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rtdimage(3)

NAME

 
rtdimage - Real-Time Display Image, a Tk Image Type

SYNOPSIS

 
image create rtdimage ?option value ...?

DESCRIPTION

 
Tk4.0 introduced a new "image" command and a C interface for
adding new image types. A Tk image is much like a Tk widget in
that it is both an object and a Tcl command. "rtdimage" is an
extended Tk image type designed for real-time image display.
Images can be loaded from shared memory or FITS format files,
over sockets or HTTP.
For real-time usage, a background daemon process rtdServer(1)
communicates with the rtdimage software over a socket
interface to display and update images rapidly from shared
memory. A more general purpose remote control interface is also
available (see rtdRemote).

CREATING RTDIMAGES

 
An "rtdimage" is created with the "image create" Tk
command. After this, you can use the image in a Tk canvas by
specifying it with the "-image" option. For example:

    set image [image create rtdimage ...]
    $canvas create image 0 0 -image $image ...

Most Tk image types may be used in any Tk widget, however,
for our purposes, it was necessary to restrict the use to
canvas widgets only. This was necessary in order to handle
scrolling efficiently.

OPTIONS

 
The following options may be specified when creating or
configuring an rtdimage:


-displaymode mode
        The rtdimage supports two different display modes: 0
        and 1.  In display mode 0, space is allocated in the X
        server for the entire image. This makes scrolling
        faster, but uses enormous amounts of memory when the
        image is very large or is scaled to a large
        size. Still, this mode is useful in cases where the
        entire image is always displayed, such as in a panning
        window.  In displaymode 1 (default), space is only
        allocated for the visible part of the image. This
        makes scrolling somewhat slower, but uses much less
        memory.

-file name
        "name" specifies a FITS format file to load and display.

-fitwidth  winwidth
-fitheight winheight
        These two options specify the size of the window into
        which the image must fit. The image will be scaled
        (shrunk) equally in the X and Y directions to fit as
        closely as possible inside the window.

-newimagecmd command
        The given tcl command is evaluated every time a new
        image is loaded. This command is not called for
        real-time image updates, unless the image dimensions
        or data type changed. See the "camera" subcommand
        for getting notification of real-time image updates.

-subsample bool
        If bool is true, subsampling is used when shrinking
        the image, i.e.: if the image is shrunk by 1/3, only
        every third pixel is displayed. Otherwise, the maximum
        value is taken from the group of pixels.

-usexshm bool
        If bool is true (default), attempt to use X shared
        memory for the image display, if available. This
        improves performance considerably, but is only
        available when working on the system console.

-verbose bool
        If bool is true, diagnostic messages are printed out
        to show what is going on internally (for debugging
        use).

shm_header bool
shm_data bool
        If bool is true, the image FITS header (or data) is kept in
        shared memory so that it can be accessed from a remote process
        (see rtdRemote).

COORDINATES

 
The rtdimage subcommands support the following types of coordinates:

    canvas     - canvas coordinates (canvas scroll area)
    screen     - canvas window coordinates (visible area)
    image      - basic image pixel coords (at mag 1, no transformations)
    wcs        - world coordinates in H:M:S D:M:S
    deg        - world coordinates in degrees

The rtdimage "convert" subcommand can be used to convert between any
two coordinate systems. In addition, most rtdimage subcommands accept
coordinates using the following syntax:

    $x $y  coord_type

For example:

    set val [$image get $x $y canvas]
    set val [$image get $ra $dec "wcs 1950"]
    set val [$image get 42.1 38.3 "deg 2000"]

For world coordinates, the equinox may be optionally specified as part
of the coordinate type. The default is 2000.

IMAGE FORMATS

 
An rtdimage can load and display FITS format images or images written
to shared memory via rtdServer(1). The following FITS image data types
are supported: float, long, short, ushort, byte or XImage.  Except for
XImage, The order of lines is the same as for FITS files, with the
origin at lower left. XImage is a special image type, which is taken
to be already in a format that can be displayed with no color
scaling. Support for other image types is planned, however the
internal image type will remain FITS. New image types can be added by
deriving a new subclass from the ImageIO class.

COLOR ALLOCATION

 
All rtdimages in an application share the same default
colormap.  On startup, the rtdimage attempts to allocate as
many color cells as possible, leaving about 10 free for other
applications.  The number of color cells allocated can be
changed with the "alloccolors" subcommand. If another
application (netscape, for example) has already grabbed all of
the colors, a private colormap will be used. An attempt is made
to keep most of the window manager colors intact, to avoid color
flashing, at least in the GUI elements.

