NAME
combine - combine images to create new images.
SYNOPSIS
combine [ options ... ] input_file1 input_file2 output_file
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
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 remain unchanged.
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, XYZ, YCbCr,
YIQ, YPbPr, or YUV.
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 -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 scene number by embedding
special format characters. Embed %f for filename, %m
for magick, %w for width, %h for height, %s for scene
number, or \n for newline. 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 cooresponding image tile pixel. You can
choose an alternate composite operation:
over
in
out
atop
xor
plus
minus
add
subtract
difference
replace
How each operator behaves is described below. P is the
image read as input_file1 and Q is image input_file2.
over The result will be the union of the two image
shapes, with P obscuring Q in the region of
overlap.
in The result is simply P cut by the shape of Q. None
of the image data of Q will be in the result.
out The resulting image is P with the shape of Q cut
out.
atop The result is the same shape as image Q, with P
obscuring Q where the image shapes overlap. Note
this differs from over because the portion of P
outside Q's shape does not appear in the result.
xor The result is the image data from both P and Q 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 P - Q, with underflow cropped to
zero. The matte channel is ignored (set to 255,
full coverage).
add The result of P + Q, with overflow wrapping around
(mod 256).
subtract The result of P - Q, with underflow wrapping around
(mod 256). The add and subtract operators can be
used to perform reversible transformations.
difference
The result of abs(P - Q). This is useful for
comparing two very similar images.
replace The resulting image is Q replaced with P. Here the
matte information is ignored.
image
The image compositor requires an matte, or alpha channel in the
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. If
image does not have an 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: QEncoded or
RunlengthEncoded.
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 for a Postscript
page. The default is 72 pixels per inch in the
horizontal and vertical direction. The density is
given to Ghostscript as the -r option when decoding a
Postscript image. See gs(1) for details.
-display host:display[.screen]
specifies the X server to contact; see X(1).
-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 option is required for dithering to take
effect.
-font name
This option specifies the font to be used for
displaying normal text. The default is fixed.
-geometry <width>{%}x<height>{%}{+-}<x offset>{+-
}<y offset>{!}
the width and height of the image.
By default, the width and height are maximum values.
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 exclamation 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.
By default the images are combined relative to the top
left corner, location (0,0). Use <x offset> and <y
offset> to specify a particular location to combine the
images.
-interlace type
the type of interlacing scheme: NONE, LINE, or PLANE.
This option is used to specify the type of interlacing
scheme for raw image formats such as RGB or YUV. NONE
means do not interlace (RGBRGBRGBRGBRGBRGB...), LINE
uses scanline interlacing
(RRR...GGG...BBB...RRR...GGG...BBB...), and PLANE uses
plane interlacing (RRRRRR...GGGGGG...BBBBBB...).
Use LINE, or PLANE to create an interlaced GIF 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 scene number in the label by
embedding special format characters. Embed %f for
filename, %m for magick, %w for width, %h for height,
or %s for scene number. 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.
-matte
store matte channel if the image has one.
-monochrome
transform the image to black and white.
-page <width>x<height>{+-}<x offset>{+-}<y offset>
preferred size and location of the Postscript page.
Use this option to specify the dimensions of the
Postscript page in pixels per inch or a TEXT page in
pixels. The default for a Postscript page is to center
the image on a letter page 612 by 792 pixels. The
margins are 1/2" (i.e. 612x792+36+36). Other common
sizes are:
Letter 612x 792
Tabloid 792x1224
Ledger 1224x 792
Legal 612x1008
Statement 396x 612
Executive 540x 720
A3 842x1190
A4 595x 842
A5 420x 595
B4 729x1032
B5 516x 729
Folio 612x 936
Quarto 610x 780
10x14 720x1008
For convenience you can specify the page size by media
(e.g. A4, Ledger, etc.).
The page geometry is relative to the vertical and
horizontal density of the Postscript page. See
-density for details.
The default page dimensions for a TEXT image is
612x792.
-quality value
JPEG quality setting.
Quality is 0 (worst) to 100 (best). The default is 85.
-scene value
image scene number.
-size <width>{%}x<height>{%}{+colors}{!}
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
tell the number of colors in a MAP image file, (e.g.
-size 640x512+256).
-stereo
combine two images into a red-green stereo image.
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.
-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.
Change '-' to '+' in any option above to reverse its effect.
For example, specify +matte to store the image without its
matte channel.
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 input_file as - for standard input, output_file as -
for standard output. If input_file has the extension .Z or
.gz, the file is uncompressed with uncompress or gunzip
respectively. If output_file 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]).
If output_file 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), segment(1), xtp(1)
COPYRIGHT
Copyright 1995 E. I. du Pont de Nemours and Company
Permission to use, copy, modify, distribute, and sell this
software and its documentation for any purpose is hereby
granted without fee, provided that the above copyright
notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting
documentation, and that the name of E. I. du Pont de Nemours
and Company not be used in advertising or publicity
pertaining to distribution of the software without specific,
written prior permission. E. I. du Pont de Nemours and
Company makes no representations about the suitability of
this software for any purpose. It is provided "as is"
without express or implied warranty.
E. I. du Pont de Nemours and Company disclaims all
warranties with regard to this software, including all
implied warranties of merchantability and fitness, in no
event shall E. I. du Pont de Nemours and Company be liable
for any special, indirect or consequential damages or any
damages whatsoever resulting from loss of use, data or
profits, whether in an action of contract, negligence or
other tortuous action, arising out of or in connection with
the use or performance of this software.
AUTHORS
John Cristy, E.I. du Pont De Nemours and Company
Incorporated