viewfax(1) Frank's Hacks (14 October 1995) viewfax(1)
NAME
viewfax - display fax files in an X11 window
SYNOPSIS
viewfax [-fnluirv24] [-hheight] [-wwidth] [-zzoom] [-ddisplay] [-
gwxh+x+y] [-bbell] [-mmemory] filename...
DESCRIPTION
viewfax displays one or more fax files in an X11 window.
The input files may be either raw, single-page faxes
received by a fax modem with a program such as mgetty(1), or
tiff files such as those used by hylafax. The first (or
only) page of "PC-Research"-style (DigiFAX) files produced
by the ghostscript dfaxhigh or dfaxlow drivers can also be
displayed.
Input files using any common fax encoding such as group 3 (1
and 2 dimensional) and group 4 can be displayed.
The fax images are rendered at full resolution and then
successively scaled down by a linear factor of 2 prior to
display, until they fit on the screen. The display can be
controlled interactively using mouse and keyboard commands.
The left mouse button expands the image by a factor of two
and the right button reduces it by the same factor. If the
image is bigger than the available window size, the middle
mouse button can be used to reposition it within the window.
Hold down the middle button while dragging the image to its
new position.
Further interaction is controlled by single-key commands:
h or Help
displays a page of help information. Type 'q' to
return to the original document.
p or Prior or PgUP or - or BackSpace
displays the previous page from the command-line list.
n or Next or PgDn or + or space
displays the next page from the command-line list.
Shift HOME
displays the first page from the command-line list.
Shift END
displays the last page from the command-line list.
z zoom in (same as right mouse button).
Shift Z
zoom out (same as left mouse button).
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viewfax(1) Frank's Hacks (14 October 1995) viewfax(1)
u turns the image upside down, which is useful if the fax
was originally fed the wrong way into the machine.
Shift U
turns this and all following pages upside down.
l turns the image through 90 degrees, to view landscape
text.
Shift L
turns this and all following pages sideways.
m produce a left/right mirror image of the page.
Shift M
mirror this and all following pages.
cursor arrows
reposition the displayed image if it exceeds the window
size.
HOME repositions so that the top left corner is visible.
END makes the bottom right corner visible.
q terminates the program.
Shift Q
terminates the program with non-zero exit status. Can
be used to abort a shell script, e.g. when the user is
previewing an outbound fax and decides not to send it.
OPTIONS
viewfax is designed to "do the right thing" when given just
a filename. Special cases can be handled with the following
options. (Note that tiff-files contain a header which
overrides the -f, -n, -h, -w, -l, -m, and -u flags.)
-f indicates that raw input files are fine resolution (7.7
lines/mm) faxes. This is the default unless the
filename begins with "fn". Tiff and "PC-Research"
(DigiFAX) files are self-specifying.
-n indicates that raw input files are normal resolution
(3.85 lines/mm) faxes. Each fax line is duplicated in
the displayed image to give approximately equal
vertical and horizontal scales.
-hheight
specifies the number of fax lines. If this option is
missing, viewfax counts the number of lines in the
input file.
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viewfax(1) Frank's Hacks (14 October 1995) viewfax(1)-wwidth
specifies the number of pixels in each scan-line. The
default value is 1728.
-l display in landscape mode.
-u turn the image upside down.
-i invert pixels (black/white).
-b preferred warning style: 'a' for audible bell (console
beep), 'v' for visible bell (flash the window), 'n' for
neither. 'v' is the default.
-d or -display
use specified X server
-g or -geometry
the preferred size and position of the window,
specified as widthxheight+x+y. If a position is given
(x and y values), viewfax asks the window manager to
place the window there. The initial size of the window
is constrained to be at most widthxheight.
If the window is subsequently resized due to the user
zooming in or out, the geometry is taken as a
constraint on the screen area which may be used by
viewfax.
If you do not supply a geometry value, everything works
fine with ICCCM-compliant window managers like olwm,
mwm, twm, and tvtwm. When fully zoomed out the viewfax
window will occupy the entire screen.
Users of fvwm will notice that the title bar and left
border are moved off screen when viewfax repositions
the window to (0,0). A workaround is to use -geometry
+5+23 when using fvwm. The proper fix would be for
someone to update the routine HandleConfigureRequest()
in fvwm/events.c to correspond to the code in
twm/events.c.
-mmemory limit
each page is kept in memory after being fetched and
expanded, which saves time if the user returns to it in
the same session. To prevent viewfax from using all
the available swap space, a limit is placed on the
total size of cached images. This defaults to 4
MBytes, enough for about 6 typical pages. If the
memory limit is exceeded, old images are discarded and
must be reloaded from disk if the user returns to them.
The operation of this mechanism is transparent apart
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viewfax(1) Frank's Hacks (14 October 1995) viewfax(1)
from the occasional delays due to reloading. The value
specified on the command line can be suffixed k or m
for kilo- or megabytes.
-r the bit order of the bytes in the input file is
reversed. The fax specification deals only with serial
data transmission. Modem manufacturers have to decide
whether the first bit received should be placed in the
most significant or the least significant position in a
byte. The consensus is to pack most significant first,
but the -r flag is available to deal with the opposite
order.
-v produce some informative messages (verbose mode).
-zzoom
specifies an initial zoom factor. A full-scale fax
will usually not fit on the screen. If the -z option
is not specified, viewfax scales the image by a power
of 2 such that it is fully visible at a reduced size.
The user can then use the mouse buttons (see above) to
view expanded portions of the image.
-2 Assume that raw input files use group 3 two dimensional
coding.
-4 Assume that raw input files use group 4 coding. The
number of fax lines (-h option) is required in this
case.
SEE ALSO
mgetty
(ftp://ftp.leo.org/pub/comp/networking/communication/modem/mgetty)
controls data/fax/voice modems.
hylafax (ftp://sgi.com/sgi/fax) is a full-function fax
client/server system.
g3topbm(1) and xv(1) can be used in a pipeline to view
faxes. This will usually be slower than using viewfax, but
xv has many capabilities for manipulating the image and
saving it in other formats.
xli(1) can display a wide variety of image formats,
including g3 faxes. Version 1.15 has difficulty recognising
damaged fax files.
faxview.tcl, a simple dialog for viewing FAX messages by
Ralph Schleicher (rs@purple.in-ulm.de). This is a useful
tool which provides a file menu from which incoming faxes
can be selected for display with viewfax.
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viewfax(1) Frank's Hacks (14 October 1995) viewfax(1)
CCITT (now ITU) Recommendation T.4, Standardization of Group
3 Facsimile Apparatus Transmission.
CCITT (now ITU) Recommendation T.6, Facsimile Coding Schemes
and Coding Control Facsimile Apparatus.
BUGS
The user interface does not comply with any known style
guide.
The help text looks moth-eaten because it is encoded as a
fax. This avoids dealing with X11 fonts.
The program does not refer to the X resources database.
AUTHOR
Frank D. Cringle (fdc@cliwe.ping.de).
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