Ģeometrisko figūru zīmēšana pa pikseļiem

procedure Aplis(xc,yc,r:integer);
var
x, y :integer;
p :real;
begin
x:=0;
y:=r;
p:=5/4-r;
Form1.Canvas.Pixels[x+xc,y+yc]:=0;
Form1.Canvas.Pixels[-x+xc,y+yc]:=0;
Form1.Canvas.Pixels[x+xc,-y+yc]:=0;
Form1.Canvas.Pixels[-x+xc,-y+yc]:=0;
Form1.Canvas.Pixels[y+xc,x+yc]:=0;
Form1.Canvas.Pixels[-y+xc,x+yc]:=0;
Form1.Canvas.Pixels[y+xc,-x+yc]:=0;
Form1.Canvas.Pixels[-y+xc,-x+yc]:=0;
while x<=y do begin
if p<0 then begin
x:=x+1;
p:=p+2*x+1;
end
else begin
x:=x+1; y:=y-1; p:=p+2*x-2*y+1;…