Нарисовать график в Паскале, используя модуль GraphABC

uses graphABC;
var r,x,y,m:real;
    w,h,xc,yc,k,n:integer;
    s:string;
begin
repeat
writeln('Введите радиус от 2 до 10 r=');
readln(r);
until(r>=2)and(r<=10);
repeat
writeln('Введите ',-2*r:0:2,'<x<',4*r,' x=');
readln(x);
until(x>=-2*r-1)and(x<=4*r);
if x<=-r then y:=r
else if x<=r then y:=-sqrt(r*r-x*x)+r
else if x<=2*r then y:=-2*x+3*r
else y:=x-3*r;
h:=300;
m:=(h-40)/2/r;
w:=round(6*r*m)+50;
setwindowsize(w,h);
centerwindow;
clearwindow;
xc:=w div 3;
yc:=h div 2;
line(0,yc,w,yc);
line(xc,0,xc,h);
if r<6 then k:=1
else k:=2;
n:=trunc(4*r);
if frac(r)<>0 then n:=n+1;
for var i:=1 to n do
if i mod k=0 then
 begin
  line(xc+round(i*m),yc-3,xc+round(i*m),yc+3);
  textout(xc+round(i*m)-5,yc+10,inttostr(i));
 end;
n:=trunc(2*r);
if frac(r)<>0 then n:=n+1; 
for var i:=1 to n do
if i mod k=0 then
 begin
  line(xc-round(i*m),yc-3,xc-round(i*m),yc+3);
  textout(xc-round(i*m)-5,yc+10,inttostr(-i));
 end; 
n:=trunc(r);
if frac(r)<>0 then n:=n+1;
for var i:=1 to n do
if i mod k=0 then
 begin
  line(xc-3,yc-round(i*m),xc+3,yc-round(i*m));
  textout(xc-20,yc-round(i*m)-5,inttostr(i));
  line(xc-3,yc+round(i*m),xc+3,yc+round(i*m));
  textout(xc-20,yc+round(i*m)-5,inttostr(-i));
 end;
setpenwidth(2); 
line(xc-round(2*r*m),yc-round(r*m),xc-round(r*m),yc-round(r*m)); 
arc(xc,yc-round(r*m),round(r*m),180,360);
line(xc+round(r*m),yc-round(r*m),xc+round(2*r*m),yc+round(r*m));
line(xc+round(2*r*m),yc+round(r*m),xc+round(4*r*m),yc-round(r*m));
str(y:0:2,s);
textout(20,h-40,'x='+floattostr(x)+'  y='+s);
setpenwidth(1);
setpencolor(clRed);
circle(xc+round(x*m),yc,2);
circle(xc+round(x*m),yc-round(y*m),2);
line(xc+round(x*m),yc,xc+round(x*m),yc-round(y*m));
end.