display(1)display(1)NAMEdisplay - display an image on any workstation running X
SYNOPSISdisplay [ 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 run‐
ning an X server. Display can read and write many of the more popular
image formats (e.g. JPEG, TIFF, PNM, Photo CD, etc.). With display,
you can perform these functions on an image:
o load an image from a file
o display the next image
o display the former image
o display a sequence of images as a slide show
o write the image to a file
o print the image to a Postscript printer
o delete the image file
o create a Visual Image Directory
o select the image to display by its thumbnail rather than name
o copy a region of the image
o paste a region to the image
o undo last image transformation
o half the image size
o double the image size
o resize the image
o restore the image to its original size
o refresh the image
o crop the image
o cut the image
o flop image in the horizontal direction
o flip image in the vertical direction
o rotate the image 90 degrees clockwise
o rotate the image 90 degrees counter-clockwise
o rotate the image
o shear the image
o trim the image edges
o invert the colors of the image
o vary the color brightness
o vary the color saturation
o vary the image hue
o gamma correct the image
o sharpen the image contrast
o dull the image contrast
o perform histogram equalization on the image
o perform histogram normalization on the image
o negate the image colors
o convert the image to grayscale
o set the maximum number of unique colors in the image
o reduce the speckles within an image
o eliminate peak noise from an image
o detect edges within the image
o emboss an image
o segment the image by color
o simulate an oil painting
o simulate a charcoal drawing
o annotate the image with text
o draw on the image
o edit an image pixel color
o edit the image matte information
o composite an image with another
o add a border to the image
o surround image with an ornamental border
o add an image comment
o apply image processing techniques to a region of interest
o display information about the image
o show a histogram of the image
o display image to background of a window
o set user preferences
o display information about this program
o discard all images and exit program
o change the level of magnification
o display images specified by a World Wide Web (WWW) uniform
resource locator (URL)
EXAMPLES
To scale an image of a cockatoo to exactly 640 pixels in width and 480
pixels in height and position the window at location (200,200), use:
display-geometry 640x480+200+200! cockatoo.miff
To display an image of a cockatoo without a border centered on a 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
OPTIONS-backdrop
display the image centered on a backdrop.
This backdrop covers the entire workstation screen and is useful
for hiding other X window activity while viewing the image.
The color of the backdrop is specified as the background color.
Refer to X RESOURCES for details.
-border <width>x<height>
surround the image with a border of color. See X(1) for details
about the geometry specification.
The color of the border is obtained from the X server and is
defined as bordercolor (class borderColor). See X(1) for
details.
-cache threshold
megabytes of memory available to the pixel cache.
Image pixels are stored in memory until 80 megabytes of memory
have been consumed. Subsequent pixel operations are cached on
disk. Operations to memory are significantly faster but if your
computer does not have a sufficient amount of free memory you
may want to adjust this threshold value.
-colormap type
the type of colormap: Shared or Private.
This option only applies when the default X server visual is
PseudoColor or GrayScale. Refer to -visual for more details.
By default, a shared colormap is allocated. The image shares
colors with other X clients. Some image colors could be approx‐
imated, therefore your image may look very different than
intended. Choose Private and the image colors appear exactly as
they are defined. However, other clients may go technicolor
when the image colormap is installed.
-colors value
preferred number of colors in the image.
The actual number of colors in the image may be less than your
request, but never more. Note, this is a color reduction
option. Images with less unique colors than specified with this
option will have any duplicate or unused colors removed. Refer
to quantize(9) for more details.
Note, options -dither, -colorspace, and -treedepth affect the
color reduction algorithm.
-colorspace value
the type of colorspace: GRAY, OHTA, RGB, Transparent, XYZ,
YCbCr, YIQ, YPbPr, YUV, or CMYK.
Color reduction, by default, takes place in the RGB color space.
Empirical evidence suggests that distances in color spaces such
as YUV or YIQ correspond to perceptual color differences more
closely than do distances in RGB space. These color spaces may
give better results when color reducing an image. Refer to
quantize(9) for more details.
The Transparent color space behaves uniquely in that it pre‐
serves the matte channel of the image if it exists.
The -colors or -monochrome option is required for this option to
take effect.
-comment string
annotate an image with a comment.
By default, each image is commented with its file name. Use
this option to assign a specific comment to the image. Option‐
ally you can include the image filename, type, width, height, or
other image attributes by embedding special format characters:
%b file size
%c comment
%d directory
%e filename extention
%f filename
%h height
%i input filename
%l label
%m magick
%n number of scenes
%o output filename
%p page number
%q quantum depth
%s scene number
%t top of filename
%u unique temporary filename
%w width
%x x resolution
%y y resolution
\n newline
\r carriage return
For example,
-comment "%m:%f %wx%h"
produces an image comment of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image comment is read
from a file titled by the remaining characters in the string.
-compress type
the type of image compression: None, BZip, Fax, Group4, JPEG,
LZW, RunlengthEncoded, or Zip.
Use this option with -write to specify the the type of image
compression. See miff(5) for details.
Specify +compress to store the binary image in an uncompressed
format. The default is the compression type of the specified
image file.
-contrast
enhance or reduce the image contrast.
This option enhances the intensity differences between the
lighter and darker elements of the image. Use -contrast to
enhance the image or +contrast to reduce the image contrast.
-crop <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 cropping to crop a particular area of an image. Use -crop
0x0 to trim edges that are the background color. Add an x and y
offset to leave a portion of the trimmed edges with the image.
The equivalent X resource for this option is cropGeometry (class
CropGeometry). See X RESOURCES for details.
-delay <1/100ths of a second>
display the next image after pausing.
This option is useful when viewing several images in sequence.
1/100ths of a second must expire before the next image is dis‐
played. The delay is rounded to the nearest second. The
default is to display the image and wait until you choose to
display the next image or terminate the program.
-density <width>x<height>
vertical and horizontal resolution in pixels of the image.
This option specifies an image density when decoding a Post‐
script or Portable Document page. The default is the same as
the resolution of your X server (see xdpyinfo(1)). This option
is used in concert with -page.
-despeckle
reduce the speckles within an image.
-display host:display[.screen]
specifies the X server to contact; see X(1).
-dispose method
GIF disposal method.
