Canvas-2D-Context-API-Primer/lineTo.html at master · rroa/Canvas-2D-Context-API-Primer · GitHub

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<!DOCTYPE html>
<html>
    <head>
      <title>Canvas 2D Context API Primer</title>
      <meta charset="utf-8" />
      <meta name="viewport" content="width=1024" />
      <meta name="apple-mobile-web-app-capable" content="yes" />

      <!--SCRIPTS-->
      <script type="text/javascript">
        /*
          # Context 2d API: lineTo
          Adds a new point to a subpath and connects that point to the last point in the subpath by using a straight line.

          # Standard Definition.
          http://www.w3.org/html/wg/drafts/2dcontext/html5_canvas/#dom-context-2d-lineto

          # Function signature
          void lineTo(unrestricted double x, unrestricted double y);

        */

        function draw() {

          // Get a reference to the canvas
          var canvas = document.getElementById('canvas');

          // Get a reference to the drawing context
          var ctx = canvas.getContext('2d');

          // Let's translate the drawing to the center of the canvas
          ctx.translate( canvas.width/2, canvas.height/2);

          // Set the stroke pattern to red
          ctx.strokeStyle = "#FF0000";

          // Set the fill pattern to grey
          ctx.fillStyle = "grey";

          // Set the triangle side size
          var side = 200;

          // Calculate the triangle height
          var height = side * Math.cos( Math.PI / 4 );

          // Reset the path
          ctx.beginPath();

          // Let's move to our starting point
          ctx.moveTo( 0, -height / 2);

          // Let's draw our triangle lines
          ctx.lineTo( -side / 2, height / 2);
          ctx.lineTo(side / 2, height / 2);
          ctx.lineTo(0, -height / 2);

          ctx.stroke();
          ctx.fill();

          // Close the path
          ctx.closePath();
        }
  </script>
</head>
<body onload="draw();">
  <p>
      <a href="index.html">Back to index</a>
    </p>
  <canvas id="canvas" width="300" height="300">
    This browser or document mode doesn't support canvas
  </canvas>
</body>
</html>