Contour

Contour is one of Pablo's display functional units.  It accepts a two-
dimensional array of input values and represents the data as contour lines
drawn within a grid in the plotting array.  Contours are drawn according
to the magnitude of the data:  larger values correspond to contours having
more lines.

The grid line defining the region in which each contour appears may or may 
not be drawn.  The intersection points of the grid lines (_NOT_ the squares
themselves) define identify particular (row,column) locations; location (0,0)
is the top-left intersection, and rows grow to the right and columns grow
downward.

Clicking the left mouse button with the cursor inside the contour invokes
a callback displaying the current data value at that (row,column) location
and also the row and column location for the click.


Functional Unit Inputs:  array

Contour attributes:

	XtNheight	height (in pixels) of the contour widget
	XtNwidth	width (in pixels) of the contour widget
	XtNbackground	the background color of the widget
	XtNrows		number of row elements in the matrix
	XtNcolumns	number of column elements in the matrix
	XtNcontourColor	color of the lines used to draw a contour
	XtNcontourCnt	number of contours to be drawn
	XtNgridColor	color of the grid lines drawn in a contour
	XtNtextColor	color of the text written to show min/max
	            		value information
	XtNshowRange	set to TRUE if the min and max information are to
	                        be displayed along with the contour plot
	XtNshowRangeAbove   set to TRUE if min/max information is to be
				displayed _above_ the plot area (otherwise,
	                        it is displayed beneath).
	XtNshowContours set to TRUE if contour list information		
	XtNshowGrid	set to true if grid lines are to be drawn on the
				plot area