MOTION EVENTS

 
Since handling pointer motion events in Tcl code is fairly slow, the
rtdimage code does some of the common work internally by setting
values in a global array called "RtdImage". These values can be best
accessed by specifying the "-textvariable" option to a Tk label or
entry widget. The global "RtdImage" array contains the following
values, which are updated on motion events:

        RtdImage(X)            X image coordinate
        RtdImage(Y)            Y image coordinate
        RtdImage(VALUE)        pixel value at X,Y
        RtdImage(RA)           world coordinate RA value
        RtdImage(DEC)          world coordinate DEC value
        RtdImage(EQUINOX)      world coordinate equinox

The world coordinate values are set to empty strings if the image
header does not support world coordinates.

The same motion handler that sets the above variables also contains
support for zoom windows (zoom and zoomview commands) and pixel tables
(pixtab command).

IMAGE COMMANDS

 
The return value from the "image create rtdimage" command is
the name of the image and also the name of a new Tcl command
that can be used to operate on the image. The Tcl command
has the following subcommands:

<imageName> alloccolors ?numColors?
        With no arguments, this command returns a Tcl list
        containing the number of allocated and the number of
        free colors.  With one argument, the command attempts
        to reallocate numColors colors.  The number of colors
        actually allocated depends on what other applications
        are running (see COLOR ALLOCATION).

<imageName> autocut ?-percent number?
        This command automatically sets the cut levels (the
        lowest and highest image pixel values considered in
        colormap scaling).  Two different algorithms are
        supported. The default (and fastest version) is median
        filtering.  If -percent is specified, the argument is
        a number between 0 and 100, such as 90 for 90%, where
        that percent of the image pixels should be within the
        cut values. i.e.: if you look at the graph (see
        graphdist command) of the pixel value distribution,
        you would take the top 90% of the graph and set the
        cut levels to left and right ends of the graph.
        Note: if this command is called, it is assumed that
        cut levels can be set automatically when a new image
        is loaded. See also the "cut" command.

<imageName> camera start cameraName ?tclCommand?
<imageName> camera stop
<imageName> camera pause
<imageName> camera continue
        The "camera start" command sends a message to the
        rtdServer daemon process telling it to start sending
        images from the given camera.  Actually the server
        sends only image events, short messages over a socket
        interface, while the images are written to and read
        from shared memory. Camera is the name of a camera
        that must be known to the rtdServer (see rtdServer(1)
        for more information).  The optional ?tclCommand?
        argument to "start" should be a string containing a
        Tcl command to be evaluated whenever a new image event
        is received and displayed. The "camera stop" command
        tells the rtdServer to stop sending image events. The
        "pause" and "continue" subcommands can be used to
        temporarily stop the image events and restart them,
        without having to know the name of the camera.

<imageName> clear
<imageName> clear ximage
<imageName> clear ?-reuse $reuse
                   -ra $ra -dec $dec -equinox $equinox -radius $radius
                   -width $width -height $height?
        This command is used to blank out the display by generating and
        loading a blank image. With no arguments a small blank image is
        generated with a default header. If "-ximage" is specified, the
        image is only cleared temporarily, until the next image update.

        In the last case, the optional arguments are used to generate
        a dummy image that supports world coordinates, so that you can
        plot objects on a blank background. Any missing values are set
        to a default value.

        Optional arguments:

        reuse   - flag: if true, reuse previous image, if it is the same
        ra, dec - center point for WCS coords (in decimal degrees)
        radius  - used to initialize WCS coords (CDELT1 and 2)
        equinox - equinox for WCS coords
        width   - width of generated image in pixels
        height  - height of generated image in pixels

<imageName> cmap file   <colormapFile>
<imageName> cmap rotate <amount>
<imageName> cmap shift  <amount>
<imageName> cmap pixels
<imageName> cmap reset
        This command performs operations and queries on the colormap.
        If a colormap file is specified, it should contain 256 lines
        of red, green and blue values between 0.0 and 1.0 (MIDAS
        colormaps are saved in this format).  The values will be
        distributed among the available colors and installed as a new
        colormap. For rotate and shift, the amount can be any
        integer. The colormap will be rotated (or shifted) by that
        amount. "pixels" returns a Tcl list of the colormap pixel
        values (for use by external applications using the RTI
        library, class ImageData). To get the number of colors in the
        colormap, you can use the "alloccolors" subcommand with no
        arguments or "llength" on the result of the pixels subcommand.
        "reset" resets the colormap to its original state.  The RTD
        release includes a large number of MIDAS colormap files in the
        colormap directory.