Here are the valid methods:
0 No disposal specified.
1 Do not dispose between frames.
2 Overwrite frame with background color from header.
3 Overwrite with previous frame.
-dither
apply Floyd/Steinberg error diffusion to the image.
The basic strategy of dithering is to trade intensity resolution
for spatial resolution by averaging the intensities of several
neighboring pixels. Images which suffer from severe contouring
when reducing colors can be improved with this option.
The -colors or -monochrome option is required for this option to
take effect.
Use +dither to render Postscript without text or graphic alias‐
ing.
-edge factor
detect edges with an image. Specify factor as the percent
enhancement (0.0 - 99.9%).
-enhance
apply a digital filter to enhance a noisy image.
-filter value
use this type of filter when resizing an image.
Use this option to affect the resizing operation of an image
(see -geometry). Choose from these filters:
Point
Box
Triangle
Hermite
Hanning
Hamming
Blackman
Gaussian
Quadratic
Cubic
Catrom
Mitchell
Lanczos
Bessel
Sinc
The default filter is Lanczos.
-flip create a "mirror image" by reflecting the image scanlines in the
vertical direction.
-flop create a "mirror image" by reflecting the image scanlines in the
horizontal direction.
-frame <width>x<height>+<outer bevel width>+<inner bevel width>
surround the image with an ornamental border. See X(1) for
details about the geometry specification.
The color of the border is specified with the -mattecolor com‐
mand line option.
-gamma value
level of gamma correction.
The same color image displayed on two different workstations may
look different due to differences in the display monitor. Use
gamma correction to adjust for this color difference. Reason‐
able values extend from 0.8 to 2.3.
You can apply separate gamma values to the red, green, and blue
channels of the image with a gamma value list delineated with
slashes (i.e. 1.7/2.3/1.2).
Use +gamma to set the image gamma level without actually adjust‐
ing the image pixels. This option is useful if the image is of
a known gamma but not set as an image attribute (e.g. PNG
images).
-geometry <width>x<height>{+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
preferred size and location of the image window. See X(1) for
details about the geometry specification. By default, the win‐
dow 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.
To specify a percentage width or height instead, append %. The
image size is multiplied by the width and height percentages to
obtain the final image dimensions. To increase the size of an
image, use a value greater than 100 (e.g. 125%). To decrease an
image's size, use a percentage less than 100.
Use > to change the dimensions of the image only if its size
exceeds the geometry specification. < resizes the image only if
its dimensions is less than the geometry specification. For
example, if you specify 640x480> and the image size is 512x512,
the image size does not change. However, if the image is
1024x1024, it is resized to 640x480.
When displaying an image on an X server, <x offset> and <y off‐
set> is relative to the root window.
The equivalent X resource for this option is geometry (class
Geometry). See X RESOURCES for details.
-interlace type
the type of interlacing scheme: None, Line, Plane, or Partition.
The default is None.
This option is used to specify the type of interlacing scheme
for raw image formats such as RGB or YUV. No means do not
interlace (RGBRGBRGBRGBRGBRGB...), Line uses scanline interlac‐
ing (RRR...GGG...BBB...RRR...GGG...BBB...), and Plane uses plane
interlacing (RRRRRR...GGGGGG...BBBBBB...). Partition is like
plane except the different planes are saved to individual files
(e.g. image.R, image.G, and image.B).
Use Line, or Plane to create an interlaced GIF or progressive
JPEG image.
-immutable
displayed image cannot be modified",
-label string
assign a label to an image.
Use this option to assign a specific label to the image.
Optionally you can include the image filename, type, width,
height, or other image attribute in the label by embedding spe‐
cial format characters. See -comment for details.
For example,
-label "%m:%f %wx%h"
produces an image label of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
If the first character of string is @, the image label is read
from a file titled by the remaining characters in the string.
When converting to Postscript, use this option to specify a
header string to print above the image. Specify the label font
with -font.
-map type
display image using this Standard Colormap type.
Choose from these Standard Colormap types:
best
default
gray
red
green
blue
The X server must support the Standard Colormap you choose, oth‐
erwise an error occurs. Use list as the type and display(1)
searches the list of colormap types in top-to-bottom order until
one is located. See xstdcmap(1) for one way of creating Standard
Colormaps.
-matte store matte channel if the image has one otherwise create an
opaque one.
-monochrome
transform the image to black and white.
-negate
replace every pixel with its complementary color (white becomes
black, yellow becomes blue, etc.).
The red, green, and blue intensities of an image are negated.
Use +negate to only negate the grayscale pixels of the image.
-page <width>x<height>{+-}<x offset>{+-}<y offset>{%}{!}{<}{>}
preferred size and location of an image canvas.
Use this option to specify the dimensions of the Postscript page
in dots per inch or a TEXT page in pixels. The choices for a
Postscript page are:
Letter 612x 792
Tabloid 792x1224
Ledger 1224x 792
Legal 612x1008
Statement 396x 612
Executive 540x 720
A3 842x1190
A4 595x 842
A5 420x 595
B4 729x1032
B5 516x 729
Folio 612x 936
Quarto 610x 780
10x14 720x1008
For convenience you can specify the page size by media (e.g.
A4, Ledger, etc.). Otherwise, -page behaves much like -geometry
(e.g. -page letter+43+43>).
To position a GIF image, use -page {+-}<x offset>{+-}<y offset>
(e.g. -page +100+200).
For a Postscript page, the image is sized as in -geometry and
positioned relative to the lower left hand corner of the page by
{+-}<x offset>{+-}<y offset>. Use -page 612x792>, for example,
to center the image within the page. If the image size exceeds
the Postscript page, it is reduced to fit the page.
The default page dimensions for a TEXT image is 612x792.
This option is used in concert with -density.
-quality value
JPEG/MIFF/PNG compression level.
For the JPEG image format, quality is 0 (worst) to 100 (best).
The default quality is 75.
Quality for the MIFF and PNG image format sets the amount of
image compression (quality / 10) and filter-type (quality % 10).
Compression quality values range from 0 (worst) to 100 (best).
If filter-type is 4 or less, the specified filter-type is used
for all scanlines:
0: none
1: sub
2: up
3: average
4: Paeth
If filter-type is 5, adaptive filtering is used when quality is
greater than 50 and the image does not have a color map, other‐
wise no filtering is used.
