convert(1)convert(1)NAMEconvert - converts an input file using one image format to an output
file with the same or differing image format.
SYNOPSISconvert [ options ... ] file [ file... ] file
DESCRIPTIONconvert converts an input file using one image format to an output file
with the same or differing image format.
convert recognizes the following image formats:
Tag Description
-------------------------------------------------------------------------------
AVS AVS X image file.
BIE+ Joint Bi-level Image experts Group file interchange format.
BMP+ Microsoft Windows bitmap image file.
BMP24+ Microsoft Windows 24-bit bitmap image file.
CGM Computer Graphics Metafile.
CMYK Raw cyan, magenta, yellow, and black bytes.
DCX+ ZSoft IBM PC multi-page Paintbrush file.
DIB Microsoft Windows bitmap image file.
DICOM Medical image file.
EPDF Encapsulated Portable Document Format.
EPI Adobe Encapsulated PostScript Interchange format.
EPS Adobe Encapsulated PostScript file.
EPS2 Adobe Level II Encapsulated PostScript file.
EPSF Adobe Encapsulated PostScript file.
EPSI Adobe Encapsulated PostScript Interchange format.
EPT Adobe Encapsulated PostScript Interchange format with TIFF pre‐
view.
FAX+ Group 3.
FIG TransFig image format.
FITS Flexible Image Transport System.
FPX FlashPix Format.
GIF+ CompuServe graphics interchange format; 8-bit color.
GIF87+ CompuServe graphics interchange format; 8-bit color (version
87a).
GRAY Raw gray bytes.
GRADIENT
gradual passing from one shade to another. Specify the desired
shading as the filename (e.g. gradient:red-blue).
GRANITE
granite texture.
HDF+ Hierarchical Data Format.
HISTOGRAM
HPGL HP-GL plotter language.
HTML Hypertext Markup Language with a client-side image map.
JBIG+ Joint Bi-level Image experts Group file interchange format.
JPEG Joint Photographic Experts Group JFIF format; compressed 24-bit
color.
ICO Microsoft icon.
LABEL text image.
MAP Red, green, and blue colormap bytes followed by the image col‐
ormap indexes.
MIFF+ Magick image file format. MNG Multiple-image Network Graphics.
MONO Bi-level bitmap in least-significant-byte (LSB) first order.
MPEG+ Motion Picture Experts Group file interchange format.
MTV+ MTV Raytracing image format.
NETSCAPE
Netscape 216 color cube.
NULL NULL image.
PBM+ Portable bitmap format (black and white).
PCD Photo CD. The maximum resolution written is 512x768 pixels.
PCL Page Control Language.
PCX ZSoft IBM PC Paintbrush file.
PDF+ Portable Document Format.
PGM+ Portable graymap format (gray scale).
PICT Apple Macintosh QuickDraw/PICT file.
PIX Alias/Wavefront RLE image format.
PLASMA plasma fractal image. Specify the base color as the filename
(e.g. plasma:gray). Use fractal to initialize to a random
value (e.g. plasma:fractal).
PNG Portable Network Graphics.
PNM+ Portable anymap.
PPM+ Portable pixmap format (color).
PS+ Adobe PostScript file.
PSD Adobe Photoshop bitmap file.
PS2+ Adobe Level II PostScript file.
P7 Xv's visual schnauzer format.
RAD Radiance image format.
RGB Raw red, green, and blue bytes.
RGBA Raw red, green, blue and matte bytes.
RLA Alias/Wavefront image file; read only
RLE Utah Run length encoded image file; read only.
SGI+ Irix RGB image file.
SHTML Hypertext Markup Language with a client-side image map.
SUN+ SUN Rasterfile.
TEXT raw text file; read only.
TGA+ Truevision Targa image file.
TIFF+ Tagged Image File Format.
TIFF24+
24-bit Tagged Image File Format.
TILE tile image with a texture.
TIM PSX TIM file.
TTF TrueType font file.
UIL X-Motif UIL table.
UYVY Interleaved YUV.
