program rajzolo;

uses newdelay,crt,graph;
type
   pont=record
    x:integer;
    y:integer;
   end;
   tomb=array[1..3] of pont;
var a,b,c:pont;
    t:tomb;
    kf,ka,kj,kb:integer;
    x1,x2,y1,y2,c1,c2:integer;

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 csere(var a,b:pont);
var s:pont;
begin
s:=a;
a:=b;
b:=s;
end;


procedure rendez(var t:tomb;n:integer);
var i,j,min:integer;
begin
min:=1;
for i:=1 to n-1 do
   begin
   for j:=i+1 to n do
      if t[j].y<t[min].y then min:=j;
   csere(t[min],t[i]);
   end;
end;


procedure haromszogfest(var a,b,c:pont);
var i,o1,o2:integer;
   begin
   t[1]:=a;
   t[2]:=b;
   t[3]:=c;
   rendez(t,3);
   for i:=t[1].y to t[2].y do
   begin
       o1:=round((i-t[1].y)*(t[2].x-t[1].x)/(t[2].y-t[1].y)+t[1].x);
       o2:=round((i-t[1].y)*(t[3].x-t[1].x)/(t[3].y-t[1].y)+t[1].x);
       line(o1,i,o2,i);
   end;
   for i:=t[2].y to t[3].y do
   begin
       o1:=round((i-t[2].y)*(t[3].x-t[2].x)/(t[3].y-t[2].y)+t[2].x);
       o2:=round((i-t[3].y)*(t[1].x-t[3].x)/(t[1].y-t[3].y)+t[3].x);
       line(o1,i,o2,i);
   end;
  end;

function vonalveg(x,y,j:integer):integer;
var ye:integer;
begin
ye:=y;
while (getpixel(x,ye+j)<>white) do
   ye:=ye+j;
vonalveg:=ye;
end;

procedure fest(x,y:integer);
var y1,y2,i:integer;
   begin
   y1:=vonalveg(x,y,-1);
   y2:=vonalveg(x,y,1);
   line(x,y1,x,y2);
   for i:=y1 to y2 do
   begin
      if getpixel(x+1,i)<>white then fest(x+1,i);
      if getpixel(x-1,i)<>white then fest(x-1,i);
   end;
   end;

procedure rajzh(a,b,c:pont);
begin
line(a.x,a.y,b.x,b.y);
line(c.x,c.y,b.x,b.y);
line(a.x,a.y,c.x,c.y);
end;

procedure vegp(x1,y1,x2,y2:integer; var c1,c2:integer);
begin
c1:=0;
c2:=0;
if y1>kf then c1:=(c1 or 1);
if y2>kf then c2:=(c2 or 1);
if x1>kj then c1:=(c1 or 2);
if x2>kj then c2:=(c2 or 2);
if y1<ka then c1:=(c1 or 4);
if y2<ka then c2:=(c2 or 4);
if x1<kb then c1:=(c1 or 8);
if x2<kb then c2:=(c2 or 8);
end;

procedure csere2(var c1,x1,y1,c2,x2,y2:integer);
var s:integer;
begin
s:=c1;
c1:=c2;
c2:=s;

s:=x1;
x1:=x2;
x2:=s;

s:=y1;
y1:=y2;
y2:=s;
end;

procedure vagaf(x1,y1,x2,y2:integer);
var x:integer;
begin
   x:=round(x1+(x2-x1)*(kf-y1)/(y2-y1));
   y1:=kf;
   x:=x1;
end;

procedure vagaa(x1,y1,x2,y2:integer);
var x:integer;
begin
   x:=round(x1+(x2-x1)*(ka-y1)/(y2-y1));
   y1:=ka;
   x1:=x
end;

procedure vagaj(x1,y1,x2,y2:integer);
var y:integer;
begin

   y:=round(y1+(y2-y1)*(kj-x1)/(x2-x1));
     x1:=kj;
     y1:=y;
end;

procedure vagab(x1,y1,x2,y2:integer);
var y:integer;
begin
   y:=round(y1+(y2-y1)*(kb-x1)/(x2-x1));
   x1:=kb;
   y1:=y;

end;

procedure vago(x1,y1,x2,y2:integer);
var c1,c2,i:integer;
begin
vegp(x1,y1,x2,y2,c1,c2);
while not (((c1=0) and (c2=0)) or ((c1 and c2)<>0)) do
begin
if c1=0 then csere2(c1,x1,y1,c2,x2,y2);
if (c1 and 1)=1 then vagaf(x1,y1,x2,y2);
if (c1 and 2)=1 then vagaj(x1,y1,x2,y2);
if (c1 and 4)=1 then vagaa(x1,y1,x2,y2);
if (c1 and 8)=1 then vagab(x1,y1,x2,y2);
vegp(x1,y1,x2,y2,c1,c2);
end;
if ((c1=0) and (c2=0)) then line(x1,y1,x2,y2);
end;


begin
if graphinit then
begin
a.x:=100;
a.y:=200;
b.x:=300;
b.y:=300;
c.x:=200;
c.y:=100;
kf:= 300;
ka:= 100;
kb:= 100;
kj:= 400;
x1:=50;
y1:=50;
x2:=500;
y2:=450;
{egyenes(50,50,500,450);}
vago(50,50,500, 450);
{haromszogfest(a,b,c);}
{rajzh(a,b,c);
fest(200,150);}
end;
repeat until keypressed;
end.