How to create a canvas with Rectangle using FabricJS?



In this tutorial, we are going to learn how to create a canvas with a Rectangle object using FabricJS. Rectangle is one of the various provided by FabricJS. In order to create a rectangle, we will have to create an instance of fabric.Rect class and add it to the canvas.

Syntax

new fabric.Rect({ width: Number, height: Number }: 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 rectangle object of which width and height are properties.

Options Keys

  • width This property accepts a Number which specifies the object’s width.

  • height This property accepts a Number which specifies the object’s height.

Example 1

Creating an instance of fabric.Rect() and adding it to our canvas

Let’s see a code example of how we can add a rectangle to our canvas. Here we have created an object with a width of 100px and a height of 70px. Also, we have used the colour "green" as a fill colour.

<!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>Creating an instance of fabric.Rect() and adding it to our canvas</h2>    <p>You can click on the rectangle and interact with it</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: 115,          top: 50,          width: 100,          height: 70,          fill: "green",       });       // Add it to the canvas       canvas.add(rect);    </script> </body> </html>

Example 2

Manipulating the Rectangle object by using the set method

In this example, we have assigned the properties to the rectangle by using the set method which is a setter for values. Any property related to stroke, strokeWidth, angle, scaling, rotation, etc, can be mutated by using this method.

<!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>Manipulating the Rectangle object by using the set method</h2>    <p>You can click on the rectangle and interact with it</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();             // Using set to set the properties       rect.set("left", 119);       rect.set("top", 60);       rect.set("width", 170);       rect.set("height", 90);       rect.set("angle", 45);       rect.set("fill", "#bdda57");       rect.set("stroke", "#d9e650");       rect.set("strokeWidth", 4);       // Add it to the canvas       canvas.add(rect);    </script> </body> </html>
Updated on: 2022-06-28T12:31:54+05:30

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