display
display(1) display(1)
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 dis-
play 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 undo last image transformation
o copy a region of the image
o paste a region to the image
o restore the image to its original size
o refresh the image
o half the image size
o double the image size
o resize 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 roll 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 apply image processing techniques to a region of interest
o display information about the image
o zoom a portion of 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 back-
drop, 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 -
OPTIONS
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 three images, the first with 32 colors, the second with an
unlimited number of colors, and the third with only 16 colors, use:
display -colors 32 cockatoo.miff -noop duck.miff
-colors 16 macaw.miff
Display options can appear on the command line or in your X resources
file. See X(1). Options on the command line supersede values specified
in your X resources file.
For a more detailed description of each option, see imagemagick(1).
-backdrop <color>
display the image centered on a backdrop.
-background <color>
the background color
-border <width>x<height>
surround the image with a border of color
-bordercolor <color>
the border color
-borderwidth <geometry>
the border width
-cache <threshold>
megabytes of memory available to the pixel cache
-colormap <type>
define the colormap type
-colors <value>
preferred number of colors in the image
-colorspace <value>
the type of colorspace
-comment <string>
annotate an image with a comment
-compress <type>
the type of image compression
-contrast
enhance or reduce the image contrast
-crop <width>x<height>{+-}<x>{+-}<y>{%}
preferred size and location of the cropped image
-debug enable debug printout
-delay <1/100ths of a second>
display the next image after pausing
-density <width>x<height>
vertical and horizontal resolution in pixels of the image
-depth <value>
depth of the image
-despeckle
reduce the speckles within an image
-display <host:display[.screen]>
specifies the X server to contact
-dispose <method>
GIF disposal method
-dither
apply Floyd/Steinberg error diffusion to the image
-edge <radius>
detect edges within an image
-endian <type>
specify endianness (MSB or LSB) of output image
-enhance
apply a digital filter to enhance a noisy image
-filter <type>
use this type of filter when resizing an image
-flip create a "mirror image"
-flop create a "mirror image"
-font <name>
use this font when annotating the image with text
-foreground <color>
define the foreground color
-frame <width>x<height>+<outer bevel width>+<inner bevel width>
surround the image with an ornamental border
-gamma <value>
level of gamma correction
-geometry <width>x<height>{+-}<x>{+-}<y>{%}{@} {!}{<}{>}
preferred size and location of the Image window.
-help print usage instructions
-iconGeometry <geometry>
specify the icon geometry
-iconic
iconic animation
-immutable
make image immutable
-interlace <type>
the type of interlacing scheme
-label <name>
assign a label to an image
-magnify <factor>
magnify the image
-map <type>
display image using this type.
-matte store matte channel if the image has one
-mattecolor <color>
specify the matte color
-monochrome
transform the image to black and white
-name name an image
-negate
replace every pixel with its complementary color
-noop NOOP (no option)
-page <width>x<height>{+-}<x>{+-}<y>{%}{!}{<}{>}
size and location of an image canvas
-quality <value>
JPEG/MIFF/PNG compression level
-raise <width>x<height>
lighten or darken image edges
-remote
perform a remote operation
-roll {+-}<x>{+-}<y>
roll an image vertically or horizontally
-rotate <degrees>{<}{>}
apply Paeth image rotation to the image
-sample <geometry>
scale image with pixel sampling
-sampling_factor <horizontal_factor>x<vertical_factor>
sampling factors used by JPEG or MPEG-2 encoder and YUV
decoder/encoder.
-scenes <value-value>
range of image scene numbers to read
-segment <cluster threshold>x<smoothing threshold>
segment an image
-shared_memory
use shared memory
-sharpen <radius>x<sigma>
sharpen the image
-size <width>x<height>{+offset}
width and height of the image
-text_font <name>
font for writing fixed-width text
-texture <filename>
name of texture to tile onto the image background
-title <string>
assign title to displayed image [animate, display, montage]
-treedepth <value>
tree depth for the color reduction algorithm
-trim trim an image
-update <seconds>
detect when image file is modified and redisplay.
-use_pixmap
use the pixmap
-verbose
print detailed information about the image
-visual <type>
animate images using this X visual type
-window <id>
make image the background of a window
-window_group
specify the window group
-write <filename>
write the image to a file [display]
For a more detailed description of each option, see ImageMag-
ick(1).
