How to add superscript with Text using FabricJS?



In this tutorial, we are going to learn how to add superscript with Text using FabricJS. We can display text on canvas by adding an instance of fabric.Text. Not only does it allow us to move, scale and change the dimensions of the text but it also provides additional functionality like text alignment, text decoration, line height which can be obtained by the properties textAlign, underline and lineHeight respectively. We can also add superscripts by using the setSuperscript method.

Syntax

setSuperscript(start: Number, end: Number)

Parameters

  • start − This parameter accepts a Number as value. The value given determines the starting point for superscript.

  • end − This parameter accepts a Number as value. The value given determines the ending point for superscript.

Example 1

Default appearance of the Text object

Let’s see a code example to see how our text object looks when the setSuperscript method is not used. In this case, no superscript will be present.

<!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>Default appearance of the Text object</h2> <p>You can see that no superscript is present</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 text object var text = new fabric.Text("Add sample
text here."
, { width: 300, left: 50, top: 70, fill: "green", }); // Add it to the canvas canvas.add(text); </script> </body> </html>

Example 2

Using the setSuperscript method with custom values

In this example, we will see how by using the setSuperscript method, we are able to turn certain characters into “superior figures”. Such characters would be present slightly above the baseline. In this example we have used the values as 0 and 4 which means the selection will start at the 0th index and end at the 4th index.

<!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>Using the setSuperscript method with custom values</h2> <p>You can see that superscript has been added to the 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 a text object var text = new fabric.Text("Add sample
text here."
, { width: 300, left: 50, top: 70, fill: "green", }); // Using the setSuperscript method text.setSuperscript(0,4) // Add it to the canvas canvas.add(text); </script> </body> </html>

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