Web/API/CanvasRenderingContext2D/bezierCurveTo

The CanvasRenderingContext2D.bezierCurveTo() method of the Canvas 2D API adds a cubic Bézier curve to the current sub-path. It requires three points: the first two are control points and the third one is the end point. The starting point is the latest 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 coordinate of the first control point.

cp1y

The y-axis coordinate of the first control point.

cp2x

The x-axis coordinate of the second control point.

cp2y

The y-axis coordinate of the second control point.

x

The x-axis coordinate of the end point.

y

The y-axis coordinate of the end point.

Examples

How bezierCurveTo works

This example shows how a cubic Bézier curve is drawn.

HTML

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

JavaScript

// Define canvas and context
const canvas = document.getElementById('canvas');
const ctx = canvas.getContext('2d');

// Define the points as {x, y}
let start = { x: 50,    y: 20  };
let cp1 =   { x: 230,   y: 30  };
let cp2 =   { x: 150,   y: 80  };
let end =   { x: 250,   y: 100 };

// Cubic Bézier curve
ctx.beginPath();
ctx.moveTo(start.x, start.y);
ctx.bezierCurveTo(cp1.x, cp1.y, cp2.x, cp2.y, end.x, end.y);
ctx.stroke();

// Start and end points
ctx.fillStyle = 'blue';
ctx.beginPath();
ctx.arc(start.x, start.y, 5, 0, 2 * Math.PI);  // Start point
ctx.arc(end.x, end.y, 5, 0, 2 * Math.PI);      // End point
ctx.fill();

// Control points
ctx.fillStyle = 'red';
ctx.beginPath();
ctx.arc(cp1.x, cp1.y, 5, 0, 2 * Math.PI);  // Control point one
ctx.arc(cp2.x, cp2.y, 5, 0, 2 * Math.PI);  // Control point two
ctx.fill();

Result

In this example, the control points are red and the start and end points are blue.

A simple Bézier curve

This example draws a simple Bézier curve using bezierCurveTo().

HTML

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

JavaScript

The curve begins at the point specified by moveTo(): (30, 30). The first control point is placed at (120, 160), and the second at (180, 10). The curve ends at (220, 140).

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

ctx.beginPath();
ctx.moveTo(30, 30);
ctx.bezierCurveTo(120,160, 180,10, 220,140);
ctx.stroke();

Specifications

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

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
bezierCurveTo	Chrome Full support 1	Edge Full support 12	Firefox Full support 1.5	IE Full support 9	Opera Full support 11.6	Safari Full support 2	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 12	Safari iOS Full support 1	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

See also

• The interface defining this method: CanvasRenderingContext2D
• Wikipedia article on Bézier curves

CanvasRenderingContext2D.bezierCurveTo() by Mozilla Contributors is licensed under CC-BY-SA 2.5.