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) com-
mands. This button behaves differently if the image being dis-
played 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:
Open
Next
Former
Delete
Update
If you choose Open, the image represented by the tile is dis-
played. 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 and miff 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
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
Overview
Browse Documentation
About Display
Menu items with a indented triangle have a sub-menu. They are repre-
sented 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 com-
mand. The keyboard accelerators that display understands is:
Ctl+O Press to load an image from a file.
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 preceding this command with a num-
ber. 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 preceding this command with a num-
ber. For example to display the fourth page preceding 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.
Ctl-C Press to copy a region of
the image.
Ctl-V Press to paste a region to
the image.
< Press to halve 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 "Cmd-A".
@ Press to refresh the image window.
C Press to crop the image.
[ Press to chop the image.
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.
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.
Shft-~ Press to negate the colors of the image.
. Press to convert the image colors to gray.
Shft-# Press to set the maximum number of unique
colors in the image.
F2 Press to reduce the speckles in an image.
F2 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-X Press to composite the image
with another.
Alt-A Press to annotate the image with text.
Alt-D Press to draw a line on the image.
Alt-P Press to edit an image pixel color.
Alt-M Press to edit the image matte information.
Alt-X Press to composite the image with another.
Alt-A 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 image processing techniques to a
region of interest.
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
the "display" utility.
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, dis-
play uses the following X resources:
background (class Background)
Specifies the preferred color to use for the Image window back-
ground. The default is #ccc.
borderColor (class BorderColor)
Specifies the preferred color to use for the Image window bor-
der. 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 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 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 for-
matted 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, vari-
able, 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 dis-
playGamma). 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.
Offsets, if present, are handled in X(1) style. A negative x
offset is measured from the right edge of the screen to the
right edge of the icon, and a negative y offset is measured from
the bottom edge of the screen to the bottom edge of the icon.
iconGeometry (class IconGeometry)
Specifies the preferred size and position of the application
when iconified. It is not necessarily obeyed by all window man-
agers.
Offsets, if present, are handled in the same manner as in class
Geometry.
iconic (class Iconic)
This resource indicates that you would prefer that the applica-
tion'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 magni-
fication 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 annotat-
ing 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: 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 (type-
writer style) formatted text. The default is 14 point Courier.
title (class Title)
This resource specifies the title to be used for the image win-
dow. 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
Megabytes.
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 use-
ful 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 particu-
lar 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 direc-
tory 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 cre-
ate a Visual Image Directory from all the images in the current direc-
tory, 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 thumb-
nail and press button 3 and drag. Finally, select Open. The image rep-
resented 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 col-
ormapped 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 wid-
get. 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:
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 fol-
lows 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 rect-
angle corners, pressing a button, and dragging. Finally, press Cut to
commit your copy region. To exit without cutting the image, press Dis-
miss.
IMAGE COPYING
To begin, press choose Copy of the Edit sub-menu from the Command wid-
get. 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:
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 fol-
lows 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 rect-
angle corners, pressing a button, and dragging. Finally, press Copy to
commit your copy region. To exit without copying the image, press Dis-
miss.
IMAGE PASTING
To begin, press choose Paste of the Edit sub-menu from the Command wid-
get. 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:
Operators
over
in
out
atop
xor
plus
minus
add
subtract
difference
multiply
bumpmap
replace
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 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.
multiply
The result of image * image window. This is useful for the cre-
ation of drop-shadows.
bumpmap
The result of image window shaded by window.
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 initial-
ized 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 Col-
ormap.
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 exam-
ple, 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 Pseu-
doClass image to remain PseudoClass, use -colors.
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:
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. 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:
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. To interactively choose the degree of rotation, choose
Rotate... of the Transform submenu from the Command Widget. Alterna-
tively, 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:
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.
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.
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 his-
tograms of the three color components of the image and identifies a set
of classes. The extents of each class is used to coarsely segment the
image with thresholding. The color associated with each class is
determined by the mean color of all pixels within the extents of a par-
ticular class. Finally, any unclassified pixels are assigned to the
closest class with the fuzzy c-means technique. The fuzzy c-Means
algorithm can be summarized as follows:
Build a histogram, one for each color component of the image.
