miff
MIFF(4) MIFF(4)
NAME
MIFF - Magick Image File Format is a platform-independent format for
storing bitmap images.
SYNOPSIS
#include <image.h>
DESCRIPTION
A MIFF image file consist of two sections. The first section is a
header composed of keys describing the image in text form. The next
section is the binary image data. The header is separated from the
image data by a : character immediately followed by a newline.
The MIFF header is composed entirely of LATIN-1 characters. The
fields in the header are key and value combination in the key=value
format, with each key and value separated by an equal sign (=). Each
key=value combination is delimited by at least one control or whites-
pace character. Comments may appear in the header section and are
always delimited by braces. The MIFF header always ends with a colon
(:) character, followed by a ctrl-Z character. It is also common to
proceed the colon with a formfeed and a newline character. The form-
feed prevents the listing of binary data when using more(1) under Unix
where the ctrl-Z has the same effect with the type command on the
Win32 command line.
The following is a list of key=value combinations that may be found in
a MIFF file:
background-color=color
border-color=color matte-color=color these optional keys
reflects the image background, border, and matte colors respec-
tively. A color can be a name (e.g. white) or a hex value (e.g.
#ccc).
class=DirectClass
class=PseudoClass the type of binary image data stored in the
MIFF file. If this key is not present, DirectClass image data
is assumed.
colors=value
the number of colors in a DirectClass image. For a PseudoClass
image, this key specifies the size of the colormap. If this
key is not present in the header, and the image is PseudoClass,
a linear 256 color grayscale colormap is used with the image
data. The maximum number of colormap entries is 65535. col-
orspace=CMYK the colorspace of the pixel data. The default is
RGB.
columns=value
the width of the image in pixels. This is a required key and
has no default.
compression=BZip
compression=Fax compression=JPEG compression=LZW compres-
sion=RLE compression=Zip the type of algorithm used to compress
the image data. If this key is not present, the image data is
assumed to be uncompressed.
delay <1/100ths of a second>
the interframe delay in an image sequence. The maximum delay
is 65535.
depth=8
depth=16 the depth of a single color value representing values
from 0 to 255 (depth 8) or 65535 (depth 16). If this key is
absent, a depth of 8 is assumed.
dispose value
GIF disposal method.
Here are the valid methods:
0 No disposal specified.
1 Do not dispose between frames.
2 Overwrite frame with background color from header.
3 Overwrite with previous frame.
gamma=value
the gamma of the image. If it is not specified, a gamma of 1.0
(linear brightness response) is assumed,
id=ImageMagick
identifies the file as a MIFF-format image file. This key is
required and has no default. Although this key can appear any-
where in the header, it should start as the first key of the
header in column 1. This will allow programs like file(1) to
easily identify the file as MIFF.
iterations value
the number of times an image sequence loops before stopping.
label={value}
defines a short title or caption for the image. If any whites-
pace appears in the label, it must be enclosed within braces.
matte=True
matte=False specifies whether a DirectClass image has matte
data. Matte data is generally useful for image compositing.
This key has no meaning for pseudo-color images.
montage=<width>x<height>{+-}<x offset>{+-}<y offset>
size and location of the individual tiles of a composite image.
See X(1) for details about the geometry specification.
Use this key when the image is a composite of a number of dif-
ferent tiles. A tile consists of an image and optionally a
border and a label. <width> is the size in pixels of each
individual tile in the horizontal direction and <height> is the
size in the vertical direction. Each tile must have an equal
number of pixels in width and equal in height. However, the
width can differ from the height. <x offset> is the offset in
number of pixels from the vertical edge of the composite image
where the first tile of a row begins and <y offset> is the off-
set from the horizontal edge where the first tile of a column
begins.
