<!DOCTYPE html>
<html>
<head>
  <style>
    .fixed {
      position: fixed;
      width: 10px;
      height: 10px;
    }
  </style>
</head>
<body onload="window.scrollTo(300, 600)">
  <div style="width: 1500px; height: 1500px"></div>
  <!-- When the size of the frame is 800x600, the first 3 divs are out-of-view and should not be composited, and the last 2 divs should be composited. -->
  <div class="fixed" style="top: -100px"></div>
  <div class="fixed"></div>
  <div class="fixed" style="top: 0px; left: 1000px"></div>
  <div class="fixed" style="top: 0px; left: 600px"></div>
  <div class="fixed" style="top: 0px; left: 0px"></div>
</body>
</html>