HTML Canvas Quadratic Curve Random Curve 2

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HTML Canvas Quadratic Curve Random Curve 2

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<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Multi Curve 2</title>
  </head>/*  ww w . j a va  2 s .co m*/
  <body>
    <canvas id="canvas" width="400" height="400"></canvas>
    <aside>Refresh page for random curves.</aside>
    
    <script>
    window.onload = function () {
      var canvas = document.getElementById('canvas'),
          context = canvas.getContext('2d'),
          points = [],
          numPoints = 19,
          ctrlPoint = {};

      for (var i = 0; i < numPoints; i++) {
        points.push({
          x: Math.random() * canvas.width,
          y: Math.random() * canvas.height
        });
      }

      //move to the first point
      context.beginPath();
      context.moveTo(points[0].x, points[1].y);
      //curve through the rest, stopping at each midpoint
      for (i = 1; i < numPoints - 2; i++) {
        ctrlPoint.x = (points[i].x + points[i+1].x) / 2;
        ctrlPoint.y = (points[i].y + points[i+1].y) / 2;
        context.quadraticCurveTo(points[i].x, points[i].y,
                                 ctrlPoint.x, ctrlPoint.y);
      }
      //curve through the last two points
      context.quadraticCurveTo(points[i].x, points[i].y,
                               points[i+1].x, points[i+1].y);
      context.stroke();
    };
    </script>
  </body>
</html>



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