ZIMG(1)ZIMG(1)NAMEzimg - render 2d data of arbitrary format
SYNOPSISzimg [options] [file ...]
DESCRIPTION
The zimg program generates png images from arbitrary formatted 2-D
ascii or binary data. Optionally, jpeg, ppm or pgm images can be gener‐
ated instead of png.
INPUT FILES
If no input files are given, zimg reads from stdin.
If the input file ends in .gz, .bz2, .z or .Z and your operating system
supports the popen() call, the file is filtered through gunzip, bunzip2
or uncompress, respectively.
If an input file is not accessible, the availability of the file with
the suffixes .gz, .bz2, .z or .Z appended is checked (multiview).
If no command line options are specified, zimg assumes plain ascii
input, where the dimensions of the image are taken from the first two
convertable integers and comment lines are marked by a hash `#' mark at
the very first column of each line. If ascii data is read the first
lines are parsed for zimg modelines until the first data point is read.
See below in the section MODELINES.
Currently the `ESRF data format' (edf and ehf) is the only binary input
format which is detected automatically by zimg (if this option was not
disabled at compile time). In the case of ehf, the data is read from a
different file as specified by the tag EDF_BinaryFileName.
If the size was not specified and no binary option was selected, the
first bytes of the source file are examined to check if the source is
already a png file. This works only on systems where there's no differ‐
ence between reading ascii and binary data (UNIX). If the source file
is a png, all options except the colormap, labelling and output options
are ignored. This is mainly useful for labelling a png file later (or a
png file that was not created by zimg). It can also be used to just
convert png to jpeg. Or you can specify a different colormap, to
change the colormap entries of the source png. Note that this check
for source png's is not available if zimg was linked with an older
libgd version. If the source is a png, the --dump-colormap switch
dumps the colormap entries of the png file instead of the zimg colors.
OPTIONS
In almost all cases you'll need to specify at least a few command line
options to tell zimg something about the input format and specify the
output style.
Note, that the order of command line options is important: in the case
of mutually exclusive options the last one wins; in the case of a
switch which turns an option on, a second occurence of this switch
turns the option off again. Example: -x -x does nothing. This is use‐
ful for overwriting options which were set in the resource files
~/.zimgrc and .zimgrc (see section FILES). If an options overwrites
another option (e.g. in `--red --blue', the second switch would over‐
write the first), this is silently ignored.
Some switches can be defined more than once and are position dependent.
These switches include
--differentiate
--curvature
--smooth
--logarithmic
--fabs
--absolute
--relative
This means that in
zimg --relative=10-60 --differentiate
the relative scaling applies to the raw data, but in
zimg--differentiate --relative=10-60
the relative scaling applies to the differentiated data.
Spaces separating the single-letter options from their parameters are
optional.
The availability of some options are compile-time dependent. Use the
--help option to get a list of valid options for your binary version of
zimg.
-r, --size=width[,height]
specifies the width and height of the 2-D data. If height is not
given it is set equal to width. The separator 'x' (instead of ',')
can be used also for backwards compatibility.
-M, --matrix
Input is assumed to be in ascii matrix format. The ascii input
file should have the data in rows and columns. The number of rows
is the image dimension in vertical direction. The number of col‐
umns is the image in horizontal direction. The dimension of the
data can be overwritten by the --size switch.
-p, --pattern=pattern
Mark comment blocks. This option is used when reading unformatted
ascii data. Each line will be truncated at pattern. This options
might be used repeatedly to specify more than one comment pattern.
This option was not really tested and might be still buggy. For
the future it is planned to include also regular expressions.
-n, --column=number
read column number (ascii input). Multiple columns can be selected
by using this option repeatedly. Currently this is limited to the
32 first columns. If number is omitted, the data of all columns
will be used.
--skip[=bytes/lines]
skip this amount of lines when reading ascii data. Skip bytes, if
reading binary data. Note that the unit is bytes, irrespective of
the input type (short ..). If the optional size argument is miss‐
ing, the option is reset to its default. This default behavior is
as follows: for binary data, all available data is read from the
input stream and the header size (which will be skipped) is then
calculated as the difference between the size of input data and
the size of the image as specified by the -r switch. Or in short:
the last <width>x<height> items of the input stream will be taken.
