Display

Contents

Synopsis

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

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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:

*load an image from a file
*display the next image
*display the former image
*display a sequence of images as a slide show
*write the image to a file
*print the image to a PostScript printer
*delete the image file
*create a Visual Image Directory
*select the image to display by its thumbnail rather
*than name
*undo last image transformation
*copy a region of the image
*paste a region to the image
*restore the image to its original size
*refresh the image
*half the image size
*double the image size
*resize the image
*crop the image
*cut the image
*flop image in the horizontal direction
*flip image in the vertical direction
*rotate the image 90 degrees clockwise
*rotate the image 90 degrees counter-clockwise
*rotate the image
*shear the image
*trim the image edges
*invert the colors of the image
*vary the color brightness
*vary the color saturation
*vary the image hue
*gamma correct the image
*sharpen the image contrast
*dull the image contrast
*perform histogram equalization on the image
*perform histogram normalization on the image
*negate the image colors
*convert the image to grayscale
*set the maximum number of unique colors in the image
*reduce the speckles within an image
*eliminate peak noise from an image
*detect edges within the image
*emboss an image
*oil paint an image
*segment the image by color
*annotate the image with text
*draw on the image
*edit an image pixel color
*edit the image matte information
*composite an image with another
*add a border to the image
*add a border to the image
*surround image with an ornamental border
*apply image processing techniques to a region of interest
*display information about the image
*zoom a portion of the image
*show a histogram of the image
*display image to background of a window
*set user preferences
*display information about this program
*discard all images and exit program
*change the level of magnification
*display images specified by a World Wide Web (WWW) uniform resource locator (URL)

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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
To display histogram of an image, use: 
    convert file.jpg HISTOGRAM:- | display -

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Options

-annotate string
annotate an image with text.

Use this option to annotate an image with text. Optionally you can include the image filename, type, width, height, or scene number by embedding special format characters. Embed %f for filename, %m for magick, %w for width, %h for height, %s for scene number, or \n for newline. For example, 
      -annotate "%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.

You can set the text position, font, font color, and bounding box color with -geometry, -font, -pen, and -box respectively. Options are processed in command line order so be sure to use -geometry, -font, -pen, or -box before the -annotate option.

-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 <width>x<height>
surround the image with a border or 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.

-box color
set the color of the annotation bounding box. See -annotate for further details.

See \fBX(1)\fP for details about the color specification.

-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 remain unchanged. Refer to quantize for more details.

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

-colorspace value
the type of colorspace: GRAY, OHTA, RGB, XYZ, YCbCr, YIQ, YPbPr, or YUV.

Color reduction, by default, takes place in the RGB color space. Empirical evidence suggests that distances in color spaces such as YUV or YIQ correspond to perceptual color differences more closely than do distances in RGB space. These color spaces may give better results when color reducing an image. Refer to quantize for more details.

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

-comment string
annotate an image with a comment.

By default, each image is commented with its file name. Use this option to assign a specific comment to the image. Optionally you can include the image filename, type, width, height, or scene number by embedding special format characters. Embed %f for filename, %m for magick, %w for width, %h for height, %s for scene number, or \n for newline. For example,

-comment "%m:%f %wx%h"

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

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

-compress type
the type of image compression: Zlib or RunlengthEncoded.

Use this option with -write to specify the the type of image compression. See miff 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 <width>{%}x<height>{%}{+-}<x offset>{+-}<y offset>
preferred size and location of the cropped image. See X(1) for details about the geometry specification.

To specify a percentage width or height instead, append %. For example to crop the image by ten percent on all sides of the image, use -crop 10%.

Use cropping to apply image processing options to, or display, a particular area of an image. Use -crop 0x0 to remove edges that are the background color.

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

-delay seconds
display the next image after pausing.

This option is useful when viewing several images in sequence. Each image will display and wait the number of seconds specified before the next image is displayed. The default is to display the image and wait until you choose to display the next image or terminate the program.

-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 the same as the resolution of your X server (see xdpyinfo(1)).

-despeckle
reduce the speckles within an image.

-display host:display[.screen]
specifies the X server to contact; see X(1).

-dither
apply Floyd/Steinberg error diffusion to the image.

The basic strategy of dithering is to trade intensity resolution for spatial resolution by averaging the intensities of several neighboring pixels. Images which suffer from severe contouring when reducing colors can be improved with this option.

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

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

-equalize
perform histogram equalization to the image.

-flip
scanlines in the vertical direction.

-flop
create a "mirror image" by reflecting the image scanlines in the horizontal direction.

-frame <width>x<height+<outer bevel width>+<inner bevel width>
surround the image with an 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 commas (i.e. 1.7,2.3,1.2).

-geometry <width>{%}x<height>{%}{+-}<x offset>{+-}<yoffset>{!}{<}{>}
preferred size and location of the Image window. See X(1) for details about the geometry specification. By default, the window size is the image size and the location is chosen by you when it is mapped.