<imageName> colorramp
        This command generates an rtdimage displaying the
        colors in the colormap as a ramp or colorbar. This
        image will have the same size as the window containing
        it. This command should be called again from Tcl if
        the window is resized.

<imageName> colorscale ?scale_type?
        This command sets or queries the algorithm to be used
        for assigning the limited number of available colors
        to image pixels. If scale_type is specified, it should
        be one of: linear, log, sqrt or histeq, indicating the
        color scaling algorithm: linear scaling, logarithmic,
        square root or histogram equalization, resp.  With no
        arguments, the current color scale type is returned.

<imageName> convert coords inx iny in_coord_type outx outy out_coord_type
<imageName> convert dist inx iny in_coord_type outx outy out_coord_type
        This command is used to convert between different coordinate
        representations. inx and iny and the input coords (or
        distance) in the given input coordinate system. "convert
        coords" treats x,y as a point, while "convert dist" treats it
        as a distance. outx and outy, if not empty, are the names of
        variables that will hold the resulting coordinates.  If outx
        and outy are empty strings, the values are returned as a tcl
        list "x y".

        The available coordinate systems are:

        canvas     - canvas coordinates (canvas scroll area)
        screen     - canvas window coords (visible area)
        image      - basic image pixel coords (at mag 1, no transformations)
        wcs        - world coordinates in H:M:S
        deg        - world coordinates in degrees

        The world coordinate types: "wcs" and "deg" may also include
        the epoch: Example:

        $image convert coords $ra $dec "wcs 1950" x y canvas

        Note: the coordinate types may be abbrieviated, since only the
        first char is actually checked.

<imageName> cut ?low high?
        This command sets or queries the cut levels. If low
        and high are specified, then the cut levels are set so
        that pixels below the low value will all have the
        lowest color while those above high will all have the
        highest color value.  If no arguments are given, the
        current cut values are returned.
        Note: if the cut levels are set with this command,
        it is assumed that they should not be changed automatically
        when a new image is loaded (see autocut subcommand).

<imageName> dispwidth
<imageName> dispheight
        These commands return the logical width and height of
        the image after transformations (scaling and
        rotating).  This is the size of the displayed image,
        assuming the window is large enough. This command also
        takes the image's "requested width" into account (set by
        by "view update" subcommand).

<imageName> dump <filename>
        This command dumps the current image to the given file in FITS
        format.  If a FITS header is present, it is used, otherwise
        FITS keywords are inserted indicating the image type, width
        and height along with the date and a number of numbered "blank
        cards" or FITS keyword fields that can be modified by other
        applications as needed.  The fields have names starting with
        BLANK followed by 2 digits (from BLANK00 to BLANK28).

<imageName> flip <direction> ?bool?
        With two arguments, flip (or stop flipping) the image
        in the given direction, where direction is one of x,
        y, xy or "none" for flipping in the x, y, or x and y
        directions or neither.  The boolean value turns
        flipping on (1) or off (0) in the given direction(s).
        With one argument, the command returns the current
        value for the given argument.

<imageName> frameid
        This command returns the frame Id of this image. The
        frame Id is a unique number used to identify the image
        to the rtdServer for use with rapid frames.

<imageName> get x y coord_type ?nrows ncols?
        Returns a Tcl list of image values at the given X,Y
        coordinates.  X and Y are interpreted in the given coordinate
        system (see COORDINATES above).  The return value is a tcl
        list where each item consists of a list of {X Y Value}, where
        X and Y are the adjusted coordinates in the raw image and
        Value is the raw data value at that point or "-" if out of
        range.  If nrows and ncols are greater than 1, the command
        returns a Tcl list of nrows x ncols values, each a list of
        rows, centered at the given point.

<imageName> graphdist bltGraph bltElem numValues
        This command displays the distribution of pixel values
        in the image in the given BLT graph widget. The data
        for the given BLT graph element will be set directly
        to the graph without going through tcl (see
        blt_graph(n)). The number of points to plot is given
        by the numValues argument.

