Fabric.js | Ellipse borderScaleFactor Property

Last Updated : 13 May, 2020

In this article, we are going to see how to scale the controlling borders of canvas ellipse using FabricJS. The canvas means ellipse is movable and can be stretched according to requirement. Further, the ellipse can be customized when it comes to initial stroke color, fill color, stroke width, or radius.

Approach: To make it possible, we are going to use a JavaScript library called FabricJS. After importing the library using CDN, we will create a canvas block in the body tag that will contain our ellipse. After this, we will initialize instances of Canvas and Ellipse provided by FabricJS and scale the controlling borders of canvas ellipse using borderScaleFactor property and render the Ellipse on the Canvas as given in the below example.

Syntax:

fabric.Ellipse({
    rx: number,
    ry: number,
    borderScaleFactor: number
});

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

rx: It specifies the horizontal radius.
ry: It specifies the vertical radius.
borderScaleFactor: It specifies the scale factor of the controlling borders.

Program: This example uses FabricJS to scale the controlling borders of the canvas-like ellipse as given below.

<!DOCTYPE html> 
<html> 
  
<head> 
    <title> 
        Fabric.js | Ellipse borderScaleFactor Property 
    </title> 
  
    <!-- Loading the FabricJS library -->
    <script src= 
"https://cdnjs.cloudflare.com/ajax/libs/fabric.js/3.6.2/fabric.min.js"> 
    </script> 
</head> 
  
<body> 
    <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 Ellipse instance 
        var ellipse = new fabric.Ellipse({ 
            rx: 80, 
            ry: 40, 
            borderScaleFactor: 3 
        }); 
  
        // Render the Ellipse in canvas 
        canvas.add(ellipse); 
    </script> 
</body> 
  
</html> 