combine(1)combine(1)NAMEcombine - combine images to create new images.
SYNOPSIScombine [ options ... ] image composite [ mask ] combined
DESCRIPTIONcombine combine images to create new images.
EXAMPLES
To combine a image of a cockatoo with a perch, use
combine cockatoo.miff perch.ras composite.miff
To compute the difference between images in a series, use
combine-compose difference series.1 series.2 difference.miff
To combine a image of a cockatoo with a perch starting at location
(100,150), use
combine-geometry +100+150 cockatoo.miff perch.ras composite.miff
To tile a logo across your image of a cockatoo, use
convert +shade 30x60 cockatoo.miff mask.miff
combine-compose bumpmap -tile logo.gif cockatoo.miff mask.miff composite.miff
To combine a red, green, and blue color plane into a single composite
image, try
combine-compose CopyGreen red.png green.png red-green.png
combine-compose CopyBlue red-green.png blue.png composite.png
OPTIONS-cache threshold
megabytes of memory available to the pixel cache.
Image pixels are stored in memory until 80 megabytes of memory
have been consumed. Subsequent pixel operations are cached on
disk. Operations to memory are significantly faster but if your
computer does not have a sufficient amount of free memory you
may want to adjust this threshold value.
-colors value
preferred number of colors in the image.
The actual number of colors in the image may be less than your
request, but never more. Note, this is a color reduction
option. Images with less unique colors than specified with this
option will have any duplicate or unused colors removed. Refer
to quantize(9) for more details.
Note, options -dither, -colorspace, and -treedepth affect the
color reduction algorithm.
-colorspace value
the type of colorspace: GRAY, OHTA, RGB, Transparent, XYZ,
YCbCr, YIQ, YPbPr, YUV, or CMYK.
Color reduction, by default, takes place in the RGB color space.
Empirical evidence suggests that distances in color spaces such
as YUV or YIQ correspond to perceptual color differences more
closely than do distances in RGB space. These color spaces may
give better results when color reducing an image. Refer to
quantize(9) for more details.
The Transparent color space behaves uniquely in that it pre‐
serves the matte channel of the image if it exists.
The -colors or -monochrome option is required for this option to
take effect.
-comment string
annotate an image with a comment.
By default, each image is commented with its file name. Use
this option to assign a specific comment to the image. Option‐
ally you can include the image filename, type, width, height, or
other image attributes by embedding special format characters:
%b file size
%c comment
%d directory
%e filename extention
%f filename
%h height
%i input filename
%l label
%m magick
%n number of scenes
%o output filename
%p page number
%q quantum depth
%s scene number
%t top of filename
%u unique temporary filename
%w width
%x x resolution
%y y resolution
\n newline
\r carriage return
For example,
-comment "%m:%f %wx%h"
produces an image comment of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image comment is read
from a file titled by the remaining characters in the string.
-compose operator
the type of image composition.
By default, each of the composite image pixels are replaced by
the corresponding image tile pixel. You can choose an alternate
composite operation:
Over
In
Out
Atop
Xor
Plus
Minus
Add
Subtract
Difference
Multiply
Bumpmap
Copy
CopyRed
CopyGreen
CopyBlue
CopyOpacity
How each operator behaves is described below.
over The result will be the union of the two image shapes, with com‐
posite image obscuring image in the region of overlap.
In The result is simply composite image cut by the shape of image.
None of the image data of image will be in the result.
Out The resulting image is composite image with the shape of image
cut out.
Atop The result is the same shape as image image, with composite
image obscuring image where the image shapes overlap. Note this
differs from over because the portion of composite image outside
image's shape does not appear in the result.
Xor The result is the image data from both composite image and image
that is outside the overlap region. The overlap region will be
blank.
Plus The result is just the sum of the image data. Output values are
cropped to 255 (no overflow). This operation is independent of
the matte channels.
Minus The result of composite image - image, with underflow cropped to
zero. The matte channel is ignored (set to 255, full coverage).
Add The result of composite image + image, with overflow wrapping
around (mod 256).
Subtract
The result of composite image - image, with underflow wrapping
around (mod 256). The add and subtract operators can be used to
perform reversible transformations.
Difference
The result of abs(composite image - image). This is useful for
comparing two very similar images.
Multipy
The result of composite image image. This is useful for the
creation of drop-shadows.
Bumpmap
The result image shaded by composite image.
Copy The resulting image is image replaced with composite image.
Here the matte information is ignored.
CopyRed
The resulting image is the red layer in image replaced with the
red layer in composite image. The other layers are copied
untouched.
CopyGreen
The resulting image is the green layer in image replaced with
the green layer in composite image. The other layers are copied
untouched.
CopyBlue
The resulting image is the blue layer in image replaced with the
blue layer in composite image. The other layers are copied
untouched.
CopyOpacity
The resulting image is the matte layer in image replaced with
the matte layer in composite image. The other layers are copied
untouched.
The image compositor requires a matte, or alpha channel in the
image for some operations. This extra channel usually defines a
mask which represents a sort of a cookie-cutter for the image.