<imageName> itt file <ITTFile>
<imageName> itt scale <scaleFactor>
        This command operates on MIDAS style intensity
        transfer tables or ITTs. If an ITT file is specified,
        it should contain 256 intensity values in the range
        0.0 to 1.0, one per line. The colormap will be
        modified by applying the intensities to it.  The
        colormap can also be stretched or squeezed by applying
        an integer scale factor to the ITT.  The RTD release
        contains a number of ITTs in the colormaps directory.

<imageName> max
        Returns the highest pixel value in the image.

<imageName> mband x0 y0 x1 y1 cord_type show_angle
        Draw a measure band on the canvas to show the distance in
        world coordinates (diagonal, vertical and horizontal).

        This method was originaly implemented in Tcl/[incr Tk], but
        was redone here for better performance.

        x0 and y0 are the starting coordinates of the drag, x1 and y1
        are the coordinates from the motion events and show_angle is a
        flag: if true, show the horizontal and vertical distance,
        otherwise only the diagonal.

        The coordinates are accepted in the given coordinate system
        "coord_type", see COORDINATES above.

<imageName> min
        Returns the lowest pixel value in the image.

<imageName> pan start <tclCommand> <shrinkFactor>
            pan stop
        This command supports a panning image, which is, in
        this case, a second rtdimage image or "view" of the
        main image, scaled to a small size with a rectangle
        indicating the visible portion of the image.  If
        "start" is specified, the given tcl command will be
        evaluated whenever the image size changes, due to
        scaling or loading a new image, or whenever the image
        position has changed due to scrolling.  The tcl
        command will be called with 5 arguments: x1 y1 x2 y2,
        which are the coordinates of the visible part of the
        image, scaled by the given "shrinkFactor", and a flag
        indicating whether the image is new (1) or an update
        of the existing image (0).  This can be used to draw
        the panning rectangle on the panning image.  To stop
        the command from being called, use the "pan stop"
        subcommand.

<imageName> pixtab start <nrows> <ncols>
<imageName> pixtab stop
        This command supports displaying a table of pixel values
        around a point.  All this commmand does is set a flag causing
        Tcl array variables to be updated on motion events, which can
        cause the display to be updated via the "-textvariable" widget
        option on the table items.
        The array name is fixed as: RtdPixTab and the elements are
        indexed as $RtdPixTab(i,j), where the left and top sides of
        the table (array) are the X and Y image coordinates, resp. and
        the rest are image pixel values.

<imageName> preview <bool>
        If bool is true and real-time images are being
        displayed, the viewing mode is set to "preview mode",
        otherwise, it is set back to "real-time mode". In
        preview mode, the camera is stopped (if it was
        running) and a local copy of the shared memory image
        is made, so that it can be freed or modified without
        affecting the image.

<imageName> radecbox <ra> <dec> <radius>
        ra and dec are the world coords (h:m:s or decimal deg) and
        radius is expected in arcmin.  The return value in Tcl is a
        list of 4 values {ra0 dec0 ra1 dec1} that form a ra,dec box
        with the given center point and radius.

<imageName> remote -server ?$port?
<imageName> remote -client $host $port
        This command is used to enable remote control of the RTD image
        widget. The -server option is used by the application
        containing the rtdimage widget. The -client option is used by
        the remote client via the rtdRemote interface (internally
        only).

        If -server is specified, the widget starts listening for
        commands on the given port. If port is 0 (default), a port
        number will be chosen. A file is created in the user's home
        directory "~/.rtd-remote", which contains the pid, hostname
        and port number of the running Rtd process.

        If -client is specified, the given port will be used to send
        results to clients when they have requested this type of
        "callback" operation.  The client should be already listening
        on the given port. Note that this command is only used by the
        rtdRemote library internally.

<imageName> rotate ?bool?
        Rotate (or stop rotating) the image. Currently,
        rotation is only done by swapping the x and y axis. If
        bool is specified, rotation is turned on(1) or off(0).
        Otherwise, the current setting is returned.

<imageName> scale ?sx sy?
        With 2 arguments, the image is scaled (magnified) by
        the given X and Y amount.  With no arguments, the
        current scaling factors are returned (as a tcl list of
        2 integers). The scaling factors are positive or
        negative integers (default 1). Positive integers are
        used to zoom in on the image (2 means twice the
        original size). Negative integers are used to zoom out
        (-2 means 1/2 the original size). The software imposes
        an arbitrary limit on the minimum and maximum scaling
        factor allowed.