VICAR read only.
VID Visual Image Directory.
VIFF+ Khoros Visualization image file.
WIN select image from or display image to your computer screen.
X select image from or display image to your X server screen.
XC constant image of X server color. Specify the desired color as
the filename (e.g. xc:yellow).
XBM X11 bitmap file.
XPM X Windows system pixmap file (color).
XWD X Windows system window dump file (color).
YUV+ CCIR 601 4:1:1 file.
Note, a format delineated with + means that if more than one
image is specified, it is combined into a single multi-image
file. Use +adjoin if you want a single image produced for each
frame.
Raw images are expected to have one byte per pixel unless
ImageMagick is compiled in 16-bit mode. Here, the raw data is
expected to be stored two bytes per pixel in most-significant-
byte-first order.
EXAMPLES
To convert a MIFF image of a cockatoo to a SUN raster image, use:
convert cockatoo.miff sun:cockatoo.ras
To convert a multi-page Postscript document to individual FAX pages,
use:
convert-monochrome document.ps fax:page
To convert a TIFF image to a Postscript A4 page with the image in the
lower left-hand corner, use:
convert-page A4+0+0 image.tiff document.ps
To convert a raw GRAY image with a 128 byte header to a portable
graymap, use:
convert-size 768x5.2.228 gray:raw image.pgm
To convert a Photo CD image to a TIFF image, use:
convert-size 1536x1024 img0009.pcd image.tiff
convert img0009.pcd[4] image.tiff
To create a visual image directory of all your JPEG images, use:
convert 'vid:*.jpg' directory.miff
To annotate an image with blue text using font 12x24 at position
(100,100), use:
convert-font helvetica -fill blue -draw "text 100,100 Cockatoo" bird.jpg bird.miff
To tile a 640x480 image with a JPEG texture with bumps use:
convert-size 640x480 tile:bumps.jpg tiled.png
To surround an icon with an ornamental border to use with Mosaic(1),
use:
convert-mattecolor #ccc -frame 6x6 bird.jpg icon.png
To create a GIF animation image from a DNA molecule sequence, use:
convert-delay 20 dna.* dna.gif
OPTIONS-adjoin
join images into a single multi-image file.
By default, all images of an image sequence are stored in the
same file. However, some formats (e.g. JPEG) do not support
more than one image and are saved to separate files. Use
+adjoin to force this behavior.
-antialias
remove pixel aliasing.
-append
append an image sequence.
All the input images must have the same width or height. Images
of the same width are stacked top-to-bottom. Images of the same
height are stacked left-to-right. Use +append to stack rectan‐
gular images left-to-right.
-average
averages an image sequence.
-blur <radius>x<sigma>
blur the image with a Gaussian operator of the given radius and
standard deviation (sigma).
-border <width>x<height>
surround the image with a border of color. See X(1) for details
about the geometry specification.
-bordercolor color
the border color.
-box color
set the color of the annotation bounding box. See -draw or for
further details.
See X(1) for details about the color specification.
-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.
-charcoal radius
simulate a charcoal drawing.
-coalesce
merge a sequence of images.
-colorize value
colorize the image with the fill color.
Specify the amount of colorization as a percentage. You can
apply separate colorization values to the red, green, and blue
channels of the image with a colorization value list delineated
with slashes (e.g. 0/0/50).
-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.
Use this option to assign a specific comment to the image. 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.
-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.
-contrast
enhance or reduce the image contrast.
This option enhances the intensity differences between the
lighter and darker elements of the image. Use -contrast to
enhance the image or +contrast to reduce the image contrast.
-crop <width>x<height>{+-}<x offset>{+-}<y offset>{%}
preferred size and location of the cropped image. See X(1) for
details about the geometry specification.
To specify a percentage width or height instead, append %. For
example to crop the image by ten percent on all sides of the
image, use -crop 10%.
Omit the x and y offset to generate one or more subimages of a
uniform size.
