How to add shadow to a Circle using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to add a shadow to a Circle using FabricJS. Circle is one of the various shapes provided by FabricJS. In order to create a circle, we will create an instance of fabric.Circle class and add it to the canvas. Our circle object can be customized in various ways like changing its dimensions, adding a background color or even adding a shadow to it. We can add a shadow to a Circle by using the shadow property.

Syntax

new fabric.Circle({ shadow : fabric.Shadow }: 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 shadow is a property.

Options Keys

  • shadow − This property accepts a fabric.Shadow object which allows us to add a shadow to our triangle object. For example, in order to add a shadow to our Circle object we need to create a new instance of fabric.Shadow and then assign that instance to shadow property.

Example 1

Passing the shadow object to the shadow property

Let's see an example to understand how we can assign the shadow property value, by which a shadow will be added to our Circle object. Firstly, we need to make a new instance of fabric.Shadow and then assign that instance to our shadow property.

<!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 shadow to a circle using FabricJS</h2>
      <p>Notice the shadow around the circle object. Here we have applied the <b>shadow</b> property. </p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         
         // Initiate a shadow instance
         var shadow = new fabric.Shadow({
            color: "black",
            blur: 20
         });
         var circle = new fabric.Circle({
            left: 115,
            top: 50,
            radius: 50,
            fill: "#85bb65",
            shadow: shadow
         });
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>

Example 2

Passing an 'rgba' value to the shadow object

We can also adjust the shadow and give it a blurred out appearance by assigning it an 'rgba' value which stands for red, blue, green and alpha. Alpha determines the opacity of the colour.

<!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 shadow to a circle using FabricJS</h2>
         <p>Notice the shadow around the circle object. Here we have passed an 'rgba' value to assign the color.</p>
         <canvas id="canvas"></canvas>

         <script>
            // Initiate a canvas instance
            var canvas = new fabric.Canvas("canvas");
           
            // Initiate a shadow instance
            var shadow = new fabric.Shadow({
               color: "rgba(0,128,0,0.8)",
               blur: 20
            });
            var circle = new fabric.Circle({
               left: 115,
               top: 50,
               radius: 50,
               fill: "#85bb65",
               shadow: shadow
            });
            canvas.add(circle);
            canvas.setWidth(document.body.scrollWidth);
            canvas.setHeight(250);
         </script>
   </body>
</html>
raja
Updated on 25-May-2022 07:28:53

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