If you don't like this feature you can disable it explicitly by
using the switch `--skip=0'. For ascii data no skipping will be
done by default.
--options=/regexp/switches
apply switches, if the input filename matches regexp. Especially
useful if used in a .zimgrc file. The separator character can be
any character which is not present in regexp, for example
--options=#/usr/local#switches. See also the --input-filter
switch. --options is only available if your system provides the
POSIX regular expression functions regcomp / regexec (check zimg-V for availability).
--input-filter=filter
filter input files thru filter. If filter contains a %s, it is
substituted with the file name, else the filename is appended to
the filter. This switch is especially useful if used in a .zimgrc
file. Example: --options='/.int$/--input-filter=int < %s'. See
also the --options switch. --input-filter is only available if
your system supports the popen() call (check zimg-V for avail‐
ability).
-o, --output=path
normally zimg writes to stdout. You don't ever need this option,
if you redirect stdout to you destination file or pipe. If more
than one input file is given, path should be an existing directory
where the output files should be stored. In this case the output
names are constructed from path, the input file name and a suffix
".gif", ".png", ".jpg", "ppm" or "pgm" depending on the gd version
which was used at compile time and eventually the -j, -P, --ppm or
--pgm switch. Using - for path will force stdout also for multi‐
ple input files; however, this makes sense only with ppm and pgm
output image formats because png and jpeg formats do not allow
multiple images in one file (only the first one would be read).
--big-endian
binary input data is big-endian. This option overwrites --swap and
can be overwritten by --swap and --little-endian. This switch
does nothing if the machine where zimg runs is also big-endian,
otherwise the words get swapped.
--little-endian
binary input data is little-endian. This option is the opposite of
big-endian, overwrites --swap and can be overwritten by --swap and
--big-endian. This switch does nothing if the machine where zimg
runs is also little-endian, otherwise the words get swapped.
--swap
swap bytes when reading binary input. This might be necessary when
using binary files from different platforms. If zimg runs on a
little-endian machine (e.g. Intel) --swap assumes the binary input
data created by a big-endian machine and vice versa. All three
switches --swap, --big-endian and --little-endian overwrite each
other and therefore it is recommended to use only one of these
switches.
-f, --float
read binary float (normally 4 bytes) data.
-d, --double
read binary double (normally 8 bytes) data.
--char
read signed char data.
--short
read signed short data.
--int
read signed int data.
--long-int
read signed long-int data.
-c, --unsigned-char
read unsigned char data.
-s, --unsigned-short
read unsigned short data.
-i, --unsigned-int
read unsigned int data.
--unsigned-long-int
read unsigned long int data.
--complex-float[=(abs/length|phase|real|imaginary)]
input data is binary complex float. (ascii parsing of complex num‐
bers is not implemented yet. The value of the switch determines
how to display the complex numbers. The default is abs or the
alias length (the length of the complex number).
--complex-double=(abs/length|phase|real|imaginary)
Like --complex-float, but for complex double binary input data.
--red
use a red scale color map.
--blue
use a blue scale color map.
--grey, --gray
use a grey scale color map.
-m, --colormap[=path]
use custom colormap from the file path. The file must hold r g b
triplets with values ranging from 0 to 0xff (255). There must be
exactly one triplet per line, where empty lines and lines begin‐
ning with a hash `#' mark are skipped. The maximum number of col‐
ors is defined in zimg.h and it is currently 240 (16 colors are
reserved for "LINE COLORS"). The colormap file is searched in the
current directory, then in ~/.zimg/cmap, then in
/usr/local/share/zimg/cmap. If the optional argument number is
omitted, the colormap is reset to the default.
-m, --colormap[=red[,green[,blue]]]
create a colormap using predefined colormap formulae. red, green
and blue must be integers between -36 and 36. If blue and/or
green are missing, they're set to green or red respectively (so a
gray colormap value can be created by specifying red only). The
numbers select one of the predefined formulae which are used to
map the z value to a color intensity. Negative numbers invert the
color intensity. Currently the following formulae are defined
where x ranges from [0, 1]: If the optional argument number is
omitted, the colormap is reset to the default. Note: these formu‐
lae are the same as in gnuplot (version 3.8 and later), where you
can try and test them using commands [set|show|test] palette.
