Fabric.js Polygon centeredScaling Property

Last Updated : 18 Jan, 2021

In this article, we are going to see how to enable the centered scaling of the canvas Polygon using FabricJS. The canvas Polygon means Polygon is movable and can be stretched according to requirement. Further, the Polygon can be customized when it comes to initial stroke color, height, width, fill color, or stroke width.

To make this 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 Polygon. After this, we will initialize instances of Canvas and Polygon provided by FabricJS and enable the centered scaling of canvas Polygon using centeredScaling property and render the Polygon on the Canvas as given below.

Syntax:

fabric.Polygon([ 
        { x: pixel, y: pixel }, 
        { x: pixel, y: pixel }, 
        { x: pixel, y: pixel }, 
        { x: pixel, y: pixel }, 
        { x: pixel, y: pixel }],
        {
                centeredScaling: boolean
        });

Parameters: This parameters accepts a single parameter as mentioned above and described below:

centeredScaling: It specifies whether to enable or disable centered scaling.

Example: This example uses FabricJS to enable the centered scaling of the canvas-like Polygons given below. Try scaling the object after enabling centered scaling, it will scale from all sides when you will scale it.

HTML

<!DOCTYPE html>  
<html>  
  
<head>  
    <!-- Loading 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 | Polygon centeredScaling 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 polygon instance  
        var polygon = new fabric.Polygon([  
            { x: 295, y: 10 },  
            { x: 235, y: 198 },  
            { x: 385, y: 78},  
            { x: 205, y: 78},  
            { x: 355, y: 198 }], {  
                stroke: 'green',  
                strokeWidth: 3,  
                centeredScaling: true  
            });  
  
        // Render the polygon in canvas  
        canvas.add(polygon);  
    </script>  
</body>  
  
</html>