<!doctype html>
<script src="code/chapter/16_game.js"></script>
<script src="code/levels.js"></script>
<script src="code/chapter/17_canvas.js"></script>

<canvas width="600" height="300"></canvas>
<script>
  let cx = document.querySelector("canvas").getContext("2d");
  let total = results.reduce(function(sum, choice) {
    return sum + choice.count;
  }, 0);

  let currentAngle = -0.5 * Math.PI;
  let centerX = 300, centerY = 150;

  results.forEach(function(result) {
    let sliceAngle = (result.count / total) * 2 * Math.PI;
    cx.beginPath();
    cx.arc(centerX, centerY, 100,
           currentAngle, currentAngle + sliceAngle);

    let middleAngle = currentAngle + 0.5 * sliceAngle;
    let textX = Math.cos(middleAngle) * 120 + centerX;
    let textY = Math.sin(middleAngle) * 120 + centerY;
    cx.textBaseLine = "middle";
    if (Math.cos(middleAngle) > 0) {
      cx.textAlign = "left";
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      cx.textAlign = "right";
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    cx.font = "15px sans-serif";
    cx.fillStyle = "black";
    cx.fillText(result.name, textX, textY);

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    cx.lineTo(centerX, centerY);
    cx.fillStyle = result.color;
    cx.fill();
  });
</script>