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.
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.
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: <bq>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.</bq>
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 win-
dow.
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.
Choose a font color from the Font Color sub-menu. Additional font col-
ors 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 loca-
tion of the underscore and advance the underscore cursor. Enter your
text and once completed press Apply 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. How-
ever, 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. Alternatively, press x in the Image win-
dow.
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 Dis-
miss. 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
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 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 window.
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 initial-
ized 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 fac-
tor. 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 dis-
placement. White is a maximum negative displacement and middle
gray is neutral. The displacement is scaled to determine the
pixel shift. By default, the displacement applies in both the
horizontal and vertical directions. However, if you specify
mask, image is the horizontal X displacement and mask the verti-
cal 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 Col-
ormap.
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 exam-
ple, 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 col-
ors. 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.
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. Alterna-
tively, 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 Dis-
miss. In color edit mode, the Command widget has these options:
Method
point
replace
floodfill
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
changes the matte value of 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.
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. additional pixels by increasing the Delta 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 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. How-
ever, 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 pro-
moted to DirectClass To force a PseudoClass image to remain Pseudo-
Class, use -colors.
MATTE EDITING
Matte information within an image is useful for some operations such as
image compositing. This extra channel usually defines a mask which rep-
resents 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 Dis-
miss. In matte edit mode, the Command widget has these options:
Method
point
replace
floodfill
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 recolors 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 win-
dow to change its matte value. You can change the matte value of addi-
tional pixels by increasing the Delta value. The Delta value is first
added then subtracted from the red, green, and blue of the target
color. Any pixels within the range also have their matte value updated.
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 wid-
get. 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. Note that matte information for PseudoClass is
not retained for colormapped X server visuals (e.g. StaticColor, Stat-
icColor, 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. 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:
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. 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 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 Pixel Transform sub-
menu from the Command widget. Alternatively, press R in the image win-
dow.
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 con-
tracts 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
Solarize...
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 drag-
ging. 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 Dis-
miss.
IMAGE PANNING
When an image exceeds the width or height of the X server screen, dis-
play 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.
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 .dis-
playrc:
display image centered on a backdrop"
.in 20
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"
.in 20
Ask for a confirmation before exiting the display(1) pro-
gram.
correct image for display gamma"
.in 20
If the image has a known gamma, the gamma is corrected to
match that of the X server (see the X Resource dis-
playGamma).
apply Floyd/Steinberg error diffusion to image"
.in 20
The basic strategy of dithering is to trade intensity res-
olution for spatial resolution by averaging the intensi-
ties 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"
.in 20
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 col-
ors 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"
.in 20
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. Pan-
ning 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.
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 implemen-
tation of Alan Paeth's image rotation algorithm.
David Pensak, ImageMagick Studio, for providing a computing environment
that made this program possible.
Paul Raveling, USC Information Sciences Institute. The spatial subdivi-
sion color reduction algorithm is based on his Img software.
SEE ALSO
animate(1), composite(1), conjure(1), convert(1), identify(1),
ImageMagick(1), import(1), mogrify(1), montage(1)
COPYRIGHT
Copyright (C) 2002 ImageMagick Studio
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files ("ImageMag-
ick"), to deal in ImageMagick without restriction, including without
limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of ImageMagick, and to permit persons to
whom the ImageMagick is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of ImageMagick.
The software is provided "as is", without warranty of any kind, express
or implied, including but not limited to the warranties of mer-
chantability, fitness for a particular purpose and noninfringement.In
no event shall ImageMagick Studio be liable for any claim, damages or
other liability, whether in an action of contract, tort or otherwise,
arising from, out of or in connection with ImageMagick or the use or
other dealings in ImageMagick.
Except as contained in this notice, the name of the ImageMagick Studio
LLC shall not be used in advertising or otherwise to promote the sale,
use or other dealings in ImageMagick without prior written authoriza-
tion from the ImageMagick Studio.
AUTHORS
John Cristy, ImageMagick Studio LLC,
Glenn Randers-Pehrson, ImageMagick Studio LLC.
ImageMagick Date: 2002/02/15 01:00:00 display(1)
