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get_orion - get RLE images to an Orion graphics display
get_orion
[ -D ] [ -b ] [ -f ] [ -g gam ] [ -l ] [ -r ] [ infile ]
This program
displays an 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 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.
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.
- -D
- "Debug mode". The operations in the input RLE(5)
file will be printed as
they are read.
- -b
- Forces 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.
- -f
- Normally 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
- -g gam
- Specifies, as a floating
point number, the gamma correction factor to be used when correcting the
colour map.
- -l
- Use a linear colour map. Identical to having a gamma of 1.
- -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.
- infile
- Name of file to display. If none specified, the image will
be read from standard input.
urt(1)
, RLE(5)
.
Gianpaolo Tommasi,
Computer Laboratory, University of Cambridge. The code is based on other
"get" routines.
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.
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