How to lock the horizontal scaling of Ellipse using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to lock the horizontal scaling of an Ellipse using FabricJS. Just as we can specify the position, color, opacity and dimension of an ellipse 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.Ellipse({ lockScalingX : Boolean }: Object)

Parameters

  • options (optional) − This parameter is an Object which provides additional customizations to our ellipse. Using this parameter color, 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 an Ellipse object in the canvas

Let's take an example to understand the default behaviour of an Ellipse 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>How to lock the horizontal scaling of Ellipse using FabricJS?</h2>
      <p>Here you can select the object and scale it both horizontally and vertically because we have not used the <b>lockScalingX</b> property. </p>
      <canvas id="canvas"></canvas>
     
      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         
         // Initiate an ellipse instance
         var ellipse = new fabric.Ellipse({
            left: 115,
            top: 50,
            fill: "white",
            rx: 80,
            ry: 50,
            stroke: "black",
            strokeWidth: 5,
         });
         
         // Adding it to the canvas
         canvas.add(ellipse);
         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 an ellipse object to scale horizontally using the lockScalingX property. Although we can scale the ellipse 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>How to lock the horizontal scaling of Ellipse using FabricJS?</h2>
      <p>Here you can select the object and scale it vertically, but you can't scale it horizontally because we have set <b>lockScalingX</b> to True. </p>
      <canvas id="canvas"></canvas>
     
      <script>
         // Initiate a canvas instance
         var canvas = new fabric.Canvas("canvas");
         
         // Initiate an ellipse instance
         var ellipse = new fabric.Ellipse({
            left: 115,
            top: 50,
            fill: "white",
            rx: 80,
            ry: 50,
            stroke: "black",
            strokeWidth: 5,
            lockScalingX: true,
         });
         
         // Adding it to the canvas
         canvas.add(ellipse);
         canvas.setWidth(document.body.scrollWidth);
         canvas.setHeight(250);
      </script>
   </body>
</html>
raja
Updated on 24-May-2022 12:54:00

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