FILE LOAD 

        The basic function of the file load window is for user to load a 
file into VolVis.  In order to simplify that task, the user will get a good 
idea of what to expect before even loading the file.  Icons are created to
represent each file.  Slice, texture and image files have icons that
closely represent the actual image.  The funciton and environment files
have standard icons representations.  The user can click on one of those
icons and some information about that file will appear in a text displaying
area.  The user may double click on the icon to load the file, or hit
enter on the file name area to load the file, or click on the accept 
button.

	The icons that appear when the window is started for the first
time is obtain through the default path of VolVis.  The initial path is set
according to the environment file VOLVIS_HOME.

        In the Path Name Area, in order for anything to happen, the
user must hit the return key after he/she finishes typing the path name.
All path names can be entered three different ways.  The first is to enter
the full path name.  An example would be:

                    /home/vovlis/data/SLC

The " ~ " sign can be used just like it is used in UNIX. So the user can
also enter the above this way:

                    ~volvis/data/SLC

In case the user is working with data files in his/her own directory.  We
can simplify the path name even more.  For example, lets say the user is
volvis, then he/she could enter the above path as:

                       ~/data/SLC 

There is an error checking function on the path name.  If it is not a 
valid path name, then the error message window will popup and the user 
will be notified that they have just entered a wrong path.  If the path
were valid, the files in that directory with the current data type will
have an icon representation in the scroll area. 

        File Name Area is a text area which allows the user to enter
the name of the file to load.  The file name can be any valid UNIX file
name.  But the user should make sure that the file is either a slice file,
image file, texture file, function file or environment file with valid 
extension.  When the return key is pressed, the file will be loaded.

        The icons are displayed in the Scroll Window Area.  The icons
are created when the user enters a valid path name or when the file type 
changes.  The screen is refreshed and new icons are displayed.  If the 
directory name were invalid, nothing happens.  Each file represented by the
icon must end with either a "slc", "img", "tex", "fun" or "env"  extension. 
For slice, image, and texture files, the icons created are a simplified 
version of what the data file would have look like if it had been read by 
VolVis.  The maximum values were used to create the icon files.  The other 
types of files are given a generic image for each icon representation.

        If the user clicks on the icon once with the mouse, then some 
information about the file is displayed in a text area.  The file name in the
file name text area would be set to the current file name.  The file would
be loaded if the user double clicks on the icon.

        The Header Area is a text displaying area where the
corresponding information about that file is displayed when the user clicks
on an icon.  Information about the file will be printed in this area, such
as size, data origin, data compression, etc.  No file header will be printed
for environment file.

        The Action Area has three buttons in it.  The accept, close,
and help button.  If the user has entered a file name in the file name text
area, he/she could load the file by clicking the accept button instead of
hitting return in the file name text area.  If the user has clicked once on
a icon, he/she could load that file also by clicking on the accept button.
The close button is for closing the file load window.  The help button 
opens up this window. 