By default, the width and height are maximum values. That is, the image is expanded or contracted to fit the width and height value while maintaining the aspect ratio of the image. Append an exclamation point to the geometry to force the image size to exactly the size you specify. For example, if you specify 640x480! the image width is set to 640 pixels and height to 480. If only one factor is specified, both the width and height assume the value.

Use < to change the dimensions of the image only if its size exceeds the geometry specification. > resizes the image only if its dimensions is less than the geometry specification. For example, if you specify 640x480> and the image size is 512x512, the image size does not change. However, if the image is 1024x1024, it is resized to 640x480.

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.

When displaying an image on an X server, <x offset> and <y offset> 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, or PLANE.

This option is used to specify the type of interlacing scheme for raw image formats such as RGB or YUV. NONE means do not interlace (RGBRGBRGBRGBRGBRGB...), LINE uses scanline interlacing (RRR...GGG...BBB...RRR...GGG...BBB...), and PLANE uses plane interlacing (RRRRRR...GGGGGG...BBBBBB...).

Use LINE, or PLANE to create an interlaced GIF or progressive JPEG image.

-immutable
displayed image cannot be modified.

-label name
assign a label to an image.

Use this option to assign a specific label to the image. Optionally you can include the image filename, type, width, height, or scene number in the label by embedding special format characters. Embed %f for filename, %m for magick, %w for width, %h for height, or %s for scene number, or \n for newline. 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.

-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 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 (transparent channel) if the image has one.

-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 20,-10.

-monochrome
transform the image to black and white.

-negate
apply color inversion to image.

The red, green, and blue intensities of an image are negated.

-noise
reduce the noise in an image with a noise peak elimination filter.

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 3 x 3 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 3 x 3 window.

-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. See -pen for more details.
-page <width>x<height>{+-}<x offset>{+-}<y offset>
size and location of the PostScript page.

Use this option to specify the dimensions of the PostScript page in pixels per inch or a TEXT page in pixels. The default for a PostScript page is to center the image on a letter page 612 by 792 pixels. The margins are 1/2" (i.e. 723x935+42+42). Other common sizes are: 
       Letter      612x 792
       Tabloid     792x1224
       Ledger     1224x 792
       Legal       612x1008
       Statement   396x 612
       Executive   540x 720
       A3          842x1190
       A4          595x 842
       A5          420x 595
       B4          729x1032
       B5          516x 729
       Folio       612x 936
       Quarto      610x 780
       10x14       720x1008
For convenience you can specify the page size by media (e.g. A4, Ledger, etc.).

The page geometry is relative to the vertical and horizontal density of the PostScript page. See -density for details.

The default page dimensions for a TEXT image is 723x935.

-pen color
set the color of the font or opaque color. See -annotate or -opaque for further details.

See X(1) for details about the color specification.

-quality value
JPEG quality setting.

Quality is 0 (worst) to 100 (best). The default is 72.

-raise <bevel width>
lighten or darken image edges to create a 3-D effect.

Bevel width is the width of an edge. Use -raise to create a raised effect, otherwise use +raise.

-roll {+-}<x offset>{+-}<y offset>
roll an image vertically or horizontally. See X(1) for details about the geometry specification.

A negative x offset rolls the image left-to-right. A negative y offset rolls the image top-to-bottom.

-rotate degrees
apply Paeth image rotation to the image.

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

-sample geometry
scale image with pixel sampling. 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.

-sharpen factor
sharpen an image. Specify factor as the percent enhancement (0.0 - 99.9%).

-shear <x degrees>x<y degrees>
shear the image along the X or Y axis by a positive or negative shear angle.

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

-size <width>{%}x<height>{%}{+offset}{!}
width and height of the image.

Use this option to specify the width and height of raw images whose dimensions are unknown such as GRAY, RGB, or CMYK. In addition to width and height, use -size to skip any header information in the image 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 image (e.g. -size 1024x768).

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

-transparency color
make this color transparent within the image.

-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 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 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.

-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
Change - to + in any option above to reverse its effect. For example, specify +matte to store the image without its matte channel.

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

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]).

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.

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Mouse 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. 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:

If you choose Delete, the image represented by the tile is deleted. Otherwise, it is displayed. To return to the visual image directory, choose Next from the Command widget (refer to Command Widget). See montage and miff for more details.

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Command Widget

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

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 a button 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.

