How to make a circle invisible using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to make a Circle invisible using FabricJS. Circle is one of the various shapes provided by FabricJS. In order to create a circle, we have to 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 by making it visible or invisible. We can do this by using the visible property.

Syntax

new fabric.Circle( { visible: Boolean }: 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 visible is a property.

Options Keys

  • visible − This property accepts a Boolean value which allows us to render an object onto the canvas. Its default value is True.

Example 1

Passing visible property as key with a 'true' value

Let's see a code to understand what happens when we pass the visible property a True value. By assigning the value as 'true' we make sure that our Circle object is rendered onto the canvas. This is also the default behaviour in FabricJS.

<!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>Making a circle invisible using FabricJS</h2>
      <p>Here, the circle is visible because we have set <b>visible</b> to True. This is the default behavior. So, even if we don't apply the <b>visible</b> property, it will be set to True, by defalt. </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",
            visible: true
         });

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

Example 2

Passing visible property as key with a 'false' value

In this example, we are passing the visible property as key with a False value. Assigning a false value will make sure that our circle object does not get rendered onto the canvas. It simply does not make the object 'invisible' but gets rid of it altogether. It can be used to remove an object from canvas without removing its code.

<!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>Making a circle invisible using FabricJS</h2>
      <p>Notice that the circle is invisible here, as we have set <b>visible</b> to False. </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",
            visible: false
         });
   
         // Adding it to the canvas
         canvas.add(cir);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>
raja
Updated on 25-May-2022 12:09:09

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