Use cropping to crop a particular area of an image. Use -crop
0x0 to trim edges that are the background color. Add an x and y
offset to leave a portion of the trimmed edges with the image.
-cycle amount
displace image colormap by amount.
Amount defines the number of positions each colormap entry is
shifted.
-deconstruct
break down an image sequence into constituent parts.
-delay <1/100ths of a second>
display the next image after pausing.
This option is useful for regulating the animation of a sequence
of GIF images within Netscape. 1/100ths of a second must expire
before the redisplay of the image sequence. The default is no
delay between each showing of the image sequence.
You can specify a delay range (e.g. -delay 10-500) which sets
the minimum and maximum delay.
-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.
-depth value
depth of the image. This is the number of bits in a pixel. The
only acceptable values are 8 or 16.
-despeckle
reduce the speckles within an image.
-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 alias‐
ing.
-draw string
annotate an image with one or more graphic primitives.
Use this option to annotate an image with one or more graphic
primitives. The primitives include
point
line
rectangle
roundRectangle
arc
ellipse
circle
polyline
polygon
bezier
path
color
matte
text
image
Point, line, color, matte, text, and image each require a single
coordinate. Line requires a start and end coordinate, while
rectangle expects an upper left and lower right coordinate.
Circle has a center coordinate and a coordinate on the outer
edge. Use Arc to circumscribe an arc within a rectangle. Arcs
require a start and end point as well as the degree of rotation
(e.g. 130,30 200,100 45,90). Use Ellipse to draw a partial
ellipse centered at the given point with the x-axis and y-axis
radius and start and end of arc in degrees (e.g. 100,100 100,150
0,360). Finally, polyline and polygon require three or more
coordinates to define its boundaries. Coordinates are integers
separated by an optional comma. For example, to define a circle
centered at 100,100 that extends to 150,150 use:
-draw 'circle 100,100 150,150'
Paths represent an outline of an object which is defined in
terms of moveto (set a new current point), lineto (draw a
straight line), curveto (draw a curve using a cubic bezier), arc
(elliptical or circular arc) and closepath (close the current
shape by drawing a line to the last moveto) elements. Compound
paths (i.e., a path with subpaths, each consisting of a single
moveto followed by one or more line or curve operations) are
possible to allow effects such as "donut holes" in objects.
Use color to change the color of a pixel. Follow the pixel
coordinate with a method:
point
replace
floodfill
filltoborder
reset
Consider the target pixel as that specified by your coordinate.
The point method recolors the target pixel. The replace method
recolors any pixel that matches the color of the target pixel.
Floodfill recolors any pixel that matches the color of the tar‐
get pixel and is a neighbor, whereas filltoborder recolors any
neighbor pixel that is not the border color. Finally, reset
recolors all pixels.
Use matte to the change the pixel matte value to transparent.
Follow the pixel coordinate with a method (see the color primi‐
tive for a description of methods). The point method changes
the matte value of the target pixel. The replace method changes
the matte value of any pixel that matches the color of the tar‐
get pixel. Floodfill changes the matte value of any pixel that
matches the color of the target pixel and is a neighbor, whereas
filltoborder changes the matte value of any neighbor pixel that
is not the border color (-bordercolor). Finally reset changes
the matte value of all pixels.
Use text to annotate an image with text. Follow the text coor‐
dinates with a string. If the string has embedded spaces,
enclose it in double quotes. Optionally you can include the
image filename, type, width, height, or other image attribute by
embedding special format characters. See -comment for details.
For example,
-draw 'text 100,100 "%m:%f %wx%h"'
annotates the image with MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480. To
generate a Unicode character (TrueType fonts only), embed the
code as an escaped hex string (e.g. \0x30a3).
Use image to composite an image with another image. Follow the
image primitive with a composite operator, image position, image
size, and filename:
-draw 'image Over 100,100 225,225 image.jpg'
If the first character of string is @, the text is read from a
file titled by the remaining characters in the string.
You can set the primitive color, font color, and font bounding
box color with -fill, -font, and -box respectively. Options are
processed in command line order so be sure to use -fill before
the -draw option.
