Convert converts an input file using one image format to an output
file with a differing image format. In addition, various types of image
processing can be performed on the converted image during the conversion
process. Convert recognizes the image formats listed in
ImageMagick(1).
In this example, '-size 120x120' gives a hint to the JPEG decoder
that the image is going to be downscaled to 120x120, allowing it to run
faster by avoiding returning full-resolution images to ImageMagick for
the subsequent resizing operation. The
output image. It will be scaled so its largest dimension is 120 pixels. The
that might be present in the input and aren't needed in the thumbnail.
To convert a MIFF image of a cockatoo to a SUN raster image, use:
convert cockatoo.miff sun:cockatoo.ras
To convert a multi-page PostScript document to individual FAX pages,
use:
convert -monochrome document.ps fax:page
To convert a TIFF image to a PostScript A4 page with the image in
the lower left-hand corner, use:
convert -page A4+0+0 image.tiff document.ps
To convert a raw Gray image with a 128 byte header to a portable graymap,
use:
In this example, "raw" is the input file. Its format is "gray" and it
has the dimensions and number of header bytes specified by the -size
option and the sample depth specified by the
-depth option. The output file is "image.pgm". The suffix ".pgm"
specifies its format.
To create a MNG animation from a DNA molecule sequence, use:
convert -delay 20 dna.* dna.mng
OPTIONS
Options are processed in command line order. Any option you specify on
the command line remains in effect for the set of images that follows,
until the set is terminated by the appearance of any option or -noop.
Some options only affect the decoding of images and others only the encoding.
The latter can appear after the final group of input images.
For a more detailed description of each option, see
Options, above.
ImageMagick(1).
-adjoin
join images into a single multi-image file
-affine <matrix>
drawing transform matrix
-antialias
remove pixel aliasing
-append
append a set of images
-authenticate <string>
decrypt image with this password
-average
average a set of images
-background <color>
the background color
-blue-primary <x>,<y>
blue chromaticity primary point
-blur <radius>{x<sigma>}
blur the image with a Gaussian operator
-border <width>x<height>
surround the image with a border of color
-bordercolor <color>
the border color
-box <color>
set the color of the annotation bounding box
-cache <threshold>
(This option has been replaced by the -limit option)
-channel <type>
the type of channel
-charcoal <factor>
simulate a charcoal drawing
-chop <width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image
-clip
apply the clipping path, if one is present
-coalesce
merge a sequence of images
-colorize <value>
colorize the image with the fill color
-colors <value>
preferred number of colors in the image
-colorspace <value>
the type of colorspace
-combine
combine one or more images into a single image
-comment <string>
annotate an image with a comment
-compose <operator>
the type of image composition
-compress <type>
the type of image compression
-contrast
enhance or reduce the image contrast
-convolve <kernel>
convolve image with the specified convolution kernel
-crop <width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-cycle <amount>
displace image colormap by amount
-debug <events>
enable debug printout
-deconstruct
break down an image sequence into constituent parts
-define <key>{=<value>},...
add coder/decoder specific options
-delay <1/100ths of a second>
display the next image after pausing
-delete <index>
delete the image from the image sequence
-density <width>x<height>
horizontal and vertical resolution in pixels of the image
-depth <value>
depth of the image
-despeckle
reduce the speckles within an image
-display <host:display[.screen]>
specifies the X server to contact
-dispose <method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-draw <string>
annotate an image with one or more graphic primitives
-edge <radius>
detect edges within an image
-emboss <radius>
emboss an image
-encoding <type>
specify the text encoding
-endian <type>
specify endianness (MSB or LSB) of the image
-enhance
apply a digital filter to enhance a noisy image
-equalize
perform histogram equalization to the image
-evaluate <operator> <constant>
evaluate an arithmetic, relational, or logical expression
For a more detailed description of each option, see
Options, above.
ImageMagick(1).
SEGMENTATION
Use -segment to segment an image by analyzing the histograms of
the color components and identifying units that are homogeneous with the
fuzzy c-means technique. The scale-space filter analyzes the histograms
of the three color components of the image and identifies a set of classes.
The extents of each class is used to coarsely segment the image with thresholding.
The color associated with each class is determined by the mean color of
all pixels within the extents of a particular class. Finally, any unclassified
pixels are assigned to the closest class with the fuzzy c-means technique.
