Fabric.js | Rect lockScalingFlip Property

Last Updated : 20 May, 2020

In this article, we are going to see how to lock flipping by scaling a canvas rectangle using FabricJS so that it can not be inverted by pulling the width to the negative side. The canvas rectangle means rectangle is movable and can be stretched according to requirement. Further, the rectangle can be customized when it comes to initial stroke color, height, width, fill color, or stroke width.

To make it possible, we are going to use a JavaScript library called FabricJS. After importing the library, we will create a canvas block in the body tag which will contain the rectangle. After this, we will initialize instances of Canvas and Rect provided by FabricJS and lock flipping by scaling of the rectangle using lockScalingFlip property and render the Rect on the Canvas as given in the example below.

Syntax:

fabric.Rect({
    width: number,
    height: number,
    lockScalingFlip: Boolean
});

Parameters: This function accepts three parameters as mentioned above and described below:

width: It specifies the width of rectangle.
height: It specifies the height of rectangle.
lockScalingFlip: It specifies whether to lock flipping by scaling or not.

Example: This example uses FabricJS to lock flipping by scaling of a canvas rectangle.

<!DOCTYPE html>  
<html>  
  
<head>  
    <title>  
        Fabric.js | Rect lockScalingFlip Property 
    </title>  
      
    <!-- Adding the FabricJS library -->
    <script src=  
"https://cdnjs.cloudflare.com/ajax/libs/fabric.js/3.6.2/fabric.min.js">  
    </script>  
</head>  
  
<body>  
        <div style="text-align: center;width: 600px;">  
          <h1 style="color: green;">  
            GeeksforGeeks  
          </h1>  
          <b> 
            Fabric.js | Rect lockScalingFlip Property 
          </b> 
        </div> 
    <canvas id="canvas" width="600" height="200"
        style="border:1px solid #000000">  
    </canvas>  
      
    <script>  
      
        // Initiate a Canvas instance  
        var canvas = new fabric.Canvas("canvas");  
  
        // Initiate a Rect instance  
        var rectangle = new fabric.Rect({  
            width: 200, 
            height: 100, 
            fill: '',  
            stroke: 'green', 
            strokeWidth: 3, 
            lockScalingFlip: true 
        });  
  
        // Render the Rect in canvas  
        canvas.add(rectangle);  
        canvas.centerObject(rectangle); 
    </script>  
</body>  
  
</html> 