q198994208

program q198994208;
uses GraphABC, Events;

const maxSize = 360;

var size, dir: integer;

procedure keyDown(key: integer);
begin
  case key of
    VK_Up: dir := 1;
    VK_Down: dir := - 1;
  end;
end;

begin
  SetWindowCaption('by CLazStudio');
  SetWindowSize(600,400);
  OnKeyDown:=keyDown;
  CenterWindow;
  LockDrawing;

  size := 60;
  dir := 0;

  while (true) do
  begin
    size := size + dir;

    if size < 1 then
    begin
      size := 1;
      dir := 0;
    end;

    if size > maxSize then
    begin
      size := maxSize;
      dir := 0;
    end;

    ClearWindow();
    Circle(300, 200, size);
    Redraw;
    sleep(10);
  end;
end.