viewfax(1) Local commands viewfax(1)
viewfax - display fax files in an X11 window
viewfax [-fnluirv24] [-hheight] [-wwidth] [-zzoom] [-ddisplay] [-gwxh+x+y] [-bbell] [-mmemory]
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 dis-
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 lin-
ear factor of 2 prior to display, until they fit on the screen. The display can be con-
trolled 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 re-
position 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.
displays the first page from the command-line list.
displays the last page from the command-line list.
z zoom in (same as right mouse button).
zoom out (same as left mouse button).
u turns the image upside down, which is useful if the fax was originally fed the
wrong way into the machine.
turns this and all following pages upside down.
l turns the image through 90 degrees, to view landscape text.
turns this and all following pages sideways.
m produce a left/right mirror image of the page.
mirror this and all following pages.
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.
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
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 over-
rides 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.
specifies the number of fax lines. If this option is missing, viewfax counts the
number of lines in the input file.
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 widthx-
If the window is subsequently resized due to the user zooming in or out, the geome-
try 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
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 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.
mgetty (http://alpha.greenie.net/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, (ftp://ftp.leo.org/pub/comp/os/unix/networking/mgetty/faxview.tcl.gz) a sim-
ple dialog for viewing FAX messages by Ralph Schleicher (email@example.com). This is a
useful tool which provides a file menu from which incoming faxes can be selected for dis-
play with viewfax.
CCITT (now ITU) Recommendation T.4, Standardization of Group 3 Facsimile Apparatus for
CCITT (now ITU) Recommendation T.6, Facsimile Coding Schemes and Coding Control Functions
for Group 4 Facsimile Apparatus.
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
The program does not refer to the X resources database.
Frank D. Cringle (firstname.lastname@example.org).
4th Berkeley Distribution 14 October 1995 viewfax(1)