If filter-type is 6 or more, adaptive filtering with minimum-
sum-of-absolute-values is used.
The default is quality is 75. Which means nearly the best com‐
pression with adaptive filtering.
For further information, see the PNG specification (RFC 2083),
<http://www.w3.org/pub/WWW/TR>.
-raise <width>x<height>
lighten or darken image edges to create a 3-D effect. See
X(1) for details about the geometry specification.
Use -raise to create a raised effect, otherwise use +raise.
-remote string
execute a command in an remote display process.
The only command recognized at this time is the name of an image
file to load.
-roll {+-}<x offset>{+-}<y offset>
roll an image vertically or horizontally. See X(1) for details
about the geometry specification.
A negative x offset rolls the image left-to-right. A negative y
offset rolls the image top-to-bottom.
-rotate degrees{<}{>}
apply Paeth image rotation to the image.
Use > to rotate the image only if its width exceeds the height.
< rotates the image only if its width is less than the height.
For example, if you specify -90> and the image size is 480x640,
the image is not rotated by the specified angle. However, if
the image is 640x480, it is rotated by -90 degrees.
Empty triangles left over from rotating the image are filled
with the color defined as bordercolor (class borderColor).
-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 file‐
name. See the discussion of file below for details.
-segment value
eliminate clusters that are insignificant.
The number of pixels in each cluster must exceed the the cluster
threshold to be considered valid.
See IMAGE SEGMENTATION for details.
-sharpen <radius>x<sigma>
sharpen the image with a gaussian operator of the given radius
and standard deviation (sigma).
-size <width>x<height>+<offset>
width and height of the image.
Use this option to specify the width and height of raw images
whose dimensions are unknown such as GRAY, RGB, or CMYK. In
addition to width and height, use -size to skip any header
information in the image or tell the number of colors in a MAP
image file, (e.g. -size 640x512+256).
For Photo CD images, choose from these sizes:
192x128
384x256
768x512
1536x1024
3072x2048
Finally, use this option to choose a particular resolution layer
of a JBIG or JPEG image (e.g. -size 1024x768).
-texture filename
name of texture to tile onto the image background.
-title string
assign a title to the displayed image.
Use this option to assign a specific title to the image. This
is assigned to the image window and is typically displayed in
the window title bar. Optionally you can include the image
filename, type, width, height, or other image attributes by
embedding special format characters. See -comment for details.
For example,
-title "%m:%f %wx%h"
produces an image title of MIFF:bird.miff 512x480 for an image
titled bird.miff and whose width is 512 and height is 480.
-treedepth value
Normally, this integer value is zero or one. A zero or one
tells display to choose a optimal tree depth for the color
reduction algorithm.
An optimal depth generally allows the best representation of the
source image with the fastest computational speed and the least
amount of memory. However, the default depth is inappropriate
for some images. To assure the best representation, try values
between 2 and 8 for this parameter. Refer to quantize(9) for
more details.
The -colors or -monochrome option is required for this option to
take effect.
-update seconds
detect when image file is modified and redisplay.
Suppose that while you are displaying an image the file that is
currently displayed is over-written. display will automatically
detect that the input file has been changed and update the dis‐
played image accordingly.
-verbose
print detailed information about the image.
This information is printed: image scene number; image name;
image size; the image class (DirectClass or PseudoClass); the
total number of unique colors; and the number of seconds to
read and transform the image. Refer to miff(5) for a descrip‐
tion of the image class.
If -colors is also specified, the total unique colors in the
image and color reduction error values are printed. Refer to
quantize(9) for a description of these values.
-visual type
display image using this visual type.
Choose from these visual classes:
StaticGray
GrayScale
StaticColor
PseudoColor
TrueColor
DirectColor
default
visual id
The X server must support the visual you choose, otherwise an
error occurs. If a visual is not specified, the visual class
that can display the most simultaneous colors on the default X
server screen is chosen.
-window id
set the background pixmap of this window to the image.
id can be a window id or name. Specify root to select X's root
window as the target window.
By default the image is tiled onto the background of the target
window. If -backdrop or -geometry are specified, the image is
surrounded by the background color. Refer to X RESOURCES for
details.
The image will not display on the root window if the image has
more unique colors than the target window colormap allows. Use
-colors to reduce the number of colors. -window_group id exit
program when this window id is destroyed.
id can be a window id or name.
-write filename
write image to a file.
If file already exists, you will be prompted as to whether it
should be overwritten.
By default, the image is written in the format that it was read
in as. To specify a particular image format, prefix file with
the image type and a colon (i.e. ps:image) or specify the image
type as the filename suffix (i.e. image.ps). See convert(1) for
a list of valid image formats. Specify file as - for standard
output. If file has the extension .Z or .gz, the file size is
compressed using with compress or gzip respectively. Precede
the image file name | to pipe to a system command. If file
already exists, you will be prompted as to whether it should be
overwritten.
Use -compress to specify the type of image compression.
The equivalent X resource for this option is writeFilename
(class WriteFilename). See X RESOURCES for details.
In addition to those listed above, you can specify these standard X
resources as command line options: -background, -bordercolor, -border‐
width, -font, -foreground, -iconGeometry, -iconic, -mattecolor, -name,
or -title. See X RESOURCES for details.
Options are processed in command line order. Any option you specify on
the command line remains in effect until it is explicitly changed by
specifying the option again with a different effect. For example to
display two images, the first with 32 colors, and the second with only
16 colors, use:
display-colors 32 cockatoo.miff -colors 16 macaw.miff
By default, the image format is determined by its magic number. To
specify a particular image format, precede the filename with an image
format name and a colon (i.e. ps:image) or specify the image type as
the filename suffix (i.e. image.ps). See convert(1) for a list of
valid image formats.
When you specify X as your image type, the filename has special mean‐
ing. It specifies an X window by id, name, or root. If no filename is
specified, the window is selected by clicking the mouse in the desired
window.
Specify file as - for standard input. If file has the extension .Z or
.gz, the file is uncompressed with uncompress or gunzip respectively.
Precede the image file name | to pipe from a system command.
