man pages for display

ImageMagick Last change: 1 Feb 1995
NAME
     display - display an image on any workstation running X

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

DESCRIPTION
     Display is a machine architecture independent image
     processing and display program.  It can display an image on
     any workstation screen running an X server.  Display can
     read and write many of the more popular image formats (e.g.
     JPEG, TIFF, PNM, Photo CD, etc.).  With display, you can
     perform these functions on an image:

         o load an image from a file
         o display the next image
         o display the former image
         o display a sequence of images as a slide show
         o write the image to a file
         o print the image to a Postscript printer
         o delete the image file
         o create a Visual Image Directory
         o select the image to display by its thumbnail rather
     than name
         o copy a region of the image
         o paste a region to the image
         o undo last image transformation
         o half the image size
         o double the image size
         o resize the image
         o restore the image to its original size
         o refresh the image
         o crop the image
         o cut the image
         o flop image in the horizontal direction
         o flip image in the vertical direction
         o rotate the image 90 degrees clockwise
         o rotate the image 90 degrees counter-clockwise
         o rotate the image
         o shear the image
         o trim the image edges
         o invert the colors of the image
         o vary the color brightness
         o vary the color saturation
         o vary the image hue
         o gamma correct the image
         o sharpen the image contrast
         o dull the image contrast
         o perform histogram equalization on the image
         o perform histogram normalization on the image
         o negate the image colors
         o convert the image to grayscale

         o set the maximum number of unique colors in the image
         o reduce the speckles within an image
         o eliminate peak noise from an image
         o detect edges within the image
         o emboss an image
         o segment the image by color
         o simulate an oil painting
         o simulate a charcoal drawing
         o annotate the image with text
         o draw on the image
         o edit an image pixel color
         o edit the image matte information
         o composite an image with another
         o add a border to the image
         o surround image with an ornamental border
         o add an image comment
         o apply image processing techniques to a region of
     interest
         o display information about the image
         o show a histogram of the image
         o display image to background of a window
         o set user preferences
         o display information about this program
         o discard all images and exit program
         o change the level of magnification
         o display images specified by a World Wide Web (WWW)
     uniform resource locator (URL)

EXAMPLES
     To scale an image of a cockatoo to exactly 640 pixels in
     width and 480 pixels in height and position the window at
     location (200,200), use:

          display -geometry 640x480+200+200! cockatoo.miff

     To display an image of a cockatoo without a border centered
     on a backdrop, use:

          display +borderwidth -backdrop cockatoo.miff

     To tile a slate texture onto the root window, use:

          display -size 1280x1024 -window root slate.png

     To display a visual image directory of all your JPEG images,
     use:

          display 'vid:*.jpg'

     To display a MAP image that is 640 pixels in width and 480
     pixels in height with 256 colors, use:

          display -size 640x480+256 cockatoo.map

     To display an image of a cockatoo specified with a World
     Wide Web (WWW) uniform resource locator (URL), use

          display ftp://wizards.dupont.com/images/cockatoo.jpg

OPTIONS
     -backdrop
          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.  Refer to X
          RESOURCES for details.

     -border x
          surround the image with a border of color.  See X(1)
          for details about the geometry specification.

          The color of the border is obtained from the X server
          and is defined as bordercolor (class borderColor).  See
          X(1) for 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.

     -colormap type
          the type of colormap: 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(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
          preserves the matte channel of the image if it exists.

          The -colors or -monochrome option is required for this
          option to take effect.

     -comment string
          annotate an image with a comment.

          By default, each image is commented with its file name.
          Use this option to assign a specific comment to the
          image.  Optionally you can include the image filename,
          type, width, height, or other image attributes by
          embedding special format characters:

              %b   file size
              %d   directory
              %e   filename 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.

          Use this option with -write to specify the the type of
          image compression.  See miff(5) for details.

          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 x{+-}{+-}{%}
          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%.

          Use cropping to apply image processing options to, or
          display, a particular area of an image.

          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.

          The equivalent X resource for this option is
          cropGeometry (class CropGeometry).  See X RESOURCES for
          details.

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

          This option is useful when viewing several images in
          sequence.  1/100ths of a second must expire before the
          next image is displayed.  The delay is rounded to the
          nearest second.  The default is to display the image
          and wait until you choose to display the next image or
          terminate the program.

     -density x
          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
          the same as the resolution of your X server (see
          xdpyinfo(1)).  This option is used in concert with
          -page.

     -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 aliasing.

     -edge factor
          detect edges with an image.  Specify factor as the
          percent enhancement (0.0 - 99.9%).

     -enhance
          apply a digital filter to enhance a noisy image.

     -filter value
          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.

     -
          frame x++
          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 command line option.

     -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 (i.e. 1.7/2.3/1.2).

          Use +gamma 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).

offset>{%}{!}{<}{>}
     -geometry x{+-}{+-} 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.

          When displaying an image on an X server,  and
           is relative to the root window.

          The equivalent X resource for this option is geometry
          (class Geometry).  See X RESOURCES for details.

     -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 interlacing
          (RRR...GGG...BBB...RRR...GGG...BBB...), and Plane uses
          plane interlacing (RRRRRR...GGGGGG...BBBBBB...).
          Partition is like plane except the different planes are
          saved to individual files (e.g.  image.R, image.G, and
          image.B).

          Use Line, or Plane to create an interlaced GIF or
          progressive JPEG image.

     -immutable
          displayed image cannot be modified",

     -label string
          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 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.

     -map type
          display image using this Standard Colormap type.

          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(1) 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.

     -matte
          store matte channel if the image has one otherwise
          create an opaque one.

     -monochrome
          transform the image to black and white.

     -negate
          replace every pixel with its complementary color (white
          becomes black, yellow becomes blue, etc.).

          The red, green, and blue intensities of an image are
          negated.   Use +negate to only negate the grayscale
          pixels of the image.

     -page x{+-}{+-
          }{%}{!}{<}{>}
          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:

              Letter      612x 792
              Tabloid     792x1224
              Ledger     1224x 792
              Legal       612x1008
              Statement   396x 612
              Executive   540x 720
              A3          842x1190
              A4          595x 842
              A5          420x 595
              B4          729x1032
              B5          516x 729
              Folio       612x 936
              Quarto      610x 780
              10x14       720x1008

          For convenience you can specify the page size by media

          (e.g.  A4, Ledger, etc.).  Otherwise, -page behaves
          much like -geometry (e.g. -page letter+43+43>).

