How to lock the flipping during scaling of Ellipse using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to lock the flipping during 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 flipping an object during scaling. This can be done by using the lockScalingFlip property.

Syntax

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

Options Keys

  • lockScalingFlip − This property accepts a Boolean value. If we assign it a 'true' value, then the object will not be allowed to flip during scaling.

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 lockScalingFlip property is not used.

<!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 flipping during scaling of Ellipse using FabricJS?</h2>
      <p>Select the object and scale it up. The object will flip. This is the default behavior.</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 lockScalingFlip as key with 'true' value

In this example, we will see how we can cease the ability of an ellipse object to flip while scaling by using the lockScalingFlip property. As we can see, although we try to flip the ellipse object, it is no longer allowed.

<!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 flipping during scaling of Ellipse using FabricJS?</h2>
      <p>Select the object and stretch it from its corners. The object will not flip because we have set the property <b>lockScalingFlip</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,
            lockScalingFlip: 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 12:43:50

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