How to add dashed stroke to a Circle using FabricJS?

In this tutorial, we are going to learn how to add a dashed stroke to a Circle using FabricJS. Circle is one of the various shapes provided by FabricJS. In order to create a circle, we will have to create an instance of fabric.Circle class and add it to the canvas. The strokeDashArray property allows us to specify a dash pattern for the object's stroke.

Syntax

new fabric.Circle( { strokeDashArray: Array }: Object)

Parameters

options (optional) − This parameter is an Object which provides additional customizations to our circle. Using this parameter, a lot of properties such as colour, cursor, and stroke width can be changed related to the object of which strokeDashArray is a property.

Options Keys

strokeDashArray − This option is an Array which is used to define the pattern of the dash. For example, if we pass an array with values [2,3], it means a dash pattern of 2px dash and 3px gap and repeating this pattern infinitely.

Example 1

Default appearance of an object's stroke

Let's see an example that depicts the default appearance of the stroke of a circle object. Since we have not used the strokeDashArray property, there is no dash pattern being displayed.

<!DOCTYPE html>
<html>
   <head>
      <!-- Adding the Fabric JS Library-->
      <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js">         </script>
   </head>
   <body>
      <h2>Adding dashed stroke to a circle using FabricJS</h2>
      <p>Here you cannot see the dashed stokes as we have not used the <b>strokeDashArray</b> property. This is the default appearance.</p>
      <canvas id="canvas"></canvas>
     
      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var cir = new fabric.Circle({
            left: 215,
            top: 100,
            fill: "#adff2f",
            radius: 50,
            stroke: "#228b22",
            strokeWidth: 15
         });
         
         // Adding it to the canvas
         canvas.add(cir);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>

Example 2

Passing strokeDashArray property as key

In this example, we are passing the strokeDashArray property a value of [9,2]. This means that a dash pattern will be created such that there is a 9px long line followed by a 2px gap, then again a 9px long line will be drawn and so on.

<!DOCTYPE html>
   <html>
      <head>
         <!-- Adding the Fabric JS Library-->
         <script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/510/fabric.min.js"></script>
      </head>
     
      <body>
         <h2>Adding dashed stroke to a circle using FabricJS</h2>
         <p>Notice that here we have used the <b>strokeDashArray</b> property. </p>
         <canvas id="canvas"></canvas>

         <script>
            // Initiate a canvas instance
            var canvas = new fabric.Canvas("canvas");
            var cir = new fabric.Circle({
               left: 215,
               top: 100,
               fill: "#adff2f",
               radius: 50,
               stroke: "#228b22",
               strokeWidth: 15,
               strokeDashArray: [9, 2]
            });
           
            // Adding it to the canvas
            canvas.add(cir);
            canvas.setWidth(document.body.scrollWidth);
            canvas.setHeight(250);
         </script>
   </body>
</html>