How to lock the horizontal movement of Ellipse using FabricJS?

FabricJSJavascriptHTML5 Canvas

In this tutorial, we are going to learn how to lock the horizontal movement 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 it to move only in the Y-axis. This can be done by using the lockMovementX property.

Syntax

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

Options Keys

  • lockMovementX − This property accepts a Boolean value. If we assign it a 'true' value, then the object will no longer be able to move in the horizontal direction.

Example 1

Default behaviour of an Ellipse object in the canvas

Let's take an example to understand how we can move our ellipse object in the X-axis freely when lockMovementX property is not assigned a 'true' value.

<!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 movement of Ellipse using FabricJS?</h2>
      <p>You can select the object and move it freely horizontally. Here we haven't used the <b>lockMovementX</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 lockMovementX as key with 'true' value

In this example, we will see how we can lock the horizontal movement of an ellipse object. By assigning the lockMovementX property a "true" value, we essentially cease movement in the horizontal direction.

<!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 movement of Ellipse using FabricJS?</h2>
      <p>Here you can select the object but can't move it horizontally because we have set the <b>lockMovementX</b> property 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,
            lockMovementX: 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 12:47:48

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