The fuzzy c-Means algorithm can be summarized as follows:
Build a histogram, one for each color component of the image.
For each histogram, successively apply the scale-space filter and build
an interval tree of zero crossings in the second derivative at each scale.
Analyze this scale-space "fingerprint" to determine which peaks or valleys
in the histogram are most predominant.
The fingerprint defines intervals on the axis of the histogram. Each interval
contains either a minima or a maxima in the original signal. If each color
component lies within the maxima interval, that pixel is considered "classified"
and is assigned an unique class number.
Any pixel that fails to be classified in the above thresholding pass is
classified using the fuzzy c-Means technique. It is assigned to one of
the classes discovered in the histogram analysis phase.
The fuzzy c-Means technique attempts to cluster a pixel by finding the
local minima of the generalized within group sum of squared error objective
function. A pixel is assigned to the closest class of which the fuzzy membership
has a maximum value.
For additional information see:
<bq>Young Won Lim, Sang Uk Lee, ``On The Color Image Segmentation
Algorithm Based on the Thresholding and the Fuzzy c-Means Techniques'',
Pattern Recognition, Volume 23, Number 9, pages 935-952, 1990.</bq>
ENVIRONMENT
COLUMNS
Output screen width. Used when formatting text for the screen. Many
Unix systems keep this shell variable up to date, but it may need to be
explicitly exported in order for ImageMagick to see it.
DISPLAY
X11 display ID (host, display number, and screen in the form
hostname:display.screen).
HOME
Location of user's home directory. ImageMagick searches for
configuration files in $HOME/.magick if the directory exists. See
MAGICK_CODER_MODULE_PATH, MAGICK_CONFIGURE_PATH, and
MAGICK_FILTER_MODULE_PATH if more flexibility is needed.
MAGICK_CODER_MODULE_PATH
Search path to use when searching for image format coder modules.
This path allows the user to arbitrarily extend the image formats
supported by ImageMagick by adding loadable modules to an arbitrary
location rather than copying them into the ImageMagick installation
directory. The formatting of the search path is similar to operating
system search paths (i.e. colon delimited for Unix, and semi-colon
delimited for Microsoft Windows). This user specified search path is used
before trying the default search path.
MAGICK_CONFIGURE_PATH
Search path to use when searching for configuration (.mgk) files.
The formatting of the search path is similar to operating system search
paths (i.e. colon delimited for Unix, and semi-colon delimited for
Microsoft Windows). This user specified search path is used before trying
the default search path.
MAGICK_DEBUG
Debug options (see -debug for details)
MAGICK_FILTER_MODULE_PATH
Search path to use when searching for filter process modules
(invoked via -process). This path allows the user to arbitrarily
extend ImageMagick's image processing functionality by adding loadable
modules to an arbitrary location rather than copying them into the
ImageMagick installation directory. The formatting of the search path
is similar to operating system search paths (i.e. colon delimited for
Unix, and semi-colon delimited for Microsoft Windows). This user
specified search path is used before trying the default search path.
MAGICK_FONT_PATH
Directory where ImageMagick should look for TrueType and
Postscript Type1 font files if the font file is not found in the current
directory. It is preferred to define the available fonts via type.mgk
rather than use MAGICK_FONT_PATH.
MAGICK_HOME
Path to top of ImageMagick installation directory. Only observed
by "uninstalled" builds of ImageMagick which do not have their location
hard-coded or set by an installer.
MAGICK_DISK_LIMIT
Maximum amount of disk space allowed for use by the pixel cache.
MAGICK_FILES_LIMIT
Maximum number of open files.
MAGICK_MAP_LIMIT
Maximum size of a memory map.
MAGICK_MEMORY_LIMIT
Maximum amount of memory to allocate from the heap.
MAGICK_TMPDIR
Path to directory where ImageMagick should write temporary
files. The default is to use the system default, or the location set by
TMPDIR.
TMPDIR
For POSIX-compatible systems (Unix-compatible), the path to the
directory where all applications should write temporary files.
Overridden by MAGICK_TMPDIR if it is set.
TMP or TEMP
For Microsoft Windows, the path to the directory where applications
should write temporary files. Overridden by MAGICK_TMPDIR if it
is set.
CONFIGURATION FILES
ImageMagick uses a number of XML format configuration files: