NAME
combine - combine images to create new images.
SYNOPSIS
combine [ options ... ] image composite [ mask ] combined
DESCRIPTION
combine 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 ReplaceGreen red.png green.png red-green.png
combine -compose ReplaceBlue red-green.png blue.png composite.png
OPTIONS
-blend value
blend the two images a given percent.
-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
preserves 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. Optionally you can include the image filename,
type, width, height, or other image attributes by
embedding special format characters:
%b file size
%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
Bumpmap
Replace
ReplaceRed
ReplaceGreen
ReplaceBlue
ReplaceMatte
How each operator behaves is described below.
over The result will be the union of the two image shapes,
with composite 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.
Bumpmap
The result image shaded by composite image.
Replace
The resulting image is image replaced with composite
image. Here the matte information is ignored.
ReplaceRed
The resulting image is the red layer in image replaced
with the red layer in composite image. The other
layers are copied untouched.
ReplaceGreen
The resulting image is the green layer in image
replaced with the green layer in composite image. The
other layers are copied untouched.
ReplaceBlue
The resulting image is the blue layer in image replaced
with the blue layer in composite image. The other
layers are copied untouched.
ReplaceMatte
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 properly 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 x
vertical and horizontal resolution in pixels of the
image.
This option specifies an image density when decoding a
Postscript 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 x
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 displacement. 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.
-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 aliasing.
-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
font (e.g. helvetica).
-geometry {+-}{+-}{%}{!}{<}{>}
location of the composite image.
By default the images are combined relative to the
image gravity (see -gravity). Use and to specify a particular location to combine the
images.
-gravity type
direction image gravitates to within the composite:
NorthWest, North, NorthEast, West, Center, East,
SouthWest, South, SouthEast. 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 interlacing
(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 x{+-}{+-
}{%}{!}{<}{>}
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 {+-}{+-} (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 {+-}{+-}. 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, otherwise 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 compression with adaptive filtering.
For further information, see the PNG specification (RFC
2083), .
-scene value
image scene number.
-size x{+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.
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.
-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 meaning. 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 output. 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 composite 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 intensities 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 ALSO
display(1), animate(1), import(1), montage(1), mogrify(1),
convert(1), xtp(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
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AUTHORS
John Cristy, E.I. du Pont De Nemours and Company
Incorporated