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display




SYNOPSIS

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


DESCRIPTION

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

       With display, you can perform these functions on an image:

                o  load an image from a file
                o  display the next image
                o  display the former image
                o  display a sequence of images as a slide show
                o  write the image to a file
                o  print the image to a PostScript printer
                o  delete the image file
                o  create a Visual Image Directory
                o  select the image to display by  its  thumbnail
               rather than name
                o  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  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  cen­
       tered on a backdrop, use:

           display +borderwidth -backdrop cockatoo.miff

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

           display -size 1280x1024 -window root slate.png

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

           display 'vid:*.jpg'

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

           display -size 640x480+256 cockatoo.map

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

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

       To display histogram of an image, use:

           convert file.jpg HISTOGRAM:- | display -


OPTIONS

       For  a  more  detailed  description  of  each  option, see
       ImageMagick(1).

       -authenticate <string>
              decrypt image with this password

       -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>
              (This  option  has  been  replaced  by  the  -limit
              option)

       -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 <events>
              enable debug printout

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

       -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

       -extract <width>x<height>{+-}<x>{+-}<y>{%}{@} {!}{<}{>}
              extract an area from the image while decoding

       -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

       -map <type>

              display image using this type.

       -matte store matte channel if the image has one

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

       -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
              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

       -version
              print ImageMagick version string

       -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
              ImageMagick(1).


MOUSE BUTTONS

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

       1       Press this button to map or unmap the Command wid­
              get . 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 dis­
              play(1)  commands.  This button behaves differently
              tile  is  displayed.  To return to the visual image
              directory, choose  Next  from  the  Command  widget
              (refer  to  Command Widget).  Next and Former moves
              to the next or former  image  respectively.  Choose
              Delete  to delete a particular image tile. Finally,
              choose Update to synchronize all  the  image  tiles
              with  their respective images. See montage and miff
              for more details.


COMMAND WIDGET

       The Command widget lists a number of  sub-menus  and  com­
       mands. 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


           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...
           Slide Show
           Preferences...

           Help

           Overview
           Browse Documentation
           About Display

       Menu  items with a indented triangle have a sub-menu. They
       are represented above as the indented items. To  access  a
       sub-menu  item,  move  the pointer to the appropriate menu
       and press button 1 and drag. When  you  find  the  desired
       sub-menu  item, release the button and the command is exe­
       cuted.  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 par­
       ticular command.  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 number.  For example to dis­
       play 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 number.  For example to dis­
       play 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.
                    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  direc­
       tion.
           V         Press  to  flip image in the vertical direc­
       tion.
           /        Press to rotate the image 90  degrees  clock­
       wise.
           \        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.

       ter.
           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 ImageMag­
       ick.
           1-9      Press to change the level of magnification.

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

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


X RESOURCES

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

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

       background (class Background)

              Specifies the preferred color to use for the  Image
              window background. The default is #ccc.

       borderColor (class BorderColor)

              Specifies  the preferred color to use for the Image

              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  formatted  text.   The  default is 14 point
              Helvetica.

       font[1-9] (class Font[1-9])

              Specifies the name of the  preferred  font  to  use
              when  annotating  the  image  window with text. The
              default  fonts  are  fixed,  variable,  5x8,  6x10,
              7x13bold, 8x13bold, 9x15bold, 10x20, and 12x24.

       foreground (class Foreground)

              Specifies  the  preferred  color  to  use  for text
              within the image window.  The default is black.

       gammaCorrect (class gammaCorrect)

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

       geometry (class Geometry)

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

       iconic (class Iconic)

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

       magnify (class Magnify)

              specifies an integral factor  by  which  the  image
              should be enlarged. The default is 3.

              This  value  only  affects the magnification window
              which is invoked with button  number  3  after  the
              image is displayed.

       matteColor (class MatteColor)

              Specify  the  color  of windows. It is used for the
              backgrounds of windows, menus, and  notices.  A  3D
              effect  is  achieved  by using highlight and shadow
              colors derived  from  this  color.  Default  value:
              #697B8F.

       name (class Name)

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

       pen[1-9] (class Pen[1-9])

              Specifies the color of the preferred  font  to  use
              when  annotating  the  image  window with text. The
              default colors are black, blue, green, cyan,  gray,
              red, magenta, yellow, and white.

       printCommand (class PrintCommand)

              This  command is executed whenever Print is issued.
              In general, it is the command to  print  PostScript
              to your printer. Default value: lp -c -s %i.

       sharedMemory (class SharedMemory)

              This  resource  specifies  whether  display  should
              This resource specifies the title to  be  used  for
              the  image  window.  This  information is sometimes
              used by a window manager to provide a header  iden­
              tifying  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  useful  if  your  image
              exceeds the dimensions of your  server  screen  and
              you intend to pan the image. Panning is much faster
              with Pixmaps than with a XImage. Pixmaps  are  con­
              sidered  a precious resource, use them with discre­
              tion.

