jpg(1) — the Plan 9 manual

JPG(1)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 ... | -E ]
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 corresponding 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 totif 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 display 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 improve the appearance of images on color-mapped displays, typically 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 image(6), and write it to standard output.

-9

Like -c, but produce an uncompressed image. This saves processing time, particularly when the output is being piped to another program such as page(1), since it avoids compression and decompression.

-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 representing frames of the movie. Sets -f.

The tojpg, togif, toppm and topng programs go the other way: they convert 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 images. Togeordi is an rc(1) script that invokes tojpg -s. Totif accepts 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 decoders 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 support 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 rendered. This option specifies the time, in milliseconds, to pause while displaying the next named file.

-E

Specifying this option instead of a list of files will read the frames from a pipe on fd 0. Each frame is terminated with EOF. End of the animation is specified by an extra EOF.

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 displayed. 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 creates 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

BUGS

Writing an animated GIF using togif is a clumsy undertaking.

HISTORY

Tojpg first appeared in 9front (May, 2013). Tif and totif first appeared in 9front (July, 2013).