.SH 
DESCRIPTION
.PP
\fBViewimage\fP is an interactive imagery/elevation display package;
it is a new application that combines capabilities of the \fBxprism3\fP
plotting package and the \fBeditimage\fP display package.  The main purpose of
\fBviewimage\fP is to take a Khoros VIFF file and use its image data as
the \fIimagery\fP.  This data provides the "picture" that is displayed,
draped over the \fIelevation\fP data that is provided via another Khoros VIFF
file.  It is very important that the VIFF file used for the imagery and the
VIFF file used for the elevation data be of the \fIsame size\fP - that is,
they must have the same number of rows and the same number of columns.
.PP
\fBViewimage\fP accepts any Khoros VIFF file as its imagery input, and will 
convert the data type of the input image when necessary. Currently, 
\fBviewimage\fP can utilize a maximum of 256 colors.  Any image that has more 
than this number of colors is converted to fit into the available number 
of colors with the \fBvgamut\fP program.  Note that this conversion will 
normalize the image to the total number of colors that are available to 
be displayed on the workstation being used.  For the elevation data, 
\fBviewimage\fP will accept Khoros VIFF files of type Byte, Short, Integer, 
Float, and Double.  Note that the same VIFF file may be used as both the
imagery data and the elevation data;  in this case, only the -i option flag
is used.
.PP
\fBViewimage\fP provides all of the same plot types for representing 
elevation data that \fBxprism3\fP does: 3D, Scatter, Impulse, Wireframe, 
Mesh, Horizon, Surface, 3D Contour, 2D Contour, and Color Mesh.  However, 
when the elevation data is displayed as Color Mesh or Surface, the imagery
data is used to fill in the plot rather than the colors that are used in 
\fBxprism3\fP.  If the display of colors is desired instead, the "Use Imagery"
option on the "Attributes" subform may be turned off.
.PP
\fBViewimage\fP provides three of the same display utilities that are available
with \fBeditimage\fP;  all of these work with respect to the RGB, CMY, HSV, 
HLS, UVW, XYZ, YIQ, and GREY color spaces.  In order to fully understand 
the information imparted by the display utilities of \fBviewimage\fP, it is 
important for you to have an understanding of the operation of each of these 
color spaces, as well as a feeling for how each of the available colorspaces 
relates to the others.  For this reason, a brief explanation of each is 
provided under "Colorspaces"; however, a full understanding can only be 
accomplished by the study of appropriate texts, and by university courses 
taken in the field of image processing.  \fBViewimage\fP was written with 
the assumption that the user has the knowledge necessary to correctly 
interpret visual results generated and to recognize when those results are 
not valid.  Invalid results can be generated when the colorspace of the imagery 
does not match the colorspace of the display;  however, \fBviewimage\fP 
follows the philosophy that it is better to allow the uneducated user to 
generate incorrect results than to limit the experimenting researcher with 
rigid errorchecking.
.sp
.SH 
RUNNING VIEWIMAGE
.PP
\fBViewimage\fP can be executed from within \fBcantata\fP, or directly from 
the command line. When using the command line interface, the imagery data
contained in an input VIFF image may be specified at the time of execution, 
or it may be specified once the \fBviewimage\fP program is already started.  
To input the imagery data directly from the command line, use the -i option 
flag; to input the elevation data directly from the command line, use the 
-e option flag (see "Options" for additional command line options). 
Alternatively, you may start \fBviewimage\fP with no initial images, and use 
the "Input/Output" pane, which is available from the "Image Utilities" 
pulldown menu, to input the desired data.  The minimum syntax specification 
to run \fBviewimage\fP from the command line is:
.sp
\f(CW
% viewimage 
\fP
.PP
Place the \fBviewimage\fP master form with your window manager (your window 
manager may use automatic placement).  The \fBviewimage\fP graphical user
interface has the same layout as that of \fBeditimage\fP; it has a workspace 
attached beneath it, in which the elevation data provided as input will 
immediately be plotted as a three dimensional wireframe;  elevation data may
also be viewed as a 3D plot, a scatter plot, an impulse plot, a mesh
plot, a horizon plot, a 3D contour plot, or a 2D contour plot.  To see the 
imagery data draped over the elevation data, you must use the "Attributes" 
pane of the "VIEW UTILITIES" pull-down menu to change the plot type to either
a surface plot or a color mesh plot.
.PP
The \fBviewimage\fP master form has two pulldown menus, one labeled 
"DISPLAY UTILITIES", and the other labeled "VIEW UTILITIES".  
.sp
.IP "DISPLAY UTILITIES"
By clicking on "DISPLAY UTILITIES", you can access the LUT, Pseudo Color, and
Windowing/Threshold subforms, from which one can take advantage of these 
display utilities that are identical to those offered by \fBeditimage\fP.  
From the "DISPLAY UTILITIES" pulldown menu, one can also change the image 
band that is displayed (for multiband images).  The "HELP" selection on this 
pulldown menu provides access to online help which gives a much more detailed 
explanation of these features.
.sp
.IP "VIEW UTILITIES"
The second pulldown menu, labeled "VIEW UTILITIES", provides access to the
Input/Output File, Perspective, Colormap Conversion, and Attributes features.  
Again, a "HELP" selection on the "VIEW UTILITIES" pulldown
menu will offer more extensive online help for each of these features.
.sp
.SH
GLYPH
.PP
Clicking on the "Glyph" button that appears on the upper left hand corner 
of the \fBviewimage\fP master form will cause the master form
and any displayed subforms to be compacted into a small box labeled "Edit".
This allows the user to reduce clutter on the screen.  
The glyphed \fBviewimage\fP program can be recovered by clicking the left mouse 
button inside the glyph.
