visprint(1)visprint(1)NAME
visprint- Fractal fingerprint generator.
SYNTAX
md5sum (sha1sum) foo.bar | visprint [Options] > foo.png
DESCRIPTION
Visprint makes cool fractal fingerprint png images based on the con‐
tents of any file. The image will be different for almost every
file with even slightly different contents. Visprint uses the IFS frac‐
tal generation process, pioneered by Michael Barnsley. It is a way to
create images which are self-similar to infinite depths. In other
words, the picture is made up of smaller versions of itself.
Visprint takes a checksum as its input. This is usually a 32-byte
number which is generated from a file. In order to generate the check‐
sum, you will also need a hash function command such as md5sum or
sha1sum.
OPTIONS
-b(0-255)
Use the given background brightness. 0 means black, 255 means
white. You can try other values, but the resultant image will be
quite ugly. The default is 0 (black).
-c Use the alternate coloring method. Flips RGB to BGR.
-a Create the fractal with 4 different color areas.
-g Create a semi-grayscale image. The output varies heavily depend‐
ing on the -b switch.
-i(1-lots)
Use the given intensity of color. With a black background, a
higher intensity produces a brighter image. With a white back‐
ground, higher intensity produces a darker image. In all cases,
calculation time doubles every time you double the intensity.
The default is 30.
-l(32-128)
Use the given checksum length. Modify this number to match the
hash function you are using. Examples: 32 for md5, 40 for sha1,
64 for sha256, 128 for sha512... The output of 128 is foggy
(but still useful). Higher values will result in crappy images,
therefore 128 is the maximum accepted. The default value is 32.
-r(1-1000)
Use the given value for both the x and y resolutions. The calcu‐
lation time will quadruple every time you double this value. The
default is 300.
-t Create the image with a transparent background.
-v Output version information and exit.
-?, -h, --help
Output help information and exit.
EXAMPLES
To create a nice 500x500 fingerprint of your kernel type:
md5sum /boot/mykernel | visprint-r500 > mykernel.png
Let's say that you want a 100x100 sha1 fingerprint of your website's
index file, with png transparency that looks good on a white back‐
ground:
sha1sum index.html | visprint-l -r100 -b255 -t > index.png
AUTHORS
Current Maintainer:
Goizeder Ruiz de Gopegui http://www.tastyrabbit.net/visprint
Previous Geniuses:
Ian Golderg: http://http.cs.berkeley.edu/~iang/
Raph Leviev: http://www.cs.berkeley.edu/~raph/
Hal Finney: http://www.rain.org/~hal/
David Johnston: http://www.cybercities.com/ston/
Soren Andersen: http://intrepid.perlmonk.org/
The original code was written by Ian Goldberg, based on an idea
by Hal Finney, in a post to the coderpunks mailing list. The
most excellent color enhancements were added by Raph Levien.
David Johnston made a port for Win95 console mode and added a
bunch of nice features. Soren Andersen developed the png and
transparency code. Goizeder Ruiz de Gopegui, the current main‐
tainer, cleaned the code, created the documentation and put
everything together.
COPYRIGHT
Copyright 2007 Goizeder Ruiz de Gopegui
This is free software. You may redistribute copies of it under the
terms of the GNU General Public License.
http://www.gnu.org/licenses/gpl.html.
There is NO WARRANTY, to the extent permitted by law.
SEE ALSOmd5sum(1)sha1sum(1)Goizeder Ruiz de Gopegui 2.0 visprint(1)
