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JavaScript canvas2d object method: quadraticCurveTo()

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The quadraticCurveTo() method of the JavaScript DOM object returned by the getContext("2d") method applied to the HTML <canvas> element creates a quadratic Bézier curve. To create a cubic Bézier curve use the bezierCurveTo() method.

 

It has the following syntax with the following parameters.

 

context.quadraticCurveTo(x, y, r, startAngle, endAngle, counterclockwise)

 

Parameter

Required / Optional

Description

ptx

Required

x-coordinate of control point of curve

pty

Required

y-coordinate of control point of curve

x

Required

x-coordinate of end point

y

Required

y-coordinate of end point

 

EXAMPLE:


HTML USED IN THIS EXAMPLE:
<!DOCTYPE html>
<html> <!-- Copyright (c) Nematrian Limited 2018 -->
<head></head>
<body>
<span id="element"></span>

<script>
var x2 = document.createElement("CANVAS");
x2.setAttribute("width", "200");
x2.setAttribute("height", "100");
x2.setAttribute("style", "border: 1px solid black");
var c2 = x2.getContext("2d");

c2.strokeStyle = "blue";
c2.beginPath();
c2.moveTo(30, 10);
c2.quadraticCurveTo(20,130,150,20);
c2.stroke();

document.getElementById("element").appendChild(x2);
</script>

</body>
</html>

FUNCTION THAT MAY ASSIST IN TESTING WHETHER FEATURE IS SUPPORTED:
function isSupportedJavaScriptMethodCanvas2dQuadraticCurveTo() {
  var x = document.createElement("CANVAS"); var c = x.getContext("2d"); return !!c.quadraticCurveTo;
}


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