program rajzolo;

uses newdelay,crt,graph;

function GraphInit:boolean;
var gd,gm:integer;
    utv:string;
begin
  utv:='';
  DetectGraph(gd,gm);
  {$I-}
  InitGraph(gd,gm,utv);
  while (GraphResult<>grOK) and (utv<>'exit') do
   begin
     {writeln('K‚rem az utvonalat a BGI filehoz vagy exit');}
     utv:='c:\bp\bgi';
     {readln(utv);}
     DetectGraph(gd,gm);
     Initgraph(gd,gm,utv);
   end;
  GraphInit:=(utv<>'exit');
  {$I+}
end;

procedure keret(x0,y0,x1,y1:integer);
   begin
      setcolor(white);
      rectangle(x0,y0,x1,y1);
      setfillstyle(solidfill ,blue);
      bar(x0+1,y0+1,x1-1,y1-1);
   end;

procedure egyenes(x1,y1,x2,y2:integer);
var hx,hy,h,i,x,y:integer;
    lx,ly:real;

   begin
      hx:=x2-x1;
      hy:=y2-y1;
      if abs(hx)>abs(hy) then h:=abs(hx)
                         else h:=abs(hy);
      if h=0 then putpixel(x1,y1,red)
                  else begin
                      lx:=hx/h;
                      ly:=hy/h;
                      x:=x1;
                      y:=y1;
                      for i:=1 to (h+1) do
                       begin
                          putpixel(x,y,red);
                          x:=round(x+lx);
                          y:=round(y+ly);
                       end;
                    end;
   end;

procedure kor(r,u,v:integer);
var x,y:integer;

begin
   x:=0;
   y:=r;
   while (y>=x) do
      begin
         putpixel(x+u,y+v,green);
         putpixel(y+u,x+v,green);
         putpixel(y+u,-x+v,green);
         putpixel(x+u,-y+v,green);
         putpixel(-x+u,-y+v,green);
         putpixel(-y+u,-x+v,green);
         putpixel(-y+u,x+v,green);
         putpixel(-x+u,y+v,green);

         if ((x+1)*(x+1)+(y*y)) > r*r then y:=y-1;
         x:=x+1;
     end;
end;


procedure ellipszis(a,b,u,v:integer);
var x,y,y1:integer;
{y:ellipszist,y1:kort}
begin
   x:=0;
   y1:=a;
   while (y1>0) do
      begin
         {y:=y1*round(b/a);}
         y:=y1;
         putpixel(x+u,y+v,green);
         putpixel(x+u,-y+v,green);
         putpixel(-x+u,-y+v,green);
         putpixel(-x+u,y+v,green);

         if ((x+1)*(x+1)+(y1*y1)) > a*a then y1:=y1-1;
         x:=x+1;
     end;
end;

Procedure negyedkor(r,u,v:integer);
var i,x,y:integer;
    alfa,alfafok:real;
   begin
      alfafok:=1;
      alfa:=(alfafok/360)*2*pi;
      for i:=0 to trunc(pi/2/alfa) do
         begin
            x:=round(r*cos(i*alfa));
            y:=round(r*sin(i*alfa));
            putpixel(x+u,y+v,lightred);
            putpixel(-x+u,y+v,lightred);
            putpixel(-x+u,-y+v,lightred);
            putpixel(x+u,-y+v,lightred);
         end;
end;

Procedure negyedellipszis(a,b,u,v:integer);
var i,x,y:integer;
    alfa,alfafok:real;
   begin
      alfafok:=0.10;
      alfa:=(alfafok/360)*2*pi;
      for i:=0 to trunc(pi/2/alfa) do
         begin
            x:=round(a*cos(i*alfa));
            y:=round(a*sin(i*alfa)*(b/a));
            putpixel(x+u,y+v,lightred);
            putpixel(-x+u,y+v,lightred);
            putpixel(-x+u,-y+v,lightred);
            putpixel(x+u,-y+v,lightred);
         end;
end;

begin
   IF graphinit then  begin
{keret(20,100,500,150);}
egyenes(200,100,200,220);
kor(40,300,100);
circle(400,100,40);
ellipszis(40,40,200,300);
negyedkor(40,500,300);
negyedellipszis(40,100,350,350);

end;
repeat until keypressed;

end.