How to change the font weight of IText using FabricJS?

In this tutorial, we are going to see how to change the font weight of IText using FabricJS. The IText class was introduced in FabricJS version 1.4, extends fabric.Text and is used to create IText instances. An IText instance gives us the freedom to select, cut, paste or add new text without additional configurations. There are also various supported key combinations and mouse/touch combinations which make text interactive which are not provided in Text.

Textbox, however, which is based on IText allows us to resize the text rectangle and wraps lines automatically. This is not true for IText as height is not adjusted based on the wrapping of lines. We can manipulate our IText object by using various properties. Font weight refers to the value which determines how bold or light our text will appear. We can change the font weight by using the fontWeight property

Syntax

new fabric.IText(text: String , { fontWeight: Number|String }: Object)

Parameters

text − This parameter accepts a String which is the text string that we want to display.
options (optional) − This parameter is an Object which provides additional customizations to our IText object. Using this parameter colour, cursor, stroke width and a lot of other properties can be changed related to the object of which fontWeight is a property.

Options Keys

fontWeight − This property accepts a Number or String value which determines how bold or light our text shall appear inside the IText object. Its default value is normal.

Example 1

Passing the fontWeight property as key with a numerical value

Let’s see a code example to understand how our IText object would appear when the fontWeight property is used as key with a numerical value. In this case we have set the value as 400 which means that our text will have normal font. We can also use other values such as 600 or 800.


<!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>Passing the fontWeight property as key with a numerical value</h2>
   <p>You can see that the text is of normal font</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 an itext object
      var itext = new fabric.IText(
         "Add sample text here.
Lorem ipsum dolor sit amet",{
            width: 300,
            left: 60,
            top: 70,
            fill: "#6abfe1",
            fontWeight: 400,
         }
      );

      // Add it to the canvas
      canvas.add(itext);
   </script>
</body>
</html>

Example 2

Passing the fontWeight property as key with the value as “bold”

In this example, we are passing the fontWeight property as key, with a value as “bold”. This means that our itext object will be rendered with text that has thicker letters.


<!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>Passing the fontWeight property as key with the value as “bold”</h2>
   <p>You can see that the IText object has been rendered with bold text</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 an itext object
      var itext = new fabric.IText(
         "Add sample text here.
Lorem ipsum dolor sit amet",{
            width: 300,
            left: 60,
            top: 70,
            fill: "#6abfe1",
            fontWeight: "bold",
         }
      );
   
      // Add it to the canvas
      canvas.add(itext);
   </script>
</body>
</html>