|
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.
| 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.
|
| 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 for
more details.
|
|
Note, options -dither, -colorspace, and -treedepth
affect the color reduction algorithm.
|
|
Choices are: 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 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.
|
| annotate an image with a comment |
|
Use this option to assign a specific comment to the image. You can include the
image filename, type, width, height, or other image attribute by embedding
special format characters:
|
%b file size
%c comment
%d directory
%e filename extention
%f filename
%h height
%i input filename
%k number of unique colors
%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
-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.
|
| 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 opaque areas of
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.
- Multiply
-
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 properly borderwidth must be 0).
|
| the type of image compression |
|
Choices are: None, BZip, Fax,
Group4,
JPEG,
LZW, RLE or Zip.
|
|
Specify +compress to store the binary image in an uncompressed format.
The default is the compression type of the specified image file.
|
| 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 dots per inch in the horizontal
and vertical direction. This option is used in concert with -page.
|
|
This is the number of bits in a pixel. The only acceptable
values are 8 or 16. Use this option to specify the depth of raw images whose
depth is unknown such as GRAY, RGB, or CMYK, or to change the depth of any
image after it has been read.
|
|
-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 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.
|
| specifies the X server to contact |
|
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.
| 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.
|
| use this type of filter when resizing an image |
|
Use this option to affect the resizing operation of an image (see
-geometry).
Choose from these filters:
|
Point
Box
Triangle
Hermite
Hanning
Hamming
Blackman
Gaussian
Quadratic
Cubic
Catrom
Mitchell
Lanczos
Bessel
Sinc
|
The default filter is Lanczos
|
| use this font when annotating the image with text |
|
You can tag a font to specify whether it is a Postscript, Truetype, or OPTION1
font. For example, Arial.ttf is a Truetype font, ps:helvetica
is Postscript, and x:fixed is OPTION1.
|
|
-geometry <width>x<height>{+-}<x offset>{+-}<y offset>{%}{@}{!}{<}{>}
|
| preferred size and location of the Image window. |
|
See X(1) for details
about the geometry specification. By default, the window size is the image
size and the location is chosen by you when it is mapped.
|
|
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.
|
|
Use @ to specify the maximum area in pixels of an image.
|
|
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.
|
|
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.
|
|
There are 72 pixels per inch in PostScript coordinates.
|
| direction text gravitates to when annotating the image. |
|
Choices are: NorthWest, North,
NorthEast, West, Center, East, SouthWest, South, SouthEast. See X(1) for
details about the gravity specification.
|
|
The direction you choose specifies where to position the text when annotating
the image. For example Center gravity forces the text to be centered
within the image. By default, the image gravity is NorthWest.
|
| the type of interlacing scheme |
|
Choices are: 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. None 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 PNG or GIF or
progressive JPEG image.
|
| 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 attribute
by embedding special format character. See -comment for details.
|
-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.
|
| store matte channel if the image has one |
|
If the image does not have a matte channel, create an opaque one.
|
| transform the image to black and white |
| replace every pixel with its complementary color |
|
The red, green, and blue intensities of an image are negated.
White becomes black,
yellow becomes blue, etc.
Use +negate
to only negate the grayscale pixels of the image.
|
|
-page <width>x<height>{+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
|
| 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
{+-}<xoffset>{+-}<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.
|
| add ICM color or IPTC newswire information profile to image |
|
Use +profile icm or +profile iptc to remove the respective
profile.
|
| 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.
|
| apply Paeth image rotation to the image |
|
Use > to rotate the image only if its width exceeds the height.
< rotates the image only if its width is less than the
height. For example, if you specify -90> and the image size is
480x640, the image is not rotated by the specified angle. However, if the
image is 640x480, it is rotated by -90 degrees.
|
|
Empty triangles left over from rotating the image are filled with the color
defined as background (class backgroundColor). See X(1)
for details.
|
| image scene number or range |
|
Use this option to specify an image sequence with a single filename. See
the discussion of file below for details. |
|
-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 with an offset to skip any header information in
the image or tell the number of colors in a MAP image
file, (e.g. -size 640x512+256).
|
|
For Photo CD images, choose from these sizes: |
192x128
384x256
768x512
1536x1024
3072x2048
|
Finally, use this option to choose a particular resolution layer of a JBIG
or JPEG image (e.g. -size 1024x768).
|
| stack some images in "drop" mode |
|
This feature is untested.
|
| stack some images in "replace" mode |
|
This feature is untested.
|
| tree depth for the color reduction algorithm |
|
Normally, this integer value is zero or one. A zero or one tells display
to choose an 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 for more details.
|
|
The -colors or -monochrome option is required for this option
to take effect.
|
|
Choose from:
Bilevel, Grayscale, Palette,
PaletteMatte, TrueColor, TrueColorMatte,
ColorSeparation, ColorSeparationMatte, or Optimize.
|
| the type of image resolution |
|
Choose from: Undefined, PixelsPerInch, or
PixelsPerCentimeter.
|
| sharpen the image with an unsharp mask operator |
|
Use the given radius and standard deviation (sigma).
|
| print detailed information about the image |
|
This information is printed: image scene number; image name; image size;
the image class (DirectClass or PseudoClass); the total number
of unique colors; and the number of seconds to read and transform the image.
Refer to miff for a description of the image class.
|
|
If -colors is also specified, the total unique colors in the image
and color reduction error values are printed. Refer to quantize
for a description of these values.
|
|