term% cat index.txt JPG(1) General Commands Manual JPG(1)
NAME
jpg, gif, png, tif, ppm, bmp, v210, yuv, ico, tga, tojpg, togeordi,
togif, toppm, topng, totif, toico - view and convert pictures
SYNOPSIS
jpg [ -39cdefFkJrtvy ] [ file ... ]
gif [ -39cdektv ] [ file ... ]
png [ -39cdektv ] [ file ... ]
tif [ -39cdektv ] [ file ... ]
ppm [ -39cdektv ] [ file ... ]
bmp [ -39cdektv ] [ file ... ]
v210 [ -39cdektv ] [ file ... ]
tga [ -39cdektv ] [ file ... ]
yuv [ -39cdektv ] [ file ... ]
tojpg [ -c comment ] [ -ks ] [ file ]
togeordi [ -c comment ] [ -k ] [ file ]
togif [ -c comment ] [ -l loopcount ] [ -d msec ] [ -t transindex ] [
file ... [ -d msec ] file ... ]
toppm [ -c comment ] [ -r ] [ file ]
topng [ -c comment ] [ -g gamma ] [ file ]
totif [ -c comment ] [ -3bgGhklLptvyY ] [ file ]
ico [ -c ] [ file ]
toico [ file ... ]
DESCRIPTION
These programs read, display, and write image files in public formats.
Jpg, gif, png, tif, ppm, bmp, tga, v210, and yuv read files in the cor‐
responding formats and, by default, display them in the current window;
options cause them instead to convert the images to Plan 9 image format
and write them to standard output. Tojpg, togif, toppm, topng, and to‐
tif read Plan 9 images files, convert them to JPEG, GIF, PPM, PNG, or
TIFF and write them to standard output.
The default behavior of jpg, gif, png, tif, ppm, bmp, tga, v210, and
yuv is to display the file, or standard input if no file is named.
Once a file is displayed, typing a character causes the program to dis‐
play the next image. Typing a q, DEL, or control-D exits the program.
For a more user-friendly interface, use page(1), which invokes these
programs to convert the images to standard format, displays them, and
offers scrolling, panning, and menu-driven navigation among the files.
These programs share many options:
-e Disable Floyd-Steinberg error diffusion, which is used to im‐
prove the appearance of images on color-mapped displays, typi‐
cally with 8 bits per pixel. Primarily useful for debugging; if
the display has true RGB color, the image will be displayed in
full glory.
-k Convert and display the image as a black and white (really grey-
scale) image.
-v Convert the image to an RGBV color-mapped image, even if the
display has true RGB color.
-d Suppress display of the image; this is set automatically by any
of the following options:
-c Convert the image to a Plan 9 representation, as defined by im‐
age(6), and write it to standard output.
-9 Like -c, but produce an uncompressed image. This saves process‐
ing time, particularly when the output is being piped to another
program such as page(1), since it avoids compression and decom‐
pression.
-t Convert the image, if it is in color, to a true color RGB image.
-3 Like -t, but force the image to RGB even if it is originally
grey-scale.
Jpg has two extra options used to process the output of the LML video
card:
-f Merge two adjacent images, which represent the two fields of a
video picture, into a single image.
-F The input is a motion JPEG file, with multiple images represent‐
ing frames of the movie. Sets -f.
The tojpg, togif, toppm and topng programs go the other way: they con‐
vert from Plan 9 images to JPEG, GIF, PPM, PNG, and TIFF and have no
display capability. They all accept an option -c to set the comment
field of the resulting file. The -r option makes toppm output raw PPM.
The default is to output plain PPM. The -k option makes tojpg output
grey-scale images, and the -s option makes it output scratched JPEG im‐
ages. Togeordi is an rc(1) script that invokes tojpg -s. Totif ac‐
cepts many options. Choosing Huffman, T4, or T6 compression forces the
image to GREY1.
-3 Convert the image to a true color RGB image.
-b Convert the image to a GREY1 black and white image.
-g Use T4 one-dimensional compression.
-G Use T4 two-dimensional compression.
-h Use Huffman compression.
-k Convert the image to a GREY8 grey-scale image.
-l Use LZW compression.
-L Use LZW compression with horizontal differencing. Some TIFF de‐
coders may not support horizontal differencing applied to images
of depths less than eight.
-p Use Packbits compression.
-t Use T6 compression.
-v Convert the image to an RGBV color-mapped image.
-y Convert the image to a GREY2 grey-scale image. Totif will then
convert it to GREY4 before encoding because TIFF does not sup‐
port depths of two.
-Y Convert the image to a GREY4 grey-scale image.
If there is only one input picture, togif converts the image to GIF
format. If there are many files, though, it will assemble them into an
animated GIF file. The options control this process:
-lloopcount
By default, the animation will loop forever; loopcount specifies
how many times to loop. A value of zero means loop forever and
a negative value means to stop after playing the sequence once.
-dmsec By default, the images are displayed as fast as they can be ren‐
dered. This option specifies the time, in milliseconds, to
pause while displaying the next named file.
Gif translates files that contain a `transparency' index by attaching
an alpha channel to the converted image.
Ico displays or converts a Windows icon (.ico) file. If no file is
specified, ico reads from standard input. Icon files contain sets of
icons represented by an image and a mask. The -c option causes ico to
convert the first icon in the set and write it to standard output in
compressed Plan 9 image format. Otherwise, the whole icon set is dis‐
played. Clicking the right button pops up a menu that lets you write
any icon's image as a Plan 9 image (widthxheight.image), write any
icon's mask as a Plan 9 image (widthxheight.mask), or exit. Selecting
one of the write menu items yields a sight cursor. Move the sight over
the icon and right click again to write.
Toico takes a list of Plan 9 image files (or standard input) and cre‐
ates a single icon file. The masks in the icon file will be the white
space in the image. The icon file is written to standard output.
SOURCE
/sys/src/cmd/jpg
/rc/bin/togeordi
SEE ALSO
page(1), image(6).
http://www.w3.org/Graphics/JPEG/jfif3.pdf
http://www.w3.org/Graphics/JPEG/itu-t81.pdf
http://en.wikibooks.org/wiki/JPEG_-_Idea_and_Practice
http://en.wikipedia.org/wiki/JPEG
http://www.w3.org/Graphics/GIF/spec-gif89a.txt
http://www.w3.org/TR/2003/REC-PNG-20031110
http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf
http://netpbm.sourceforge.net/doc/ppm.html
http://en.wikipedia.org/wiki/Windows_bitmap
http://en.wikipedia.org/wiki/Yuv
BUGS
Writing an animated GIF using togif is a clumsy undertaking.
HISTORY
Tojpg first appeared in 9front (May, 2013). Tif and totif first ap‐
peared in 9front (July, 2013).
JPG(1)