          To position a GIF image, use -page {+-}{+-} (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 {+-}{+-}.  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.

     -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, otherwise no filtering is used.

          If filter-type is 6 or more, adaptive filtering with
          minimum-sum-of-absolute-values is used.

          The default is quality is 75.  Which means nearly the
          best compression with adaptive filtering.

          For further information, see the PNG specification (RFC
          2083), .

     -raise x
          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.

     -remote string
          execute a command in an remote display process.

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

     -roll {+-}{+-}
          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).

     -sample geometry
          scale image with pixel sampling.  See -geometry for
          details about the geometry specification.

     -scene value
          image scene number.

          Use this option to specify an image sequence with a
          single filename.  See the discussion of file below for
          details.

     -segment value
          eliminate clusters that are insignificant.

          The number of pixels in each cluster must exceed the
          the cluster threshold to be considered valid.

          See IMAGE SEGMENTATION for details.

     -sharpen x

          sharpen the image with a gaussian operator of the given
          radius and standard deviation (sigma).

     -size x+
          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).

     -texture filename
          name of texture to tile onto the image background.

     -title string
          assign a title to the displayed image.

          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 attributes by embedding
          special format characters.  See -comment for details.

          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.

     -treedepth value
          Normally, this integer value is zero or one.  A zero or
          one tells display 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 or -monochrome option is required for this
          option to take effect.

     -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.

     -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(5) 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(9) for a description of
          these values.

     -visual type
          display image using this 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 X server screen is
          chosen.

     -window id
          set the background pixmap of this window to the image.

          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 id exit program when this window
          id is destroyed.

          id can be a window id or name.

     -write filename
          write image to a file.

          If file 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 file with the image type and a colon (i.e.
          ps:image) or specify the image type as the filename
          suffix (i.e. image.ps).  See convert(1) for a list of
          valid image formats.  Specify file as - for standard
          output.  If file has the extension .Z or .gz, the file
          size is compressed using with compress or gzip
          respectively.  Precede the image file name | to pipe to
          a system command. If file already exists, you will be
          prompted as to whether it should be overwritten.

          Use -compress to specify the type of image compression.

          The equivalent X resource for this option is
          writeFilename (class WriteFilename).  See X RESOURCES
          for details.

     In addition to those listed above, you can specify these
     standard X resources as command line options:  -background,
     -bordercolor, -borderwidth, -font, -foreground,
     -iconGeometry, -iconic, -mattecolor, -name, or -title.  See
     X RESOURCES for details.

     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.  For example to display two images, the
     first with 32 colors, and the second with only 16 colors,
     use:

          display -colors 32 cockatoo.miff -colors 16 macaw.miff

     By default, the image format is determined by its magic
     number. To specify a particular image format, precede the
     filename with an image format name and a colon (i.e.
     ps:image) or specify the image type as the filename suffix
     (i.e. image.ps).  See convert(1) for a list of valid image
     formats.

     When you specify X as your image type, the filename has
     special meaning.  It specifies an X window by id, name, or
     root.  If no filename is specified, the window is selected
     by clicking the mouse in the desired window.

     Specify file as - for standard input.  If file has the
     extension .Z or .gz, the file is uncompressed with
     uncompress or gunzip respectively.  Precede the image file
     name | to pipe 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 read with the filename you specify.
     Alternatively, you can display an image sequence with a
     single filename.  Define the range of the image sequence
     with -scene.  Each image in the range is read 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,

          -scene 0-9 image%02d.miff

     displays files image00.miff, image01.miff, through
     image09.miff.

BUTTONS
     The effects of each button press is described below.  Three
     buttons are required.  If you have a two button mouse,
     button 1 and 3 are returned.  Press ALT and button 3 to
     simulate button 2.

     1    Press this button to map or unmap the Command widget.
          See the next section for more information about the

          Command widget.

     2    Press and drag to define a region of the image to
          magnify.

     3    Press and drag to choose from a select set of
          display(1) commands.  This button behaves differently
          if the image being displayed is a visual image
          directory.  Here, choose a particular tile of the
          directory and press this button and drag to select a
          command from a pop-up menu.  Choose from these menu
          items:

              Open
              Next
              Former
              Delete
              Update

          If you choose Open, the image represented by the tile
          is displayed.  To return to the visual image directory,
          choose Next from the Command widget (refer to COMMAND
          WIDGET).  Next and Former moves to the next or former
          image respectively.  Choose Delete to delete a
          particular image tile.  Finally, choose Update to
          synchronize all the image tiles with their respective
          images.  See montage(1) and miff(5) for more details.

COMMAND WIDGET
     The Command widget lists a number of sub-menus and commands.
     They are

         File
           Open...
           Next
           Former
           Select...
           Save...
           Print...
           Delete...
           Canvas...
           Visual Directory...
           Quit
         Edit
           Undo
           Redo
           Cut
           Copy
           Paste
         View
           Half Size
           Original Size

           Double Size
           Resize...
           Apply
           Refresh
           Restore
         Transform
           Crop
           Chop
           Flop
           Flip
           Rotate Right
           Rotate Left
           Rotate...
           Shear...
           Roll...
           Trim Edges
         Enhance
           Hue...
           Saturation...
           Brightness...
           Gamma...
           Spiff...
           Dull
           Equalize
           Normalize
           Negate
           Grayscale
           Map...
           Quantize...
         Effects
           Despeckle
           Emboss
           Reduce Noise
           Add Noise
           Sharpen...
           Blur...
           Threshold...
           Edge Detect...
           Spread...
           Shade...
           Raise...
           Segment...
         F/X
           Solarize...
           Swirl...
           Implode...
           Wave...
           Oil Paint...
           Charcoal Draw...
         Image Edit
           Annotate...
           Draw...

           Color...
           Matte...
           Composite...
           Add Border...
           Add Frame...
           Comment...
           Launch...
           Region of Interest...
         Miscellany
           Image Info
           Zoom Image
           Show Preview...
           Show Histogram
           Show Matte
           Background...
           Slide Show
           Preferences...
         Help
           Help
           Browse Documentation
           About Display

     Menu items with a indented triangle have a sub-menu.  They
     are represented above as the indented items.  To access a
     sub-menu item, move the pointer to the appropriate menu and
     press button 1 and drag.  When you find the desired sub-menu
     item, release the button and the command is executed.  Move
     the pointer away from the sub-menu if you decide not to
     execute a particular command.

KEYBOARD ACCELERATORS
     Accelerators are one or two key presses that effect a
     particular command.  The keyboard accelerators that
     display(1) understands is:

     Ctl+O
          Press to load an image from a file.

          Refer to IMAGE LOADING for more details.

     space
          Press to display the next image.

          If the image is a multi-paged document such as a
          Postscript document, you can skip ahead several pages
          by preceeding this command with a number.  For example
          to display the fourth page beyond the current page,
          press 4space.

     backspace
          Press to display the former image.

          If the image is a multi-paged document such as a
          Postscript document, you can skip behind several pages
          by preceeding this command with a number.  For example
          to display the fourth page preceeding the current page,
          press 4n.

     Ctl+S
          Press to save the image to a file.

     Ctl+P
          Press to print the image to a Postscript printer.

     Ctl+D
          Press to delete an image file.

     Ctl+N
          Press to create a blank canvas.

     Ctl+Q
          Press to discard all images and exit program.

     Ctl+Z
          Press to undo last image transformation.

     Ctl+R
          Press to redo last image transformation.

     Ctl+X
          Press to cut a region of the image.

          Refer to IMAGE CUTTING for more details.

     Ctl+C
          Press to copy a region of the image.

          Refer to IMAGE COPYING for more details.

     Ctl+V
          Press to paste a region to the image.

          Refer to IMAGE PASTING for more details.

     <    Press to half the image size.

     -    Press to return to the original image size.

     >    Press to double the image size.

     %    Press to resize the image to a width and height you
          specify.

     Cmd-A

          Press to make any image transformations permanent.

          By default, any image size transformations are applied
          to the original image to create the image displayed on
          the X server.  However, the transformations are not
          permanent (i.e. the original image does not change size
          only the X image does).  For example, if you press >
          the X image will appear to double in size, but the
          original image will in fact remain the same size.  To
          force the original image to double in size, press >
          followed by A.

     @    Press to refresh the image window.

     C    Press to crop the image.

          Refer to IMAGE CROPPING for more details.

     [    Press to chop the image.

          Refer to IMAGE CHOPPING for more details.

     H    Press to flop image in the horizontal direction.

     V    Press to flip image in the vertical direction.

     /    Press to rotate the image 90 degrees clockwise.

     Press to rotate the image 90 degrees counter-clockwise.

     *    Press to rotate the image the number of degrees you
          specify.

          Refer to IMAGE ROTATION for more details.

     s    Press to shear the image the number of degrees you
          specify.

     r    Press to roll the image.

     t    Press to trim the image edges.

     Shft-H
          Press to vary the color hue.

     Shft-S
          Press to vary the color saturation.

     Shft-L
          Press to vary the image brightness.

     Shft-G

          Press to gamma correct the image.

     Shft-C
          Press to spiff up the image contrast.

     Shft-Z
          Press to dull the image contrast.

     =    Press to perform histogram equalization on the image.

     Shft-N
          Press to perform histogram normalization on the image.

     ~    Press to negate the colors of the image.

     .    Press to convert the image colors to gray.

     #    Press to set the maximum number of unique colors in the
          image.

     F2   Press to reduce the speckles in an image.

     F3   Press to emboss an image.

     F4   Press to eliminate peak noise from an image.

     F5   Press to add noise to an image.

     F6   Press to sharpen an image.

     F7   Press to blur image an image.

     F8   Press to threshold the image.

     F9   Press to detect edges within an image.

     F10  Press to displace pixels by a random amount.

     F11  Press to shade the image using a distant light source.

     F12  Press to lighten or darken image edges to create a 3-D
          effect.

     F13  Press to segment the image by color.

     Meta-S
          Press to swirl image pixels about the center.

     Meta-I
          Press to implode image pixels about the center.

     Meta-W

          Press to alter an image along a sine wave.

     Meta-P
          Press to simulate an oil painting.

     Meta-C
          Press to simulate a charcoal drawing.

     Alt-A
          Press to annotate the image with text.

          Refer to IMAGE ANNOTATION for more details.

     Alt-D
          Press to draw a line on the image.

          Refer to IMAGE DRAWING for more details.

     Alt-P
          Press to edit an image pixel color.

          Refer to COLOR EDITING for more details.

     Alt-M
          Press to edit the image matte information.

          Refer to MATTE EDITING for more details.

     Alt-V
          Press to composite the image with another.

          Refer to IMAGE COMPOSITING for more details.

     Alt-B
          Press to add a border to the image.

     Alt-F
          Press to add a ornamental frame to the image.

     Alt-Shft-!
          Press to add an image comment.

     Ctl-A
          Press to apply an image processing technique to a
          region of interest.

          Refer to REGION OF INTEREST for more details.

     Shft-?
          Press to display information about the image.

     Shft-+

          Press to map the zoom image window.

     Shft-P
          Press to preview an image enhancement, effect, or f/x.

     F1   Press to display helpful information about display(1).

     Find Press to browse documentation about ImageMagick.

     1-9  Press to change the level of magnification.

          Use the arrow keys to move the image one pixel up,
          down, left, or right within the magnify window.  Be
          sure to first map the magnify window by pressing button
          2.

          Press ALT and one of the arrow keys to trim off one
          pixel from any side of the image.

X RESOURCES
     Display options can appear on the command line or in your X
     resource file.  Options on the command line supersede values
     specified in your X resource file.  See X(1) for more
     information on X resources.

     Most display options have a corresponding X resource.  In
     addition, display uses the following X resources:

     background (class Background)
          Specifies the preferred color to use for the image
          window background.  The default is #ccc.

     borderColor (class BorderColor)
          Specifies the preferred color to use for the image
          window border.  The default is #ccc.

     borderWidth (class BorderWidth)
          Specifies the width in pixels of the image window
          border.  The default is 2.

     browseCommand (class browseCommand)
          Specifies the name of the preferred browser when
          displaying ImageMagick documentation.  The default is
          netscape %s.

     confirmExit (class ConfirmExit)
          Display pops up a dialog box to confirm exiting the
          program when exiting the program.  Set this resource to
          False to exit without a confirmation.

     displayGamma (class DisplayGamma)
          Specifies the gamma of your X server.

          You can apply separate gamma values to the red, green,
          and blue channels of the image with a gamma value list
          delineated with slashes (i.e. 1.7/2.3/1.2).

          The default is 2.2.

     displayWarnings (class DisplayWarnings)
          Display pops up a dialog box whenever a warning message
          occurs.  Set this resource to False to ignore warning
          messages.

     font (class FontList)
          Specifies the name of the preferred font to use in
          normal formatted text.  The default is 14 point
          Helvetica.

     font[1-9] (class Font[1-9])
          Specifies the name of the preferred font to use when
          annotating the image window with text.  The default
          fonts are fixed, variable, 5x8, 6x10, 7x13bold,
          8x13bold, 9x15bold, 10x20, and 12x24.  Refer to IMAGE
          ANNOTATION for more details.

     foreground (class Foreground)
          Specifies the preferred color to use for text within
          the image window.  The default is black.

     gammaCorrect (class gammaCorrect)
          This resource, if true, will lighten or darken an image
          of known gamma to match the gamma of the display (see
          resource displayGamma).  The default is True.

     geometry (class Geometry)
          Specifies the preferred size and position of the image
          window.  It is not necessarily obeyed by all window
          managers.

     iconGeometry (class IconGeometry)
          Specifies the preferred size and position of the
          application when iconified.  It is not necessarily
          obeyed by all window managers.

     iconic (class Iconic)
          This resource indicates that you would prefer that the
          application's windows initially not be visible as if
          the windows had be immediately iconified by you.
          Window managers may choose not to honor the
          application's request.

     magnify (class Magnify)
          specifies an integral factor by which the image should
          be enlarged.  The default is 3.

          This value only affects the magnification window which
          is invoked with button number 3 after the image is
          displayed.  Refer to BUTTONS for more details.

     matteColor (class MatteColor)
          Specify the color of windows.  It is used for the
          backgrounds of windows, menus, and notices.  A 3D
          effect  is achieved  by using highlight and shadow
          colors derived from this color.  Default value: #ccc.

     name (class Name)
          This resource specifies the name under which resources
          for the application should be found.  This resource is
          useful in shell aliases to distinguish between
          invocations of an application, without resorting to
          creating links to alter the executable file name.  The
          default is the application name.

     pen[1-9] (class Pen[1-9])
          Specifies the color of the preferred font to use when
          annotating the image window with text.  The default
          colors are black, blue, green, cyan, gray, red,
          magenta, yellow, and white.  Refer to IMAGE ANNOTATION
          for more details.

     printCommand (class PrintCommand)
          This command is executed whenever Print is issued (see
          BUTTONS.  In general, it is the command to print
          Postscript to your printer.  Default value: lp -c -s
          %i.

     sharedMemory (class SharedMemory)
          This resource specifies whether display 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
          resource is ignored.  The default is True.

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

     title (class Title)
          This resource specifies the title to be used for the
          image window.  This information is sometimes used by a
          window manager to provide a header identifying the
          window.  The default is the image file name.

     undoCache (class UndoCache)
          Specifies, in mega-bytes, the amount of memory in the
          undo edit cache.  Each time you modify the image it is

          saved in the undo edit cache as long as memory is
          available.  You can subsequently undo one or more of
          these transformations.  The default is 16 mega-bytes.

     usePixmap (class UsePixmap)
          Images are maintained as a XImage by default.  Set this
          resource to True to utilize a server Pixmap instead.
          This option is useful if your image exceeds the
          dimensions of your server screen and you intend to pan
          the image.  Panning is much faster with Pixmaps than
          with a XImage.  Pixmaps are considered a precious
          resource, use them with discretion.

          To set the geometry of the Magnify or Pan or window,
          use the geometry resource.  For example, to set the Pan
          window geometry to 256x256, use:

               display.pan.geometry: 256x256

IMAGE LOADING
     To select an image to display, choose Open of the File sub-
     menu from the Command widget.  A file browser is displayed.
     To choose a particular image file, move the pointer to the
     filename and press any button.  The filename is copied to
     the text window.  Next, press Open or press the RETURN key.
     Alternatively, you can type the image file name directly
     into the text window.  To descend directories, choose a
     directory name and press the button twice quickly.  A
     scrollbar allows a large list of filenames to be moved
     through the viewing area if it exceeds the size of the list
     area.

     You can trim the list of file names by using shell globbing
     characters.  For example, type *.jpg to list only files that
     end with .jpg.

     To select your image from the X server screen instead of
     from a file, Choose Grab of the Open widget.

VISUAL IMAGE DIRECTORY
     To create a Visual Image Directory, choose Visual Directory
     of the File sub-menu from the Command widget.  A file
     browser is displayed.  To create a Visual Image Directory
     from all the images in the current directory, press
     Directory or press the RETURN key.  Alternatively, you can
     select a set of image names by using shell globbing
     characters.  For example, type *.jpg to include only files
     that end with .jpg.  To descend directories, choose a
     directory name and press the button twice quickly.  A
     scrollbar allows a large list of filenames to be moved
     through the viewing area if it exceeds the size of the list

     area.

     After you select a set of files, they are turned into
     thumbnails and tiled onto a single image.  Now move the
     pointer to a particular thumbnail and press button 3 and
     drag.  Finally, select Open.  The image represented by the
     thumbnail is displayed at its full size.  Choose Next from
     the File sub-menu of the Command widget to return to the
     Visual Image Directory.

IMAGE CUTTING
     Note that cut information for image window is not retained
     for colormapped X server visuals (e.g. StaticColor,
     StaticColor, GrayScale, PseudoColor).  Correct cutting
     behavior may require a TrueColor or DirectColor visual or a
     Standard Colormap.

     To begin, press choose Cut of the Edit sub-menu from the
     Command widget (see COMMAND WIDGET).  Alternatively, press
     F3 in the image window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window.  You are now in cut mode.  In cut mode,
     the Command widget has these options:

         Help
         Dismiss

     To define a cut region, press button 1 and drag.  The cut
     region is defined by a highlighted rectangle that expands or
     contracts as it follows the pointer.  Once you are satisfied
     with the cut region, release the button.  You are now in
     rectify mode.  In rectify mode, the Command widget has these
     options:

         Cut
         Help
         Dismiss

     You can make adjustments by moving the pointer to one of the
     cut rectangle corners, pressing a button, and dragging.
     Finally, press Cut to commit your copy region.  To exit
     without cutting the image, press Dismiss.

IMAGE COPYING
     To begin, press choose Copy of the Edit sub-menu from the
     Command widget (see COMMAND WIDGET).  Alternatively, press
     F4 in the image window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window.  You are now in copy mode.  In copy mode,
     the Command widget has these options:

         Help
         Dismiss

     To define a copy region, press button 1 and drag.  The copy
     region is defined by a highlighted rectangle that expands or
     contracts as it follows the pointer.  Once you are satisfied
     with the copy region, release the button.  You are now in
     rectify mode.  In rectify mode, the Command widget has these
     options:

         Copy
         Help
         Dismiss

     You can make adjustments by moving the pointer to one of the
     copy rectangle corners, pressing a button, and dragging.
     Finally, press Copy to commit your copy region.  To exit
     without copying the image, press Dismiss.

IMAGE PASTING
     To begin, press choose Paste of the Edit sub-menu from the
     Command widget (see COMMAND WIDGET).  Alternatively, press
     F5 in the image window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window. You are now in Paste mode.  To exit
     immediately, press Dismiss.  In Paste mode, the Command
     widget has these options:

         Operators
           Over
           In
           Out
           Atop
           Xor
           Plus
           Minus
           Add
           Subtract
           Difference
           Bumpmap
           Replace
           ReplaceRed
           ReplaceGreen
           ReplaceBlue
           ReplaceMatte
         Help
         Dismiss

     Choose a composite operation from the Operators sub-menu of
     the Command widget.  How each operator behaves is described
     below.  image window is the image currently displayed on

     your X server and image is the image obtained with the File
     Browser widget.

     Over The result is the union of the two image shapes, with
          image obscuring image window in the region of overlap.

     In   The result is simply image cut by the shape of image
          window.  None of the image data of image window is in
          the result.

     Out  The resulting image is image with the shape of image
          window cut out.

     Atop The result is the same shape as image image window,
          with image obscuring image window where the image
          shapes overlap.  Note this differs from over because
          the portion of image outside image window's shape does
          not appear in the result.

     Xor  The result is the image data from both image and image
          window that is outside the overlap region.  The overlap
          region is 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 image - image window, with underflow
          cropped to zero.  The matte channel is ignored (set to
          255, full coverage).

     Add  The result of image + image window, with overflow
          wrapping around (mod 256).

     Subtract
          The result of image - image window, with underflow
          wrapping around (mod 256).  The add and subtract
          operators can be used to perform reversible
          transformations.

     Difference
          The result of abs(image - image window).  This is
          useful for comparing two very similar images.

     Bumpmap
          The result of image window  shaded by image.

     Replace
          The resulting image is image window replaced with
          image.  Here the matte information is ignored.

     ReplaceRed
          The resulting image is the red layer of image window
          replaced with the red layer of image.  The remaining
          layers remain untouched.

     ReplaceGreen
          The resulting image is the green layer of image window
          replaced with the green layer of image.  The remaining
          layers remain untouched.

     ReplaceBlue
          The resulting image is the blue layer of image window
          replaced with the blue layer of image.  The remaining
          layers remain untouched.

     ReplaceMatte
          The resulting image is the matte layer of image window
          replaced with the matte layer of image.  The remaining
          layers remain 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.  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.  See MATTE
          EDITING for a method of defining a matte channel.

          Note that matte information for image window is not
          retained for colormapped X server visuals (e.g.
          StaticColor, StaticColor, GrayScale, PseudoColor).
          Correct compositing behavior may require a TrueColor or
          DirectColor visual or a Standard Colormap.

          Choosing a composite operator is optional.  The default
          operator is replace.  However, you must choose a
          location to composite your image and press button 1.
          Press and hold the button before releasing and an
          outline of the image will appear to help you identify
          your location.

          The actual colors of the pasted image is saved.
          However, the color that appears in image window may be
          different.  For example, on a monochrome screen image
          window will appear black or white even though your
          pasted image may have many colors.  If the image is
          saved to a file it is written with the correct colors.
          To assure the correct colors are saved in the final
          image, any PseudoClass image is promoted to DirectClass

          (see miff(5)).  To force a PseudoClass image to remain
          PseudoClass, use -colors.

IMAGE CROPPING
     To begin, press choose Crop of the Transform sub-menu from
     the Command widget (see COMMAND WIDGET).  Alternatively,
     press [ in the image window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window.  You are now in crop mode.  In crop mode,
     the Command widget has these options:

         Help
         Dismiss

     To define a cropping region, press button 1 and drag.  The
     cropping region is defined by a highlighted rectangle that
     expands or contracts as it follows the pointer.  Once you
     are satisfied with the cropping region, release the button.
     You are now in rectify mode.  In rectify mode, the Command
     widget has these options:

         Crop
         Help
         Dismiss

     You can make adjustments by moving the pointer to one of the
     cropping rectangle corners, pressing a button, and dragging.
     Finally, press Crop to commit your cropping region.  To exit
     without cropping the image, press Dismiss.

IMAGE CHOPPING
     An image is chopped interactively.  There is no command line
     argument to chop an image.  To begin, choose Chop of the
     Transform sub-menu from the Command widget (see COMMAND
     WIDGET).  Alternatively, press ] in the image window (see
     KEYBOARD ACCELERATORS).

     You are now in Chop mode.  To exit immediately, press
     Dismiss.  In Chop mode, the Command widget has these
     options:

         Direction
           horizontal
           vertical
         Help
         Dismiss

     If the you choose the horizontal direction (this is the
     default), the area of the image between the two horizontal
     endpoints of the chop line is removed.  Otherwise, the area
     of the image between the two vertical endpoints of the chop

     line is removed.

     Select a location within the image window to begin your
     chop, press and hold any button.  Next, move the pointer to
     another location in the image.  As you move a line will
     connect the initial location and the pointer.  When you
     release the button, the area within the image to chop is
     determined by which direction you choose from the Command
     widget.

     To cancel the image chopping, move the pointer back to the
     starting point of the line and release the button.

IMAGE ROTATION
     Press the / key to rotate the image 90 degrees or \ to
     rotate -90 degrees (see KEYBOARD ACCELERATORS).  To
     interactively choose the degree of rotation, choose
     Rotate... of the Pixel Transform submenu from the Command
     Widget (see COMMAND WIDGET).  Alternatively, press * in the
     image window (see KEYBOARD ACCELERATORS).

     A small horizontal line is drawn next to the pointer.  You
     are now in rotate mode.  To exit immediately, press Dismiss.
     In rotate mode, the Command widget has these options:

         Pixel Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           Browser...
         Direction
           horizontal
           vertical
         Crop
           false
           true
         Sharpen
           false
           true
         Help
         Dismiss

     Choose a background color from the Pixel Color sub-menu.
     Additional background colors can be specified with the color
     browser.  You can change the menu colors by setting the X
     resources pen1 through pen9.  Refer to X RESOURCES for more

     details.

     If you choose the color browser and press Grab, you can
     select the background color by moving the pointer to the
     desired color on the screen and press any button. The
     transparent color updates the image matte channel and is
     useful for image compositing.

     Choose a point in the image window and press this button and
     hold.  Next, move the pointer to another location in the
     image.  As you move a line connects the initial location and
     the pointer.  When you release the button, the degree of
     image rotation is determined by the slope of the line you
     just drew.  The slope is relative to the direction you
     choose from the Direction sub-menu of the Command widget.

     To cancel the image rotation, move the pointer back to the
     starting point of the line and release the button.

IMAGE ANNOTATION
     An image is annotated interactively.  There is no command
     line argument to annotate an image.  To begin, choose
     Annotate of the Image Edit sub-menu from the Command widget
     (see COMMAND WIDGET).  Alternatively, press a in the image
     window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window.  You are now in annotate mode.  To exit
     immediately, press Dismiss.  In annotate mode, the Command
     widget has these options:

         Font Name
           fixed
           variable
           5x8
           6x10
           7x13bold
           8x13bold
           9x15bold
           10x20
           12x24
           Browser...
         Font Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white

           transparent
           Browser...
         Box Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           transparent
           Browser...
         Rotate Text
           -90
           -45
           -30
           0
           30
           45
           90
           180
           Dialog...
         Help
         Dismiss

     Choose a font name from the Font Name sub-menu.  Additional
     font names can be specified with the font browser.  You can
     change the menu names by setting the X resources font1
     through font9.  Refer to X RESOURCES for more details.

     Choose a font color from the Font Color sub-menu.
     Additional font colors can be specified with the color
     browser.  You can change the menu colors by setting the X
     resources pen1 through pen9.  Refer to X RESOURCES for more
     details.

     If you select the color browser and press Grab, you can
     choose the font color by moving the pointer to the desired
     color on the screen and press any button.

     If you choose to rotate the text, choose Rotate Text from
     the menu and select an angle.  Typically you will only want
     to rotate one line of text at a time.  Depending on the
     angle you choose, subsequent lines may end up overwriting
     each other.

     Choosing a font and its color is optional.  The default font
     is fixed and the default color is black.  However, you must
     choose a location to begin entering text and press button 1.
     An underscore character will appear at the location of the

     pointer.  The cursor changes to a pencil to indicate you are
     in text mode.  To exit immediately, press Dismiss.

     In text mode, any key presses will display the character at
     the location of the underscore and advance the underscore
     cursor.  Enter your text and once completed press Dismiss to
     finish your image annotation.  To correct errors press BACK
     SPACE.  To delete an entire line of text, press DELETE.  Any
     text that exceeds the boundaries of the image window is
     automatically continued onto the next line.

     The actual color you request for the font is saved in the
     image.  However, the color that appears in your image window
     may be different.  For example, on a monochrome screen the
     text will appear black or white even if you choose the color
     red as the font color.  However, the image saved to a file
     with -write is written with red lettering.  To assure the
     correct color text in the final image, any PseudoClass image
     is promoted to DirectClass (see miff(5)).  To force a
     PseudoClass image to remain PseudoClass, use -colors.

IMAGE COMPOSITING
     An image composite is created interactively.  There is no
     command line argument to composite an image.  To begin,
     choose Composite of the Image Edit from the Command widget
     (see COMMAND WIDGET).  Alternatively, press x in the image
     window (see KEYBOARD ACCELERATORS).

     First a popup window is displayed requesting you to enter an
     image name.  Press Composite, Grab or type a file name.
     Press Cancel if you choose not to create a composite image.
     When you choose Grab, move the pointer to the desired window
     and press any button.

     If the Composite image does not have any matte information,
     you are informed and the file browser is displayed again.
     Enter the name of a mask image.  The image is typically
     grayscale and the same size as the composite image.  If the
     image is not grayscale, it is converted to grayscale and the
     resulting intensities are used as matte information.

     A small window appears showing the location of the cursor in
     the image window. You are now in composite mode.  To exit
     immediately, press Dismiss.  In composite mode, the Command
     widget has these options:

         Operators
           over
           in
           out
           atop
           xor

           plus
           minus
           add
           subtract
           difference
           bumpmap
           replace
         Blend
         Displace
         Help
         Dismiss

     Choose a composite operation from the Operators sub-menu of
     the Command widget.  How each operator behaves is described
     below.  image window is the image currently displayed on
     your X server and image is the image obtained with the File
     Browser widget.

     over The result is the union of the two image shapes, with
          image obscuring image window in the region of overlap.

     in   The result is simply image cut by the shape of image
          window.  None of the image data of image window is in
          the result.

     out  The resulting image is image with the shape of image
          window cut out.

     atop The result is the same shape as image image window,
          with image obscuring image window where the image
          shapes overlap.  Note this differs from over because
          the portion of image outside image window's shape does
          not appear in the result.

     xor  The result is the image data from both image and image
          window that is outside the overlap region.  The overlap
          region is 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 image - image window, with underflow
          cropped to zero.  The matte channel is ignored (set to
          255, full coverage).

     add  The result of image + image window, with overflow
          wrapping around (mod 256).

     subtract

          The result of image - image window, with underflow
          wrapping around (mod 256).  The add and subtract
          operators can be used to perform reversible
          transformations.

     difference
          The result of abs(image - image window).  This is
          useful for comparing two very similar images.

     bumpmap
          The result of image window  shaded by image.

     replace
          The resulting image is image window replaced with
          image.  Here the matte information is ignored.

          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.  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.  See MATTE
          EDITING for a method of defining a matte channel.

          If you choose blend, the composite operator becomes
          over.  The image matte channel percent transparency is
          initialized to factor.  The image window is initialized
          to (100-factor).  Where factor is the value you specify
          in the Dialog widget.

          Displace shifts the image pixels as defined by a
          displacement map.  With this option, 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 a mask, image is the horizontal X displacement
          and mask the vertical Y displacement.

          Note that matte information for image window is not
          retained for colormapped X server visuals (e.g.
          StaticColor, StaticColor, GrayScale, PseudoColor).
          Correct compositing behavior may require a TrueColor or
          DirectColor visual or a Standard Colormap.

          Choosing a composite operator is optional.  The default
          operator is replace.  However, you must choose a

          location to composite your image and press button 1.
          Press and hold the button before releasing and an
          outline of the image will appear to help you identify
          your location.

          The actual colors of the composite image is saved.
          However, the color that appears in image window may be
          different.  For example, on a monochrome screen image
          window will appear black or white even though your
          composited image may have many colors.  If the image is
          saved to a file it is written with the correct colors.
          To assure the correct colors are saved in the final
          image, any PseudoClass image is promoted to DirectClass
          (see miff(5)).  To force a PseudoClass image to remain
          PseudoClass, use -colors.

COLOR EDITING
     Changing the the color of a set of pixels is performed
     interactively.  There is no command line argument to edit a
     pixel.  To begin, choose Color from the Image Edit submenu
     of the Command widget (see COMMAND WIDGET).  Alternatively,
     press c in the image window (see KEYBOARD ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window. You are now in color edit mode.  To exit
     immediately, press Dismiss.  In color edit mode, the Command
     widget has these options:

         Method
           point
           replace
           floodfill
           filltoborder
           reset
         Pixel Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           Browser...
         Border Color
           black
           blue
           cyan
           green
           gray
           red

           magenta
           yellow
           white
           Browser...
         Fuzz
           0
           2
           4
           8
           16
           Dialog...
         Undo
         Help
         Dismiss

     Choose a color editing method from the Method sub-menu of
     the Command widget.  The point method recolors any pixel
     selected with the pointer unless the button is released.
     The replace method recolors any pixel that matches the color
     of the pixel you select with a button press.  Floodfill
     recolors any pixel that matches the color of the pixel you
     select with a button press and is a neighbor.  Whereas
     filltoborder recolors any neighbor pixel that is not the
     border color.  Finally reset changes the entire image to the
     designated color.

     Next, choose a pixel color from the Pixel Color sub-menu.
     Additional pixel colors can be specified with the color
     browser.  You can change the menu colors by setting the X
     resources pen1 through pen9.  Refer to X RESOURCES for more
     details.

     Now press button 1 to select a pixel within the image window
     to change its color.  Additional pixels may be recolored as
     prescribed by the method you choose.

     If the Magnify widget is mapped, it can be helpful in
     positioning your pointer within the image (refer to button
     2).  Alternatively you can select a pixel to recolor from
     within the Magnify widget.  Move the pointer to the Magnify
     widget and position the pixel with the cursor control keys.
     Finally, press a button to recolor the selected pixel (or
     pixels).

     The actual color you request for the pixels is saved in the
     image.  However, the color that appears in your image window
     may be different.  For example, on a monochrome screen the
     pixel will appear black or white even if you choose the
     color red as the pixel color.  However, the image saved to a
     file with -write is written with red pixels.  To assure the
     correct color text in the final image, any PseudoClass image
     is promoted to DirectClass (see miff(5)).  To force a

     PseudoClass image to remain PseudoClass, use -colors.

MATTE EDITING
     Matte information within an image is useful for some
     operations such as image compositing (See IMAGE
     COMPOSITING).  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.

     Setting the matte information in an image is done
     interactively.  There is no command line argument to edit a
     pixel.  To begin, and choose Matte of the Image Edit sub-
     menu from the Command widget (see COMMAND WIDGET).
     Alternatively, press m in the image window (see KEYBOARD
     ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window. You are now in matte edit mode.  To exit
     immediately, press Dismiss.  In matte edit mode, the Command
     widget has these options:

         Method
           point
           replace
           floodfill
           filltoborder
           reset
         Border Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           Browser...
         Fuzz
           0
           2
           4
           8
           16
           Dialog...
         Matte
         Undo
         Help
         Dismiss

     Choose a matte editing method from the Method sub-menu of
     the Command widget.  The point method changes the matte
     value of the any pixel selected with the pointer until the
     button is released.  The replace method changes the matte
     value of any pixel that matches the color of the pixel you
     select with a button press.  Floodfill changes the matte
     value of any pixel that matches the color of the pixel you
     select with a button press and is a neighbor. Whereas
     filltoborder changes the matte value of any neighbor pixel
     that is not the border color.  Finally reset changes the
     entire image to the designated matte value.

     Choose Matte Value and a dialog appears requesting a matte
     value.  Enter a value between 0 and 255.  This value is
     assigned as the matte value of the selected pixel or pixels.

     Now, press any button to select a pixel within the image
     window to change its matte value.

     If the Magnify widget is mapped, it can be helpful in
     positioning your pointer within the image (refer to button
     2).  Alternatively you can select a pixel to change the
     matte value from within the Magnify widget.  Move the
     pointer to the Magnify widget and position the pixel with
     the cursor control keys.  Finally, press a button to change
     the matte value of the selected pixel (or pixels).

     Matte information is only valid in a DirectClass image.
     Therefore, any PseudoClass image is promoted to DirectClass
     (see miff(5)).  Note that matte information for PseudoClass
     is not retained for colormapped X server visuals (e.g.
     StaticColor, StaticColor, GrayScale, PseudoColor) unless you
     immediately save your image to a file (refer to Write).
     Correct matte editing behavior may require a TrueColor or
     DirectColor visual or a Standard Colormap.

IMAGE DRAWING
     An image is drawn upon interactively.  There is no command
     line argument to draw on an image.  To begin, choose Draw of
     the Image Edit sub-menu from the Command widget (see COMMAND
     WIDGET).  Alternatively, press d in the image window (see
     KEYBOARD ACCELERATORS).

     The cursor changes to a crosshair to indicate you are in
     draw mode.  To exit immediately, press Dismiss.  In draw
     mode, the Command widget has these options:

         Primitive
           point
           line
           rectangle
           fill rectangle

           circle
           fill circle
           ellipse
           fill ellipse
           polygon
           fill polygon
         Color
           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           transparent
           Browser...
         Stipple",
           Brick",
           Diagonal",
           Scales",
           Vertical",
           Wavy",
           Translucent",
           Opaque",
           Open...",
         Width
           1
           2
           4
           8
           16
           Dialog...
         Undo
         Help
         Dismiss

     Choose a drawing primitive from the Primitive sub-menu.

