CanvasRenderingContext2D.setLineDash()

The setLineDash() method of the Canvas 2D API's CanvasRenderingContext2D interface sets the line dash pattern used when stroking lines, using an array of values which specify alternating lengths of lines and gaps which describe the pattern.

To return to using solid lines, set the line dash list to an empty array.

Syntax

ctx.setLineDash(segments);

Parameters

segments
An Array of numbers which specify distances to alternately draw a line and a gap (in coordinate space units). If the number of elements in the array is odd, the elements of the array get copied and concatenated. For example, [5, 15, 25] will become [5, 15, 25, 5, 15, 25]. If the array is empty, the line dash list is cleared and line strokes return to being solid.

Return value

undefined.

Examples

This is just a simple code snippet which uses the setLineDash() method to draw a dashed line above a solid line.

HTML

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

JavaScript

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

ctx.beginPath();
ctx.setLineDash([5, 15]);
ctx.moveTo(0, 50);
ctx.lineTo(400, 50);
ctx.stroke();

ctx.beginPath();
ctx.setLineDash([]);
ctx.moveTo(0, 150);
ctx.lineTo(400, 150);
ctx.stroke();

Try it

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

Playable code
<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" style="height:150px">
ctx.beginPath();
ctx.setLineDash([5, 15]);
ctx.moveTo(0, 50);
ctx.lineTo(400, 50);
ctx.stroke();

ctx.beginPath();
ctx.setLineDash([]);
ctx.moveTo(0, 150);
ctx.lineTo(400, 150);
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.setLineDash' in that specification.
Living Standard  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support YesEdge Full support 12Firefox Full support 27IE Full support 11Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android No support NoOpera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support

Gecko-specific notes

  • Starting with Gecko 7.0 (Firefox 7.0 / Thunderbird 7.0 / SeaMonkey 2.4), the non-standard and deprecated property mozDash has been implemented to set and get a dash list. This property will be deprecated and removed in the future, see bug 931389. Use setLineDash() instead.

WebKit-specific notes

  • In WebKit-based browsers (e.g. Safari), the non-standard and deprecated property webkitLineDash is implemented besides this method. Use setLineDash() instead.

See also

Document Tags and Contributors

Contributors to this page: fscholz, LeeTaylor, Sheppy, nmve, erikadoyle
Last updated by: fscholz,