Use an optional index enclosed in brackets after a file name to specify
a desired subimage of a multi-resolution image format like Photo CD
(e.g. img0001.pcd[4]) or a range for MPEG images (e.g.
video.mpg[50-75]). A subimage specification can be disjoint (e.g.
image.tiff[2,7,4]). For raw images, specify a subimage with a geometry
(e.g. -size 640x512 image.rgb[320x256+50+50]).
Single images are read with the filename you specify. Alternatively,
you can display an image sequence with a single filename. Define the
range of the image sequence with -scene. Each image in the range is
read with the filename followed by a period (.) and the scene number.
You can change this behavior by embedding a printf format specification
in the file name. For example,
-scene 0-9 image%02d.miff
displays files image00.miff, image01.miff, through image09.miff.
BUTTONS
The effects of each button press is described below. Three buttons are
required. If you have a two button mouse, button 1 and 3 are returned.
Press ALT and button 3 to simulate button 2.
1 Press this button to map or unmap the Command widget. See the
next section for more information about the Command widget.
2 Press and drag to define a region of the image to magnify.
3 Press and drag to choose from a select set of display(1) com‐
mands. This button behaves differently if the image being dis‐
played is a visual image directory. Here, choose a particular
tile of the directory and press this button and drag to select a
command from a pop-up menu. Choose from these menu items:
Open
Next
Former
Delete
Update
If you choose Open, the image represented by the tile is 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(1) and miff(5) for more details.
COMMAND WIDGET
The Command widget lists a number of sub-menus and commands. They are
File
Open...
Next
Former
Select...
Save...
Print...
Delete...
Canvas...
Visual Directory...
Quit
Edit
Undo
Redo
Cut
Copy
Paste
View
Half Size
Original Size
Double Size
Resize...
Apply
Refresh
Restore
Transform
Crop
Chop
Flop
Flip
Rotate Right
Rotate Left
Rotate...
Shear...
Roll...
Trim Edges
Enhance
Hue...
Saturation...
Brightness...
Gamma...
Spiff...
Dull
Equalize
Normalize
Negate
Grayscale
Map...
Quantize...
Effects
Despeckle
Emboss
Reduce Noise
Add Noise
Sharpen...
Blur...
Threshold...
Edge Detect...
Spread...
Shade...
Raise...
Segment...
F/X
Solarize...
Swirl...
Implode...
Wave...
Oil Paint...
Charcoal Draw...
Image Edit
Annotate...
Draw...
Color...
Matte...
Composite...
Add Border...
Add Frame...
Comment...
Launch...
Region of Interest...
Miscellany
Image Info
Zoom Image
Show Preview...
Show Histogram
Show Matte
Background...
Slide Show
Preferences...
Help
Help
Browse Documentation
About Display
Menu items with a indented triangle have a sub-menu. They are 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(1) understands is:
Ctl+O Press to load an image from a file.
Refer to IMAGE LOADING for more details.
space Press to display the next image.
If the image is a multi-paged document such as a Postscript doc‐
ument, you can skip ahead several pages by preceeding this com‐
mand with a number. For example to display the fourth page
beyond the current page, press 4space.
backspace
Press to display the former image.
If the image is a multi-paged document such as a Postscript doc‐
ument, you can skip behind several pages by preceeding this com‐
mand with a number. For example to display the fourth page pre‐
ceeding the current page, press 4n.
Ctl+S Press to save the image to a file.
Ctl+P Press to print the image to a Postscript printer.
Ctl+D Press to delete an image file.
Ctl+N Press to create a blank canvas.
Ctl+Q Press to discard all images and exit program.
Ctl+Z Press to undo last image transformation.
Ctl+R Press to redo last image transformation.
Ctl+X Press to cut a region of the image.
Refer to IMAGE CUTTING for more details.
Ctl+C Press to copy a region of the image.
Refer to IMAGE COPYING for more details.
Ctl+V Press to paste a region to the image.
Refer to IMAGE PASTING for more details.
< Press to half the image size.
- Press to return to the original image size.
> Press to double the image size.
% Press to resize the image to a width and height you specify.
Cmd-A Press to make any image transformations permanent.
By default, any image size transformations are applied to the
original image to create the image displayed on the X server.
However, the transformations are not permanent (i.e. the origi‐
nal image does not change size only the X image does). For
example, if you press > the X image will appear to double in
size, but the original image will in fact remain the same size.
To force the original image to double in size, press > followed
by A.
@ Press to refresh the image window.
C Press to crop the image.
Refer to IMAGE CROPPING for more details.
[ Press to chop the image.
Refer to IMAGE CHOPPING for more details.
H Press to flop image in the horizontal direction.
V Press to flip image in the vertical direction.
/ Press to rotate the image 90 degrees clockwise.
Press to rotate the image 90 degrees counter-clockwise.
* Press to rotate the image the number of degrees you specify.
Refer to IMAGE ROTATION for more details.
s Press to shear the image the number of degrees you specify.
r Press to roll the image.
t Press to trim the image edges.
Shft-H Press to vary the color hue.
Shft-S Press to vary the color saturation.
Shft-L Press to vary the image brightness.
Shft-G Press to gamma correct the image.
Shft-C Press to spiff up the image contrast.
Shft-Z Press to dull the image contrast.
= Press to perform histogram equalization on the image.
Shft-N Press to perform histogram normalization on the image.
~ Press to negate the colors of the image.
. Press to convert the image colors to gray.
# Press to set the maximum number of unique colors in the image.
F2 Press to reduce the speckles in an image.
F3 Press to emboss an image.
F4 Press to eliminate peak noise from an image.
F5 Press to add noise to an image.
F6 Press to sharpen an image.
F7 Press to blur image an image.
F8 Press to threshold the image.
F9 Press to detect edges within an image.
F10 Press to displace pixels by a random amount.
F11 Press to shade the image using a distant light source.
F12 Press to lighten or darken image edges to create a 3-D effect.
F13 Press to segment the image by color.
Meta-S Press to swirl image pixels about the center.
Meta-I Press to implode image pixels about the center.
Meta-W Press to alter an image along a sine wave.
Meta-P Press to simulate an oil painting.
Meta-C Press to simulate a charcoal drawing.
Alt-A Press to annotate the image with text.
Refer to IMAGE ANNOTATION for more details.
Alt-D Press to draw a line on the image.
Refer to IMAGE DRAWING for more details.
