How to set the width of stroke of 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 strokeWidth property allows us to specify the width of a stroke for an object.

Syntax

new fabric.Circle( { strokeWidth: Number }: Object)

Parameters

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

Options Keys

strokeWidth − This property accepts a Number value which allows us to specify the width of a stroke for an object. Its default value is 1.

Example 1

Default appearance of an object's stroke

Let's see a code that depicts the default appearance of the stroke of a circle object. Since we have not used the strokeWidth property, the default width is being rendered.

<!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>Setting the width of stroke of circle using FabricJS</h2>
      <p>Notice the outline border of the circle. This is the default thickness of outline. Here we have not used the <b>strokeWidth</b> property, but by default, it is set to 1. </p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var cir = new fabric.Circle({
            left: 215,
            top: 40,
            fill: "#adff2f",
            radius: 100,
            stroke: "#228b22",
            //strokeWidth: 1
         });

         // Adding it to the canvas
         canvas.add(cir);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>

Example 2

Passing strokeWidth property as key

In this example, we are passing the strokeWidth property with a value of 5. This will make sure that our circle object is rendered with a stroke that has a width of 5 pixels.

<!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>Setting the width of stroke of circle using FabricJS</h2>
      <p>Notice the outline border of the circle. Here we have used the <b>strokeWidth</b> property and assigned it a value of 5.</p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var cir = new fabric.Circle({
            left: 215,
            top: 40,
            fill: "#adff2f",
            radius: 100,
            stroke: "#228b22",
            strokeWidth: 5
         });

         // Adding it to the canvas
         canvas.add(cir);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>