
Cantata(HELP)                Khoros                 Cantata(HELP)

     USING CANTATA TO CONSTRUCT A VISUAL PROGRAM

     A glyph is a small icon representing a processing routine,
     which may be selected from the routines list or from a sub-
     form. A visual program consists of a number of glyphed rou-
     tines connected together in a pipeline or flow graph.

     GLYPH INPUT/OUTPUT

     Glyphs contain "input" and "output" connections, represented
     by buttons located on the left and right sides of the glyph,
     respectively. Input buttons have arrows which point INTO the
     glyph, and output arrows point OUT.  If an arrow is dark,
     then its corresponding input/output is a required parameter
     for that routine.  If the arrow is a lighter color, then it
     is an optional parameter. Required parameters must always be
     connected in the flow graph. The `Check' function via the
     `Workspace' menu may be used to check a workspace for any
     missing required input/output connections.

     GLYPH CONNECTIONS

     The connections between glyphs are made by clicking the
     mouse on the output button of one glyph and then on the
     input button of another glyph (or vice versa).  Upon a suc-
     cessful connection, a line will be drawn between the two
     glyphs.  Connections can go from one output button to more
     than one input button if needed.

     Once a connection has been made between two glyphs, it can
     be changed by either connecting that glyph to a different
     glyph or by deleting the connection altogether.  Clicking on
     the line connecting two glyphs will bring up a form which
     you may use to delete a connection, save the file associated
     with that connection, or choose the data transport mechanism
     that you want used for that connection.  `Delete Connection'
     will remove that connection. `Save Data to File' bring up a
     text widget in which you can enter the filename in which to
     save a copy of the file associated with that connection.
     Under these two action buttons will be a list of the avail-
     able data transport mechanisms.  You may click on the
     desired data transport mechanism, and it will be used to
     transport the data involved with that connection.  Selecting
     `Cancel' leaves the connection unchanged.

     EXECUTING A GLYPH

     The "run" button, a stylized light switch, in the upper
     right corner of the glyph is used to execute the glyphed
     pane.  After a flow graph is constructed, each of the
     glyphed panes must either be run individually using this
     button, or the `RUN' action button on the master form may be
     used to execute the entire flow graph.  When the process
     that a glyph represents is executing, its glyph will be
     displayed in reverse video.  This provides animated feedback
     as to the execution state of the flow graph.  In addition,
     the run button "light switch" on the executing glyph will
     change from an "OFF switch" to an "ON switch". To stop an
     individual glyph that is running, click the mouse on the
     "run" button again and the execution of that routine will be
     halted.

     If an error is detected during the execution of a glyph rou-
     tine, a "frowning face" error button will appear (flashing)
     on the glyph.  Clicking the mouse on the button will pop up
     an error message window indicating the problem.

     REMOTE EXECUTION OF A GLYPH

     First, you must use the "Workspace" pulldown menu to bring
     up the "Attributes" subform.  On the "Attributes" subform,
     set the logical selection labelled, "Enable Remote Execu-
     tion" to 'Yes'.  This will cause all displayed glyphs that
     represent a Khoros program to have a network symbol in the
     middle.  Clicking on this network symbol will bring up a
     list of all available machines for remote execution.  Select
     the machine from the list on which you wish the program to
     run.  When the workspace is run, that glyph will have its
     associated program executed on the remote machine specified.
     The list of available remote machines is derived from the
     file specified by the KHOROS_HOSTS environment variable
     (default: $KHOROS_HOME/.khoros_hosts). Your ".rhosts" file
     must be set up correctly, with a listing of the machine that
     you request for remote execution, and there must be a dis-
     tributed processing daemon started at the time when you
     attempt to execute the glyph.  If any of these conditions is
     not met, the remote execution of the glyph will fail;  for
     complete details on setting the KHOROS_HOSTS environment
     variable, initializing the ".rhosts" file, and beginning the
     distributed processing daemon, see Chapter 1 of the Khoros
     User's Manual, or the Help section on Distributed Processing
     available on the "Attributes" subform.

     CONVERTING A GLYPH TO A SUBFORM

     The center button located on the top of the glyph (with the
     small picture of a subform) is used to access the subform
     associated with that glyph.  This is useful when parameters
     for the glyphed routine need to be changed or a different
     routine on that subform is needed.  When clicked on, the
     glyph will disappear if the workspace attribute `Always
     Display Glyph' is set to NO, and will be replaced by the
     subform.  To return to the glyphed form, click on the
     `Glyph' button of the subform.

     RESETTING A CONTROL GLYPH

     Control glyphs have an extra "reset" button (top, right
     center) which may be used to reinitialize loop control
     glyphs.

     DESTROYING THE GLYPH

     The leftmost button on the top of the glyph (bomb with lit
     fuse) is used to "destroy" or quit the glyph. It is
     equivalent to clicking on the `QUIT' button on the guide
     pane of its associated subform. When clicked on, the glyph
     will be removed from the screen. If that glyph has a process
     running, it will be stopped.

     MOVING A GLYPH

     Glyphs may be moved by placing the mouse cursor on the
     glyph, pressing the mouse key and dragging the glyph to the
     desired position, then releasing the key.

     Copyright 1991, University of New Mexico. All rights
     reserved.

Khoros                    Release: 1.0                          1