0 x = 0
1 x = 0.5
2 x = 1
3 x = x (identity)
4 x = x * x
5 x = x * x * x
6 x = x * x * x * x
7 x = sqrt(x)
8 x = sqrt(sqrt(x))
9 x = sin(90 * x)
10 x = cos(90 * x)
11 x = fabs(x - 0.5);
12 x = (2 * x - 1) * (2 * x - 1);
13 x = sin(180 * x);
14 x = fabs(cos(180 * x));
15 x = sin(360 * x);
16 x = cos(360 * x);
17 x = fabs(sin(360 * x));
18 x = fabs(cos(360 * x));
19 x = fabs(sin(720 * x));
20 x = fabs(cos(720 * x));
21 x = 3 * x;
22 x = 3 * x - 1;
23 x = 3 * x - 2;
24 x = fabs(3 * x - 1);
25 x = fabs(3 * x - 2);
26 x = (1.5 * x - 0.5);
27 x = (1.5 * x - 1.0);
28 x = fabs(1.5 * x - 0.5);
29 x = fabs(1.5 * x - 1.0);
30
if (x <= 0.25)
return 0;
if (x >= 0.57)
return 1;
x = x / 0.32 - 0.78125;
31
if (x <= 0.42)
return 0;
if (x >= 0.92)
return 1;
x = 2 * x - 0.84;
32
if (x <= 0.42)
x *= 4;
else
x = (x <= 0.92) ? -2 * x + 1.84 : x / 0.08 - 11.5;
33
x = fabs(2 * x - 0.5);
34
x = 2 * x;
35
x = 2 * x - 0.5;
36
x = 2 * x - 1;
-b, --cbox, --colorbox[=n]
draw a labelled colorbox right to the image. If the number of
labels n isn't given, it is calculated automatically according to
the image and font heights. Labelling can be turned off by speci‐
fying --colorbox=0.
--cbox-fmt, --cbox-format=format
format is a c sprintf format string for floats, e.g. %3.6g (see
the sprintf(3) manual), which is used for formatting the colorbox
legend. Turns on --cbox implicitely.
--cbox-label=string
Print string next to the colorbox (e.g. a unit for the colorbox
numbers). Turns on --cbox implicitely. string can be a multiline
string, see for example the --label switch.
--dump-colormap
dump a colormap to stdout as it can be read back with the -m
switch. This can be useful for manually editing and reading back
the colormap. The --dump-colormap switch disables most of the
other switches -- no processing of data files is done. The only
exception is if the source files are png files: in this case not
the (specified) colormap of zimg, but the color entries of the
source png are dumped.
-I, --invert
invert the selected color map.
-x, --xor[=color]
do an exclusive or with the specified color (defaults to white).
For the gray scale color map this equivalent to the --invert
switch.
--differentiate
apply a discrete differentiation (1'st derivative) to the data.
This is a position dependent switch
-u, --curvature
display the curvature (2'nd derivative) of the data. This is a
position dependent switch
--smooth[=threshold]
wipe out hot spots. The average and sigma of the nearest neighbors
of each pixel are calculated. If the pixel's value is greater than
(`threshold' * sigma + average), it will be set to the average of
the neighbors. This is a position dependent switch
-z, --crange=min,max
sets data range for the color mappings to min to min. Default is
autoscaled color range according to the image data values. The
partial notations --crange=min, and --crange=,max can be used,
denoting the missing limiting value to be autoscaled.
-l, --logarithmic[=scale]
use a logarithmic color scale where scale must be strictly posi‐
tive. The data is scaled to the range 0 - scale, then the log1p ()
is taken. The default for scale is 1. The best way to understand
this is to compare the results for different scale values. This
is a position dependent switch
-a, --fabs
take the absolute value of the input data. The long option --fabs
was named after the c function fabs(), because the --absolute
switch is used for absolute scaling (see below). This is a posi‐
tion dependent switch
--absolute=min,max
set everything below min to min and every thing above max to max.
