convert – linux man page
August 26th, 2009
| Tags: animate, composite, convert, display, identify, ImageMagick, mogrify, montage
convert - converts an input file using one image format to another
USAGE
convert [ options ... ] input_file output_file
DESCRIPTION
Convert converts an input file using one image format to an output file
with a differing image format. In addition, various types of image pro-
cessing can be performed on the converted image during the conversion
process. Convert recognizes the image formats listed in ImageMagick(1).
EXAMPLES
To make a thumbnail of a JPEG image, use:
convert -size 120x120 cockatoo.jpg -resize 120x120
+profile "*" thumbnail.jpg
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:
convert -depth 8 -size 768x512+128 gray:raw
image.pgm
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 convert a Photo CD image to a TIFF image, use:
convert -size 1536x1024 img0009.pcd image.tiff
convert img0009.pcd[4] image.tiff
To create a visual image directory of all your JPEG images, use:
convert ’vid:*.jpg’ directory.miff
To annotate an image with blue text using font 12x24 at position
(100,100), use:
convert -font helvetica -fill blue
-draw "text 100,100 Cockatoo"
bird.jpg bird.miff
To tile a 640x480 image with a JPEG texture with bumps use:
convert -size 640x480 tile:bumps.jpg tiled.png
To surround an icon with an ornamental border to use with Mosaic(1),
use:
convert -mattecolor "#697B8F" -frame 6x6 bird.jpg
icon.png
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
drawing transform matrix
-antialias
remove pixel aliasing
-append
append a set of images
-authenticate
decrypt image with this password
-average
average a set of images
-background
the background color
-blue-primary ,
blue chromaticity primary point
-blur {x}
blur the image with a Gaussian operator
-border x
surround the image with a border of color
-bordercolor
the border color
-box
set the color of the annotation bounding box
-cache
(This option has been replaced by the -limit option)
-channel
the type of channel
-charcoal
simulate a charcoal drawing
-chop x{+-}{+-}{%}
remove pixels from the interior of an image
-clip apply the clipping path, if one is present
-coalesce
merge a sequence of images
-colorize
colorize the image with the fill color
-colors
preferred number of colors in the image
-colorspace
the type of colorspace
-combine
combine one or more images into a single image
-comment
annotate an image with a comment
-compose
the type of image composition
-compress
the type of image compression
-contrast
enhance or reduce the image contrast
-convolve
convolve image with the specified convolution kernel
-crop x{+-}{+-}{%}
preferred size and location of the cropped image
-cycle
displace image colormap by amount
-debug
enable debug printout
-deconstruct
break down an image sequence into constituent parts
-define {=},...
add coder/decoder specific options
-delay <1/100ths of a second>
display the next image after pausing
-delete
delete the image from the image sequence
-density x
horizontal and vertical resolution in pixels of the image
-depth
depth of the image
-despeckle
reduce the speckles within an image
-display
specifies the X server to contact
-dispose
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-draw
annotate an image with one or more graphic primitives
-edge
detect edges within an image
-emboss
emboss an image
-encoding
specify the text encoding
-endian
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
evaluate an arithmetic, relational, or logical expression
-fill
color to use when filling a graphic primitive
-filter
use this type of filter when resizing an image
-flatten
flatten a sequence of images
-flip create a "mirror image"
-flop create a "mirror image"
-font
use this font when annotating the image with text
-frame x++
surround the image with an ornamental border
-fuzz {%}
colors within this distance are considered equal
-fx
apply a mathematical expression an image or image channels
-gamma
level of gamma correction
-Gaussian {x}
blur the image with a Gaussian operator
-geometry x{+-}{+-}{%}{@} {!}{<}{>}
preferred size and location of the Image window.
-gravity
direction primitive gravitates to when annotating the image.
