How to lock the horizontal scaling of a Circle using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to lock the horizontal scaling of a Circle using FabricJS. Just as we can specify the position, colour, opacity and dimension of a circle object in the canvas, we can also specify whether we want to stop scaling an object horizontally. This can be done by using the lockScalingX property.

Syntax

new fabric.Circle({ lockScalingX : 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 lockScalingX is a property.

Options Keys

  • lockScalingX − This property accepts a Boolean value. If we assign it a 'true' value, then the object's horizontal scaling will be locked.

Example 1

Default behaviour of a Circle object in the canvas

Let's see an example to understand the default behaviour of a Circle object when lockScalingX property is not used. Scaling the object in both horizontal and vertical directions is feasible.

<!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>Locking the horizontal scaling of a circle using FabricJS</h2>
      <p>You can select the circle and scale it freely in any direction. This is the default behavior. Here we have not applied the <b>lockScalingX</b> property, but by default, it is set to False. </p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 115,
            top: 50,
            fill: "white",
            radius: 50,
            stroke: "black",
            strokeWidth: 5
         });

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

Example 2

Passing lockScalingX as key with 'true' value

In this example, we will see how we can cease the ability of a circle object to scale horizontally using the lockScalingX property. As we can see, although we can scale the circle object vertically, we are not allowed to perform the same action horizontally.

<!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>Locking the horizontal scaling of circle using FabricJS</h2>
      <p>Here, you will no longer be able to scale the circle horizontally, as we have set <b>lockScalingX</b> to True. You can however scale the circle in vertical direction. </p>
      <canvas id="canvas"></canvas>

      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         var circle = new fabric.Circle({
            left: 115,
            top: 50,
            fill: "white",
            radius: 50,
            stroke: "black",
            strokeWidth: 5,
            lockScalingX: true
         });

         // Adding it to the canvas
         canvas.add(circle);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>
raja
Updated on 25-May-2022 11:42:32

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