E-book comb.as

 a = Math.atan2(y,x);
   r = Math.sqrt(x*x+y*y);
   if (r>w) r=w;
   x = Math.cos(a)*r;
   y = Math.sin(a)*r;

   // Calculate point Z and dy,dx of line C
   dx = w-x;
   dy = y;
   Zx = x+dx/2;
   Zy = y-dy/2;

   // Calculate line D
   Px = Zx-Zy*dy/dx;
   Py = 0;
   Qx = w;

   if (dy*dy<1) { a = 0; Qx = x; Qy = Ry = h; Rx = (x+w)/2; }
   else {
       Qy = Zy+(w-Zx)*dx/dy;
       if (Qy>h || Qy<0) {
           a = Math.atan2(Qy-y,Qx-x);
           if (Qy<0) a += Math.PI;
           Qx = x+Math.cos(a)*h;
           Qy = y+Math.sin(a)*h;
           Rx = Qx+(Qy-h)/(y-Py)*(Px-x);
           Ry = h;
           }
       else { Rx = Qx; Ry = Qy; }
       if (Qy==0) Rx = w-Qx;
       if (Rx<0) return;
       }