-edge <radius>
enhance the edges of the image with a convolution filter of the
given radius.
-emboss <radius>x<sigma>
emboss the image with a convolution kernel of the given radius
and standard deviation (sigma).
-enhance
apply a digital filter to enhance a noisy image.
-equalize
perform histogram equalization to the image.
-fill color
color to use when filling a graphic primitive. See -draw for
further details.
-filter type
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.
-flip create a "mirror image" by reflecting the image scanlines in the
vertical direction.
-flop create a "mirror image" by reflecting the image scanlines in the
horizontal direction.
-font name
use this font when annotating the image with 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).
-frame <width>x<height>+<outer bevel width>+<inner bevel width>
surround the image with an ornamental border. See X(1) for
details about the geometry specification.
The color of the border is specified with the -mattecolor com‐
mand line option.
-fuzz distance
colors within this distance are considered equal.
A number of algorithms search for a target color. By default
the color must be exact. Use this option to match colors that
are close to the target color in RGB space. For example, if you
want to automatically trim the edges of an image with -crop 0x0
but the image was scanned. The target background color may dif‐
fer by a small amount. This option can account for these dif‐
ferences.
-gamma value
level of gamma correction.
The same color image displayed on two different workstations may
look different due to differences in the display monitor. Use
gamma correction to adjust for this color difference. Reason‐
able values extend from 0.8 to 2.3.
You can apply separate gamma values to the red, green, and blue
channels of the image with a gamma value list delineated with
slashes (e.g. 1.7/2.3/1.2).
Use +gamma to set the image gamma level without actually adjust‐
ing the image pixels. This option is useful if the image is of
a known gamma but not set as an image attribute (e.g. PNG
images).
-gaussian <radius>x<sigma>
blur the image with a Gaussian operator of the given radius and
standard deviation (sigma).
-geometry <width>x<height>{+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
preferred size or location of the image when encoding.
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 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.
-gravity type
direction text gravitates to when annotating the image: North‐
West, North, NorthEast, West, Center, East, SouthWest, South,
SouthEast. See X(1) for details about the gravity specifica‐
tion.
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 text
gravity is NorthWest.
-implode factor
implode image pixels about the center. Specify factor as the
percent implosion (0 - 99.9%) or explosion (-99.9 - 0%).
-intent type
use this type of rendering intent when managing the image color.
Use this option to affect the color management operation of an
image (see -profile). Choose from these intents:
Absolute
Perceptual
Relative
Saturation
The default rendering intent is undefined.
-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 scene number in the label 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.
-layer type
the type of layer: Red, Green, Blue, or Matte.
Use this option to extract a particular layer from the image.
Matte, for example, is useful for extracting the opacity values
from an image.
-loop iterations
add Netscape loop extension to your GIF animation.
A value other than zero forces the animation to repeat itself up
to iterations times.
-map filename
choose a particular set of colors from this image.
By default, color reduction chooses an optimal set of colors
that best represent the original image. Alternatively, you can
choose a particular set of colors from an image file with this
option. Use +map to reduce all images provided on the command
line to a single optimal set of colors that best represent all
the images.
-matte store matte channel if the image has one otherwise create an
opaque one.
-median radius
apply a median filter to the image.
-modulate value
vary the brightness, saturation, and hue of an image.
Specify the percent change in brightness, the color saturation,
and the color hue separated by commas. For example, to increase
the color brightness by 20% and decrease the color saturation by
10% and leave the hue unchanged, use: -modulate 120,90.
-monochrome
transform the image to black and white.
-morph morphs an image sequence.
Both the image pixels and size are linearly interpolated to give
the appearance of a meta-morphosis from one image to the next.
-mosaic
create an mosaic from an image sequence.
-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.
-noise radius
add or reduce the noise in an image.
