#
#	Two-dimensional diagram of points
#
#	The HTML version of this can be clicked at each point
#	and displays some URL
#
#	This process consists of 4 parts:
#
#	(1) An html component which is returned by ClicableDiagram_HTMLC
#	    This can be included in any html file.
#
#	(2) A picture (gif) which is given an arbitrary id and
#	    is referenced by the html component.  Produced and
#	    stored by ClicableDiagram_HTMLC.
#
#	(3) A file containing the description of the points and
#	    the url to which they are to be linked if clicked.
#	    Produced and stored by ClicableDiagram_HTMLC.
#
#	(4) A script that runs the appropriate darwin program
#	    with the file from (3) and the coordinate inputs
#	    resulting from clicking and produces the url.  This
#	    program is fixed and is not produced by this function.
#
#					Gaston H Gonnet (Sept 1, 2001)


ClicableDiagram := proc( title:string,
	points:list( {[structure,{string,HyperLink}],[structure]} ) )
noeval( procname(args) )
end:


ClicableDiagram_HTMLC := proc( cd:ClicableDiagram )
minx := miny := DBL_MAX;
maxx := maxy := -DBL_MAX;
pl := [];
for z in cd[points] do
    z := z[1];
    for i by 2 to length(z)-1 do
	if type(z[i],numeric) and type(z[i+1],numeric) then
	     if z[i] < minx then minx := z[i] fi;
	     if z[i] > maxx then maxx := z[i] fi;
	     if z[i+1] < miny then miny := z[i+1] fi;
	     if z[i+1] > maxy then maxy := z[i+1] fi;
	     fi
	od;
    pl := append(pl,z);
    od:

pl := [op(pl), CTEXT(minx,miny,'+'), CTEXT(minx,maxy,'+'),
	CTEXT(maxx,miny,'+'), CTEXT(maxx,maxy,'+') ];
DrawPlot( pl );
# CallSystem( 'ghostview -landscape temp.ps' );

end: