CanvasRenderingContext2D.arcTo()

The CanvasRenderingContext2D.arcTo() method of the Canvas 2D API adds an arc to the path with the given control points and radius, connected to the previous point by a straight line.

Syntax

void ctx.arcTo(x1, y1, x2, y2, radius);

Parameters

x1
The x axis of the coordinate for the first control point.
y1
The y axis of the coordinate for the first control point.
x2
The x axis of the coordinate for the second control point.
y2
The y axis of the coordinate for the second control point.
radius
The arc's radius.

Examples

Using the arcTo method

This is just a simple code snippet drawing an arc. The base point is blue and the two control points are red.

HTML

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

JavaScript

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

ctx.beginPath();
ctx.moveTo(150, 20);
ctx.arcTo(150,100,50,20,30);
ctx.stroke();

ctx.fillStyle = 'blue';
// base point
ctx.fillRect(150, 20, 10, 10);

ctx.fillStyle = 'red';
// control point one
ctx.fillRect(150, 100, 10, 10);
// control point two
ctx.fillRect(50, 20, 10, 10);

Trying the arcTo parameters

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

<canvas id="canvas" class="playable-canvas" height="200" width="400"></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.moveTo(150, 20);
ctx.arcTo(150,200,50,0,20);
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
WHATWG HTML Living Standard
The definition of 'CanvasRenderingContext2D.arcTo' in that specification.
Living Standard  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Edge Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also

Document Tags and Contributors

 Contributors to this page: erikadoyle, fscholz
 Last updated by: erikadoyle,