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.