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

FabricJSJavascriptHTML5 Canvas

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

Syntax

new fabric.Circle({ lockScalingY : 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 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 a Circle object in the canvas

Let's see an example to understand the default behaviour of a Circle 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>Locking the vertical scaling of 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 used the <b>lockScalingY</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 lockScalingY as key with 'true' value

In this example, we will see how we can cease the ability of a circle object to scale vertically using the lockScalingY property. As we can see, although we can scale the circle 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>Locking the vertical scaling of circle using FabricJS</h2>
      <p>Select the object and try to scale it by stretching its controlling corners. You will notice that the object can be scaled in the horizontal direction, but its vertical scaling is locked. Here we have set <b>lockScalingY</b> to True. </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,
            lockScalingY: 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 11:59:48

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