This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the
boundary. For certain operations, if image does not have a
matte channel, it is initialized with 0 for any pixel matching
in color to pixel location (0,0), otherwise 255 (to work prop‐
erly borderwidth must be 0).
-compress type
the type of image compression: None, BZip, Fax, Group4, JPEG,
LZW, RunlengthEncoded, or Zip.
Specify +compress to store the binary image in an uncompressed
format. The default is the compression type of the specified
image file.
-density <width>x<height>
vertical and horizontal resolution in pixels of the image.
This option specifies an image density when decoding a Post‐
script or Portable Document page. The default is 72 pixels per
inch in the horizontal and vertical direction. This option is
used in concert with -page.
-displace <horizontal scale>x<vertical scale>
shift image pixels as defined by a displacement map.
With this option, composite image is used as a displacement map.
Black, within the displacement map, is a maximum positive dis‐
placement. White is a maximum negative displacement and middle
gray is neutral. The displacement is scaled to determine the
pixel shift. By default, the displacement applies in both the
horizontal and vertical directions. However, if you specify
mask, composite image is the horizontal X displacement and mask
the vertical Y displacement.
-display host:display[.screen]
specifies the X server to contact; see X(1).
-dispose method
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.
-dissolve value
dissolve the two images a given percent.
-dither
apply Floyd/Steinberg error diffusion to the image.
The basic strategy of dithering is to trade intensity resolution
for spatial resolution by averaging the intensities of several
neighboring pixels. Images which suffer from severe contouring
when reducing colors can be improved with this option.
The -colors or -monochrome option is required for this option to
take effect.
Use +dither to render Postscript without text or graphic alias‐
ing.
-font name
This option specifies the font to be used for displaying normal
text.
If the font is a fully qualified X server font name, the font is
obtained from an X server (e.g. -*-helvetica-medium-
r-*-*-12-*-*-*-*-*-iso8859-*). To use a TrueType font, precede
the TrueType filename with a @ (e.g. @times.ttf). Otherwise,
specify a Postscript, X11, or TrueType font (e.g. helvetica).
-geometry {+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
location of the composite image.
By default the images are combined relative to the image gravity
(see -gravity). Use <x offset> and <y offset> to specify a par‐
ticular location to combine the images.
-gravity type
direction image gravitates to within the composite: NorthWest,
North, NorthEast, West, Center, East, SouthWest, South, South‐
East. See X(1) for details about the gravity specification.
The image may not fill the composite completely (see -geometry).
The direction you choose specifies where to position the image
within the composite. For example Center gravity forces the
image to be centered within the composite. By default, the
image gravity is NorthWest.
-interlace type
the type of interlacing scheme: None, Line, Plane, or Partition.
The default is None.
This option is used to specify the type of interlacing scheme
for raw image formats such as RGB or YUV. No means do not
interlace (RGBRGBRGBRGBRGBRGB...), Line uses scanline interlac‐
ing (RRR...GGG...BBB...RRR...GGG...BBB...), and Plane uses plane
interlacing (RRRRRR...GGGGGG...BBBBBB...). Partition is like
plane except the different planes are saved to individual files
(e.g. image.R, image.G, and image.B).
Use Line, or Plane to create an interlaced GIF or progressive
JPEG image.
-label name
assign a label to an image.
Use this option to assign a specific label to the image.
Optionally you can include the image filename, type, width,
height, or other image attributes by embedding special format
characters. See -comment for details.
For example,
-label "%m:%f %wx%h"
produces an image label of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image label is read
from a file titled by the remaining characters in the string.
When converting to Postscript, use this option to specify a
header string to print above the image. Specify the label font
with -font.
-matte store matte channel if the image has one otherwise create an
opaque one.
-monochrome
transform the image to black and white.
-negate
replace every pixel with its complementary color (white becomes
black, yellow becomes blue, etc.).
The red, green, and blue intensities of an image are negated.
Use +negate to only negate the grayscale pixels of the image.
-page <width>x<height>{+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
preferred size and location of an image canvas.
Use this option to specify the dimensions of the Postscript page
in dots per inch or a TEXT page in pixels. The choices for a
Postscript page are:
11x17 792 1224
Ledger 1224 792
Legal 612 1008
Letter 612 792
LetterSmall 612 792
ArchE 2592 3456
ArchD 1728 2592
ArchC 1296 1728
ArchB 864 1296
ArchA 648 864
A0 2380 3368
A1 1684 2380
A2 1190 1684
A3 842 1190
A4 595 842
A4Small 595 842
A5 421 595
A6 297 421
A7 210 297
A8 148 210
A9 105 148
A10 74 105
B0 2836 4008
B1 2004 2836
B2 1418 2004
B3 1002 1418
B4 709 1002
B5 501 709
C0 2600 3677
C1 1837 2600
C2 1298 1837
C3 918 1298
C4 649 918
C5 459 649
C6 323 459
Flsa 612 936
Flse 612 936
HalfLetter 396 612
For convenience you can specify the page size by media (e.g.
A4, Ledger, etc.). Otherwise, -page behaves much like -geometry
(e.g. -page letter+43+43>).
To position a GIF image, use -page {+-}<x offset>{+-}<y offset>
(e.g. -page +100+200).
For a Postscript page, the image is sized as in -geometry and
positioned relative to the lower left hand corner of the page by
{+-}<x offset>{+-}<y offset>. Use -page 612x792>, for example,
to center the image within the page. If the image size exceeds
the Postscript page, it is reduced to fit the page.
The default page dimensions for a TEXT image is 612x792.
This option is used in concert with -density.
-quality value
JPEG/MIFF/PNG compression level.
For the JPEG image format, quality is 0 (worst) to 100 (best).
The default quality is 75.
Quality for the MIFF and PNG image format sets the amount of
image compression (quality / 10) and filter-type (quality % 10).
Compression quality values range from 0 (worst) to 100 (best).
If filter-type is 4 or less, the specified filter-type is used
for all scanlines:
0: none
1: sub
2: up
3: average
4: Paeth
If filter-type is 5, adaptive filtering is used when quality is
greater than 50 and the image does not have a color map, other‐
wise no filtering is used.
If filter-type is 6 or more, adaptive filtering with minimum-
sum-of-absolute-values is used.
The default is quality is 75. Which means nearly the best com‐
pression with adaptive filtering.
For further information, see the PNG specification (RFC 2083),
<http://www.w3.org/pub/WWW/TR>.
-scene value
image scene number.
-size <width>x<height>{+offset}
width and height of the image.
Use this option to specify the width and height of raw images
whose dimensions are unknown such as GRAY, RGB, or CMYK. In
addition to width and height, use -size to skip any header
information in the image or tell the number of colors in a MAP
image file, (e.g. -size 640x512+256).
-stegano offset
hide watermark within an image. <p> Use an offset to start the
image hiding some number of pixels from the beginning of the
image. Note this offset and the image size. You will need this
information to recover the steganographic image (e.g. display
-size 320x256+35 stegano:image.png).
-stereo
combine two image to create a stereo anaglyph.
The left side of the stereo pair is saved as the red channel of
the output image. The right sife is saved as the green channel.
Red-blue stereo glasses are required to properly view the stereo
image.
-tile repeat composite operation across image.
-treedepth value
Normally, this integer value is zero or one. A zero or one
tells combine to choose a optimal tree depth for the color
reduction algorithm.
An optimal depth generally allows the best representation of the
source image with the fastest computational speed and the least
amount of memory. However, the default depth is inappropriate
for some images. To assure the best representation, try values
between 2 and 8 for this parameter. Refer to quantize(9) for
more details.
The -colors option is required for this option to take effect.
-type type
set the image type: Bilevel, Grayscale, Palette, PaletteMatte,
TrueColor, TrueColorMatte, or ColorSeparation.
-verbose
print detailed information about the image.
This information is printed: image scene number; image name;
combined image name; image size; the image class (DirectClass
or PseudoClass); the total number of unique colors; and the
number of seconds to read and combine the image.
Options are processed in command line order. Any option you specify on
the command line remains in effect until it is explicitly changed by
specifying the option again with a different effect.
By default, the image format is determined by its magic number. To
specify a particular image format, precede the filename with an image
format name and a colon (i.e. ps:image) or specify the image type as
the filename suffix (i.e. image.ps). See convert(1) for a list of
valid image formats.
When you specify X as your image type, the filename has special mean‐
ing. It specifies an X window by id, name, or root. If no filename is
specified, the window is selected by clicking the mouse in the desired
window.
Specify image as - for standard input, combined as - for standard out‐
put. If image has the extension .Z or .gz, the file is uncompressed
with uncompress or gunzip respectively. If combined has the extension
.Z or .gz, the file size is compressed using with compress or gzip
respectively. Finally, precede the image file name with | to pipe to
or from a system command.
Use an optional index enclosed in brackets after a file name to specify
a desired subimage of a multi-resolution image format like Photo CD
(e.g. img0001.pcd[4]) or a range for MPEG images (e.g.
video.mpg[50-75]). A subimage specification can be disjoint (e.g.
image.tiff[2,7,4]). For raw images, specify a subimage with a geometry
(e.g. -size 640x512 image.rgb[320x256+50+50]).
The optional mask can be used to provide matte information for compos‐
ite when it has none or if you want a different mask. A mask image is
typically grayscale and the same size as composite. If the image is
not grayscale, it is converted to grayscale and the resulting intensi‐
ties are used as matte information.
If combined already exists, you will be prompted as to whether it
should be overwritten.
ENVIRONMENT
display
To get the default host, display number, and screen.
SEE ALSOdisplay(1), animate(1), import(1), montage(1), mogrify(1), convert(1),
xtp(1)COPYRIGHT
Copyright (C) 2001 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
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arising from, out of or in connection with ImageMagick or the use or
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Except as contained in this notice, the name of the ImageMagick Studio
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AUTHORS
John Cristy, E.I. du Pont De Nemours and Company Incorporated
ImageMagick 10 January 1993 combine(1)