miff
MIFF(4) MIFF(4)
NAME
MIFF - Magick Image File Format is a platform-independent format for
storing bitmap images. MIFF is a part of the ImageMagick toolkit of
image manipulation utilities for the X Window System. ImageMagick is
capable of converting many different image file formats to and from
MIFF (e.g. JPEG, XPM, TIFF, etc.).
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 whitespace charac-
ter. Comments may appear in the header section and are always delim-
ited by braces. The MIFF header always ends with a colon (:) charac-
ter, followed by a ctrl-Z character. It is also common to proceed the
colon with a formfeed and a newline character. The formfeed 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=RunlengthEncoded 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 bor-
der and a label. <width> is the size in pixels of each individ-
ual 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 offset 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 rendering-
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 algorithm
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 format-
ted depends upon the class of the image as specified (or not specified)
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
Copyright (C) 2000 ImageMagick Studio, a non-profit organization dedi-
cated to making software imaging solutions freely available.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files ("ImageMag-
ick"), to deal in ImageMagick without restriction, including without
limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of ImageMagick, and to permit persons to
whom the ImageMagick is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of ImageMagick.
The software is provided "as is", without warranty of any kind, express
or implied, including but not limited to the warranties of mer-
chantability, fitness for a particular purpose and noninfringement. In
no event shall ImageMagick Studio be liable for any claim, damages or
other liability, whether in an action of contract, tort or otherwise,
arising from, out of or in connection with ImageMagick or the use or
other dealings in ImageMagick.
Except as contained in this notice, the name of the ImageMagick Studio
shall not be used in advertising or otherwise to promote the sale, use
or other dealings in ImageMagick without prior written authorization
from the ImageMagick Studio.
AUTHORS
John Cristy, ImageMagick Studio
ImageMagick $Date: 2001/09/19 13:59:11 $ MIFF(4)