Alt-P Press to edit an image pixel color.
Refer to COLOR EDITING for more details.
Alt-M Press to edit the image matte information.
Refer to MATTE EDITING for more details.
Alt-V Press to composite the image with another.
Refer to IMAGE COMPOSITING for more details.
Alt-B Press to add a border to the image.
Alt-F Press to add a ornamental frame to the image.
Alt-Shft-!
Press to add an image comment.
Ctl-A Press to apply an image processing technique to a region of
interest.
Refer to REGION OF INTEREST for more details.
Shft-? Press to display information about the image.
Shft-+ Press to map the zoom image window.
Shft-P Press to preview an image enhancement, effect, or f/x.
F1 Press to display helpful information about display(1).
Find Press to browse documentation about ImageMagick.
1-9 Press to change the level of magnification.
Use the arrow keys to move the image one pixel up, down, left,
or right within the magnify window. Be sure to first map the
magnify window by pressing button 2.
Press ALT and one of the arrow keys to trim off one pixel from
any side of the image.
X RESOURCES
Display options can appear on the command line or in your X resource
file. Options on the command line supersede values specified in your X
resource file. See X(1) for more information on X resources.
Most display options have a corresponding X resource. In addition,
display uses the following X resources:
background (class Background)
Specifies the preferred color to use for the image window 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 your X server.
You can apply separate gamma values to the red, green, and blue
channels of the image with a gamma value list delineated with
slashes (i.e. 1.7/2.3/1.2).
The default is 2.2.
displayWarnings (class DisplayWarnings)
Display pops up a dialog box whenever a warning message occurs.
Set this resource to False to ignore warning messages.
font (class FontList)
Specifies the name of the preferred font to use in normal 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.
Refer to IMAGE ANNOTATION for more details.
foreground (class Foreground)
Specifies the preferred color to use for text within the image
window. The default is black.
gammaCorrect (class gammaCorrect)
This resource, if true, will lighten or darken an image of known
gamma to match the gamma of the display (see resource 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.
iconGeometry (class IconGeometry)
Specifies the preferred size and position of the application
when iconified. It is not necessarily obeyed by all window man‐
agers.
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 magnification window which is
invoked with button number 3 after the image is displayed.
Refer to BUTTONS for more details.
matteColor (class MatteColor)
Specify the color of windows. It is used for the backgrounds of
windows, menus, and notices. A 3D effect is achieved by
using highlight and shadow colors derived from this color.
Default value: #ccc.
name (class Name)
This resource specifies the name under which resources for the
application should be found. This resource is useful in shell
aliases to distinguish between invocations of an application,
without resorting to creating links to alter the executable file
name. The default is the application name.
pen[1-9] (class Pen[1-9])
Specifies the color of the preferred font to use when annotating
the image window with text. The default colors are black, blue,
green, cyan, gray, red, magenta, yellow, and white. Refer to
IMAGE ANNOTATION for more details.
printCommand (class PrintCommand)
This command is executed whenever Print is issued (see BUTTONS.
In general, it is the command to print Postscript to your
printer. Default value: lp -c -s %i.
sharedMemory (class SharedMemory)
This resource specifies whether display should attempt use
shared memory for pixmaps. ImageMagick must be compiled with
shared memory support, and the display must support the MIT-SHM
extension. Otherwise, this resource is ignored. The default is
True.
textFont (class textFont)
Specifies the name of the preferred font to use in fixed (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
mega-bytes.
usePixmap (class UsePixmap)
Images are maintained as a XImage by default. Set this resource
to True to utilize a server Pixmap instead. This option is 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
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 thumb‐
nail and press button 3 and drag. Finally, select Open. The image
represented by the thumbnail is displayed at its full size. Choose
Next from the File sub-menu of the Command widget to return to the Vis‐
ual 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 widget
(see COMMAND WIDGET). Alternatively, press F3 in the image window (see
KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in cut mode. In cut mode, the Command widget has
these options:
Help
Dismiss
To define a cut region, press button 1 and drag. The cut region is
defined by a highlighted rectangle that expands or contracts as it 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 rec‐
tangle 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 (see COMMAND WIDGET). Alternatively, press F4 in the image window
(see KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in copy mode. In copy mode, the Command widget
has these options:
Help
Dismiss
To define a copy region, press button 1 and drag. The copy region is
defined by a highlighted rectangle that expands or contracts as it 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 rec‐
tangle corners, pressing a button, and dragging. Finally, press Copy
to commit your copy region. To exit without copying the image, press
Dismiss.
IMAGE PASTING
To begin, press choose Paste of the Edit sub-menu from the Command wid‐
get (see COMMAND WIDGET). Alternatively, press F5 in the image window
(see KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in Paste mode. To exit immediately, press Dismiss.
In Paste mode, the Command widget has these options:
Operators
Over
In
Out
Atop
Xor
Plus
Minus
Add
Subtract
Difference
Multiply
Bumpmap
Copy
CopyRed
CopyGreen
CopyBlue
CopyOpacity
Help
Dismiss
Choose a composite operation from the Operators sub-menu of the Command
widget. How each operator behaves is described below. image window is
the image currently displayed on your X server and image is the image
obtained with the File Browser widget.
Over The result is the union of the two image shapes, with image
obscuring image window in the region of overlap.
In The result is simply image cut by the shape of image window.
None of the image data of image window is in the result.
Out The resulting image is image with the shape of image window cut
out.
Atop The result is the same shape as image image window, with image
obscuring image window where the image shapes overlap. Note
this differs from over because the portion of image outside
image window's shape does not appear in the result.
Xor The result is the image data from both image and image window
that is outside the overlap region. The overlap region is
blank.
Plus The result is just the sum of the image data. Output values are
cropped to 255 (no overflow). This operation is independent of
the matte channels.
Minus The result of image - image window, with underflow cropped to
zero. The matte channel is ignored (set to 255, full coverage).
Add The result of image + image window, with overflow wrapping
around (mod 256).
Subtract
The result of image - image window, with underflow wrapping
around (mod 256). The add and subtract operators can be used to
perform reversible transformations.
Difference
The result of abs(image - image window). This is useful for
comparing two very similar images.
Multipy
The result of composite image image. This is useful for the
creation of drop-shadows.
