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Man Pages

Manual Reference Pages  -  URT (1)


urt - overview of the Utah Raster Toolkit


See Also


applymap   Apply color map to image data.
avg4       Simple 2x2 downsizing filter.
crop       Crop image.
cubitorle  Convert Cubicomp format to RLE.
dvirle     Typeset TeX ".dvi" files as RLE images.
fant       Image scale/rotate with anti-aliasing.
get4d      Display on SGI Iris/4D display.
get_orion  Display on "Orion" display.
getap      Display on Apollo.
getbob     Display under HP window system.
getcx3d    Display RLE on Chromatics CX3D.
getfb      Display using BRL generic fb library.
getgmr     Display on Grinnell GMR-27 frame buffer.
getiris    Display on SGI 2400/3000 w/o window manager.
getmac     Display on Mac under MPW.
getmex     Display on SGI under the window manager.
getqcr     Display on Matrix QCR camera.
getren     Display on HP SRX.
getsun     Display using SunTools.
getx10     Display on X10 display.
getx11     Display using X11.
giftorle   Convert GIF files to RLE.
graytorle  Convert separate rrr ggg bbb files to RLE.
mcut       Median cut color quantization.
mergechan  Merge colors from multiple images.
painttorle Convert MacPaint to RLE.
pgmtorle   Convert PBMPLUS pgm format to RLE.
ppmtorle   Convert PBMPLUS ppm format to RLE.
pyrmask    Generate "pyramid" filter mask.
rastorle   Convert Sun Raster to RLE.
rawtorle   Convert various raw formats to RLE.
read98721  Read the screen of an HP 98721 "Renaissance" to an RLE file.
repos      Reposition an image.
rlatorle   Convert Wavefront RLA format to RLE.
rleClock   Draws a clock face.
rleaddcom  Add comments to an RLE file.
rleaddeof  Add an EOF code to an RLE file.
rlebg      Generate a "background".
rlebox     Find bounding box of an image.
rlecomp    Image composition.
rledither  Floyd-Steinberg dither an image to a given colormap.
rleflip    Flip an image or rotate it 90.
rlehdr     Print info about an RLE file.
rlehisto   Make a histogram of an image.
rleldmap   Load a new colormap into a file.
rlemandl   Make a Mandelbrot image.
rlenoise   Add noise to an image.
rlepatch   Patch smaller images on a big one.
rleprint   Print all pixel values in image.
rlequant   Variance based color quantization.
rlescale   Generate a "gray scale".
rleselect  Select images from an RLE file.
rlesetbg   Set the background color of an image file.
rleskel    Skeleton tool. Programming example.
rlespiff   Simple contrast enhancement.
rlesplice  Splice two images horizontally or vertically.
rlesplit   Split concatenated images into files.
rlestereo  Combine two images into a "red-green" stereo pair.
rleswap    Swap or select color channels.
rletoabA60 Convert RLE to Abekas A60 format.
rletoabA62 Convert to Abekas A62 format.
rletoascii Make a line-printer/CRT version of an RLE image.
rletogif   Convert RLE images to GIF format.
rletogray  Convert RLE to separate rrr ggg bbb files.
rletopaint Convert RLE to MacPaint.
rletoppm   Convert RLE to PBMPLUS ppm format.
rletops    Convert RLE to (B&W) PostScript.
rletorast  Convert RLE to Sun Raster.
rletoraw   Convert RLE to rgbrgb raw format.
rletorla   Convert RLE to Wavefront RLA format.
rletotiff  Convert RLE to TIFF 24 bit format.
rlezoom    Scale image by sub- or super-sampling.
smush      Generic filtering.
targatorle Convert TARGA to RLE.
tifftorle  Convert TIFF 24 bit images to RLE.
to8        24 to 8 bit ordered dither color conversion.
tobw       Color->B&W conversion.
unexp      Convert "exp" format to normal colors.
unslice    Paste together "slices" into a full image.
wasatchrle Convert Wasatch paint system to RLE.


The Utah Raster Toolkit is a collection of programs and C routines for dealing with raster images commonly encountered in computer graphics. A device and system independent image format stores images and information about them. Called the RLE(5) format, it uses run length encoding to reduce storage space for most images.

The programs (tools) currently included in the toolkit are listed above, together with a short description of each one. Most of the tools read one or more input RLE files and produce an output RLE file. Some generate RLE files from other information, and some read RLE files and produce output of a different form.

An input file is almost always specified by mentioning its name on the command line. Some commands, usually those which take an indefinite number of non-file arguments (e.g., rleaddcom) require a -i flag to introduce the input file name. If the input file name is absent the tool will usually read from the standard input. An input file name of "-" also signals that the input should be taken from the standard input.

On Unix systems, there are two other specially treated file name forms. A file name starting with the character ’|’ will be passed to sh(1) to run as a command. The output from the command will be read by the tool. A file whose name ends in ".Z" (and which does not begin with a ’|’) will be decompressed by the compress(1) program. Both of these options supply input to the tool through a pipe. Consequently, certain programs (those that must read their input twice) cannot take advantage of these features. This is noted in the manual pages for the affected commands.

An output file is almost always specified using the option -o outfile. If the option is missing, or if outfile is "-", then the output will be written to the standard output.

On Unix systems, the special file name forms above may also be used for output files. File names starting with ’|’ are taken as a command to which the tool output will be sent. If the file name ends in ".Z", then compress will be used to produce a compressed output file.

Several images may be concatenated together into a single file, and most of the tools will properly process all the images. Those that will not are noted in their respective man pages.

Picture comments. Images stored in RLE form may have attached comments. There are some comments that are interpreted, created or manipulated by certain of the tools. In the list below, a word enclosed in <> is a place-holder for a value. The <> do not appear in the actual comment.
image_gamma=<float number>
  Images are sometimes computed with a particular ‘‘gamma’’ value -- that is, the pixel values in the image are related to the actual intensity by a power law, pixel_value=intensity^image_gamma. Some of the display programs, and the buildmap(3) function will look for this comment and automatically build a "compensation table" to transform the pixel values back to true intensity values.
display_gamma=<float number>
  The display_gamma is just 1/image_gamma. That is, it is the ‘‘gamma’’ of the display for which the image was computed. If an image_gamma comment is not present, but a display_gamma is, the displayed image will be gamma corrected as above. The to8 program produces a display_gamma comment.
  The length of the colormap stored in the RLE header must be a power of two. However, the number of useful entries in the colormap may be smaller than this. This comment can be used to tell some of the display programs (getx11, in particular) how many of the colormap entries are used. The assumption is that entries 0 - colormap_length-1 are used. This comment is produced by mcut, rlequant, and rledither.
  This comment is used by getx11 to set the window title. If present, the comment is used instead of the file name. (No other programs currently pay attention to this comment.) The comments IMAGE_TITLE, title, and TITLE are also recognized, in that order. No programs produce this comment.
  All toolkit programs (with the exception of rleaddcom) create or add to a HISTORY comment. Each tool appends a line to this comment that contains its command line arguments and the time it was run. Thus, the image contains a history of all the things that were done to it. No programs interpret this comment.
  This comment should be present in a file stored in ‘‘exponential’’ form. See unexp(1) and float_to_exp(3) for more information. The unexp program expects to see this comment.


compress(1), sh(1), RLE(5).


Many people contributed to the Utah Raster Toolkit. This manual page was written by Spencer W. Thomas, University of Michigan.

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1 URT (1) June 17, 1990

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