The partial notations --abs=min, and --abs=,max can be used. If
both min and max are given, a - can be used as separator instead
of the ,. This is a position dependent switch
--relative=min,max
same as above, but min and max are to be given relative (in per‐
cent) to the data's min and max. This is a position dependent
switch
-N, --no-data, --nda=[val|@percent[,color]]
set data points which are equal to val to the color color
(default: black). If val isn't specified, or if @percent is speci‐
fied instead of val, the nda value is determined automatically
from the border values: The border value which occurs most fre‐
quently will be the NDA value. The value @percent if given, must
be 0 < @percent <= 100. If @percent > 1 it is divided by 100, so
@75 is equivalent to @0.75. The @percent value gives the fraction
of nda border values compared to the number of border pixels which
must be reached at least for the automatically determined nda
value to be valid. Example: suppose your image is 100 x 200 pixels
large, so the number of border pixels is 600 - 2 = 598. If you
specify --nda=@.75 and the most frequent border value occurs 350
times, the nda feature won't be applied, since 350 is smaller than
0.75 * 598.
-e, --expr=string
filter data through the c-style string expression string. This
feature is compile-time dependent and only available, if zimg-V
shows the string dynaload. The expression string string will be
compiled on the fly by "cc -c -pipe -DHAVE_GD_FREETYPE-O2-fno-
strict-aliasing -shared". The expression is wrapped in a function
which will be called for each data value z (double) with the cur‐
rent x (unsigned int), width (unsigned int) and y (unsigned int),
height (unsigned int) values supplied. Example:
# zimg-e "cos(z) - (width - x)" ...
-R, --expr-source=file.c
Use file.c as input file name for compiling the expression. If
the switch --expr is not given, --expr-source should point to an
existing file which holds the c source for the expression func‐
tion. If the switch --expr is given, it will be wrapped in a c
function and stored in the file.c given by --expr-source. If
--expr-source is not given, the expression given by --expr will be
stored in a temporary c-file which will be deleted after the
expression evaluation.
The switch --expr-source can be used for reusing the expression
source:
# zimg-e "cos(z) - (width - x)" -R myfunc.c
# zimg-R myfunc.c ... file.dat
-O, --expr-object=file.so
Use file.so as output file name for compiling the expression. If
none of the switches --expr and --expr-source is given, file.so
should exist and be a valid object file which was probably com‐
piled before by zimg. Shared objects are searched in the current
directory, then in the directory ~/.zimg/expr, then in
/usr/local/lib/zimg/expr and then in the search path of your
dynamic loader (refer to the manual pages of dlopen() or
shl_load(), depending on the implementation). If --expr-object is
not given, the expression given by --expr or --expr-source will be
compiled to a temporary shared object file which will be deleted
after the expression evaluation.
If at least one of the switches --expr or --expr-source are given,
the expression will be compiled to file.so. This can be used for
compiling a shared object file for later use:
# zimg-e "cos(z) - (width - x)" -O myfunc.so
# zimg-O myfunc.so ... file.dat
For complicated expressions it might be useful to create the c-
source for the expression with an editor and compile it 'by hand'.
Please refer to the manual page of your c-compiler for how to cre‐
ate shared object files (for gcc it is the switch -shared). The
shared object must export a function zimg_expression with the
zimg_expression_t as given in zimg.h. Example:
#include <zimg.h>
float
zimg_expression(unsigned int x, unsigned int y,
float z, const zimg_expression_info_t* info)
{
unsigned int height = info->height;
return z - (float)x * (float)(height - y);
}
-S, --scale=xy
-S, --scale=x,y
Scaling of the image. If only one number is given, it is used for
both directions. Any non-numeric character may be used as separa‐
tor.
-C, --crop[=left-rightxtop-bottom]
crop the raw data to the specified size. Note that the numbers
given apply to the raw data, not to the eventually enlarged or
binned image. If the optional argument is omitted, the data is
cropped automatically: all data with the same value as the border
is cropped.
-A, --align=horizontal[xvertical][,bordercolor]
align to an integer multiple of the specified pixels. If vertical
is omitted, it it set to horizontal. Example: -A16 will pad the
resulting image so that its (both) dimensions are multiples of 16.
This is useful, if the images are used to create an mpeg sequence
for example (otherwise mpeg_encode will cut the images down so
that the dimensions are multiples of 16). The data is centered
within the resulting image. The optional argument bordercolor must
be given as 6-digit hexadecimal number, where the first digits are
the red value, the second two digits the green value and the last
two digits the blue value (so the color values for each color are
between 0 and ff). Note that zimg will try to choose a color out
of the existing color map which comes close to what you've speci‐
fied, but depending on the color map you might not get exactly
what you've requested. See also the --textcolor switch. If the
bordercolor is not given, the image border color is chosen to be
the most frequent color of the original data's border.
