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author | B. Watson <yalhcru@gmail.com> | 2019-03-30 03:41:23 -0400 |
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committer | B. Watson <yalhcru@gmail.com> | 2019-03-30 03:41:23 -0400 |
commit | 41640fe33b90ec675cb86bf8179a44618ee1cfa5 (patch) | |
tree | b569081fdffdeac4bf47ee79d6fc34a904840af5 /README.txt | |
download | img2atari-master.tar.gz |
Diffstat (limited to 'README.txt')
-rw-r--r-- | README.txt | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/README.txt b/README.txt new file mode 100644 index 0000000..1344c27 --- /dev/null +++ b/README.txt @@ -0,0 +1,79 @@ +img2atari - Quick & dirty image converter for Atari 8-bit computers, + using ImageMagick. + +Written by B. Watson (yalhcru@gmail.com), released under the +WTFPL. See http://www.wtfpl.net/txt/copying/ for details. + +Purpose: + +Convert images in common formats (JPEG, PNG, etc) to black & white Atari +8-bit image files or executables, in graphics modes 8, 9, or 15. + +Requirements: + +- Linux or some other UNIX/POSIX like environment (possibly including + Mac OSX). You might be able to use Cygwin or MSYS on Windows, or + the Ubuntu emulation included in modern Windows (?). + +- bash. Easily installed on most Linux and similar OSes these days, if not + already part of the OS. + +- ImageMagick. At least the convert and composite commands must be found + in $PATH. + +- Some way to run Atari 8-bit executables, either an emulator or a real + Atari with e.g. an SIO2PC cable. + +Download: + + wget http://urchlay.naptime.net/repos/img2atari/plain/img2atari + chmod +x img2atari + +...or: + + git clone http://urchlay.naptime.net/img2atari.git + +Installation: + +Just copy the img2atari script to some place that's in your $PATH, +or else run it from the directory you saved it to as "./img2atari". + +Usage: + +Run "img2atari --help" for full usage information. + +Notes: + +You don't actually need the loader.s or viewer.s files. These are the +assembly sources for the object code included in img2atari, and are pretty +much only useful for informational purposes. You can modify them, but +there's no easy way to import your modified code into the shell script. + +The input file can be in any format ImageMagick can read. This includes at +least JPEG, PNG, GIF, TIFF, BMP, XPM, EPS... for testing, you can even use +the ImageMagick built-in images (e.g. "logo:" for the ImageMagick logo). +For vector formats (e.g. SVG), you'll want to render it to a PNG first. +For multi-image formats (e.g. animated GIF, PDF), you'll want to extract +single images and convert those. + +Not all images will convert to something that looks OK on the +Atari. Photographs look OK in GR.9 (though blurry due to the low +horizontal resolution). Line art looks better in GR.8 or GR.15. + +You may have to tweak the image some, before converting it. Images that +are too dark or too bright will come out with very little detail, so +try loading the image in an image editor and altering the saturation. +Also, the conversion to black & white is simplistic. You may get better +results if you pre-convert to mono or greyscale. + +GR.8 images with dithering may show a lot of artifacting on the Atari. +About the only thing you can do to avoid this is use the chroma/luma +(s-video) output instead of composite video or RF. + +If you get errors from convert and/or composite (e.g. because the input +file doesn't exist, or isn't recognized by ImageMagick), the output file +will be useless and should be deleted. + +The 'loader' included with the -x option uses the OS to set up the +graphics mode, so custom resolutions (wide/narrow playfield, nonstandard +number of scanlines) are not supported. |