combine(1) combine(1)
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 sin
gle 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.
-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,
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Transparent, XYZ, YCbCr, YIQ, YPbPr, YUV, or CMYK.
Color reduction, by default, takes place in the RGB
color space. Empirical evidence suggests that dis
tances in color spaces such as YUV or YIQ corre
spond 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 extension
%f filename
%h height
%m magick
%p page number
%s scene number
%t top of 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.
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-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. Out
put values are cropped to 255 (no overflow). This
operation is independent of the matte channels.
Minus The result of composite image - image, with under
flow cropped to zero. The matte channel is ignored
(set to 255, full coverage).
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Add The result of composite image + image, with over
flow wrapping around (mod 256).
Subtract
The result of composite image - image, with under
flow wrapping around (mod 256). The add and sub
tract 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 compos
ite 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 repre
sents 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,
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Group4, JPEG, LZW, RunlengthEncoded, or Zip.
Specify +compress to store the binary image in an
uncompressed format. The default is the compres
sion 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 decod
ing 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 <horizontal scale>x<vertical scale>
shift image pixels as defined by a displacement
map.
With this option, composite image is used as a dis
placement 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 direc
tions. 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 inten
sity 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
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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 dis
playing 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 file
name with a @ (e.g. @times.ttf). Otherwise, spec
ify a Postscript font (e.g. helvetica).
-geometry <width>x<height>{+-}<x offset>{+-}<y off
set>{%}{!}{<}{>}
the width and height of the image.
By default, the width and height are maximum val
ues. That is, the image is expanded or contracted
to fit the width and height value while maintaining
the aspect ratio of the image. Append an exclama
tion point to the geometry to force the image size
to exactly the size you specify. For example, if
you specify 640x480! the image width is set to 640
pixels and height to 480. If only one factor is
specified, both the width and height assume the
value.
To specify a percentage width or height instead,
append %. The image size is multiplied by the
width and height percentages to obtain the final
image dimensions. To increase the size of an
image, use a value greater than 100 (e.g. 125%).
To decrease an image's size, use a percentage less
than 100.
Use > to change the dimensions of the image only if
its size exceeds the geometry specification. >
resizes the image only if its dimensions is less
than the geometry specification. For example, if
you specify 640x480> and the image size is 512x512,
the image size does not change. However, if the
image is 1024x1024, it is resized to 640x480.
By default the images are combined relative to the
image gravity (see -gravity). Use <x offset> and
<y offset> to specify a particular location to com
bine the images.
-gravity type
direction image gravitates to within the composite:
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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 speci
fies where to position the image within the compos
ite. 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 inter
lacing scheme for raw image formats such as RGB or
YUV. No means do not interlace (RGBRGBRGBRGBRG
BRGB...), 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 file
name, 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.
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-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 off
set>{%}{!}{<}{>}
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
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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 let
ter+43+43>).
To position a GIF image, use -page {+-}<x off
set>{+-}<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 cen
ter 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 fil
ter-type (quality % 10). Compression quality val
ues 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.
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The default is quality is 75. Which means nearly
the best compression 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 repre
sentation of the source image with the fastest com
putational 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.
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-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 respec
tively. If combined has the extension .Z or .gz, the file
size is compressed using with compress or gzip respec
tively. 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
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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
1998 1998 E. I. du Pont de Nemours and Company
Permission is hereby granted, free of charge, to any per
son obtaining a copy of this software and associated docu
mentation 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 per
mit 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 E. I. du
Pont de Nemours and Company be liable for any claim, dam
ages 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 ImageMag
ick.
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AUTHORS
John Cristy, E.I. du Pont De Nemours and Company Incorpo
rated
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