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procedure TMainDia.PaintBox1MouseDown(Sender: TObject;
  Button: TMouseButton; Shift: TShiftState; X, Y: Integer);
begin
  if Draw then
  begin
   PaintBox1.Canvas.MoveTo(x,y);
   Buttonpressed := true;
   XOld:=x;
   YOld:=y;
   inc(countW,1);
  end;
end;

procedure TMainDia.PaintBox1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
 i : integer;
begin
  if Draw then
  begin
   PaintBox1.Canvas.MoveTo(XOld,YOld);
   PaintBox1.Canvas.LineTo(x,y);
   Pos1[CountW].X := XOld;
   Pos1[CountW].Y := YOld;
   Pos2[CountW].X := X;
   Pos2[CountW].Y := Y;
   for i := 1 to CountW do
    begin
     PaintBox1.Canvas.MoveTo(Pos1[CountW].X,Pos1[CountW].Y);
     PaintBox1.Canvas.LineTo(Pos2[CountW].X,Pos2[CountW].Y);
    end;
    Buttonpressed := false;
  end;
end;

procedure TMainDia.PaintBox1MouseMove(Sender: TObject; Shift: TShiftState;
  X, Y: Integer);
var
 i : integer;  
begin
  if (Draw) and (Buttonpressed) then
  begin
   PaintBox1.Canvas.FloodFill(8,16,clgray,fsBorder);
   PaintBox1.Canvas.MoveTo(XOld,YOld);
   PaintBox1.Canvas.LineTo(x,y);
   for i := 1 to CountW do
    begin
     PaintBox1.Canvas.MoveTo(Pos1[CountW].X,Pos1[CountW].Y);
     PaintBox1.Canvas.LineTo(Pos2[CountW].X,Pos2[CountW].Y);
    end;
  end;
end;