MIFF(4) Device and Network Interfaces MIFF(4)

NAME

MIFF - Magick Image File Format

SYNOPSIS

#include <image.h>

DESCRIPTION

The Magick Image File Format (MIFF) 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.).

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 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 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
respectively. 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. colorspace=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
compression=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
anywhere 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
whitespace 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
different 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 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
specification 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
formatted 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 colormap 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
compression 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 precedes 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
dedicated 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
("ImageMagick"), 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
merchantability, 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 $Date$ MIFF(4)