HTML5 Game - Creating quadratic Bezier curves

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  2. HTML5 Game
  3. Canvas
  4. Quadratic Curve

Introduction

We can draw Bezier curve with either quadraticCurveTo, or bezierCurveTo.

quadraticCurveTo draws a quadratic Bezier curve, while bezierCurveTo draws a cubic Bezier curve.

Both kinds of Bezier curve use control points to manipulate a straight line into a curve.

A quadratic Bezier curve has one control point and you have only one curve along the line.

A cubic Bezier curve has two controls points and you have two curves along a single line.

Demo

ResultView the demo in separate window 

<!DOCTYPE html>

<html>
  <head>
    <title>Pushing canvas further</title>
    <meta charset="utf-8">
    /*  w w w  .j a va2 s  .co  m*/
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
    
    <script type="text/javascript">
      $(document).ready(function() {  
        let canvas = $("#myCanvas");
        let context = canvas.get(0).getContext("2d");
        // A quadratic Bezier curve
        context.lineWidth = 5;
        context.beginPath();
        context.moveTo(50, 250);
        context.quadraticCurveTo(250, 100, 450, 250);
        context.stroke();
      
      });
    </script>
  </head>
  
  <body>
    <canvas id="myCanvas" width="500" height="500">
      <!-- Insert fallback content here -->
    </canvas>
  </body>
</html>

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