How to lock the horizontal movement of a Circle using FabricJS?

FabricJSJavascriptHTML5 Canvas

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

Syntax

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

Let's see a code to understand how we can move our circle object in the X-axis or the Y-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 a circle using FabricJS?</h2>
      <p>Here you can select the circle and move it freely, as we have not applied the <b>lockMovementX</b> property. This is the default behavior. By default, <b>lockMovementX</b> 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 lockMovementX as key with 'true' value

In this example, we will see how we can lock the horizontal movement of a Circle 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 circle using FabricJS?</h2>
      <p>Select the object and try to move it horizontally. You can't do that as we have restricted the horizontal movement by setting <b>lockMovementX</b> to True. You can however move the circle in vertical direction. </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,
            lockMovementX: 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 11:38:49

Advertisements