Programming and Graphics

7.7 Three-dimensional interactive graph 237

float xrange = xmax-xmin;

float yrange = ymax-ymin;

float zrange = zmax-zmin;

float xmargin = 0.1*xrange;

float ymargin = 0.1*yrange;

float zmargin = 0.1*zrange;

ortho (xmin-0.50*xrange, xmax+0.50*xrange

,ymin-0.50*yrange, ymax+0.50*yrange

,zmin-0.50*zrange, zmax+0.50*zrange);

//--- Graphics:

color (bgc);

clear ();

lookat (vx,vy,vz,0.0,0.0,0.0,twist);

rotate (angx, ’x’);

rotate (angy, ’y’);

rotate (angz, ’z’);

scale (zoom,zoom,zoom);

/*--------------------

Draw axes and labels

--------------------*/

if(Iaxes==1)

{

color (axc);

move (xmin,ymin,zmin);

draw (xmax,ymin,zmin);

move (xmin,ymin,zmin);

draw (xmin,ymax,zmin);

move (xmin,ymin,zmin);

draw (xmin,ymin,zmax);

//--- Print axes labels:

font ("/tmp/hfonts/futura.l");

textsize(0.9*xmargin,0.9*ymargin);

float ticx = xrange/ntcx; // x tick distance

float ticy = yrange/ntcy; // y tick distance

float ticz = yrange/ntcy; // z tick distance

move (xmax+0.5*ticx, ymin-0.1*ymargin,zmin);

drawstr(labelx);