If this key is specified, a directory of tile names must follow
the image header. The format of the directory is explained
below.
page=value
preferred size and location of an image canvas.
profile-icc=value
the number of bytes in the International Color Consortium color
profile. The profile is defined by the ICC profile specifica-
tion located at ftp://sgigate.sgi.com/pub/icc/icc34.ps.
colorspace=RGB
red-primary=x,y
green-primary=x,y blue-primary=x,y white-point=x,y this
optional key reflects the chromaticity primaries and white
point.
rendering-intent=saturation
rendering-intent=perceptual rendering-intent=absolute render-
ing-intent=relative Rendering intent is the CSS-1 property that
has been defined by the International Color Consortium
(http://www.color.org).
resolution=<x-resolution>x<y-resolution>
vertical and horizontal resolution of the image. See units for
the specific resolution units (e.g. pixels per inch).
rows=value
the height of the image in pixels. This is a required key and
has no default.
scene=value
the sequence number for this MIFF image file. This optional
key is used when a MIFF image file is one in a sequence of
files used in an animation.
signature=value
this optional key contains a string that uniquely identifies
the image pixel contents. NIST’s SHA-256 message digest algo-
rithm is recommended.
units=pixels-per-inch
units=pixels-per-centimeter image resolution units.
Other key value pairs are permitted. If a value contains
whitespace it must be enclosed with braces as illustrated here:
id=ImageMagick
class=PseudoClass colors=256
compression=RunlengthEncoded packets=27601
columns=1280 rows=1024
signature=d79e1c308aa5bbcdeea8ed63df412da9
copyright={Copyright (c) 2001 ImageMagick Studio}
<FF>
:
Note that key=value combinations may be separated by newlines or
spaces and may occur in any order within the header. Comments (within
braces) may appear anywhere before the colon.
If you specify the montage key in the header, follow the header with a
directory of image tiles. This directory consists of a name for each
tile of the composite image separated by a newline character. The
list is terminated with a NULL character.
If you specify the color-profile key in the header, follow the header
(or montage directory if the montage key is in the header) with the
binary color profile.
Next comes the binary image data itself. How the image data is for-
matted depends upon the class of the image as specified (or not speci-
fied) by the value of the class key in the header.
DirectClass images (class=DirectClass) are continuous-tone, images
stored as RGB (red, green, blue), RGBA (red, green, blue, alpha), or
CMYK (cyan, yellow, magenta, black) intensity values as defined by the
colorspace key. Each intensity value is one byte in length for images
of depth 8 (0..255), whereas, images of depth 16 (0..65535) require
two bytes in most significant byte first order.
PseudoClass images (class=PseudoClass) are colormapped RGB images. The
colormap is stored as a series of red, green, and blue pixel values,
each value being a byte in size. If the image depth is 16, each col-
ormap entry consumes two bytes with the most significant byte being
first. The number of colormap entries is defined by the colors key.
The colormap data occurs immediately following the header (or image
directory if the montage key is in the header). PseudoClass image data
is an array of index values into the color map. If there are 256 or
fewer colors in the image, each byte of image data contains an index
value. If the image contains more than 256 colors or the image depth
is 16, the index value is stored as two contiguous bytes with the most
significant byte being first. If matte is true, each colormap index is
followed by a 1 or 2-byte alpha value.
The image data in a MIFF file may be uncompressed, runlength encoded,
Zip compressed, or BZip compressed. The compression key in the header
defines how the image data is compressed. Uncompressed pixels are just
stored one scanline at a time in row order. Runlength encoded compres-
sion counts runs of identical adjacent pixels and stores the pixels
followed by a length byte (the number of identical pixels minus 1).
Zip and BZip compression compresses each row of an image and preceeds
the compressed row with the length of compressed pixel bytes as a word
in most significant byte first order.
MIFF files may contain more than one image. Simply concatenate each
individual image (composed of a header and image data) into one file.
SEE ALSO
display(1), animate(1), import(1), montage(1), mogrify(1), convert(1),
more(1), compress(1)
COPYRIGHT
See http://www.imagemagick.org/www/Copyright.html
AUTHORS
John Cristy, ImageMagick Studio
ImageMagick $Date: 2004/08/30 01:12:25 $ MIFF(4)