The principal function of noise peak elimination filter is to
smooth the objects within an image without losing edge informa‐
tion and without creating undesired structures. The central
idea of the algorithm is to replace a pixel with its next neigh‐
bor in value within a pixel window, if this pixel has been found
to be noise. A pixel is defined as noise if and only if this
pixel is a maximum or minimum within the pixel window. Use
radius to specify the width of the neighborhood.
Use +noise followed by a noise type to add noise to an image.
Choose from these noise types:
Uniform
Gaussian
Multiplicative
Impulse
Laplacian
Poisson
-normalize
transform image to span the full range of color values.
This is a contrast enhancement technique.
-opaque color
change this color to the fill color within the image. See -fill
for more details.
-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.
-paint radius
simulate an oil painting.
Each pixel is replaced by the most frequent color in a circular
neighborhood whose width is specified with radius.
-pointsize value
pointsize of the Postscript, X11, or TrueType font.
-preview type
image preview type.
Use this option to affect the preview operation of an image
(e.g. convert-preview Gamma Preview:gamma.gif). Choose from
these previews:
Rotate
Shear
Roll
Hue
Saturation
Brightness
Gamma
Spiff
Dull
Grayscale
Quantize
Despeckle
ReduceNoise
AddNoise
Sharpen
Blur
Threshold
Edge Detect
Spread
Shade
Raise
Segment
Solarize
Swirl
Implode
Wave
OilPaint
CharcoalDrawing
JPEG
The default preview is JPEG.
-profile filename
add ICM color or IPTC newswire information profile to image.
Use +profile icm or +profile iptc to remove the respective pro‐
file.
-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>.
-raise <width>x<height>
lighten or darken image edges to create a 3-D effect. See
X(1) for details about the geometry specification.
Use -raise to create a raised effect, otherwise use +raise.
-region <width>x<height>{+-}<x offset>{+-}<y offset>
apply options to a portion of the image.
By default, any command line options are applied to the entire
image. Use -region to restrict operations to a particular area
of the image.
-roll {+-}<x offset>{+-}<y offset>
roll an image vertically or horizontally. See X(1) for details
about the geometry specification.
A negative x offset rolls the image left-to-right. A negative y
offset rolls the image top-to-bottom.
-rotate degrees{<}{>}
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 bordercolor (class borderColor). See
X(1) for details.
-sample geometry
scale image with pixel sampling.
-scene value
image scene number.
-seed value
pseudo-random number generator seed value.
-segment <cluster threshold>x<smoothing threshold>
segment an image by analyzing the histograms of the color compo‐
nents and identifying units that are homogeneous with the fuzzy
c-means technique.
Specify cluster threshold as the number of pixels in each clus‐
ter must exceed the the cluster threshold to be considered
valid. Smoothing threshold eliminates noise in the second de‐
rivative of the histogram. As the value is increased, you can
expect a smoother second derivative. The default is 1.5. See
IMAGE SEGMENTATION for details.
-shade <azimuth>x<elevation>
shade the image using a distant light source.
Specify azimuth and elevation as the position of the light
source. Use +shade to return the shading results as a grayscale
image.
-sharpen <radius>x<sigma>
sharpen the image with a Laplacian operator of the given radius
and standard deviation (sigma).
-shear <x degrees>x<y degrees>
shear the image along the X or Y axis by a positive or negative
shear angle.
Shearing slides one edge of an image along the X or Y axis, cre‐
ating a parallelogram. An X direction shear slides an edge
along the X axis, while a Y direction shear slides an edge along
the Y axis. The amount of the shear is controlled by a shear
angle. For X direction shears, x degrees is measured relative
to the Y axis, and similarly, for Y direction shears y degrees
is measured relative to the X axis.
Empty triangles left over from shearing the image are filled
with the color defined as bordercolor (class borderColor). See
X(1) 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 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).
-solarize factor
negate all pixels above the threshold level. Specify factor as
the percent threshold of the intensity (0 - 99.9%).
This option produces a solarization effect seen when exposing a
photographic film to light during the development process.
-spread amount
displace image pixels by a random amount.
Amount defines the size of the neighborhood around each pixel to
choose a candidate pixel to swap.
