NAME
jp2a - convert JPEG images to ASCII
SYNOPSIS
jp2a [ options ] [ filename(s) | URL(s) ]
DESCRIPTION
jp2a will convert JPEG images to ASCII characters. You can specify a
mixture of files and URLs.
OPTIONS
- Read JPEG image from standard input
--background=light --background=dark
If you don’t want to mess with --invert all the time, just use
these instead. If you are using white characters on a black
display, then use --background=dark, and vice versa.
-b --border
Frame output image in a border
--chars=...
Use the given characters when producing the output ASCII image.
Default is " ...’,;:clodxkO0KXNWM".
--colors
Use ANSI color for text output and CSS color for HTML output.
-d --debug
Print debugging information when using libcurl to download
images from the net.
-f --term-fit
Use the largest dimension that makes the image fit in your
terminal display.
--term-height
Use terminal display height and calculate width based on image
aspect ratio.
--term-width
Use terminal display width and calculate height based on image
aspect ratio.
-z --term-zoom
Use terminal display width and height.
--fill When used with --html and --color, then color each output
character’s background color. For instance, if you want to use
fill-output on a light background, do
jp2a --color --html --html-fill --background=light somefile.jpg
--output=dark.html
To do the same on a light background:
jp2a --color --html --html-fill --background=dark somefile.jpg
--output=light.html
The default is to have fill disabled.
-x --flipx
Flip output image horizontally
-y --flipy
Flip output image vertically
--height=N
Set output height. If only --height is specified, then output
width will be calculated according to the source images aspect
ratio.
-h --help
Display a short help text
--grayscale
Converts image to grayscale when using --html or --colors.
--html Make ASCII output in strict XHTML 1.0, suitable for viewing with
web browsers. This is useful with big output dimensions, and
you want to check the result with a browser with small font.
--html-fill
Same as --fill. You should use that option instead.
--html-no-bold
Do not use bold text for HTML output.
--html-raw
Output only the image in HTML codes, leaving out the rest of the
webpage, so you can construct your own.
--html-fontsize=N
Set fontsize when using --html output. Default is 4.
--html-title=...
Set HTML output title.
--output=...
Write ASCII output to given filename. To explicitly specify
standard output, use --output=-.
-i --invert
Invert output image. If you view a picture with white
background, but you are using a display with light characters on
a dark background, you shoudl invert the image.
--red=...
--green=...
--blue=...
When converting from RGB to grayscale, use the given weights to
calculate luminance. These three floating point values must add
up to exactly 1.0. The default is red=0.2989, green=0.5866 and
blue=0.1145.
--size=WIDTHxHEIGHT
Set output dimension.
-v --verbose
Print some verbose information to standard error when reading
each JPEG image.
--width=N
Set output width. If you only specify the width, the height
will be calculated automatically.
-V --version
Print program version.
--zoom Sets output dimensions to your entire terminal window,
disregarding source image aspect ratio.
RETURN VALUES
jp2a returns 1 when errors are encountered, zero for no errors.
EXAMPLES
Convert and print imagefile.jpg using ASCII characters in 40 columns
and 20 rows:
jp2a --size=40x20 imagefile.jpg
Download an image off the net, convert and print:
jp2a http://www.google.com/intl/en/logos/easter_logo.jpg
Output picture.jpg and picture2.jpg, each 80x25 characters, using the
characters " ...ooxx@@" for output:
jp2a --size=80x25 --chars=" ...ooxx@@" picture.jpg picture2.jpg
Output image.jpg using 76 columns, height is automatically calculated
from aspect ratio of image.jpg
cat image.jpg | jp2a --width=76 -
If you use jp2a together with ImageMagick’s convert(1) then you can
make good use of pipes, and have ImageMagick do all sorts of image
conversions and effects on the source image. For example:
convert somefile.png jpg:- | jp2a - --width=80
Check out convert(1) options to see what you can do. Convert can
handle almost any image format, so with this combination you can
convert images in e.g. PDF or AVI files to ASCII.
Although the default build of jp2a includes automatic downloading of
files specified by URLs, you can explicitly download them by using
curl(1) or wget(1), for example:
curl -s http://foo.bar/image.jpg | convert - jpg:- | jp2a -
DOWNLOADING IMAGES FROM THE NET
If you have compiled jp2a with libcurl(3), you can download images by
specifying URLs:
jp2a https://user:pass@foo.com/bar.jpg
The protocols recognized are ftp, ftps, file, http, https and tftp.
If you need more control of the downloading, you should use curl(1) or
wget(1) and jp2a read the image from standard input.
jp2a uses pipe and fork to download images using libcurl (i.e., no exec
or system calls) and therefore does not worry about malevolently
formatted URLs.
GRAYSCALE CONVERSION
You can extract the red channel by doing this:
jp2a somefile.jpg --red=1.0 --green=0.0 --blue=0.0
This will calculate luminance based on Y = R*1.0 + G*0.0 + B*0.0. The
default values is to use Y = R*0.2989 + G*0.5866 + B*0.1145.
PROJECT HOMEPAGE
The latest version of jp2a and news is always available from
http://jp2a.sourceforge.net
SEE ALSO
cjpeg(1), djpeg(1), jpegtran(1), convert(1)
BUGS
jp2a does not interpolate when resizing. If you want better quality,
try using convert(1) and convert the source image to the exact output
dimensions before using jp2a.
Another issue is that jp2a skips some X-pixels along each scanline.
This gives a less precise output image, and will probably be corrected
in future versions.
AUTHOR
Christian Stigen Larsen <csl@sublevel3.org> -- http://csl.sublevel3.org
jp2a uses jpeglib to read JPEG files. jpeglib is made by The
Independent JPEG Group (IJG), who have a page at http://www.ijg.org
LICENSE
jp2a is distributed under the GNU General Public License v2.