              To set the geometry of the Magnify or Pan  or  win­
              dow,  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 dis­
       played.  To choose  a  particular  image  file,  move  the
       pointer to the filename and press any button. The filename
       is copied to the text window. Next, press  Open  or  press
       the RETURN key. Alternatively, you can type the image file
       name directly into the text window.  To  descend  directo­
       ries,  choose  a directory name and press the button twice
       quickly. A scrollbar allows a large list of  filenames  to
       be  moved  through the viewing area if it exceeds the size
       of the list area.

       You can trim the list of file names by using  shell  glob­
       bing  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.

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


IMAGE CUTTING

       Note that cut information for image window is not retained
       for  colormapped X server visuals (e.g. StaticColor, Stat­
       icColor, GRAYScale, PseudoColor).  Correct cutting  behav­
       ior  may  require  a  TrueColor or DirectColor visual or a
       Standard Colormap.

       To begin, press choose Cut of the Edit sub-menu  from  the
       Command  widget. Alternatively, press F3 in the image win­
       dow.

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

           Help
           Dismiss

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

           Cut
           Help
           Dismiss

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


IMAGE COPYING

       To begin, press choose Copy of the Edit sub-menu from  the
       Command  widget. Alternatively, press F4 in the image win­
       dow.

       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:
           Dismiss

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


IMAGE PASTING

       To begin, press choose Paste of the Edit sub-menu from the
       Command  widget. Alternatively, press F5 in the image win­
       dow.

       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 dis­
       played 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 win­
              dow is in the result.

              put  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 trans­
              formations.

       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 creation 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 repre­
              sents a sort of a cookie-cutter for the image. This
              is  the  case when matte is 255 (full coverage) for
              pixels inside the shape, zero outside, and  between
              zero  and  255  on  the boundary. If image does not
              have a matte channel, it is initialized with 0  for
              any  pixel  matching  in  color  to  pixel location
              (0,0), otherwise  255.  See  Matte  Editing  for  a
              method of defining a matte channel.

              Note that matte information for image window is not
              retained for colormapped  X  server  visuals  (e.g.
              StaticColor,  StaticColor, GrayScale, PseudoColor).
              Correct compositing behavior may  require  a  True­
              Color or DirectColor visual or a Standard Colormap.
              correct  colors.  To  assure the correct colors are
              saved in the final image, any PseudoClass image  is
              promoted  to  DirectClass.   To force a PseudoClass
              image to remain PseudoClass, use -colors.


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 but­
       ton. 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. Alterna­
       tively, press ] in the Image window.

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

           Direction

           horizontal
           vertical

           Help
           Dismiss


       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.  Alternatively, press * in  the  image
       window.

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

           Pixel Color

           black
           blue
           cyan
           green
           gray
           red
           magenta
           yellow
           white
           Browser...

           Direction

           horizontal
           vertical

           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 loca­
       tion and the pointer. When you  release  the  button,  the
       degree of image rotation is determined by the slope of the
       coarsely  segment  the image with thresholding.  The color
       associated with each class is determined by the mean color
       of  all  pixels  within the extents of a particular class.
       Finally, any unclassified pixels are assigned to the clos­
       est  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 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.

       Any pixel that fails to be classified in the above thresh­
       olding pass is classified using the  fuzzy  c-Means  tech­
       nique.  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 member­
       ship 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",  Pat­
       tern  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 Anno­
       tate of the Image Edit sub-menu from the  Command  widget.
       Alternatively, press a in the image window.

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

       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

       -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. Addi­
       tional  font  colors  can  be  specified  with  the  color
       browser.  You  can change the menu colors by setting the X
       resources pen1 through pen9.

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

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

       Choosing a font and its color  is  optional.  The  default
       font is fixed and the default color is black. However, you
       must choose a location to begin entering text and press  a
       button.  An  underscore character will appear at the loca­
       tion of the pointer. The cursor changes  to  a  pencil  to
       indicate  you are in text mode. To exit immediately, press
       Dismiss.
       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  wid­
       get. Alternatively, press x in the Image window.

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

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

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

       Operators

       over

       in

       out

       atop

       xor

       plus

       minus

       add

       subtract


       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  dis­
       played 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 win­
              dow 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. Out­
              put  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 trans­
              formations.

       difference

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

       bumpmap
              zero and 255 on the boundary.  If  image  does  not
              have  a matte channel, it is initialized with 0 for
              any pixel  matching  in  color  to  pixel  location
              (0,0),  otherwise  255.  See  Matte  Editing  for a
              method of defining a matte channel.

              If you choose blend, the composite operator becomes
              over.  The image matte channel percent transparency
              is initialized to factor.  The image window is ini­
              tialized 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  displace­
              ment map, is a maximum positive displacement. White
              is a maximum negative displacement and middle  gray
              is neutral. The displacement is scaled to determine
              the  pixel  shift.  By  default,  the  displacement
              applies  in both the horizontal and vertical direc­
              tions. However, if you specify mask, image  is  the
              horizontal  X  displacement and mask the vertical Y
              displacement.

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

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

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


COLOR EDITING

       Changing the the color of a set  of  pixels  is  performed
       interactively. There is no command line argument to edit a

       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

       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. Flood­
       fill 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 neigh­
       bor  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 win­
       dow to change its color. Additional pixels may  be  recol­
       ored  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.  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 pix­
       els. To assure the correct color text in the final  image,
       any  PseudoClass image is promoted to DirectClass To force
       a PseudoClass image to remain PseudoClass, use -colors.


MATTE EDITING

       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

       reset

       Border Color

       black

       blue

       cyan

       green

       gray

       red

       magenta

       yellow

       white

       Browser...

       Fuzz

       0

       2

       4

       8
       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 dia­
       log 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. 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  wid­
       get  is  mapped,  it  can  be  helpful in positioning your
       pointer within the image (refer  to  button  2).  Alterna­
       tively  you  can  select a pixel to change the matte value
       from within the Magnify widget.  Move the pointer  to  the
       Magnify widget and position the pixel with the cursor con­
       trol keys. Finally, press a button  to  change  the  matte
       value  of  the selected pixel (or pixels).  Matte informa­
       tion 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 col­
       ormapped  X server visuals (e.g. StaticColor, StaticColor,
       GrayScale, PseudoColor) unless you immediately  save  your
       image  to  a  file (refer to Write). Correct matte editing
       behavior may require a TrueColor or DirectColor visual  or
       a Standard Colormap.


IMAGE DRAWING

       An  image is drawn upon interactively. There is no command
       line argument to draw on an image. To begin,  choose  Draw
       of  the  Image  Edit  sub-menu  from  the  Command widget.
       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

       fill polygon

       Color

       black

       blue

       cyan

       green

       gray

       red

       magenta

       yellow

       white

       transparent

       Browser...

       Stipple

       Brick

       Diagonal

       Scales

       Vertical

       Wavy

       Translucent

       Opaque

       Open...

       Width


       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.  Alterna­
       tively, press R in the image window.

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

       Help

       Dismiss

       Print...

       Edit

       Undo

       Redo

       Transform

       Flip

       Flop

       Rotate Right

       Rotate Left

       Enhance

       Hue...

       Saturation...

       Brightness...

       Gamma...

       Spiff

       Dull

       Equalize

       Normalize

       Negate

       GRAYscale

       Quantize...

       Effects


       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 mov­
       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 but­
       ton.

       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 .displayrc:

                display image centered on a backdrop"

                    This backdrop covers the  entire  workstation
                    screen  and is useful for hiding other X win­
                    dow 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).
                display warning messages"

                    Display any warning messages.
                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"


                    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 graph­
       ics 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  ini­
       tial  implementation  of Alan Paeth's image rotation algo­
       rithm.

       David Pensak, ImageMagick Studio, for providing a  comput­
       ing environment that made this program possible.

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


SEE ALSO

       animate(1),  composite(1),  conjure(1),  convert(1), iden­
       tify(1), ImageMagick(1), import(1), mogrify(1), montage(1)


COPYRIGHT

       Copyright (C) 2003 ImageMagick Studio

       Permission  is hereby granted, free of charge, to any per­
       son obtaining a copy of this software and associated docu­
       mentation  files  ("ImageMagick"),  to deal in ImageMagick
       without  restriction,  including  without  limitation  the
       rights  to  use, copy, modify, merge, publish, distribute,
       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 authorization  from  the
       ImageMagick Studio.


AUTHORS

       John Cristy, ImageMagick Studio LLC,
       Glenn Randers-Pehrson, ImageMagick Studio LLC.

ImageMagick         Date: 2003/01/01 01:00:00          display(1)
  




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