<imageName> shm set $data_size $data_id $data_owner
                    ?$header_size $header_id $header_owner?
<imageName> shm get data
<imageName> shm get header
<imageName> shm create $size
<imageName> shm delete $Id
<imageName> shm update
        This subcommand provides access to the shared memory in which
        the FITS raw image data and header are stored. The raw image
        is normally stored in mmap shared memory, but SysV shared
        memory will be used if either the -shm_data 1 or the
        -shm_header 1 option was specified when creating the image.

        The "set" command allow you to set the shared memory Ids to
        use to access the image data and header. The data and header
        in the area specified should be in FITS format. If the header
        is not specified, the previous header is reused. For both data
        and header, the size of the area (in bytes) and the shared
        memory Id must be specified. In addition a flag indicating who
        "owns" the shared memory is specified (if true, then the area
        will be deleted when no longer needed).

        The "get" command returns the shared memory Id of the data or
        header as well as the offset in the shared memory area where
        the header or data begins, the length of the header or data
        and the total size of the shared memory. The result of the
        "get header" or "get data" command is a Tcl list of the 4
        numbers {shmId offset length size}, where length is the length
        of the header or data and size is the total size of the shared
        memory area. If the data or header is not currently in shared
        memory, an error is returned. (RTD must be started with option
        -shm_data 1 and/or -shm_header 1 for this command to work).

        The "create" command creates a new shared memory area with the
        given size and returns the Id. The memory should be deleted
        with the "delete" subcommand when no longer needed.

        The "delete" command deletes the shared memory with the given
        Id (which should have been returned from the "create"
        subcommand).

        The "update" command causes the display to be updated to
        reflect any changes in the image memory.

<imageName> spectrum <bltGraph> <bltElem> x0 y0 x1 y1 coord_type
        This command is used to display a graph of a "cut" of the
        image along a given line. x0, y0, x1 and y1 are the end points
        of a line in the image (in the given coordinate system, see
        COORDINATES above).  <bltGraph> is the path name of a BLT
        graph widget to display the plot of the pixel intensities
        along the line.  <bltElem> is the name of the element in the
        graph that should receive the data.  The data is sent directly
        to the graph for display.  The return value in Tcl is the
        number of points to plot.

<imageName> statistics
        statistics subcommand: calculate statistics on the section of
        the image being displayed.  The return value in Tcl is a list
        of the following values:

          {x y ra dec equinox fwhmX fwhmY angle objectPeak meanBackground}

        where:

        x              = adjusted X image coordinate
        y              = adjusted Y image coordinate
        ra             = RA position (calculated from mean X pos within array)
        dec            = DEC position (calculated from mean Y position within array)
        equinox        = equinox of RA and DEC
        fwhmX          = FWHM in X
        fwhmY          = FWHM in Y
        angle          = angle of major axis, degrees, along X = 0
        objectPeak     = peak value of object above background
        meanBackground = mean background level

<imageName> type
        Returns the data type of the raw image as a string:
        one of: float, long, short, ushort, byte or
        XImage. The last type, XImage is a special pseudo
        type, the same as a byte image, except that the Y axis
        is reversed and it is assumed to not need color
        scaling.

<imageName> update
        This command makes sure that the image is up to date with the
        raw data (which may have changed via shared memory, mmap, etc).

<imageName> view add <path> ?propagateScale?
<imageName> view remove <path>
<imageName> view update <path> x y width height viewx viewy coord_type
<imageName> view enter  <path>
<imageName> view leave  <path>
        The view command is used to specify a viewing image to view
        the same image, possibly at a different size.  The new view
        will share data with the original and be updated when the
        original is updated.  This can be used, for example, to build
        a panning window or a rapid frame.

        <path> must be the name of a second rtdimage image. The two
        images will communicate internally to always display the same
        image, possibly scaled to different sizes. The subcommands are:

        add
                Adds a new view to this image.

        remove
                Removes the view.

        update
                Updates the view from this image with the given image
                x,y offset, width and height and the position of the
                image view origin in the given coordinate type. This
                command can be used to implement a zoom window or
                rapid frame, since it controls which portion of the
                image is displayed.

        enter
                If 2 images are in the same canvas, make <path> the
                current one (receives motion events, ...).

        leave
                Undo the enter command.

        If the optional "add" argument "propagateScale" is true,
        changes in the scale factors in the master image will
        propagate to the view (this is the default behavior).

<imageName> warp <x> <y>
        Warp (move) the mouse pointer by the given x and y amounts
        (pixels).