Bumpmap
The result of image window shaded by image.
Copy The resulting image is image window replaced with image. Here
the matte information is ignored.
CopyRed
The resulting image is the red layer of image window replaced
with the red layer of image. The remaining layers remain
untouched.
CopyGreen
The resulting image is the green layer of image window replaced
with the green layer of image. The remaining layers remain
untouched.
CopyBlue
The resulting image is the blue layer of image window replaced
with the blue layer of image. The remaining layers remain
untouched.
CopyOpacity
The resulting image is the matte layer of image window replaced
with the matte layer of image. The remaining layers remain
untouched.
The image compositor requires a matte, or alpha channel in the
image for some operations. This extra channel usually defines a
mask which represents a sort of a cookie-cutter for the image.
This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the
boundary. If image does not have a matte channel, it is ini‐
tialized with 0 for any pixel matching in color to pixel loca‐
tion (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 col‐
ors. To assure the correct colors are saved in the final image,
any PseudoClass image is promoted to DirectClass (see miff(5)).
To force a PseudoClass image to remain PseudoClass, use -colors.
IMAGE CROPPING
To begin, press choose Crop of the Transform sub-menu from the Command
widget (see COMMAND WIDGET). Alternatively, press [ in the image win‐
dow (see KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in crop mode. In crop mode, the Command widget
has these options:
Help
Dismiss
To define a cropping region, press button 1 and drag. The cropping
region is defined by a highlighted rectangle that expands or contracts
as it follows the pointer. Once you are satisfied with the cropping
region, release the button. You are now in rectify mode. In rectify
mode, the Command widget has these options:
Crop
Help
Dismiss
You can make adjustments by moving the pointer to one of the cropping
rectangle corners, pressing a button, and dragging. Finally, press
Crop to commit your cropping region. To exit without cropping the
image, press Dismiss.
IMAGE CHOPPING
An image is chopped interactively. There is no command line argument
to chop an image. To begin, choose Chop of the Transform sub-menu from
the Command widget (see COMMAND WIDGET). Alternatively, press ] in the
image window (see KEYBOARD ACCELERATORS).
You are now in Chop mode. To exit immediately, press Dismiss. In Chop
mode, the Command widget has these options:
Direction
horizontal
vertical
Help
Dismiss
If the you choose the horizontal direction (this is the default), the
area of the image between the two horizontal endpoints of the chop line
is removed. Otherwise, the area of the image between the two vertical
endpoints of the chop line is removed.
Select a location within the image window to begin your chop, press and
hold any button. Next, move the pointer to another location in the
image. As you move a line will connect the initial location and the
pointer. When you release the button, the area within the image to
chop is determined by which direction you choose from the Command wid‐
get.
To cancel the image chopping, move the pointer back to the starting
point of the line and release the button.
IMAGE ROTATION
Press the / key to rotate the image 90 degrees or \ to rotate -90
degrees (see KEYBOARD ACCELERATORS). To interactively choose the
degree of rotation, choose Rotate... of the Pixel Transform submenu
from the Command Widget (see COMMAND WIDGET). Alternatively, press *
in the image window (see KEYBOARD ACCELERATORS).
A small horizontal line is drawn next to the pointer. You are now in
rotate mode. To exit immediately, press Dismiss. In rotate mode, the
Command widget has these options:
Pixel Color
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Direction
horizontal
vertical
Crop
false
true
Sharpen
false
true
Help
Dismiss
Choose a background color from the Pixel Color sub-menu. Additional
background colors can be specified with the color browser. You can
change the menu colors by setting the X resources pen1 through pen9.
Refer to X RESOURCES for more details.
If you choose the color browser and press Grab, you can select the
background color by moving the pointer to the desired color on the
screen and press any button. The transparent color updates the image
matte channel and is useful for image compositing.
Choose a point in the image window and press this button and hold.
Next, move the pointer to another location in the image. As you move a
line connects the initial location and the pointer. When you release
the button, the degree of image rotation is determined by the slope of
the line you just drew. The slope is relative to the direction you
choose from the Direction sub-menu of the Command widget.
To cancel the image rotation, move the pointer back to the starting
point of the line and release the button.
IMAGE ANNOTATION
An image is annotated interactively. There is no command line argument
to annotate an image. To begin, choose Annotate of the Image Edit sub-
menu from the Command widget (see COMMAND WIDGET). Alternatively,
press a in the image window (see KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in annotate mode. To exit immediately, press Dis‐
miss. In annotate mode, the Command widget has these options:
Font Name
fixed
variable
5x8
6x10
7x13bold
8x13bold
9x15bold
10x20
12x24
Browser...
Font Color
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
Box Color
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
Rotate Text
-90
-45
-30
0
30
45
90
180
Dialog...
Help
Dismiss
Choose a font name from the Font Name sub-menu. Additional font names
can be specified with the font browser. You can change the menu names
by setting the X resources font1 through font9. Refer to X RESOURCES
for more details.
Choose a font color from the Font Color sub-menu. Additional font col‐
ors can be specified with the color browser. You can change the menu
colors by setting the X resources pen1 through pen9. Refer to X
RESOURCES for more details.
If you select the color browser and press Grab, you can choose the font
color by moving the pointer to the desired color on the screen and
press any button.
If you choose to rotate the text, choose Rotate Text from the menu and
select an angle. Typically you will only want to rotate one line of
text at a time. Depending on the angle you choose, subsequent lines
may end up overwriting each other.
Choosing a font and its color is optional. The default font is fixed
and the default color is black. However, you must choose a location to
begin entering text and press button 1. An underscore character will
appear at the location of the pointer. The cursor changes to a pencil
to indicate you are in text mode. To exit immediately, press Dismiss.
In text mode, any key presses will display the character at the loca‐
tion 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. 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 (see COMMAND WIDGET). Alterna‐
tively, press x in the image window (see KEYBOARD ACCELERATORS).
First a popup window is displayed requesting you to enter an image
name. Press Composite, Grab or type a file name. Press Cancel if you
choose not to create a composite image. When you choose Grab, move the
pointer to the desired window and press any button.
If the Composite image does not have any matte information, you are
informed and the file browser is displayed again. Enter the name of a
mask image. The image is typically grayscale and the same size as the
composite image. If the image is not grayscale, it is converted to
grayscale and the resulting intensities are used as matte information.
