HTML Canvas - setLineDash() Method

The HTML Canvas setLineDash() method is used to set the line dash pattern when there is a need to stroke the lines in Canvas element.

It takes an array specifying the lengths and gaps values and applies the style. It is available in the CanvasRenderingContext2D interface.

Syntax

Following is the syntax of HTML Canvas setLineDash() method −

CanvasRenderingContext2D.setLineDash(values);

Parameters

Following is the parameter used by this method

S.No	Parameter & Description
1	values An array of numbers representing the distances to maintain the space between each line dash and the length of the line dash pattern.

Return values

A line dash pattern is returned on the canvas element only when it is stroked or filled by using their respective methods.

Example

The following example draws a dashed line by using the HTML Canvas setLineDash() method for the CanvasRenderingContext2D object.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>Reference API</title>
   <style>
      body {
         margin: 10px;
         padding: 10px;
      }
   </style>
</head>
<body>
   <canvas id="canvas" width="200" height="150" style="border: 1px solid black;"></canvas>
   <script>
      var canvas = document.getElementById('canvas');
      var context = canvas.getContext('2d');
      context.setLineDash([4, 16]);
      context.beginPath();
      context.strokeStyle = 'blue';
      context.moveTo(25, 25);
      context.lineTo(125, 25);
      context.lineTo(125, 125);
      context.stroke();
   </script>
</body>
</html>

Output

The output returned by the above code on the webpage as −

Example

The following example draws a square onto the Canvas and applies setLineDash() method to its borders to get the line dash pattern.

<!DOCTYPE html>
<html lang="en">
<head>
   <title>Reference API</title>
   <style>
      body {
         margin: 10px;
         padding: 10px;
      }
   </style>
</head>
<body>
   <canvas id="canvas" width="200" height="150" style="border: 1px solid black;"></canvas>
   <script>
      var canvas = document.getElementById('canvas');
      var context = canvas.getContext('2d');
      context.beginPath();
      context.lineWidth = 10;
      context.strokeStyle = 'black';
      context.moveTo(25, 25);
      context.lineTo(25, 125);
      context.lineTo(125, 125);
      context.stroke();
      context.closePath();
      context.setLineDash([4, 16]);
      context.beginPath();
      context.lineWidth = 1;
      context.strokeStyle = 'blue';
      context.moveTo(25, 25);
      context.lineTo(125, 25);
      context.lineTo(125, 125);
      context.stroke();
      context.closePath();
   </script>
</body>
</html>

Output

The output returned by the above code on the webpage as −

html_canvas_lines.htm