MIFF(4)MIFF(4)NAMEMIFF - 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 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
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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=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 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.
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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.
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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.
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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 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 ALSOdisplay(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
ImageMagick $Date: 2001/09/19 13:59:11 $ 5
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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: 2001/09/19 13:59:11 $ 6
