Programming and Graphics

218 Introduction to C++ Programming and Graphics

xp=x[i];

yp=y[i];

if(Icheck==1) // perform crossing checks

{

if( (xp>xmax && xpp>xmax) // both points are

||(xp<xmin && xpp<xmin) // outside the plotting

||(yp>ymax && ypp>ymax) // window: move

||(yp<ymin && ypp<ymin)) // but do not draw

{

move2 (xp,yp); continue; // consider the next value of i

}

float crossxmax = (xp-xmax)*(xpp-xmax); // crossing test

if (crossxmax<tol)

{

xint = xmax-0.001;

yint = ((xint-xpp)*yp-(xint-xp)*ypp)/(xp-xpp);

if(xpp>=xmax)

{

xpp = xint; ypp = yint;

move2 (xpp,ypp);

}

else

{

xp=xint; yp=yint;

}

}

float crossxmin = (xp-xmin)*(xpp-xmin);

if (crossxmin<tol)

{

xint = xmin+0.001;

yint = ((xint-xpp)*yp-(xint-xp)*ypp)/(xp-xpp);

if(xpp<=xmin)

{

xpp = xint; ypp = yint;

move2 (xpp,ypp);

}

else

{

xp=xint; yp=yint;

}

}

float crossymax = (yp-ymax)*(ypp-ymax);