--contours=levels[,log][,bg=color|fg=color]
draw contour lines. This option is still experimental. Optional
arguments are probably subject to future changes. The optional
argument `log' distributes the contour levels logarithmically over
the image. The optional argument bg=color forces contour-only
drawing i.e. colors the background with the specified color. This
color must be given as 3 or 6 digit hex value or by the special
keyword 'black'. fg=color uses the specified color as contour
line color. bg and fg and should not be used together. The con‐
tour algorithm is pretty fast and does not spline when enlarging
the image.
--interlace
write an interlaced image. --interlace is off by default. If you
write a jpeg image using the --jpeg switch, the --interlace switch
will be interpreted to write a progressive JPEG.
-g, --gif
write a gif instead of a png image. This switch is only available
if libgd supports both png and gif.
-j, --jpeg[=quality]
write a jpeg instead of a png image. quality must be an integer
number between (inclusive) 0 and 100. If quality is omitted, an
appropriate default quality is used. Jpeg is only available, if
zimg was compiled with libgd >= 1.8. If you have set image inter‐
lacing using the --interlace switch, this switch is interpreted to
write a progressive JPEG. Some programs (e.g., Web browsers) can
display progressive JPEGs incrementally; this can be useful when
browsing over a relatively slow communications link, for example.
Progressive JPEGs can also be slightly smaller than sequential
(non-progressive) JPEGs.
-P, --ppmorpgm
write a portable pixmap (ppm) or portable graymap (pgm) instead of
a png image according to --gray palette. These image formats are
useful when piping zimg's output directly to other programs (fil‐
ters). Further, as there can be just a single png or jpeg image in
one png or jpeg file, but several ppm or pgm images in one ppm or
pgm file, it makes ppm and pgm output very useful for producing
image movies from a series of input data files, see examples
below.
--ppm
write a portable pixmap (ppm) instead of a png image.
-P, --pgm
write a portable graymap (pgm) instead of a png image; this should
be used only together with --gray option, otherwise a function of
r,g,b values of a pixel is calculated as its gray value.
-t, --label=[+-][+-]y,string
print string at the specified position of the FINAL image. 'Final'
means the image size with all padding and scaling applied. The
string can be a multiline string separated by '\n', e.g.
"this\nis\nmultiline\ntext". x and y can be negative coordinates,
in which case they're interpreted as offsets of the right and bot‐
tom text bounding box from the right and bottom border of the
image respectively. If you specify for example
--label=-1-1,string, the string is entirely visible, having the
lower right border of its bounding box in the bottom right corner
on the image. Long multiline strings should preferably be passed
by specifying this option several times (e.g. for each line sepa‐
rately) because of limitations of the option parser. See also
STRING ESCAPES.
--vlabel=[+-][+-]y,string
same as the --label option, but prints the string vertically. See
also STRING ESCAPES.
--legend=string
print string outside the image region black on white. The legend
is either placed right or botto. of the image depending on the
ratio of the resulting total image (smaller ratio wins). The
string can be a multiline string separated by '\n', e.g.
"this\nis\nmultiline\ntext". The extra space needed for the leg‐
end is reserved automatically. Long multiline strings should
preferably be passed by specifying this option several times (e.g.
for each line separately) because of limitations of the option
parser. The string can be reset to zero length (e.g. for multifile
input together with modelines) by using --legend w/o string argu‐
ment. See also STRING ESCAPES.
-F, --font=integer
font size. Must be between (inclusive) 1 and 4. If the font size
is not specified, it is chosen according to the image dimensions:
a larger image gets a larger font size. This switch selects one
of 4 built-in fonts. For pretty fonts you should rather use true‐
type fonts, see below.
-F, --font=float,fontspec
truetype font with the size given by the float parameter. The font
specification can be either a ttf file name (must end in .ttf or
.TTF) or a fontconfig specification (only available if --version
shows fontconfig). If a ttf file is specified, it must be an abso‐
lute or relative path like ./arial.ttf. If the ttf file has no
path specification (e.g. arial.ttf) it is searched in directories
given by the environment variable GDFONTPATH. Examples:
-F20,./arial.ttf
-F20,/path/to/arial.ttf
-F20,times:bold:italic # only available if fontconfig is available
-T, --textcolor=xxxxxx
The xxxxxx must be given as 6-digit or 3-digit hexadecimal number,
where the first digit(s) are the red value, the second two
digit(s) the green value and the last two digit(s) the blue value
(so the color values for each color are between 0 and ff). Note
that zimg will try to choose a color out of the existing color map
which comes close to what you've specified, but depending on the
color map you might not get exactly what you've requested. Alter‐
natively the color can be also specified by one of the predefined
color names, see the section "LINE COLORS". If the text color is
not given, it will be chosen automatically and should give nor‐
mally a high contrast.
--line=[+-]x1[+-]y1[+-]x2[+-]y2[...]
draw a line or polyline from x1, y1 to x2, y2 (and more vertices)
on the FINAL image. Example --line=+10+10+10+20 draws a horizon‐
tal line. All coordinates are absolute. Negative coordinates are
interpreted from the right and bottom border respectively.
--rline=[+-]x1[+-]y1[+-]x2[+-]y2[...]
same as --line, but all coordinates except x1 and x2 are inter‐
preted relatively to x1 and x2.
-L, --license
Display some license information. zimg is published under the
terms of a BSD type License.
-V, --version
Prints a version identifier for zimg to standard error. This is
guaranteed to always contain the string "zimg" and the version
number. Additionally the string "png" or "gif" indicates the out‐
put format which depends on the gd driver which was compiled in.
Compile time options as edf support are appended in brackets.
-v, --verbose
switch on some informational output. Might not be too useful.
--statistics
print histogram like statistics of the processed data to stderr.
--help
Prints a help message to stderr and dies.
STRING ESCAPES
The switches --label, --vlabel and --legend accept some string escapes.
The replacement of these string escape takes place after the data has
been read and processed. String escape start with a percent sign '%'
followed by a single character which indicates the type of the substi‐
tution. The following string escapes are supported:
%c Current time in RFC822-conformant format.
%f The filename of the input file
%m The minimum of the processed data.
%M The maximum of the processed data.
%i The integral of the processed data (valid data points only, see
also the --no-data switch).
%{...}
Will be substituted with the standard output of the shell command
which is given between the opening { and the closing }.
LINE COLORS
Some of the switches accept a color specification, e.g. --no-data,
--align, --contours, --textcolor and --xor. These "line colors" are
not chosen from the colormap which is used for rendering the data. Line
colors can be specified either as 6-digit or 3-digit hex value or as
one of the predefined strings "black", "white", "red", "green", "blue",
"magenta", "cyan", "yellow". In the case of a 6-digit hex value, the
first two digits represent the red value, the second two digits the
green value and the last two digits the blue value. In the case of a
3-digit hex value, the first digit represent the red value, the second
digit the green value and the last digit the blue value.
MODELINES
If the input data is ascii (or at least the header is ascii), zimg
looks for modelines like some versions of vi or vim do. This is done
only until the first data point is read. The format for modelines is as
follows:
<space>zimg:<zimg options>:
You can have multiple modelines and even use a modeline to switch to
binary input. Example:
#!/usr/local/bin/zimg
# zimg: -l10 -C50-550x200-450:
# zimg: -m7,5,15 -t -r547x633 -s --swap:
...
Note that in this case the order is important. Everything after the
line containing the -s (unsigned short binary) is considered as binary
data. So exchanging the two modelines like in the next example would
interpret the second modeline as binary data (which is probably not
what you want):
#!/usr/local/bin/zimg
# zimg: -m7,5,15 -t -r547x633 -s --swap:
# zimg: -l10 -C50-550x200-450:
...