<imageName> wcscenter ?-format <format>?
        This command returns the world coordinates of the center of
        the image.  The optional format option determines the format
        of the result:

        -format 0 ==> H:M:S [+-]D:M:S (default)
        -format 1 ==> RA DEC (in degrees)

        The return value is a tcl list, formatted according to the
        format option, or an empty string if the coordinates are out
        of range or WCS is not supported.

<imageName> wcsdist x0 y0 x1 y1
        This command returns the world coordinate distance between 2
        points after transformations.  The arguments are expected in
        canvas coords (canvasx, canvasy, doubles).  The return value
        in Tcl is the WCS distance between the given points after
        transformations.

<imageName> wcsheight
        This command returns the height of the image in arcmin or the
        empty string if WCS is not supported.

<imageName> wcswidth
        This command returns the width of the image in arcmin or the
        empty string if WCS is not supported.

<imageName> wcsradius
        This command returns the radius (distance from center to
        corner) of the image in arcmin or the empty string if WCS is
        not supported.

<imageName> wcsset <ra> <dec> <secpix> <xrefpix> <yrefpix> <nxpix> <nypix>
                   <rotate> <equinox> <epoch> <projection>
<imageName> wcsset
        If arguments are specified, this subcommand sets up the WCS
        structure from the given information about the image:
        Arguments:
          ra      = Center right ascension in H:M:S
          dec     = Center declination in D:M:S
          secpix  = Number of arcseconds per pixel
          xrefpix = Reference pixel X coordinate
          yrefpix = Reference pixel Y coordinate
          nxpix   = Number of pixels along x-axis
          nypix   = Number of pixels along y-axis
          rotate  = Rotation angle (clockwise positive) in degrees
          equinox = Equinox of coordinates, 1950 and 2000 supported
          epoch   = Epoch of coordinates, used for FK4/FK5 conversion no
                    effect if 0
          proj    = Projection

        With no arguments, the command returns a list of the basic WCS
        parameter values: {ra dec secpix nxpix nypix rotate equinox epoch}.

<imageName> wcsshift <ra> <dec> <coorsys>
        This command resets the center of the WCS structure.
        Arguments:
          ra        = New center right ascension in degrees
          dec       = New center declination in degrees
          equinox   = must be 2000 or 1950

<imageName> width
<imageName> height
        These commands return the width and height of the raw
        image in pixels.

<imageName> zoom start <frame> <zoomFactor>
<imageName> zoom stop
        (Note: This command is no longer supported: please use
        zoomview (below) instead.)

        This command is used to implement a zoom window, a window
        displaying a magnified section of the image at the location of
        the mouse pointer.  There are currently two versions of this
        command (see the zoomview subcommand below). In this version,
        a Tk frame is specified to hold the zoomed image, which is
        copied directly from the XImage whenever the mouse pointer
        moves over the image. This version is faster, but when the
        main image is shrunk, the zoom will not be very accurate.  If
        "start" is specified, zooming begins in the given window, and
        can be stopped with the "zoom stop" subcommand.

<imageName> zoomview start <view> <zoomFactor>
<imageName> zoomview stop
        This command can be used as an alternative to the zoom
        command above. It uses a "view" of the main rtdimage, so the
        zoom image is always accurate, even when main image is shrunk.
        The "view" argument to "zoomview start" should be the name of
        a second rtdimage, which is a "view" of the main image, added
        with the rtdimage "view" subcommand.  The zoomFactor is the
        magnification relative to the main image. For example, if the
        zoomFactor is 5 and the main image is scaled to 1/2, the zoom
        window scale factor would be 4.  Once started, the main image
        will automatically track mouse movements and update the zoom
        window's x and y offsets as needed to display the relevant
        magnified section of the image.


ENVIRONMENT VARIABLES

 
RTD_LIBRARY - If set, this should point to the directory
              containing the rtdimage Tcl library files.

FILES

 
$RTD_LIBRARY/                   - Tcl/Itcl library files
$RTD_LIBRARY/colormaps          - MIDAS colormap/ITT files
$RTD_LIBRARY/images             - sample FITS images
$RTD_LIBRARY/bitmaps            - X bitmaps used at runtime
$RTD_LIBRARY/demos              - rtdimage demo application

SEE ALSO

 
RtdImage(n), rtdServer(1), rtdImageEvt, RTI(3), BLT(n),
canvas(n)
 


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Last change: 07 May 99

 


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