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* VirtGIF version 1.0 - Virtual Screen GIF Viewer *
* Copyright (c) 1989, by Patrick J. Maloney *
* Compuserve ID: [73407,3676] *
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* GIF and 'Graphics Interchange Format' are trademarks (tm) of *
* Compuserve, Inc., an H&R Block Company. *
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VirtGIF is freely redistributable. This means you can give it to anyone you
like. It is NOT, however, intended for commercial sale, and copyright is
retained by me. This documentation file MUST be distributed with VirtGIF.
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VirtGIF version 1.0 - User Notes - 08/08/89
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VirtGIF is a program, runable only from the CLI, which will COMPLETELY
display any GIF picture, using HAM mode for pics with > 32 colors. Any
picture that will not fit on the screen, i.e. bigger than 640 x 400 with <=
16 colors or bigger than 320 x 200 with > 16 colors will have only a portion
of it displayed, with the user having the ability to scroll around and view
the rest of the picture. Play around with different GIF files to get a feel
of how it handles different colors/resolution.
Example: 640 x 480 w/256 colors will be displayed on a 320 x 200 HAM
screen with the ability to scroll around and see the entire
picture.
To run VirtGIF, type:
1>VirtGIF gif-file.GIF
Giving a non-gif, non-existent, or no file will cause an appropriate message
to be displayed.
Once a file is determined to be a valid GIF file, various information is
displayed in the CLI window from which it is run. Number of rows left
to process will be displayed until it is finished. Press the RIGHT mouse
button at any time to abort. (NOTE: The screen/window is opened in the
background, and is the ACTIVE screen/window upon opening. This window/
screen MUST be the ACTIVE screen for the abort function to work.) Once
the screen is processed, CLICK in the CLI window you ran VirtGIF in and
then press <RETURN> to pop screen to front and view the picture. If
scrolling is enabled, PRESS & HOLD the LEFT mouse button and move the
pointer to scroll the picture in all directions. (NOTE: If the pointer
reaches the edge of the screen, you will have to release the LEFT mouse
button, move pointer to center of screen, then PRESS/HOLD/move again since
if the pointer does not move, the program cannot detect relative positioning
to scroll.) Press RIGHT mouse button to exit program.
Additional notes:
1. Due to the nature of HAM mode, HAM pictures which scroll will have
strange color changes on the leftmost part of the screen, and possibly
in whole areas of a single color. However, for most pictures, this
should be a minor problem. A work-around is in the works for this.
2. This program has been tested up to a resolution of 1024 x 768 with 16
colors, but this requires that you have at least 430K of CHIP RAM free,
which is cutting it close. Try it and see if it will work for you.
3. This program can be slow at times, so be patient when decoding large
pictures.
4. Runs fine with expansion memory.
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Additions for future versions:
- Faster decoding.
- Display information which is currently in CLI on a window of the VirtGIF
screen
- View multiple files
- Save displayed portion (when scrolling) as IFF.
- Eliminate annoying color distortions on left border of screen
in HAM mode
- Allow user to force different resultion/scroll (i.e., display
640 x 400 pics with <=16 colors on 320 x 200 screen with scrolling)
- Allow user to select optional "smoothing" algorithm for better color
representation in HAM mode
- Any others you suggest...
ALL comments(positive/negative) and suggestions are welcome!
I can be reached on CompuServe by using my account number:
--> Patrick Maloney [73407,3676]
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