1. Computing
Linux / Unix Command: ImageMagick
Command Library

NAME

ImageMagick - commandline utilities to create, edit, or convert images

 

SYNOPSIS

animate [ options ... ] file [ [ options ... ] file ... ]

composite [ options ... ] image composite [ mask ] composited

conjure [ options ] script.msl [ [ options ] script.msl ]

convert [ [ options ... ] [ input_file ... ] ... [ output_file ] ]

display [ options ... ] file ... [ [options ... ]file ... ]

identify file [ file ... ]

import [ options ... ] file

mogrify [ options ... ] file ...

montage [ options ... ] file [ [ options ... ] file ... ] output_file

 

DESCRIPTION

ImageMagick provides a suite of commandline utilities for creating, converting, editing, and displaying images:

Display is a machine architecture independent image processing and display program. It can display an image on any workstation display running an X server.

Import reads an image from any visible window on an X server and outputs it as an image file. You can capture a single window, the entire screen, or any rectangular portion of the screen.

Montage creates a composite by combining several separate images. The images are tiled on the composite image with the name of the image optionally appearing just below the individual tile.

Convert converts an input file using one image format to an output file with a differing image format.

Mogrify transforms an image or a sequence of images. These transforms include image scaling, image rotation, color reduction, and others. The transmogrified image overwrites the original image.

Identify describes the format and characteristics of one or more image files. It will also report if an image is incomplete or corrupt.

Composite composites images to create new images.

Conjure interprets and executes scripts in the Magick Scripting Language (MSL).

The ImageMagick utilities recognize the following image formats:

Name Mode Description
 o  8BIM      *rw- Photoshop resource format
 o  AFM       *r-- TrueType font
 o  APP1      *rw- Photoshop resource format
 o  ART       *r-- PF1: 1st Publisher
 o  AVI       *r-- Audio/Visual Interleaved
 o  AVS       *rw+ AVS X image
 o  BIE       *rw- Joint Bi-level Image experts Group
                   interchange format
 o  BMP       *rw+ Microsoft Windows bitmap image
 o  CAPTION   *r+  Caption (requires separate size info)
 o  CMYK      *rw- Raw cyan, magenta, yellow, and black
                   samples (8 or 16 bits, depending on
                   the image depth)
 o  CMYKA     *rw- Raw cyan, magenta, yellow, black, and
                   matte samples (8 or 16 bits, depending
                   on the image depth)
 o  CUT       *r-- DR Halo
 o  DCM       *r-- Digital Imaging and Communications in
                    Medicine image
 o  DCX       *rw+ ZSoft IBM PC multi-page Paintbrush
 o  DIB       *rw+ Microsoft Windows bitmap image
 o  DPS       *r-- Display Postscript
 o  DPX       *r-- Digital Moving Picture Exchange
 o  EPDF      *rw- Encapsulated Portable Document Format
 o  EPI       *rw- Adobe Encapsulated PostScript
                   Interchange format
 o  EPS       *rw- Adobe Encapsulated PostScript
 o  EPS2      *-w- Adobe Level II Encapsulated PostScript
 o  EPS3      *-w- Adobe Level III Encapsulated PostScript
 o  EPSF      *rw- Adobe Encapsulated PostScript
 o  EPSI      *rw- Adobe Encapsulated PostScript
                   Interchange format
 o  EPT       *rw- Adobe Encapsulated PostScript with TIFF
                   preview
 o  FAX       *rw+ Group 3 FAX
 o  FILE      *r-- Uniform Resource Locator
 o  FITS      *rw- Flexible Image Transport System
 o  FPX       *rw- FlashPix Format
 o  FTP       *r-- Uniform Resource Locator
 o  G3        *rw- Group 3 FAX
 o  GIF       *rw+ CompuServe graphics interchange format
 o  GIF87     *rw- CompuServe graphics interchange format
                   (version 87a)
 o  GRADIENT  *r-- Gradual passing from one shade to
                   another
 o  GRANITE   *r-- Granite texture
 o  GRAY      *rw+ Raw gray samples (8 or 16 bits,
                   depending on the image depth)
 o  H         *rw- Internal format
 o  HDF       -rw+ Hierarchical Data Format
 o  HISTOGRAM *-w- Histogram of the image
 o  HTM       *-w- Hypertext Markup Language and a
                   client-side image map
 o  HTML      *-w- Hypertext Markup Language and a
                   client-side image map
 o  HTTP      *r-- Uniform Resource Locator
 o  ICB       *rw+ Truevision Targa image
 o  ICM       *rw- ICC Color Profile
 o  ICO       *r-- Microsoft icon
 o  ICON      *r-- Microsoft icon
 o  IMPLICIT  *--- 
 o  IPTC      *rw- IPTC Newsphoto
 o  JBG       *rw+ Joint Bi-level Image experts Group
                   interchange format
 o  JBIG      *rw+ Joint Bi-level Image experts Group
                   interchange format
 o  JP2       *rw- JPEG-2000 JP2 File Format Syntax
 o  JPC       *rw- JPEG-2000 Code Stream Syntax
 o  JPEG      *rw- Joint Photographic Experts Group
                   JFIF format
 o  JPG       *rw- Joint Photographic Experts Group
                   JFIF format
 o  LABEL     *r-- Text image format
 o  LOGO      *rw- ImageMagick Logo
 o  M2V       *rw+ MPEG-2 Video Stream
 o  MAP       *rw- Colormap intensities (8 or 16 bits,
                   depending on the image depth) and
                   indices (8 or 16 bits, depending
                   on whether colors exceeds 256).
 o  MAT       *-w+ MATLAB image format
 o  MATTE     *-w+ MATTE format
 o  MIFF      *rw+ Magick image format
 o  MNG       *rw+ Multiple-image Network Graphics
 o  MONO      *rw- Bi-level bitmap in least-significant-
                   -byte-first order
 o  MPC       -rw- Magick Persistent Cache image format
 o  MPEG      *rw+ MPEG-1 Video Stream
 o  MPG       *rw+ MPEG-1 Video Stream
 o  MPR       *r-- Magick Persistent Registry
 o  MSL       *r-- Magick Scripting Language
 o  MTV       *rw+ MTV Raytracing image format
 o  MVG       *rw- Magick Vector Graphics
 o  NETSCAPE  *r-- Netscape 216 color cube
 o  NULL      *r-- Constant image of uniform color
 o  OTB       *rw- On-the-air bitmap
 o  P7        *rw+ Xv thumbnail format
 o  PAL       *rw- 16bit/pixel interleaved YUV
 o  PALM      *rw- Palm Pixmap format
 o  PBM       *rw+ Portable bitmap format (black and white)
 o  PCD       *rw- Photo CD
 o  PCDS      *rw- Photo CD
 o  PCL       *-w- Page Control Language
 o  PCT       *rw- Apple Macintosh QuickDraw/PICT
 o  PCX       *rw- ZSoft IBM PC Paintbrush
 o  PDB       *r-- Pilot Image Format
 o  PDF       *rw+ Portable Document Format
 o  PFA       *r-- TrueType font
 o  PFB       *r-- TrueType font
 o  PFM       *r-- TrueType font
 o  PGM       *rw+ Portable graymap format (gray scale)
 o  PICON     *rw- Personal Icon
 o  PICT      *rw- Apple Macintosh QuickDraw/PICT
 o  PIX       *r-- Alias/Wavefront RLE image format
 o  PLASMA    *r-- Plasma fractal image
 o  PM        *rw- X Windows system pixmap (color)
 o  PNG       *rw- Portable Network Graphics
 o  PNM       *rw+ Portable anymap
 o  PPM       *rw+ Portable pixmap format (color)
 o  PREVIEW   *-w- Show a preview an image enhancement,
                   effect, or f/x
 o  PS        *rw+ Adobe PostScript
 o  PS2       *-w+ Adobe Level II PostScript
 o  PS3       *-w+ Adobe Level III PostScript
 o  PSD       *rw- Adobe Photoshop bitmap
 o  PTIF      *rw- Pyramid encoded TIFF
 o  PWP       *r-- Seattle Film Works
 o  RAS       *rw+ SUN Rasterfile
 o  RGB       *rw+ Raw red, green, and blue samples (8 or
                   16 bits, depending on the image depth)
 o  RGBA      *rw+ Raw red, green, blue, and matte samples
                   (8 or 16 bits, depending on the image
                   depth)
 o  RLA       *r-- Alias/Wavefront image
 o  RLE       *r-- Utah Run length encoded image
 o  ROSE      *rw- 70x46 Truecolor test image
 o  SCT       *r-- Scitex HandShake
 o  SFW       *r-- Seattle Film Works
 o  SGI       *rw+ Irix RGB image
 o  SHTML     *-w- Hypertext Markup Language and a
                   client-side image map
 o  STEGANO   *r-- Steganographic image
 o  SUN       *rw+ SUN Rasterfile
 o  SVG       *rw+ Scalable Vector Gaphics
 o  TEXT      *rw+ Raw text
 o  TGA       *rw+ Truevision Targa image
 o  TIF       *rw+ Tagged Image File Format
 o  TIFF      *rw+ Tagged Image File Format
 o  TILE      *r-- Tile image with a texture
 o  TIM       *r-- PSX TIM
 o  TTF       *r-- TrueType font
 o  TXT       *rw+ Raw text
 o  UIL       *-w- X-Motif UIL table
 o  UYVY      *rw- 16bit/pixel interleaved YUV
 o  VDA       *rw+ Truevision Targa image
 o  VICAR     *rw- VICAR rasterfile format
 o  VID       *rw+ Visual Image Directory
 o  VIFF      *rw+ Khoros Visualization image
 o  VST       *rw+ Truevision Targa image
 o  WBMP      *rw- Wireless Bitmap (level 0) image
 o  WMF       *r-- Windows Metafile
 o  WPG       *r-- Word Perfect Graphics
 o  X         *rw- X Image
 o  XBM       *rw- X Windows system bitmap (black
                   and white)
 o  XC        *r-- Constant image uniform color
 o  XCF       *r-- GIMP image
 o  XML       *r-- Scalable Vector Gaphics
 o  XPM       *rw- X Windows system pixmap (color)
 o  XV        *rw+ Khoros Visualization image
 o  XWD       *rw- X Windows system window dump (color)
 o  YUV       *rw- CCIR 601 4:1:1
                   
    Modes:         
              *    Native blob support
              r    Read
              w    Write
              +    Multi-image

Support for some of these formats require additional programs or libraries. README tells where to find this software.

Note, a format delineated with + means that if more than one image is specified, it is composited into a single multi-image file. Use +adjoin if you want a single image produced for each frame.

Your installation might not support all of the formats in the list. To get an up-to-date listing of the formats supported by your particular configuration, run "convert -list format".

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. You can tell if ImageMagick was compiled in 16-bit mode by typing "convert" without any options, and looking for "Q:16" in the first line of output.  

OPTIONS

Options are processed in command line order. Any option you specify on the command line remains in effect for the set of images that follows, until the set is terminated by the appearance of any option or -noop. Some options only affect the decoding of images and others only the encoding. The latter can appear after the final group of input images.

This is a combined list of the commandline options used by the ImageMagick utilities (animate, composite, convert, display, identify, import, mogrify and montage).

In this document, angle brackets ("<>") enclose variables, and curly brackets ("{}") enclose optional parameters. For example, "-fuzz <distance>{%}" means you can use the option "-fuzz 10" or "-fuzz 2%".

-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.

-affine <matrix>
drawing transform matrix

This option provides a transform matrix {sx,rx,ry,sy,tx,ty} for use by subsequent -draw or -transform options.

-antialias
remove pixel aliasing
-append
append a set of images

This option creates a single image where the images in the original set are stacked top-to-bottom. If they are not of the same width, any narrow images will be expanded to fit using the background color. Use +append to stack images left-to-right. The set of images is terminated by the appearance of any option. If the -append option appears after all of the input images, all images are appended.

-average
average a set of images

The set of images is terminated by the appearance of any option. If the -average option appears after all of the input images, all images are averaged.

-backdrop <color>
display the image centered on a backdrop.

This backdrop covers the entire workstation screen and is useful for hiding other X window activity while viewing the image. The color of the backdrop is specified as the background color. The color is specified using the format described in the "Color Names" section of X(1). Refer to "X Resources", below, for details.

-background <color>
the background color

The color is specified using the format described in the "Color Names" section of X(1).

-blur <radius>x<sigma>
blur the image with a gaussian operator

Blur with the given radius and standard deviation (sigma).

-border <width>x<height>
surround the image with a border of color

See -geometry for details about the geometry specification.

-bordercolor <color>
the border color

The color is specified using the format described in the "Color Names" section of X(1).

-borderwidth <geometry>
the border width
-box <color>
set the color of the annotation bounding box

The color is specified using the format described in the "Color Names" section of X(1).

See -draw for further details.

-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.

-channel <type>
the type of channel

Choose from: Red, Green, Blue, Opacity, Cyan, Magenta, Yellow, or Black.

Use this option to extract a particular channel from the image. Matte, for example, is useful for extracting the opacity values from an image.

-charcoal <factor>
simulate a charcoal drawing
-chop <width>x<height>{+-}<x>{+-}<y>{%}
remove pixels from the interior of an image

Width and height give the number of columns and rows to remove, and x and y are offsets that give the location of the leftmost column and topmost row to remove.

The x offset normally specifies the leftmost column to remove. If the -gravity option is present with NorthEast, East, or SouthEast gravity, it gives the distance leftward from the right edge of the image to the rightmost column to remove. Similarly, the y offset normally specifies the topmost row to remove, but if the -gravity option is present with SouthWest, South, or SouthEast gravity, it specifies the distance upward from the bottom edge of the image to the bottom row to remove.

The -chop option removes entire rows and columns, and moves the remaining corner blocks leftward and upward to close the gaps.

-clip
apply the clipping path, if one is present

If a clipping path is present, it will be applied to subsequent operations.

For example, if you type the following command:


     convert -clip -negate cockatoo.tif negated.tif

only the pixels within the clipping path are negated.

The -clip feature requires the XML library. If the XML library is not present, the option is ignored.

-coalesce
merge a sequence of images

Each image N in the sequence after Image 0 is replaced with the image created by flattening images 0 through N.

The set of images is terminated by the appearance of any option. If the -coalesce option appears after all of the input images, all images are coalesced.

-colorize <value>
colorize the image with the pen 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).

-colormap <type>
define the colormap type

Choose between shared or private.

This option only applies when the default X server visual is PseudoColor or GRAYScale. Refer to -visual for more details. By default, a shared colormap is allocated. The image shares colors with other X clients. Some image colors could be approximated, therefore your image may look very different than intended. Choose Private and the image colors appear exactly as they are defined. However, other clients may go technicolor when the image colormap is installed.

-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 for more details.

Note, options -dither, -colorspace, and -treedepth affect the color reduction algorithm.

-colorspace <value>
the type of colorspace

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.

-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 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
     %#   signature
     \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

[This option is not used by convert but this section is included because it describes the composite operators that are used by the -draw option of convert.]

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).

-compress <type>
the type of image compression

Choices are: None, BZip, Fax, Group4, JPEG, Lossless, 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.

If LZW compression is specified but LZW compression has not been enabled, the image data will be written in an uncompressed LZW format that can be read by LZW decoders. This may result in larger-than-expected GIF files.

"Lossless" refers to lossless JPEG, which is only available if the JPEG library has been patched to support it.

Use the -quality option to set the compression level to be used by JPEG, PNG, MIFF, and MPEG encoders. Use the -sampling_factor option to set the sampling factor to be used by JPEG, MPEG, and YUV encoders for downsampling the chroma channels.

-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>{+-}<y>{%}
preferred size and location of the cropped image

See -geometry for details about the geometry specification.

The width and height give the size of the image that remains after cropping, and x and y are offsets that give the location of the top left corner of the cropped image with respect to the original image. To specify the amount to be removed, use -shave instead.

To specify a percentage width or height to be removed instead, append %. For example to crop the image by ten percent (five percent on each side of the image), use -crop 10%.

If the x and y offsets are present, a single image is generated, consisting of the pixels from the cropping region. The offsets specify the location of the upper left corner of the cropping region measured downward and rightward with respect to the upper left corner of the image. If the -gravity option is present with NorthEast, East, or SouthEast gravity, it gives the distance leftward from the right edge of the image to the right edge of the cropping region. Similarly, if the -gravity option is present with SouthWest, South, or SouthEast gravity, the distance is measured upward between the bottom edges.

If the x and y offsets are omitted, a set of tiles of the specified geometry, covering the entire input image, is generated. The rightmost tiles and the bottom tiles are smaller if the specified geometry extends beyond the dimensions of the input image.

-cycle <amount>
displace image colormap by amount

Amount defines the number of positions each colormap entry is shifted.

-debug
enable debug printout
-deconstruct
break down an image sequence into constituent parts

The sequence of images is terminated by the appearance of any option. If the -deconstruct option appears after all of the input images, all images are deconstructed.

-delay <1/100ths of a second>
display the next image after pausing

This option is useful for regulating the animation of image sequences Delay/100 seconds must expire before the display of the next image. The default is no delay between each showing of the image sequence. The maximum delay is 65535.

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 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.

-depth <value>
depth of the image

This is the number of bits in a color sample within 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.

-descend
obtain image by descending window hierarchy
-despeckle
reduce the speckles within an image
-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.

-display <host:display[.screen]>
specifies the X server to contact

This option is used with convert for obtaining image or font from this X server. 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.

-dissolve <percent>
dissolve an image into another by the given percent

The opacity of the composite image is multiplied by the given percent, then it is composited over the main image.

-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 turn off dithering and to render Postscript without text or graphic aliasing.

-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 shapes, text, transformations, and pixel operations. The shape primitives are


     point           x,y
     line            x0,y0 x1,y1
     rectangle       x0,y0 x1,y1
     roundRectangle  x0,y0 x1,y1 wc,hc
     arc             x0,y0 x1,y1 a0,a1
     ellipse         x0,y0 rx,ry a0,a1
     circle          x0,y0 x1,y1
     polyline        x0,y0  ...  xn,yn
     polygon         x0,y0  ...  xn,yn
     bezier          x0,y0  ...  xn,yn
     path            path specification
     image           operator x0,y0 w,h filename

The text primitive is


     text            x0,y0 string

The transformation primitives are


     rotate          degrees
     translate       dx,dy
     scale           sx,sy
     skewX           degrees
     skewY           degrees

The pixel operation primitives are


     color           x0,y0 method
     matte           x0,y0 method

The shape primitives are drawn in the color specified in the preceding -stroke option. Except for the line and point primitives, they are filled with the color specified in the preceding -fill option. For unfilled shapes, use -fill none.

Point requires a single coordinate.

Line requires a start and end coordinate.

Rectangle expects an upper left and lower right coordinate.

RoundRectangle has the upper left and lower right coordinates and the width and height of the corners.

Circle has a center coordinate and a coordinate for 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 (See 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 image to composite an image with another image. Follow the image keyword with the composite operator, image location, image size, and filename:


     -draw 'image Over 100,100 225,225 image.jpg'

You can use 0,0 for the image size, which means to use the actual dimensions found in the image header. Otherwise, it will be scaled to the given dimensions. See -compose for a description of the composite operators.

Use text to annotate an image with text. Follow the text coordinates 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 character. 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.

If the first character of string is @, the text is read from a file titled by the remaining characters in the string.

Rotate rotates subsequent shape primitives and text primitives about the origen of the main image. If the -region option precedes the -draw option, the origen for transformations is the upper left corner of the region.

Translate translates them.

Scale scales them.

SkewX and SkewY skew them with respect to the origen of the main image or the region.

The transformations modify the current affine matrix, which is initialized from the initial affine matrix defined by the -affine option. Transformations are cumulative within the -draw option. The initial affine matrix is not affected; that matrix is only changed by the appearance of another -affine option. If another -draw option appears, the current affine matrix is reinitialized from the initial affine matrix.

Use color to change the color of a pixel to the fill color (see -fill). 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 target 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 primitive 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 target 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.

You can set the primitive color, font, and font bounding box color with -fill, -font, and -box respectively. Options are processed in command line order so be sure to use these options before the -draw option.

-edge <radius>
detect edges within an image
-emboss
emboss an image
-encoding <type>
specify the font encoding

Choose from AdobeCustom, AdobeExpert, AdobeStandard, AppleRoman, BIG5, GB2312, Latin 2, None, SJIScode, Symbol, Unicode, Wansung.

-endian <type>
specify endianness (MSB or LSB) of output image

Use +endian to revert to unspecified endianness.

-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

The color is specified using the format described in the "Color Names" section of X(1).

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

-flatten
flatten a sequence of images

The sequence of images is replaced by a single image created by composing each image after the first over the first image.

The sequence of images is terminated by the appearance of any option. If the -flatten option appears after all of the input images, all images are flattened.

-flip
create a "mirror image"

reflect the scanlines in the vertical direction.

-flop
create a "mirror image"

reflect the scanlines in the horizontal direction.

-font <name>
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.

-foreground <color>
define the foreground color

The color is specified using the format described in the "Color Names" section of X(1).

-format <type>
the image format type

This option will convert any image to the image format you specify. See ImageMagick(1) for a list of image format types supported by ImageMagick.

By default the file is written to its original name. However, if the filename extension matches a supported format, the extension is replaced with the image format type specified with -format. For example, if you specify tiff as the format type and the input image filename is image.gif, the output image filename becomes image.tiff.

-format <string>
output formatted image characteristics

Use this option to print information about the image in a format of your choosing. 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
     %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
     %#   signature
     \n   newline
     \r   carriage return

For example,


     -format "%m:%f %wx%h"

displays 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 format is read from a file titled by the remaining characters in the string.

-frame <width>x<height>+<outer bevel width>+<inner bevel width>
surround the image with an ornamental border

See -geometry for details about the geometry specification. The -frame option is not affected by the -gravity option.

The color of the border is specified with the -mattecolor command line option.

-frame
include the X window frame in the imported image
-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 -trim but the image was scanned and the target background color may differ by a small amount. This option can account for these differences.

The distance can be in absolute intensity units or, by appending "%", as a percentage of the maximum possible intensity (255 or 65535).

-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. Reasonable 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 value to set the image gamma level without actually adjusting 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

Use the given radius and standard deviation (sigma).

-geometry <width>x<height>{+-}<x>{+-}<y>{%}{@} {!}{<}{>}
preferred size and location of the Image window.

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 the width is specified, the width assumes the value and the height is chosen to maintain the aspect ratio of the image. Similarly, if only the height is specified (e.g., -geometry x256), the width is chosen to maintain the aspect ratio.

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 width or height exceeds the geometry specification. < resizes the image only if both of its dimensions are less than the geometry specification. For example, if you specify '640x480>' and the image size is 256x256, the image size does not change. However, if the image is 512x512 or 1024x1024, it is resized to 480x480. Enclose the geometry specification in quotation marks to prevent the < or > from being interpreted by your shell as a file redirection.

When used with animate and display, offsets are handled in the same manner as in X(1) and the -gravity option is not used. If the x is negative, the offset is measured leftward from the right edge of the screen to the right edge of the image being displayed. Similarly, negative y is measured between the bottom edges. The offsets are not affected by "%"; they are always measured in pixels.

When used as a composite option, -geometry gives the dimensions of the image and its location with respect to the composite image. If the -gravity option is present with NorthEast, East, or SouthEast gravity, the x represents the distance from the right edge of the image to the right edge of the composite image. Similarly, if the -gravity option is present with SouthWest, South, or SouthEast gravity, y is measured between the bottom edges. Accordingly, a positive offset will never point in the direction outside of the image. The offsets are not affected by "%"; they are always measured in pixels. To specify the dimensions of the composite image, use the -resize option.

When used as a convert, import or mogrify option, -geometry is synonymous with -resize and specifies the size of the output image. The offsets, if present, are ignored.

When used as a montage option, -geometry specifies the image size and border size for each tile; default is 256x256+0+0. Negative offsets (border dimensions) are meaningless. The -gravity option affects the placement of the image within the tile; the default gravity for this purpose is Center. If the "%" sign appears in the geometry specification, the tile size is the specified percentage of the original dimensions of the first tile. To specify the dimensions of the montage, use the -resize option.

-gravity <type>
direction primitive gravitates to when annotating the image.

Choices are: NorthWest, North, NorthEast, West, Center, East, SouthWest, South, SouthEast.

The direction you choose specifies where to position the text or other graphic primitive when annotating the image. For example Center gravity forces the text to be centered within the image. By default, the image gravity is NorthWest. See -draw for more details about graphic primitives.

The -gravity option is also used in concert with the -geometry option and other options that take <geometry> as a parameter, such as the -crop option. See -geometry for details of how the -gravity option interacts with the <x> and <y> parameters of a geometry specification.

When used as an option to composite, -gravity gives the direction that the image gravitates within the composite.

When used as an option to montage, -gravity gives the direction that an image gravitates within a tile. The default gravity is Center for this purpose.

-help
print usage instructions
-iconGeometry <geometry>
specify the icon geometry

Offsets, if present in the geometry specification, are handled in the same manner as the -geometry option, using X11 style to handle negative offsets.

-iconic
iconic animation
-immutable
make image immutable
-implode <factor>
implode image pixels about the center
-intent <type>
use this type of rendering intent when managing the image color

Use this option to affect the the color management operation of an image (see -profile). Choose from these intents: Absolute, Perceptual, Relative, Saturation

The default intent is undefined.

-interlace <type>
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.

-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 attribute by embedding special format character. 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.

-level <value>
adjust the level of image contrast

Give three point values delineated with commas: black, mid, and white (e.g. 10,1.0,65000). The white and black points range from 0 to MaxRGB and mid ranges from 0 to 10.

-linewidth
the line width for subsequent draw operations
-list <type>
the type of list

Choices are: Delegate, Format, Magic, Module, or Type.

This option lists entries from the ImageMagick configuration files.

-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.

-magnify <factor>
magnify the image
-map <filename>
choose a particular set of colors from this image

[convert or mogrify]

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 in the image sequence that follows to a single optimal set of colors that best represent all the images. The sequence of images is terminated by the appearance of any option. If the +map option appears after all of the input images, all images are mapped.

-map <type>
display image using this type.

[animate or display]

Choose from these Standard Colormap types:


     best
     default
     gray
     red
     green
     blue

The X server must support the Standard Colormap you choose, otherwise an error occurs. Use list as the type and display searches the list of colormap types in top-to-bottom order until one is located. See xstdcmap(1) for one way of creating Standard Colormaps.

-mask <filename>
Specify a clipping mask

The image read from the file is used as a clipping mask. It must have the same dimensions as the image being masked.

If the mask image contains an opacity channel, the opacity of each pixel is used to define the mask. Otherwise, the intensity (gray level) of each pixel is used.

Use +mask to remove the clipping mask.

It is not necessary to use -clip to activate the mask; -clip is implied by -mask.

-matte
store matte channel if the image has one

If the image does not have a matte channel, create an opaque one.

Use +matte to ignore the matte channel and to avoid writing a matte channel in the output file.

-mattecolor <color>
specify the color to be used with the -frame option

The color is specified using the format described in the "Color Names" section of X(1).

-median <radius>
apply a median filter to the image
-mode <value>
mode of operation
-modulate <value>
vary the brightness, saturation, and hue of an image

Specify the percent change in brightness, the color saturation, and the 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 <frames>
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.

The sequence of images is terminated by the appearance of any option. If the -morph option appears after all of the input images, all images are morphed.

-mosaic
create a mosaic from an image sequence

The -page option is used to locate the images within the mosaic.

The sequence of images is terminated by the appearance of any option. If the -mosaic option appears after all of the input images, all images are included in the mosaic.

-name
name an image
-negate
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.

-noise <radius|type>
add or reduce noise in an image

The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired structures. The central idea of the algorithm is to replace a pixel with its next neighbor 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

-noop
NOOP (no option)

The -noop option can be used to terminate a group of images and reset all options to their default values, when no other option is desired.

-normalize
transform image to span the full range of color values

This is a contrast enhancement technique.

-opaque <color>
change this color to the pen color within the image

The color is specified using the format described in the "Color Names" section of X(1).

See -fill for more details.

-page <width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
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>{+-}<y> (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 gravity for the -page option is NorthWest, i.e., positive x and y offset are measured rightward and downward from the top left corner of the page, unless the -gravity option is present with a value other than NorthWest.

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.

-pause <seconds>
pause between animation loops [animate]

Pause for the specified number of seconds before repeating the animation.

-pause <seconds>
pause between snapshots [import]

Pause for the specified number of seconds before taking the next snapshot.

-pen <color>
specify the pen color for drawing operations

The color is specified using the format described in the "Color Names" section of X(1).

-ping
efficiently determine image characteristics
-pointsize <value>
pointsize of the Postscript, OPTION1, 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.png). Choose from these previews:


     Rotate
     Shear
     Roll
     Hue
     Saturation
     Brightness
     Gamma
     Spiff
     Dull
     Grayscale
     Quantize
     Despeckle
     ReduceNoise
     Add Noise
     Sharpen
     Blur
     Threshold
     EdgeDetect
     Spread
     Shade
     Raise
     Segment
     Solarize
     Swirl
     Implode
     Wave
     OilPaint
     CharcoalDrawing
     JPEG

The default preview is JPEG.

-process <command>
process a sequence of images

The sequence of images is terminated by the appearance of any option. If the -process option appears after all of the input images, all images are processed.

-profile <filename>
add ICM, IPTC, or generic profile to image

-profile filename adds an ICM (ICC color management), IPTC (newswire information), or a generic profile to the image.

Use +profile icm, +profile iptc, or +profile profile_name to remove the respective profile. Use identify -verbose to find out what profiles are in the image file. Use +profile "*" to remove all profiles.

To extract a profile, the -profile option is not used. Instead, simply write the file to an image format such as APP1, 8BIM, ICM, or IPTC.

For example, to extract the Exif data (which is stored in JPEG files in the APP1 profile), use


    convert cockatoo.jpg exifdata.app1

-quality <value>
JPEG/MIFF/PNG compression level

For the JPEG and MPEG image formats, quality is 0 (lowest image quality and highest compression) to 100 (best quality but least effective compression). The default quality is 75. Use the -sampling_factor option to specify the factors for chroma downsampling.

For the MIFF image format, quality/10 is the zlib compression level, which is 0 (worst but fastest compression) to 9 (best but slowest). It has no effect on the image appearance, since the compression is always lossless.

For the MNG and PNG image formats, the quality value sets the zlib compression level (quality / 10) and filter-type (quality % 10). Compression levels range from 0 (fastest compression) to 100 (best but slowest). For compression level 0, the Huffman-only strategy is used, which is fastest but not necessarily the worst compression.

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, adaptive filtering with minimum-sum-of-absolute-values is used.

Only if the output is MNG, if filter-type is 7, the LOCO color transformation and adaptive filtering with minimum-sum-of-absolute-values are used.

The default is quality is 75, which means nearly the best compression with adaptive filtering. The quality setting has no effect on the appearance of PNG and MNG images, since the compression is always lossless.

For further information, see the PNG specification.

-raise <width>x<height>
lighten or darken image edges

This will create a 3-D effect. See -geometry for details details about the geometry specification. Offsets are not used.

Use -raise to create a raised effect, otherwise use +raise.

-region <width>x<height>{+-}<x>{+-}<y>
apply options to a portion of the image

The x and y offsets are treated in the same manner as in -crop.

-remote
perform a remote operation

The only command recognized at this time is the name of an image file to load.

-resize <width>x<height>{%}{@}{!}{<}{>}
resize an image

This is an alias for the -geometry option and it behaves in the same manner. If the -filter option precedes the -resize option, the specified filter is used.

There are some exceptions:

When used as a composite option, -resize conveys the preferred size of the output image, while -geometry conveys the size and placement of the composite image within the main image.

When used as a montage option, -resize conveys the preferred size of the montage, while -geometry conveys information about the tiles.

-roll {+-}<x>{+-}<y>
roll an image vertically or horizontally

See -geometry for details the geometry specification. The x and y offsets are not affected by the -gravity option.

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 -rotate "-90>" and the image size is 480x640, the image is not rotated. However, if the image is 640x480, it is rotated by -90 degrees. If you use > or <, enclose it in quotation marks to prevent it from being misinterpreted as a file redirection.

Empty triangles left over from rotating the image are filled with the color defined as background (class backgroundColor). See X(1) for details.

-sample <geometry>
scale image with pixel sampling

See -geometry for details about the geometry specification. -sample ignores the -filter selection if the -filter option is present. Offsets, if present in the geometry string, are ignored, and the -gravity option has no effect.

-sampling_factor <horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV decoder/encoder.

This option specifies the sampling factors to be used by the JPEG encoder for chroma downsampling. If this option is omitted, the JPEG library will use its own default values. When reading or writing the YUV format and when writing the M2V (MPEG-2) format, use -sampling_factor 2x1to specify the 4:2:2 downsampling method

-scale <geometry>
scale the image.

See -geometry for details about the geometry specification. -scale uses a simpler, faster algorithm, and it ignores the -filter selection if the -filter option is present. Offsets, if present in the geometry string, are ignored, and the -gravity option has no effect.

-scene <value>
set scene number

This option sets the scene number of an image or the first image in an image sequence.

-scenes <value-value>
range of image scene numbers to read

Each image in the range is read with the filename followed by a period (.) and the decimal scene number. You can change this behavior by embedding a %d, %0Nd, %o, %0No, %x, or %0Nx printf format specification in the file name. For example,


    montage -scenes 5-7 image.miff

makes a montage of files image.miff.5, image.miff.6, and image.miff.7, and


    animate -scenes 0-12 image%02d.miff

animates files image00.miff, image01.miff, through image12.miff.

-screen
specify the screen to capture

This option indicates that the GetImage request used to obtain the image should be done on the root window, rather than directly on the specified window. In this way, you can obtain pieces of other windows that overlap the specified window, and more importantly, you can capture menus or other popups that are independent windows but appear over the specified window.

-seed <value>
pseudo-random number generator seed value
-segment <cluster threshold>x<smoothing threshold>
segment an image

Segment an image by analyzing the histograms of the color components and identifying units that are homogeneous with the fuzzy c-means technique.

Specify cluster threshold as the number of pixels in each cluster must exceed the the cluster threshold to be considered valid. Smoothing threshold eliminates noise in the second derivative of the histogram. As the value is increased, you can expect a smoother second derivative. The default is 1.5. See "Image Segmentation", below, 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.

-shadow <radius>x<sigma>
shadow the montage
-shared_memory
use shared memory

This option specifies whether the utility should attempt use shared memory for pixmaps. ImageMagick must be compiled with shared memory support, and the display must support the MIT-SHM extension. Otherwise, this option is ignored. The default is True.

-sharpen <radius>x<sigma>
sharpen the image

Use a gaussian operator of the given radius and standard deviation (sigma).

-shave <width>x<height>
shave pixels from the image edges

Specify the width of the region to be removed from both sides of the image and the height of the regions to be removed from top and bottom.

-shear <x degrees>x<y degrees>
shear the image along the X or Y axis

Use the specified positive or negative shear angle.

Shearing slides one edge of an image along the X or Y axis, creating 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 background (class backgroundColor). See X(1) for details.

-silent
operate silently
-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).

-snaps <value>
number of screen snapshots

Use this option to grab more than one image from the X server screen, to create an animation sequence.

-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.

-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
composite two images to create a stereo anaglyph

The left side of the stereo pair is saved as the red channel of the output image. The right side is saved as the green channel. Red-green stereo glasses are required to properly view the stereo image.

-stroke <color>
color to use when stroking a graphic primitive

The color is specified using the format described in the "Color Names" section of X(1).

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.

-text_font <name>
font for writing fixed-width text

Specifies the name of the preferred font to use in fixed (typewriter style) formatted text. The default is 14 point Courier.

You can tag a font to specify whether it is a Postscript, Truetype, or OPTION1 font. For example, Courier.ttf is a Truetype font and x:fixed is OPTION1.

-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 intensity otherwise the minimum intensity.

-tile <filename>
tile image when filling a graphic primitive
-tile <geometry>
layout of images [montage]
-title <string>
assign title to displayed image [animate, display, montage]

Use this option to assign a specific title to the image. This is assigned to the image window and is typically displayed in the window title bar. Optionally 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
     %#   signature
     \n   newline
     \r   carriage return

For example,


     -title "%m:%f %wx%h"

produces an image title of MIFF:bird.miff 512x480 for an image titled bird.miff and whose width is 512 and height is 480.

-transform
transform the image

This option applies the transformation matrix from a previous -affine option.


    convert -affine 2,2,-2,2,0,0 -transform bird.ppm bird.jpg

-transparent <color>
make this color transparent within the image

The color is specified using the format described in the "Color Names" section of X(1).

-treedepth <value>
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.

-trim
trim an image

This option removes any edges that are exactly the same color as the corner pixels. Use -fuzz to make -trim remove edges that are nearly the same color as the corner pixels.

-type <type>
the image type

Choose from: Bilevel, Grayscale, Palette, PaletteMatte, TrueColor, TrueColorMatte, ColorSeparation, ColorSeparationMatte, or Optimize.

Normally, when a format supports different subformats such as grayscale and truecolor, the encoder will try to choose an efficient subformat. The -type option can be used to overrride this behavior. For example, to prevent a JPEG from being written in grayscale format even though only gray pixels are present, use


    convert bird.pgm -type TrueColor bird.jpg

Similarly, using -type TrueColorMatte will force the encoder to write an alpha channel even though the image is opaque, if the output format supports transparency.

-update <seconds>
detect when image file is modified and redisplay.

Suppose that while you are displaying an image the file that is currently displayed is over-written. display will automatically detect that the input file has been changed and update the displayed image accordingly.

-units <type>
the type of image resolution

Choose from: Undefined, PixelsPerInch, or PixelsPerCentimeter.

-unsharp <radius>x<sigma>
sharpen the image with an unsharp mask operator

Use the given radius and standard deviation (sigma).

-use_pixmap
use the pixmap
-verbose
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.

-view <string>
FlashPix viewing parameters
-visual <type>
animate images using this X visual type

Choose from these visual classes:


     StaticGray
     GrayScale
     StaticColor
     PseudoColor
     TrueColor
     DirectColor
     default
     visual id

The X server must support the visual you choose, otherwise an error occurs. If a visual is not specified, the visual class that can display the most simultaneous colors on the default screen is chosen.

-watermark <brightness>x<saturation>
percent brightness and saturation of a watermark
-wave <amplitude>x<wavelength>
alter an image along a sine wave

Specify amplitude and wavelength of the wave.

-window <id>
make image the background of a window

id can be a window id or name. Specify root to select X's root window as the target window.

By default the image is tiled onto the background of the target window. If backdrop or -geometry are specified, the image is surrounded by the background color. Refer to X RESOURCES for details.

The image will not display on the root window if the image has more unique colors than the target window colormap allows. Use -colors to reduce the number of colors.

-window_group
specify the window group
-write <filename>
write an image sequence [convert, composite]

The image sequence following the -write filenameoption is written out, and then processing continues with the same image in its current state if there are additional options. To restore the image to its original state after writing it, use the +write filename option.

-write <filename>
write the image to a file [display]

If filename already exists, you will be prompted as to whether it should be overwritten.

By default, the image is written in the format that it was read in as. To specify a particular image format, prefix filename with the image type and a colon (e.g., ps:image) or specify the image type as the filename suffix (e.g., image.ps). See convert(1) for a list of valid image formats. Specify file as - for standard output. If file has the extension .Z or .gz, the file size is compressed using compress or gzip respectively. Precede the image file name with | to pipe to a system command.

Use -compress to specify the type of image compression.

The equivalent X resource for this option is writeFilename (class WriteFilename). See "X Resources", below, for details.

 

FILES AND FORMATS

By default, the image format is determined by its magic number, i.e., the first few bytes of the file. 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. The magic number takes precedence over the filename suffix and the prefix takes precedence over the magic number and the suffix in input files. The prefix takes precedence over the filename suffix in output files. To read the "built-in" formats (GRANITE, H, LOGO, NETSCAPE, PLASMA, and ROSE) use a prefix (including the colon) without a filename or suffix. To read the XC format, follow the colon with a color specification. To read the CAPTION format, follow the colon with a text string or with a filename prefixed with the at symbol (@).

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 is compressed using with compress or gzip respectively.

Finally, when running on platforms that allow it, precede the image file name with | to pipe to or from a system command (this feature is not available on VMS, Win32 and Macintosh platforms).

Use an optional index enclosed in brackets after an input 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 %d, %0Nd, %o, %0No, %x, or %0Nx printf format specification in the file name. For example,


    image%02d.miff

writes files image00.miff, image01.miff, etc.

When running a commandline utility, you can 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.  

SEE ALSO

animate(1), display(1), animate(1), display(1), identify(1), import(1), montage(1), mogrify(1), composite(1)

 


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