Web/API/CanvasRenderingContext2D/lineWidth

The CanvasRenderingContext2D.lineWidth property of the Canvas 2D API sets the thickness of lines.

Note: Lines can be drawn with the stroke(), strokeRect(), and strokeText() methods.

Syntax

ctx.lineWidth = value;

Options

value: A number specifying the line width, in coordinate space units. Zero, negative, Infinity, and NaN values are ignored. This value is 1.0 by default.

Examples

Changing line width

This example draws a line and a rectangle, using a line width of 15 units.

HTML

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

JavaScript

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

ctx.lineWidth = 15;

ctx.beginPath();
ctx.moveTo(20, 20);
ctx.lineTo(130, 130);
ctx.rect(40, 40, 70, 70);
ctx.stroke();

Result

More examples

For more examples and explanation about this property, see Applying styles and color in the Canvas Tutorial.

Specifications

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

Browser compatibility

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
`lineWidth`	Chrome Full support Yes	Edge Full support 12	Firefox Full support 1.5	IE Full support Yes	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 4	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes

Legend

Full support: Full support

WebKit/Blink-specific notes

In WebKit- and Blink-based Browsers, a non-standard and deprecated method ctx.setLineWidth() is implemented in addition to this property.

Gecko-specific notes

Starting Gecko 2.0 (Firefox 4 / Thunderbird 3.3 / SeaMonkey 2.1), setting lineWidth to a negative value no longer throws an exception; instead, it properly ignores non-positive values.