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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