.\" Copyright (c) 1986, University of Utah
.TH GET_ORION 1 "July 20, 1987" 1
.UC 4 
.SH NAME
get_orion \- get RLE images to an Orion graphics display
.SH SYNOPSIS
.B get_orion
[
.B \-D
] [
.B \-b
] [
.B \-f
] [
.BI \-g " gam"
] [
.B \-l
] [
.B \-r
] [ 
.I infile
]
.SH DESCRIPTION
This program displays an
.IR RLE (5)
file on a High Level Hardware Orion graphics display running the StarPoint 
graphics system.  It uses a
dithering technique to take a full-colour or grey scale image into
the limited number of colours available.

The default behavior is to display the image in colour using
a 216 colour map (6 intensities per primary). However, an 
.IR RLE(5)
file with 1 colour and 3 colour map channels is treated as a
special case with the colour map in the header loaded as the graphics 
colour map
and the data used to index this map.  In this mode of operation no
dithering is done as the file is assumed to be the output of some
program which has selected the "best" possible colours for the image
and has already corrected some of the errors produced by the quantization.  
An option is provided to force a grey scale display of colour images.

.I Get_orion 
uses the standard window manager creation procedure to create a window at a
particular location on the screen.  The size of the window is the size of the 
image. 

.SH OPTIONS
.TP
.B \-D
"Debug mode".  The operations in the input
.IR RLE(5)
file will be printed as they are read.
.TP
.B \-b
Forces
.I getOrion
to produce a grey scale dithered image instead of a colour image using 128 
shades of grey.  Colour input will be transformed to grey level using the 
NTSC Y transform.
.TP
.B \-f
Normally 
.I get_orion 
will only use entries 0-239 of the graphics device colour map, as
the others are used by the window manager for background, icons,
etc.  This option will force it to use all 256 entries and is useful
only when the image has been specified with a 24-bit colour map
.TP
.BI \-g " gam"
Specifies, as a floating point number, the gamma correction factor to be used 
when correcting the colour map. 
.TP
.B \-l
Use a linear colour map. Identical to having a gamma of 1.
.TP
.B \-r
Use "reverse" mode for display.  The scanlines are by default displayed from 
the bottom-up, this option displays them from the top-down.  Useful
for applications which have produced the scanlines starting from the
top one.
.B 
.TP
.I infile
Name of file to display.  If none specified, the image will be read from 
standard input.
.SH SEE ALSO
.IR urt (1),
.IR RLE (5).
.SH AUTHOR
Gianpaolo Tommasi, Computer Laboratory, University of Cambridge.
The code is based on other "get" routines.
.SH DEFICIENCIES
The window cannot be moved whilst the image is being displayed.

Because of the way the graphics memory is organized displaying images in 
GM_BW mode is slow.