<!DOCTYPE html>
<html>
  <title>WebGPU canvas_composite_alpha_premultiplied (ref)</title>
  <meta charset="utf-8" />
  <link rel="help" href="https://gpuweb.github.io/gpuweb/" />
  <style>
    body { background-color: #F0E68C; }
    #c-canvas { background-color: #8CF0E6; }
  </style>
  <canvas id="c-body" width="20" height="20" style="width: 20px; height: 20px;"></canvas>
  <canvas id="c-canvas" width="20" height="20" style="width: 20px; height: 20px;"></canvas>
  <script>
    document.querySelectorAll('canvas').forEach(canvas => {
      const ctx = canvas.getContext('2d');
      ctx.globalAlpha = 0.5;
      ctx.fillStyle = '#660000';
      ctx.fillRect(0, 0, 15, 15);
      ctx.fillStyle = '#006600';
      ctx.fillRect(5, 0, 15, 15);
      ctx.fillStyle = '#000066';
      ctx.fillRect(0, 5, 15, 20);
      ctx.fillStyle = '#666600';
      ctx.fillRect(5, 5, 20, 20);
    });
  </script>
</html>
