Ppmsvgalib User Manual(0) Ppmsvgalib User Manual(0)NAMEppmsvgalib - display PPM image on Linux console using Svgalib
SYNOPSISppmsvgalib
[-mode=mode]
All options can be abbreviated to their shortest unique prefix. You
may use two hyphens instead of one to designate an option. You may use
either white space or an equals sign between an option name and its
value.
DESCRIPTION
This program is part of Netpbm(1)ppmsvgalib displays a PPM image on a Linux virtual console using the
Svgalib facility. Svgalib is a popular means of displaying Graphics in
Linux without the use of the X Window System. (To display a Netpbm
image in an X window, see pamx).
If you run ppmsvgalib with a version of Svgalib earlier than 1.9, you
must run it with CAP_SYS_RAWIO capability (on most Linux systems, that
means you run it as superuser), because Svgalib uses the ioperm() sys‐
tem call to access the console hardware. Newer Svgalib has its own
device driver, so you need only proper permissions on a device special
file to access the console.
ppmsvgalib is not capable of using color mapped video modes. These are
the old video modes that are usually called '8 bit' color modes.
ppmsvgalib is a bare displayer. It won't do any manipulation of the
image and is not interactive in any way. If you want a regular inter‐
active graphics viewer that uses Svgalib, try zgv (not part of Netpbm).
To exit ppmsvgalib while it is displaying your image, send it a SIGINTR
signal (normally, this means 'hit control C').
ppmsvgalib draws a white border around the edges of the screen. It
does this to help you isolate problems between the image you're dis‐
playing and the facilities you're using to display it.
(Note: if the image you're displaying reaches the edges of the screen,
it will replace the white border).
ppmsvgalib places the image in the center of the screen.
If your image is too big to display in the video mode you selected,
ppmsvgalib fails. You can use pamcut to cut out a part of the image to
display or use pamscale to shrink the image to fit.
If you want to play with ppmsvgalib, ppmcie is a good way to generate a
test image.
To be pedantic, we must observe that ppmsvgalib displays a PPM image in
the correct colors only if the display has a transfer function which is
the exact inverse of the gamma function that is specified in the PPM
specification. Happily, most CRT displays and the modern displays that
emulate them, are pretty close.
Running the PPM image through pnmgamma can help cause ppmsvgalib to
display the correct colors.
OPTIONS
-mode=mode
This tells ppmsvgalib what video mode to use. mode is the
Svgalib video mode number. You can get a list of all the video
modes and their Svgalib video mode numbers with the program
vgatest that is packaged with Svgalib. (Unfortunately, the var‐
ious interesting programs that are packaged with Svgalib are
typically not installed on systems that have the Svgalib library
installed).
In practice, there are probably only two modes you'll ever care
about: 25 is the standard SVGA direct color mode, which is 1024
columns by 768 rows with 8 bit red, green, and blue components
for each pixel and no fancy options. 28 is the same, but with
the popular higher resolution of 1280 x 1024.
But if you have an older video controller (with less than 4MB of
memory), those modes aren't available, you might like mode 19,
which is 640 x 480 and takes less than a megabyte of video mem‐
ory. This is a standard VGA video mode.
SEE ALSOpamx(1) , pamcut(1) , pamscale(1) , ppmcie(1) , ppm(5) , zgv, Svgalib,
vgatest
AUTHOR
By Bryan Henderson, January 2002.
Contributed to the public domain.
netpbm documentation 11 May 2005 Ppmsvgalib User Manual(0)
