seejpeg(1)

NAME

seejpeg

SYNOPSIS

seejpeg [options] <image> [ <image> ... ]

COPYRIGHT

Seejpeg is Copyright (C) 1993-1999 by Evan Harris.

This software is based in part on the work of the Indepen
dent JPEG Group.

DESCRIPTION

Seejpeg is an image displayer which uses svgalib. It cur
rently understands the JPEG, GIF, PPM, BMP and TARGA for
mats.

Seejpeg automatically decides the best video mode to use,
based on the modes supported by the video hardware. This
decision can be influenced by various program options.

A slideshow option is provided.

KEYBOARD COMMANDS

Once an image is being displayed, the following keyboard
commands are availble:

q Q Quit.

This quits immediately. If multiple images were
specified, the remainder are not displayed.

up-arrow

Scroll image up.

This does not do anything if the image is smaller
the video mode or the top of the image is already
displayed.

down-arrow

Scroll image down.

This does not do anything if the image is smaller
the video mode or the bottom of the image is
already displayed.

left-arrow

Scroll image left.

This does not do anything if the image is smaller
the video mode or the left extremity of the image
is already displayed.

right-arrow

Scroll image right.

This does not do anything if the image is smaller
the video mode or the right extremity of the image
is already displayed.

backspace

Show the previous image.

If there is no previous image, this reloads the
current image.

r R Reload the current image.

any-other-key

Show the next image.

If there is no next image, seejpeg exits.

OPTIONS

-1 --one-pass

Quantize image in one pass (implies -q). JPEG
only.

This is faster than using -q, but the resulting
image quality is not as high.

-c --centre --center

Centre the image on the screen, if its width or
height is smaller than that of the video mode.

-C --cycle

Cycle through all images repeatedly.

To exit immediately, press Q.

-dx --double=x

Double the width of the image by duplicating each
pixel.

-f F --fuzz=F

Set the video mode choosing fuzz factor. 0.5 <= F
<= 1.0.

A video mode is selected if it is the same size or
larger than the image. The fuzz factor allows a
video mode to be selected if the video mode is
equal to or larger than F * image_width and F *
image_height.

-F string --mode=string

Force the use of the given video mode. The string
must be an svgalib video mode string, such as
G640x480x256, or a corresponding video mode number.

If this is a 256 colour mode, quantization (-q) is
automatically chosen. If quantization is not pos
sible, the video mode is disallowed. The allowable
video modes may be affected by the image type as
well as the video card and svgalib configuration
file.

-g --grey --gray

Display image as greyscale (implies -1). JPEG
only.

Display the image in greyscale. This is not neces
sary for an image compressed using the greyscale
option on cjpeg as this mode will be set automati
cally. It can be used for images compressed with
out the greyscale flag, or for displaying colour
images in greyscale.

-G F --gamma=F

Set the gamma correction value. 0.1 <= F <= 5.0.

The default gamma value is 1.0. If an image is too
dark, increase the gamma correction value. 1.5 and
2.0 are often good values to try. If it is too
light, decrease it.

-h --help

Print a usage message.

-m W --min-mode-width=W

Do not select a video mode with width less than W.

This can be useful on larger monitors to avoid the
smaller video modes, such as 320x200.

-M W --max-mode-width=W

Do not select a video mode with width greater than
W.

This can be useful if a video card supports a given
mode, but the monitor doesn't.

-q --quantize --quantise

Quantize image into 256 colours. The resulting
image will be displayed using a 256 colour mode.
JPEG only.

The default quantization algorithm uses two passes
and is memory intensive. This can be a problem on
small-memory machines. A one pass algorithm that
does not use much memory can be specified using -1,
but the resulting image quality is not as high.

-r --randomize --randomise

Randomize the order of the images to be displayed.

If cycling through the images is also requested, a
new random order is chosen for each cycle.

-s T --slideshow-delay=T

Show the images in a slideshow, waiting T seconds
between each image.

The scrolling keyboard commands behave normally in
a slideshow. Other keyboard commands are acted
upon normally, but not until the end of the delay
time.

-v --verbose

Be verbose.

Prints information such as the image size and video
mode being used. Without this option, seejpeg
operates silently.

-w --width-only

Only use the image width to choose the video mode.

By default, the video mode chosen is the smallest
one possible which is not smaller than the image.
This may not be desirable for long, thin images.
This options allows the video mode to be chosen
based on the width only, rather than the width and
height.

--enable-5x4

Enable video modes with a 5x4 aspect ratio to be
used. 5x4 modes are enabled by default.

As of seejpeg 1.10, 1280x1024 is the only mode of
this type.

--disable-5x4

Do not allow video modes with a 5x4 aspect ratio to
be used. 5x4 modes are enabled by default.

--enable-4x3

Enable video modes with a 4x3 aspect ratio to be
used. 4x3 modes are enabled by default.

This is the same aspect ratio as a normal monitor
and the vast bulk of standard video modes are of
this type.

--disable-4x3

Do not allow video modes with a 4x3 aspect ratio to
be used. 4x3 modes are enabled by default.

--enable-8x5

Enable video modes with a 8x5 aspect ratio to be
used. 8x5 modes are disabled by default.

As of seejpeg 1.10, 640x400 and 320x200 are the
only modes of this type.

--disable-8x5

Do not allow video modes with a 8x5 aspect ratio to
be used. 8x5 modes are disabled by default.

--enable-16x9

Enable video modes with a 16x9 aspect ratio to be
used. 16x9 modes are disabled by default.

16x9 is the widescreen aspect ratio format used by,
for example, HDTV. As of svgalib 1.4.0, only one
modeline, for 1072x600, is provided by default and
it distorts images produced for a 4x3 screen when
used on 4x3 screens.

--disable-16x9

Do not allow video modes with a 16x9 aspect ratio
to be used. 16x9 modes are disabled by default.

NOTES

For optimum performance, use svidtune from the svgalib (source) distribution to create a mode line for each video
mode that is tuned to your video card and monitor and
placed them in the libvga.config file.

LIMITATIONS

Video modes are limited to 2048x1536, 2048x1152,
1920x1440, 1800x1012, 1600x1200, 1360x768, 1280x1024,
1280x720, 1152x864, 1072x600, 1024x768, 960x720, 848x480,
800x600, 720x540, 640x480, 640x400, 512x384, 400x300,
320x240 and 320x200 in 256, 32K, 16M or 16M32 colours.
Each mode can only be used if it is supported by the video
card, svgalib, and the svgalib configuration (libvga.con
fig).

Images that cannot be completely contained within video
memory are clipped.

No horizontal scrolling is permitted on Trident cards in
800x600x256 mode, due to an svgalib or chipset bug.

Seejpeg has had limited testing, none at all for the TARGA
format.

SEEJPEG(1)