How to lock the rotation of Rectangle using FabricJS?

In this tutorial, we are going to learn how to lock the rotation of a Rectangle using FabricJS. Just as we can specify the position, colour, opacity and dimension of a rectangle object in the canvas, we can also specify whether we want it to rotate or not. This can be done by using the lockRotation property.

Syntax

new fabric.Rect({ lockRotation : Boolean }: Object)

Parameters

Options (optional) This parameter is an Object which provides additional customizations to our rectangle. 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 lockRotation is a property.

Options Keys

lockRotation This property accepts a Boolean value. If we assign it a ‘true’ value, then the object rotation will be locked.

Example 1

Default behaviour of a Rectangle object in the canvas

Let’s see a code example to understand the default behaviour of a rectangle object when lockRotation property is not used. By default, we are able to rotate a rectangle object anticlockwise or clockwise.

<!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>Default behaviour of a Rectangle object in the canvas</h2>
   <p>You can try rotating the rectangle to see the default behaviour</p>
   <canvas id="canvas"></canvas>
   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);

      // Initiate a rectangle object
      var rect = new fabric.Rect({
         left: 55,
         top: 90,
         width: 170,
         height: 70,
         fill: "black",
         padding: 9,
         stroke: "#483d8b",
         strokeWidth: 5,
      });

      // Add it to the canvas
      canvas.add(rect);
   </script>
</body>
</html>

Example 2

Passing lockRotation as key with a True value

In this example, we will see how we can cease the ability of a rectangle object to rotate by using the lockRotation property. As we can see, as soon as we try to rotate the rectangle object, a not-allowed cursor is shown. This means that the rotation action 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>Passing lockRotation as key with a True value</h2>
   <p>Try rotating the object and you will see a not-allowed cursor on the rotate handle</p>
   <canvas id="canvas"></canvas>
   <script>
      // Initiate a canvas instance
      var canvas = new fabric.Canvas("canvas");
      canvas.setWidth(document.body.scrollWidth);
      canvas.setHeight(250);

      // Initiate a rectangle object
      var rect = new fabric.Rect({
         left: 55,
         top: 90,
         width: 170,
         height: 70,
         fill: "black",
         padding: 9,
         stroke: "#483d8b",
         strokeWidth: 5,
         lockRotation: true,
      });

      // Add it to the canvas
      canvas.add(rect);
   </script>
</body>
</html>

Rahul Gurung

Updated on: 2022-06-29T11:52:19+05:30

691 Views

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