-stroke color
color to use when stoking a graphic primitive. See -draw for
further details.
-strokewidth value
set the stroke width. See -draw for further details.
-swirl degrees
swirl image pixels about the center.
Degrees defines the tightness of the swirl.
-texture filename
name of texture to tile onto the image background.
-threshold value
threshold the image.
Create a bi-level image such that any pixel intensity that is
equal or exceeds the threshold is reassigned the maximum inten‐
sity otherwise the minimum intensity.
-tile filename
tile image when filling a graphic primitive.
-transparent color
make this color transparent within the image.
-treedepth value
Normally, this integer value is zero or one. A zero or one
tells convert 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.
-units type
the type of image resolution: Undefined, PixelsPerInch, or Pix‐
elsPerCentimeter. The default is Undefined.
-verbose
print detailed information about the image.
This information is printed: image scene number; image name;
converted 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.
-view string
FlashPix viewing parameters.
-wave <amplitude>x<wavelength>
alter an image along a sine wave.
Specify amplitude and wavelength to effect the characteristics
of the wave.
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. Some options only
effect the decoding of images and others only the encoding.
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 DESCRIPTION for a list of
valid 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 input_file as - for standard input, output_file as - for stan‐
dard 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]) 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]).
Single images are written with the filename you specify. However,
multi-part images (e.g. a multi-page Postscript document with +adjoin
specified) are written with the filename followed by a period (.) and
the scene number. You can change this behavior by embedding a printf
format specification in the file name. For example,
image%02d.miff
converts files image00.miff, image01.miff, etc.
The % character is always interpreted in output filenames. To get a %
character in the filename, use %%.
Prepend an at sign (@) to a filename to read a list of image filenames
from that file. This is convenient in the event you have too many
image filenames to fit on the command line.
IMAGE SEGMENTATION
Use -segment to segment an image by analyzing the histograms of the
color components and identifying units that are homogeneous with the
fuzzy c-means technique. The scale-space filter analyzes the his‐
tograms of the three color components of the image and identifies a set
of classes. The extents of each class is used to coarsely segment the
image with thresholding. The color associated with each class is
determined by the mean color of all pixels within the extents of a par‐
ticular class. Finally, any unclassified pixels are assigned to the
closest class with the fuzzy c-means technique.
The fuzzy c-Means algorithm can be summarized as follows:
o Build a histogram, one for each color component of the image.
o For each histogram, successively apply the scale-space filter
and build an interval tree of zero crossings in the second de‐
rivative at each scale. Analyze this scale-space ``finger‐
print'' to determine which peaks or valleys in the histogram are
most predominant.
o The fingerprint defines intervals on the axis of the his‐
togram. Each interval contains either a minima or a maxima in
the original signal. If each color component lies within the
maxima interval, that pixel is considered ``classified'' and is
assigned an unique class number.
o Any pixel that fails to be classified in the above threshold‐
ing pass is classified using the fuzzy c-Means technique. It is
assigned to one of the classes discovered in the histogram anal‐
ysis phase.
The fuzzy c-Means technique attempts to cluster a pixel by finding the
local minima of the generalized within group sum of squared error
objective function. A pixel is assigned to the closest class of which
the fuzzy membership has a maximum value.
For additional information see
Young Won Lim, Sang Uk Lee, "On The Color Image Segmentation
Algorithm Based on the Thresholding and the Fuzzy c-Means Tech‐
niques", Pattern Recognition, Volume 23, Number 9, pages
935-952, 1990.
ENVIRONMENT
DISPLAY
To get the default host, display number, and screen.
SEE ALSOdisplay(1), animate(1), import(1), montage(1), mogrify(1), combine(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
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 ImageMagick Studio
shall not be used in advertising or otherwise to promote the sale, use
or other dealings in ImageMagick without prior written authorization
from the ImageMagick Studio.
AUTHORS
John Cristy, E.I. du Pont De Nemours and Company Incorporated
ImageMagick 12 Feb 1997 convert(1)