-green-primary ,
green chromaticity primary point
-help print usage instructions
-implode
implode image pixels about the center
-insert
insert last image into the image sequence
-intent
use this type of rendering intent when managing the image color
-interlace
the type of interlacing scheme
-label
assign a label to an image
-lat x{+-}{%}
perform local adaptive thresholding
-level {%}{,}{%}{,}
adjust the level of image contrast
-limit
Area, Disk, File, Map, or Memory resource limit
-list
the type of list
-log
Specify format for debug log
-loop
add Netscape loop extension to your GIF animation
-map
choose a particular set of colors from this image
-mask
Specify a clipping mask
-matte store matte channel if the image has one
-mattecolor
specify the color to be used with the -frame option
-median
apply a median filter to the image
-modulate
vary the brightness, saturation, and hue of an image
-monochrome
transform the image to black and white
-morph
morphs an image sequence
-mosaic
create a mosaic from an image or an image sequence
-negate
replace every pixel with its complementary color
-noise
add or reduce noise in an image
-normalize
transform image to span the full range of color values
-opaque
change this color to the fill color within the image
-page x{+-}{+-}{%}{!}{<}{>}
size and location of an image canvas
-paint
simulate an oil painting
-pen
(This option has been replaced by the -fill option)
-ping efficiently determine image characteristics
-pointsize
pointsize of the PostScript, OPTION1, or TrueType font
-posterize
reduce the image to a limited number of color levels
-preview
image preview type
-process
process a sequence of images using a process module
-profile
add ICM, IPTC, or generic profile to image
-quality
JPEG/MIFF/PNG compression level
-radial-blur angle
radial blur the image
-raise x
lighten or darken image edges
-red-primary ,
red chromaticity primary point
-region x{+-}{+-}
apply options to a portion of the image
-render
render vector operations
-repage x{+-}{+-}{%}{!}{<}{>}
size and location of an image canvas. This option is like -page
but act as an image operator rather than a setting.
-resample x
Resample image to specified horizontal and vertical resolution
-resize x{%}{@}{!}{<}{>}
resize an image
-roll {+-}{+-}
roll an image vertically or horizontally
-rotate {<}{>}
apply Paeth image rotation to the image
-sample
scale image using pixel sampling
-sampling-factor x
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scale
scale the image.
-scene
set scene number
-segment x
segment an image
-shade x
shade the image using a distant light source
-sharpen {x}
sharpen the image
-shave x{%}
shave pixels from the image edges
-shear x
shear the image along the X or Y axis
-size x{+offset}
width and height of the image
-solarize
negate all pixels above the threshold level
-splice x{+-}{+-}{%}>
splice the background color into the image
-spread
displace image pixels by a random amount
-strip strip the image of any profiles or comments
-stroke
color to use when stroking a graphic primitive
-strokewidth
set the stroke width
-swap
swap two images in the image sequence
-swirl
swirl image pixels about the center
-texture
name of texture to tile onto the image background
-threshold {,,}{%}
threshold the image
-thumbnail x{%}{@}{!}{<}{>}
create a thumbnail of the image
-tile
tile image when filling a graphic primitive
-tint
tint the image with the fill color
-transform
transform the image
-transparent
make this color transparent within the image
-treedepth
tree depth for the color reduction algorithm
-trim trim an image
-type
the image type
-units
the units of image resolution
-unsharp {x}{+}{+}
sharpen the image with an unsharp mask operator
-use-pixmap
use the pixmap
-verbose
print detailed information about the image
-version
print ImageMagick version string
-view
FlashPix viewing parameters
-virtual-pixel
specify contents of "virtual pixels"
-wave x
alter an image along a sine wave
-white-point ,
chromaticity white point
-write
write an image sequence [convert, composite]
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 par-
ticular 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: 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.
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 con-
figuration files in $HOME/.magick if the directory exists. See
MAGICK_CODER_MODULE_PATH, MAGICK_CONFIGURE_PATH, and MAGICK_FIL-
TER_MODULE_PATH if more flexibility is needed.
MAGICK_CODER_MODULE_PATH
Search path to use when searching for image format coder mod-
ules. 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 Win-
dows). 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 operat-
ing 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 applica-
tions should write temporary files. Overridden by MAGICK_TMPDIR
if it is set.
CONFIGURATION FILES
ImageMagick uses a number of XML format configuration files:
colors.mgk
colors configuration file
delegates.mgk
delegates configuration file
log.mgk
logging configuration file
magic.mgk
file header magic test configuration file
modules.mgk
loadable modules configuration file
type.mgk
master type (fonts) configuration file
SEE ALSO
display(1), animate(1), identify(1), ImageMagick(1), montage(1),
mogrify(1), composite(1)
COPYRIGHT
Copyright (C) 1999-2004 ImageMagick Studio LLC. Additional copyrights
and licenses apply to this software, see http://www.imagemag-
ick.org/www/Copyright.html
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