     Next, choose a color from the Color sub-menu.  Additional
     colors can be specified with the color browser.  You can
     change the menu colors by setting the X resources pen1
     through pen9.  Refer to X RESOURCES for more details.

     If you choose the color browser and press Grab, you can
     select the primitive color by moving the pointer to the
     desired color on the screen and press any button.  The
     transparent color updates the image matte channel and is
     useful for image compositing.,

     Choose a stipple, if appropriate, from the Stipple sub-menu.

     Additional stipples can be specified with the file browser.
     Stipples obtained from the file browser must be on disk in
     the X11 bitmap format.

     Choose a line width from the Width sub-menu.  To choose a
     specific width select the Dialog widget.

     Choose a point in the image window and press button 1 and
     hold.  Next, move the pointer to another location in the
     image.  As you move, a line connects the initial location
     and the pointer.  When you release the button, the image is
     updated with the primitive you just drew.  For polygons, the
     image is updated when you press and release the button
     without moving the pointer.

     To cancel image drawing, move the pointer back to the
     starting point of the line and release the button.

REGION OF INTEREST
     To begin, press choose Region of Interest of the Transform
     sub-menu from the Command widget (see COMMAND WIDGET).
     Alternatively, press R in the image window (see KEYBOARD
     ACCELERATORS).

     A small window appears showing the location of the cursor in
     the image window.  You are now in region of interest mode.
     In region of interest mode, the Command widget has these
     options:

         Help
         Dismiss

     To define a region of interest, press button 1 and drag.
     The region of interest is defined by a highlighted rectangle
     that expands or contracts as it follows the pointer.  Once
     you are satisfied with the region of interest, release the
     button.  You are now in apply mode.  In apply mode the
     Command widget has these options:

         File
           Save...
           Print...
         Edit
           Undo
           Redo
         Transform
           Flip
           Flop
           Rotate Right
           Rotate Left
         Enhance
           Hue...

           Saturation...
           Brightness...
           Gamma...
           Spiff
           Dull
           Equalize
           Normalize
           Negate
           Grayscale
           Quantize...
         Effects
           Despeckle
           Emboss
           Reduce Noise
           Add Noise
           Sharpen...
           Blur...
           Threshold...
           Edge Detect...
           Spread...
           Shade...
           Raise...
           Segment...
         F/X
           Swirl...
           Implode...
           Wave...
           Oil Paint...
           Charcoal Draw...
         Miscellany
           Image Info
           Zoom Image
           Show Preview...
           Show Histogram
           Show Matte
         Help
         Dismiss

     You can make adjustments to the region of interest by moving
     the pointer to one of the rectangle corners, pressing a
     button, and dragging.  Finally, choose an image processing
     technique from the Command widget.  You can choose more than
     one image processing technique to apply to an area.
     Alternatively, you can move the region of interest before
     applying another image processing technique.  To exit, press
     Dismiss.

IMAGE PANNING
     When an image exceeds the width or height of the X server
     screen, display maps a small panning icon.  The rectangle
     within the panning icon shows the area that is currently
     displayed in the the image window.  To pan about the image,

     press any button and drag the pointer within the panning
     icon.  The pan rectangle moves with the pointer and the
     image window is updated to reflect the location of the
     rectangle within the panning icon.  When you have selected
     the area of the image you wish to view, release the button.

     Use the arrow keys to pan the image one pixel up, down,
     left, or right within the image window.

     The panning icon is withdrawn if the image becomes smaller
     than the dimensions of the X server screen.

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 histograms 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 particular 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 derivative at each scale.
          Analyze this scale-space ``fingerprint'' to determine
          which peaks or valleys in the histogram are most
          predominant.

          o The fingerprint defines intervals on the axis of the
          histogram.  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
          thresholding pass is classified using the fuzzy c-Means
          technique.  It is assigned to one of the classes
          discovered in the histogram analysis 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 Techniques", Pattern Recognition,
          Volume 23, Number 9, pages 935-952, 1990.

USER PREFERENCES
     Preferences affect the default behavior of display(1).  The
     preferences are either true or false and are stored in your
     home directory as .displayrc:

     display 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.  Refer to X
          RESOURCES for details.

     confirm on program exit
          Ask for a confirmation before exiting the display(1)
          program.

     correct image for display gamma
          If the image has a known gamma, the gamma is corrected
          to match that of the X server (see the X resource
          displayGamma).

     apply Floyd/Steinberg error diffusion to 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 preference.

     use a shared colormap for colormapped X visuals
          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.

     display images as an X server pixmap
          Images are maintained as a XImage by default.  Set this

          resource to True to utilize a server Pixmap instead.
          This option is useful if your image exceeds the
          dimensions of your server screen and you intend to pan
          the image.  Panning is much faster with Pixmaps than
          with a XImage.  Pixmaps are considered a precious
          resource, use them with discretion.

ENVIRONMENT
     display
          To get the default host, display number, and screen.

SEE ALSO
     animate(1), import(1), montage(1), mogrify(1), mosaic(1),
     convert(1), combine(1), xtp(1)

COPYRIGHT
     Copyright (C) 2000 ImageMagick Studio, a non-profit
     organization dedicated 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 ("ImageMagick"), to deal in ImageMagick
     without restriction, including without limitation the rights
     to use, copy, modify, merge, publish, distribute,
     sublicense, and/or sell copies of ImageMagick, and to 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 merchantability, 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.

ACKNOWLEDGEMENTS
     The MIT X Consortium for making network transparent graphics
     a reality.

     Peder Langlo, Hewlett Packard, Norway, made hundreds of
     suggestions and bug reports.  Without Peder, ImageMagick
     would not be nearly as useful as it is today.

     Rod Bogart and John W. Peterson, University of Utah.  Image
     compositing is loosely based on rlecomp of the Utah Raster
     Toolkit.

     Michael Halle, Spatial Imaging Group at MIT, for the initial
     implementation of Alan Paeth's image rotation algorithm.

     David Pensak, E. I. du Pont de Nemours and Company, for
     providing a computing environment that made this program
     possible.

     Paul Raveling, USC Information Sciences Institute. The
     spatial subdivision color reduction algorithm is based on
     his Img software.

AUTHORS
     John Cristy, ImageMagick Studio