A small window appears showing the location of the cursor in the image
window. You are now in composite mode. To exit immediately, press 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 with the File Browser widget.
over The result is the union of the two image shapes, with image
obscuring image window in the region of overlap.
in The result is simply image cut by the shape of image window.
None of the image data of image window is in the result.
out The resulting image is image with the shape of image window cut
out.
atop The result is the same shape as image image window, with image
obscuring image window where the image shapes overlap. Note
this differs from over because the portion of image outside
image window's shape does not appear in the result.
xor The result is the image data from both image and image window
that is outside the overlap region. The overlap region is
blank.
plus The result is just the sum of the image data. Output values are
cropped to 255 (no overflow). This operation is independent of
the matte channels.
minus The result of image - image window, with underflow cropped to
zero. The matte channel is ignored (set to 255, full coverage).
add The result of image + image window, with overflow wrapping
around (mod 256).
subtract
The result of image - image window, with underflow wrapping
around (mod 256). The add and subtract operators can be used to
perform reversible transformations.
difference
The result of abs(image - image window). This is useful for
comparing two very similar images.
bumpmap
The result of image window shaded by image.
replace
The resulting image is image window replaced with image. Here
the matte information is ignored.
The image compositor requires a matte, or alpha channel in the
image for some operations. This extra channel usually defines a
mask which represents a sort of a cookie-cutter for the image.
This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the
boundary. If image does not have a matte channel, it is ini‐
tialized with 0 for any pixel matching in color to pixel loca‐
tion (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 a
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
colors. To assure the correct colors are saved in the final
image, any PseudoClass image is promoted to DirectClass (see
miff(5)). To force a PseudoClass image to remain PseudoClass,
use -colors.
COLOR EDITING
Changing the the color of a set of pixels is performed interactively.
There is no command line argument to edit a pixel. To begin, choose
Color from the Image Edit submenu of the Command widget (see COMMAND
WIDGET). Alternatively, press c in the image window (see KEYBOARD
ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in color edit mode. To exit immediately, press
Dismiss. In color edit mode, the Command widget has these options:
Method
point
replace
floodfill
filltoborder
reset
Pixel Color
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Border Color
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Fuzz
0
2
4
8
16
Dialog...
Undo
Help
Dismiss
Choose a color editing method from the Method sub-menu of the Command
widget. The point method recolors any pixel selected with the pointer
unless the button is released. The replace method recolors any pixel
that matches the color of the pixel you select with a button press.
Floodfill recolors any pixel that matches the color of the pixel you
select with a button press and is a neighbor. Whereas filltoborder
recolors any neighbor pixel that is not the border color. Finally
reset changes the entire image to the designated color.
Next, choose a pixel color from the Pixel Color sub-menu. Additional
pixel colors can be specified with the color browser. You can change
the menu colors by setting the X resources pen1 through pen9. Refer to
X RESOURCES for more details.
Now press button 1 to select a pixel within the image window to change
its color. Additional pixels may be recolored as prescribed by the
method you choose.
If the Magnify widget is mapped, it can be helpful in positioning your
pointer within the image (refer to button 2). Alternatively you can
select a pixel to recolor from within the Magnify widget. Move the
pointer to the Magnify widget and position the pixel with the cursor
control keys. Finally, press a button to recolor the selected pixel
(or pixels).
The actual color you request for the pixels is saved in the image.
However, the color that appears in your image window may be different.
For example, on a monochrome screen the pixel will appear black or
white even if you choose the color red as the pixel color. However,
the image saved to a file with -write is written with red pixels. To
assure the correct color text in the final image, any PseudoClass image
is promoted to DirectClass (see miff(5)). To force a PseudoClass image
to remain PseudoClass, use -colors.
MATTE EDITING
Matte information within an image is useful for some operations such as
image compositing (See IMAGE COMPOSITING). This extra channel usually
defines a mask which represents a sort of a cookie-cutter for the
image. This is the case when matte is 255 (full coverage) for pixels
inside the shape, zero outside, and between zero and 255 on the bound‐
ary.
Setting the matte information in an image is done interactively. There
is no command line argument to edit a pixel. To begin, and choose
Matte of the Image Edit sub-menu from the Command widget (see COMMAND
WIDGET). Alternatively, press m in the image window (see KEYBOARD
ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in matte edit mode. To exit immediately, press
Dismiss. In matte edit mode, the Command widget has these options:
Method
point
replace
floodfill
filltoborder
reset
Border Color
black
blue
cyan
green
gray
red
magenta
yellow
white
Browser...
Fuzz
0
2
4
8
16
Dialog...
Matte
Undo
Help
Dismiss
Choose a matte editing method from the Method sub-menu of the Command
widget. The point method changes the matte value of the any pixel
selected with the pointer until the button is released. The replace
method changes the matte value of any pixel that matches the color of
the pixel you select with a button press. Floodfill changes the matte
value of any pixel that matches the color of the pixel you select with
a button press and is a neighbor. Whereas filltoborder changes the
matte value of any neighbor pixel that is not the border color.
Finally reset changes the entire image to the designated matte value.
Choose Matte Value and a dialog appears requesting a matte value.
Enter a value between 0 and 255. This value is assigned as the matte
value of the selected pixel or pixels.
Now, press any button to select a pixel within the image window to
change its matte value.
If the Magnify widget is mapped, it can be helpful in positioning your
pointer within the image (refer to button 2). Alternatively you can
select a pixel to change the matte value from within the Magnify 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 (see miff(5)). Note that
matte information for PseudoClass is not retained for colormapped X
server visuals (e.g. StaticColor, StaticColor, GrayScale, PseudoColor)
unless you immediately save your image to a file (refer to Write).
Correct matte editing behavior may require a TrueColor or DirectColor
visual or a Standard Colormap.
IMAGE DRAWING
An image is drawn upon interactively. There is no command line argu‐
ment to draw on an image. To begin, choose Draw of the Image Edit sub-
menu from the Command widget (see COMMAND WIDGET). Alternatively,
press d in the image window (see KEYBOARD ACCELERATORS).
