How to lock the vertical scaling of Ellipse using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to lock the vertical 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 vertically. This can be done by using the lockScalingY property.

Syntax

new fabric.Ellipse({ lockScalingY : 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 lockScalingY is a property.

Options Keys

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

Example 1

Default behaviour of an Ellipse object in the canvas

Let's see an example to understand the default behaviour of an Ellipse object when lockScalingY 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 vertical scaling of Ellipse using FabricJS?</h2>
      <p>You can select the object and scale it vertically. This is the default behavior. Here we have not used the <b>lockScaling</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 lockScalingY as key with 'true' value

In this example, we will see how we can cease the ability of an Ellipse object to scale vertically using the lockScalingY property. Although we can scale the ellipse object horizontally, we are not allowed to perform the same action vertically.

<!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 vertical scaling of Ellipse using FabricJS?</h2>
      <p>Here you can select the object and scale it horizontally, but we have locked its vertical scaling by appling <b>lockScalingY</b>. </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,
            lockScalingY: 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 13:47:04

Advertisements