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CanvasRenderingContext2D.bezierCurveTo()

The CanvasRenderingContext2D.bezierCurveTo() method of the Canvas 2D API adds a cubic Bézier curve to the path. It requires three points. The first two points are control points and the third one is the end point. The starting point is the last point in the current path, which can be changed using moveTo() before creating the Bézier curve.

Syntax

void ctx.bezierCurveTo(cp1x, cp1y, cp2x, cp2y, x, y);

Parameters

cp1x
The x axis of the coordinate for the first control point.
cp1y
The y axis of the coordinate for the first control point.
cp2x
The x axis of the coordinate for the second control point.
cp2y
The y axis of the coordinate for the second control point.
x
The x axis of the coordinate for the end point.
y
The y axis of the coordinate for the end point.

Examples

Using the bezierCurveTo method

This is just a simple code snippet drawing a bezier curve. The control points are red and the start and end points are blue.

HTML

<canvas id="canvas"></canvas>

JavaScript

var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');

ctx.beginPath();
ctx.moveTo(50,20);
ctx.bezierCurveTo(230, 30, 150, 60, 50, 100);
ctx.stroke();

ctx.fillStyle = 'blue';
// start point
ctx.fillRect(50, 20, 10, 10);
// end point
ctx.fillRect(50, 100, 10, 10);

ctx.fillStyle = 'red';
// control point one
ctx.fillRect(230, 30, 10, 10);
// control point two
ctx.fillRect(150, 60, 10, 10);

Trying the bezierCurveTo parameters

Edit the code below and see your changes update live in the canvas:

<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
  <input id="edit" type="button" value="Edit" />
  <input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code">
ctx.beginPath();
ctx.bezierCurveTo(50, 100, 180, 10, 20, 10);
ctx.stroke();</textarea>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener("click", function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", function() {
  textarea.focus();
})

textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'CanvasRenderingContext2D.beziercurveto' in that specification.
Living Standard  

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes12 Yes Yes Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes Yes Yes Yes Yes

See also

Document Tags and Contributors

Contributors to this page: fscholz, thatmichael85, nmve, erikadoyle, bleush38p
Last updated by: fscholz,