Fabric.js Polygon lockScalingX Property

Last Updated : 01 Sep, 2020

In this article, we are going to see how to lock the horizontal scaling of the canvas polygon using FabricJS. The canvas polygon means the 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 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 that will contain the polygon. After this, we will initialize instances of Canvas and polygon provided by FabricJS and lock horizontal scaling of the canvas polygon using lockScalingX property and render the polygon on the Canvas as given in the example below.

Syntax:

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

Parameter: This property accepts a single parameter as mentioned above and described below:

lockScalingX: It specifies whether to lock horizontal scaling of the canvas.

Note: Dimension pixels is must to create a polygon.

Below examples illustrate the Fabric.JS Polygon lockScalingX property in JavaScript:

Example 1: In this example, lockScalingX value is set to false.

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 lockScalingX 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 }], {  
            fill: 'yellow', 
            lockScalingX: false 
        });  
  
        // Render the polygon in canvas  
        canvas.add(polygon);  
    </script>  
</body>  
  
</html>

Output:

Example 2: In this example, lockScalingX value is set to true.

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 lockScalingX 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 }], {  
            fill: 'yellow', 
            lockScalingX: true 
        });  
  
        // Render the polygon in canvas  
        canvas.add(polygon);  
    </script>  
</body>  
  
</html>