versions of the Viewtek documentation left out a very
important statement:
This software is based in part on the work of the Independant JPEG
Group.
I'd just like to apologize to the Independant JPEG Group for not having
included this, they deserve full credit for their work in bringing this
popular compression format to the computer world at large.
INSTALLATION
~~~~~~~~~~~~
Viewtek requires no special libraries or fonts or anything to run.
Simply drag the Viewtek icon to wherever you wish to install it. It may
be run from a Shell, Workbench, or even your favorite dirutil.
The IV-24 version of Viewtek, however, requires that you have a copy of
GVP's "fye.library" in your LIBS: directory. (If you have an IV-24,
chances are pretty good you have this installed already.)
DISABILITIES
~~~~~~~~~~~~
Okay, what *doesn't* it do?
- No color cycling (yet?). Why? I have exactly one picture that
color cycles out of hundreds of images and I never look at it
anyway, so it wasn't a high priority.
- Some CTBL images may not quite show properly, more than likely
due to more palette changes per line than can be shown properly
with the copper. Same may be true for SHAM pictures. I probably
will not fix this because I don't really see much value in these
types of pictures anyway. It may help to force the images
to be shown in NTSC/PAL on an A4000, or move the picture
to the right (with control arrow keys).
USEAGE FROM SHELL
~~~~~~~~~~~~~~~~~
Files/M One or more files/directories/patterns. Standard
AmigaDOS wildcards are supported.
Delay/N Time in seconds to show each file before moving on.
Default is to wait for user to click a button.
LowMem/S Do not double-buffer pictures, saves some chip memory.
Repeat/N Number of times to repeat showing the pictures.
Hide/S Hide the process of reading the pictures; by default you
can watch as VT scans in the image. Note that for large
GIF's and IFF24's, scanning in the image can take a
while, so hiding the process can cause some confusion.
Also note that when viewing on the IV24, hide is
automatically enabled (due to the nature of the IV24).
All/S Recursively enter subdirectories to show pictures.
Iconify/S Launch VT in iconified mode (handy for putting VT in
your WBStartup drawer).
Forever/S Repeat showing the pictures forever and ever and ever.
Clip/S Show contents of clipboard instead of a file.
Unit/N Select clipboard unit number, default is 0.
Loop/N Number of times to loop animation before proceeding,
default is to loop forever.
Speed/N Animation playback speed, in jiffies/frame.
Cont/S Force animations to be considered "continuous", that is,
the animations are assumed to have 2 looping frames
built onto the end. Normally, VT will only play an
animation in continuous mode if a DPAN chunk is found
(DPaint animations are always continuous). There is no
other way that I know of to tell if an animation is
continuous or not.
Hires/S Force an image or animation into hires.
Lace/S Force an image or animation into interlace.
NoBusy/S Normally, VT displays a busy pointer as it reads in
images. This option disables that busy pointer.
Default/S Force images to use Default monitor (useful for forcing
NTSC stuff to promote to scan-doubled on an AGA machine).
NTSC/S Force images to use NTSC monitor.
PAL/S Force images to use PAL monitor.
ILBM/S Force VT to look for FORM ILBM's, regardless of
what the file actually is.
NoScroll/S Force VT not to make picture screens autoscroll.
For some reason, making a Super72 or SuperHires screen
autoscroll shifts it way over to the left (at least on
my machine), so here is the somewhat kludgy solution
until I figure out what gives here.
Save/K After looking at Steve Hines' "QuickGrab" program (an
excellent utility, BTW), I realized that it could be
useful to save the resulting images that VT renders of
GIF's and JPEG's for posterity. So, this option
(which must be followed by a filename) will save the
screen that VT produces to a standard ILBM file. Just
keep in mind that the images VT renders aren't nearly
as good as they could be.
USEAGE FROM WORKBENCH
~~~~~~~~~~~~~~~~~~~~~
All of the options above may be used (except Files/M) as a tool type.
The following additional tool type may be set:
DEFAULTDIR Choose default directory where file requester opens.
VIEWING COMMANDS
~~~~~~~~~~~~~~~~
ESCAPE Abort viewing immediately.
BACKSPACE Abort viewing current directory (when using 'ALL').
LMB/RMB Go to next picture.
CTRL+Arrows Move image/anim around on the display (overscan position).
Up Arrow (Anim Only) Return to beginning of the animation.
Right Arrow (Anim Only) Pause/single step animation.
Down Arrow (Anim Only) Resume playing animation after paused.
C (Anim Only) Toggle "continuous" mode.
THE AUTHOR
~~~~~~~~~~
I can be reached on BIX as "tkrehbiel" if you want to email me about
something (like, say, bugs).
You can also reach me on the Late Nite BBS (804-262-9944) as Tom Krehbiel
(user #13).
As a last resort my U.S. Mail address is:
Thomas Krehbiel
10747 Surry Road
Chester, VA 23831
(Don't expect quick mail response.)
SHAMELESS PLUG
~~~~~~~~~~~~~~
Buy ImageFX. You won't regret it. Honest. :)
REVISION HISTORY
~~~~~~~~~~~~~~~~
1.03b Now allows showing directories via. file requester.
Shows >= 800x600 GIF's in Super72 mode if available.
More robust error messages on display open fail.
Now uses BestModeID to show undisplayable modes.
Doesn't close screen on first click of LMB after inactivity.
1.03a 12/15/92 Fixed unbelievably stupid bug in AppIcon stuff.
1.03 12/10/92 Fixed hanging locks when used as AppIcon.
Added LORES,NOLACE,ILBM options.
Always sets autoscroll now, and still centers 'em.
Added NOSCROLL option to disable autoscroll.
Added SAVE option to save rendered pictures.
Handles animation playback a bit better.
1.02a 11/25/92 More accurate overscan calculation. (Maybe not)
1.02 11/24/92 Stock version renders to HAM8 mode if available.
Oops, fixed so you can select just one file from ASL freq.
Fixed problem with VT's abort "sticking".
Fixed problems with centering AGA animations.
Added NTSC/PAL/DEFAULT options.
Now examines DPAN chunks for frame rates.
Fixed problems with 'odd' sized anims on AGA.
Defers allocating ASL struct until needed.
More generalized copper stuff.
1.01 11/10/92 Now more intelligent about picking JPEG viewmodes.
Handles ANIMs with masking planes.
Now able to respect ANIM's reltime by pressing F10.
Added busy pointer while loading images.
1.00 11/4/92 Initial version.