The cursor changes to a crosshair to indicate you are in draw mode. To
exit immediately, press Dismiss. In draw mode, the Command widget has
these options:
Primitive
point
line
rectangle
fill rectangle
circle
fill circle
ellipse
fill ellipse
polygon
fill polygon
Color
black
blue
cyan
green
gray
red
magenta
yellow
white
transparent
Browser...
Stipple",
Brick",
Diagonal",
Scales",
Vertical",
Wavy",
Translucent",
Opaque",
Open...",
Width
1
2
4
8
16
Dialog...
Undo
Help
Dismiss
Choose a drawing primitive from the Primitive sub-menu.
Next, choose a color from the Color sub-menu. Additional colors can be
specified with the color browser. You can change the menu colors by
setting the X resources pen1 through pen9. Refer to X RESOURCES for
more details.
If you choose the color browser and press Grab, you can select the
primitive color by moving the pointer to the desired color on the
screen and press any button. The transparent color updates the image
matte channel and is useful for image compositing.,
Choose a stipple, if appropriate, from the Stipple sub-menu. Addi‐
tional stipples can be specified with the file browser. Stipples
obtained from the file browser must be on disk in the X11 bitmap for‐
mat.
Choose a line width from the Width sub-menu. To choose a specific
width select the Dialog widget.
Choose a point in the image window and press button 1 and hold. Next,
move the pointer to another location in the image. As you move, a line
connects the initial location and the pointer. When you release the
button, the image is updated with the primitive you just drew. For
polygons, the image is updated when you press and release the button
without moving the pointer.
To cancel image drawing, move the pointer back to the starting point of
the line and release the button.
REGION OF INTEREST
To begin, press choose Region of Interest of the Transform sub-menu
from the Command widget (see COMMAND WIDGET). Alternatively, press R
in the image window (see KEYBOARD ACCELERATORS).
A small window appears showing the location of the cursor in the image
window. You are now in region of interest mode. In region of interest
mode, the Command widget has these options:
Help
Dismiss
To define a region of interest, press button 1 and drag. The region of
interest is defined by a highlighted rectangle that expands or 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
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
Dismiss.
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.
IMAGE SEGMENTATION
Use -segment to segment an image by analyzing the histograms of the
color components and identifying units that are homogeneous with the
fuzzy c-means technique. The scale-space filter analyzes the his‐
tograms of the three color components of the image and identifies a set
of classes. The extents of each class is used to coarsely segment the
image with thresholding. The color associated with each class is
determined by the mean color of all pixels within the extents of a par‐
ticular class. Finally, any unclassified pixels are assigned to the
closest class with the fuzzy c-means technique.
The fuzzy c-Means algorithm can be summarized as follows:
o Build a histogram, one for each color component of the image.
o For each histogram, successively apply the scale-space filter
and build an interval tree of zero crossings in the second de‐
rivative at each scale. Analyze this scale-space ``finger‐
print'' to determine which peaks or valleys in the histogram are
most predominant.
o The fingerprint defines intervals on the axis of the his‐
togram. Each interval contains either a minima or a maxima in
the original signal. If each color component lies within the
maxima interval, that pixel is considered ``classified'' and is
assigned an unique class number.
o Any pixel that fails to be classified in the above threshold‐
ing pass is classified using the fuzzy c-Means technique. It is
assigned to one of the classes discovered in the histogram anal‐
ysis phase.
The fuzzy c-Means technique attempts to cluster a pixel by finding the
local minima of the generalized within group sum of squared error
objective function. A pixel is assigned to the closest class of which
the fuzzy membership has a maximum value.
For additional information see
Young Won Lim, Sang Uk Lee, "On The Color Image Segmentation
Algorithm Based on the Thresholding and the Fuzzy c-Means Tech‐
niques", Pattern Recognition, Volume 23, Number 9, pages
935-952, 1990.
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
This backdrop covers the entire workstation screen and is useful
for hiding other X window activity while viewing the image.
The color of the backdrop is specified as the background color.
Refer to X RESOURCES for details.
confirm on program exit
Ask for a confirmation before exiting the display(1) program.
correct image for display gamma
If the image has a known gamma, the gamma is corrected to match
that of the X server (see the X resource displayGamma).
apply Floyd/Steinberg error diffusion to image
The basic strategy of dithering is to trade intensity resolution
for spatial resolution by averaging the intensities of several
neighboring pixels. Images which suffer from severe contouring
when reducing colors can be improved with this preference.
use a shared colormap for colormapped X visuals
This option only applies when the default X server visual is
PseudoColor or GrayScale. Refer to -visual for more details.
By default, a shared colormap is allocated. The image shares
colors with other X clients. Some image colors could be approx‐
imated, therefore your image may look very different than
intended. Choose Private and the image colors appear exactly as
they are defined. However, other clients may go technicolor
when the image colormap is installed.
display images as an X server pixmap
Images are maintained as a XImage by default. Set this resource
to True to utilize a server Pixmap instead. This option is 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.
ENVIRONMENTdisplay
To get the default host, display number, and screen.
SEE ALSOanimate(1), import(1), montage(1), mogrify(1), mosaic(1), convert(1),
combine(1), xtp(1)COPYRIGHT
Copyright (C) 2001 ImageMagick Studio, a non-profit organization dedi‐
cated to making software imaging solutions freely available.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files ("ImageMag‐
ick"), to deal in ImageMagick without restriction, including without
limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of ImageMagick, and to permit persons to
whom the ImageMagick is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of ImageMagick.
The software is provided "as is", without warranty of any kind, express
or implied, including but not limited to the warranties of mer‐
chantability, fitness for a particular purpose and noninfringement. In
no event shall ImageMagick Studio be liable for any claim, damages or
other liability, whether in an action of contract, tort or otherwise,
arising from, out of or in connection with ImageMagick or the use or
other dealings in ImageMagick.
Except as contained in this notice, the name of the ImageMagick Studio
shall not be used in advertising or otherwise to promote the sale, use
or other dealings in ImageMagick without prior written authorization
from the ImageMagick Studio.
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, E. I. du Pont de Nemours and Company, for providing a
computing environment that made this program possible.
Paul Raveling, USC Information Sciences Institute. The spatial subdivi‐
sion color reduction algorithm is based on his Img software.
AUTHORS
John Cristy, ImageMagick Studio
ImageMagick 1 Feb 1995 display(1)