EXAMPLESzimg my.dat > my.png
This one of the most simple examples. The file my.dat is assumed
to hold the dimensions of your 2-D data as the first two con‐
vertable integers. Everything before the first convertable inte‐
ger is silently skipped, so it is also valid to have the dimension
specifiers after a comment (hash) mark like this:
# 128 128
45.12
76.70
...
my.dat > my.png
If your operating system supports the specification of an inter‐
preter by preceding it with #! you can make your data file an exe‐
cutable like this (you probably have also to change the permis‐
sions of my.dat e.g. `chmod +x my.dat' on UNIX):
#!/usr/local/bin/zimg
# 128 128
# zimg:--red:
45.12
76.70
...
zimg my.dat.gz | xv -
pipe the output of zimg directly to your favorite image viewer
(here: xv). The file will be filtered by gunzip.
zimg--red -r1200x1200 --skip=2400 -S0.5 -s l408_01.image | xv -
read binary data which hold 1200 x 1200 unsigned short data val‐
ues. Skip the first 2400 bytes. Use the red scale color map.
Scale the image down to 600 x 600 pixels and pipe it to xv.
Note that the skip option is not really necessary as long as the
data is located at the very end of the input file. In this case
the header size would be calculated by zimg.
zimg my.png --xlabel=10,10,'love is like oxygen' --jpeg > my.jpg
read the png as source image, apply a label and write it as jpeg.
zimg-P -o- --crange=0,100 *.edf | animate -delay 50
read all edf files, and animate them with delay of 50 ms.
zimg-P -o- --scale=0.25 --gray *.edf | convert -delay 100 - movie.mng
read all edf files, scale them down and convert them into a gray
scale movie (mng is an animated png). Note that not using --crange
makes color scaling (z-range) individually autoscaled in each
image instead of using the same z-range for all images as in the
previous example.
zimg for displaying function expressions w/o input data
First you've to create the c source which holds the function
expression, for example sinc.c:
#include <zimg.h>
#include <math.h>
float
zimg_expression(unsigned int x, unsigned int y,
float z, const zimg_expression_info_t* info)
{
double width = (double)info->width;
double height = (double)info->height;
double xd = (double)x - width * 0.5;
double yd = (double)y - height * 0.5;
double value;
xd *= 10 / width;
yd *= 10 / height;
value = sqrt(xd*xd+yd*yd);
return value ? sin(value) / value : 1
}
This expression can be displayed w/o any data file by using
/dev/zero as input source. As the input data is not used at all,
you can use the -c switch -- tell zimg to treat the input as
bytes. Furthermore you've to specify the dimension of the image
with the -r switch:
# zimg-c -r300 --skip=0 -Rsinc.c -Osinc.so < /dev/zero | xv -
The object file sinc.so can now be reused in subsequent zimg runs,
e.g.
# zimg-c -r500 --skip=0 -Osinc.so < /dev/zero | xv -
Note, that you have to tell zimg explicitly not to skip the file
header, otherwise it will read from /dev/zero infinitely as it
thinks it is the data header.
ENVIRONMENT VARIABLES
HOME When this variable is found, zimg looks there for a file with the
name .zimgrc which may contain command line options. If expres‐
sion evaluation support is compiled in, object files are searched
in the directory $HOME/.zimg/expr/.
ZIMG_VIEWER
used to view stdout, if zimg detects that stdout goes to a termi‐
nal (which is probably not what you want). Defaults to "xv -".
FILES
The following zimgrc resource files are read in this order:
/usr/local/etc/zimgrc
$HOME/.zimgrc
.zimgrc
zimgrc
These files are read before command line parsing is done, so command line
options given on the command line will eventually overwrite previously defined
settings of the resource files.
The zimgrc recource files might contain command line options separated by
any white spaces including newlines. Blank lines and everything behind a hash
`#' mark is considered to be a comment.
BUGS
probably.
SEE ALSO
The official zimg web site at:
http://zimg.sourceforge.net/
AUTHOR
Johannes Zellner <johannes@zellner.org>
HISTORY
This version of zimg was originally derived from the program z2ppm
which was able to write portable pixmap (ppm) files.
CREDITS
Thomas Boutell <boutell@boutell.com>, the author of the gd driver.
Petr Mikulik <mikulik@physics.muni.cz> for the color code in get‐
color.c, see also
http://www.sci.muni.cz/~mikulik/gnuplot.html, the OS/2 port, and
options --crange, -P, --ppm, --pgm, -o-.
Levente Novak <novak@jaguar.dote.hu> for the DOS/DJGPP port.
Johannes Zellner 5.0.0 ZIMG(1)