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Keyboard Accelerators

Accelerators are one or two key presses that effect a particular command. The keyboard accelerators that display understands is: 
    l    Press to load an image from a file.
    n    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 4n. 
    f    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. 
    F2   Press to select an image from the command line.
    s    Press to save the image to a file.
    p    Press to print the image to a PostScript printer.
    ^    Press to delete an image file.
    C    Press to create a blank canvas.
    V    Press to create a Visual Image Directory.
    q    Press to discard all images and exit program.
    F3   Press to cut a region of the image.
    F4   Press to copy a region of the image.
    F5   Press to paste a region to the image.
    u    Press to undo last image transformation.
    <    Press to half the image size.
    o    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.
    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 orginal 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.
    r    Press to restore the image to its original size.
    [    Press to crop the image.
    ]    Press to chop the image.
    |    Press to flop image in the horizontal direction.
    -    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.
    F6   Press to shear the image the number of degrees you specify.
    t    Press to trim the image edges.
    F7   Press to vary the color hue.
    F8   Press to vary the color saturation.
    F9   Press to vary the image brightness.
    g    Press to gamma correct the image.
    F10  Press to spiff up the image contrast.
    F11  Press to dull the image contrast.
    =    Press to perform histogram equalization on the image.
    N    Press to perform histogram normalization on the image.
    ~    Press to negate the colors of the image.
    G    Press to convert the image colors to gray.
    #    Press to set the maximum number of unique colors in the image.
    D    Press to reduce the speckles in an image.
    P    Press to eliminate peak noise from an image.
    S    Press to sharpen an image.
    B    Press to blur image an image.
    E    Press to detect edges within an image.
    M    Press to emboss an image.
    O    Press to oil paint an image.
    Z    Press to segment the image by color.
    R    Press to apply an image processing technique to a region of interest.
    a    Press to annotate the image with text.
    d    Press to draw a line on the image.
    C    Press to edit an image pixel color.
    m    Press to edit the image matte information.
    x    Press to composite the image with another.
    a    Press to add a border to the image.
    F    Press to add a ornamental frame to the image.
    !    Press to add an image comment.
    i    Press to display information about the image.
    z    Press to map the zoom image window.
    H    Press to show a histogram of the image.
    }    Press to display image to background of a window.
    ,    Press to display the next image after pausing.
    F12  Press to set user preferences.
    h    Press to display helpful information about display.
Function keys HELP or F1 are synonymous with the h key. 
    v    Press to display the version number of display(1).
    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.

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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 #697B8F.

borderColor (class BorderColor)
Specifies the preferred color to use for the Image window border. The default is black.

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

confirmExit (class ConfirmExit)
Whether Display will pop up a dialog box to confirm exiting the program when the Quit menu option is chosen. Default is False.

displayGamma (class displayGamma)
Specifies the gamma of the 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 commas (i.e. 1.7,2.3,1.2).

The default is 2.2.

editorCommand (class editorCommand)
Specifies the name of the preferred editor when editing image comments. The default is xterm -title "Edit Image Comment" -e vi %s.

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.

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.

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: #697B8F.

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.

printCommand (class PrintCommand)
This command is executed whenever Print is issued In general, it is the command to print PostScript to your printer. Default value: lpr %s.

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.

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

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Image Loading

To select an image to display, choose Load 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 Load 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 Load widget.

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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 Load. 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.

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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. Alternatively, press F3 in the Image window.

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:

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:

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.

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Image Copying

To begin, press choose Copy of the Edit sub-menu from the Command widget. Alternatively, press F4 in the Image window.

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:

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:

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.

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Image Pasting

To begin, press choose Paste of the Edit sub-menu from the Command widget. Alternatively, press F5 in the Image window.

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:

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.

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.

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 a button. 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. To force a PseudoClass image to remain PseudoClass, use -colors.

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Image Cropping

To begin, press choose Crop of the Transform submenu from the Command widget. Alternatively, press [ in the Image window.

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:

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:

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.

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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. Alternatively, press ] in the Image window.

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

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.

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Image Rotation

Press the / key to rotate the image 90 degrees or \ to rotate -90 degrees. To interactively choose the degree of rotation, choose Rotate... of the Transform submenu from the Command Widget. Alternatively, press * in the Image window.

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:

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.

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.

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.

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Image Segmentation

Choose Effects->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:

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.

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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. Alternatively, press a in the Image window.

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:

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.

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.

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 a button. 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.

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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. Alternatively, press x in the Image window.

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.

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:

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

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.

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.

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 a button. 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). To force a PseudoClass image to remain PseudoClass, use -colors.

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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. Alternatively, press c in the image window.

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:

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Matte Editing

Matte information within an image is useful for some operations such as 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.

Alternatively, press m in the image window.

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:

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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 Alternatively, press d in the Image window.

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:

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. The transparent color updates the image matte channel and is useful for image compositing.

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, if appropriate, from the Width sub-menu. To choose a specific width select the Dialog widget.

Choose a point in the Image window and press a 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 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.

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Region of Interest

To begin, press choose Region of Interest of the Pixel Transform sub-menu from the Command widget. Alternatively, press R in the Image window.

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:

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:

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.

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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.

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User Preferences

Preferences affect the default behavior of display(1). The preferences are either true or false:

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 perference.

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. Otherwise 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.

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Environment

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

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Copyright

Copyright 1995 E. I. du Pont de Nemours and Company Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of E. I. du Pont de Nemours and Company not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. E. I. du Pont de Nemours and Company makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

E. I. du Pont de Nemours and Company disclaims all warranties with regard to this software, including all implied warranties of merchantability and fitness, in no event shall E. I. du Pont de Nemours and Company be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortuous action, arising out of or in connection with the use or performance of this software.

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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 spacial subdivision color reduction algorithm is based on his Img software.

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Authors

John Cristy, cristy@dupont.com E.I. du Pont de Nemours and Company Incorporated.

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