Surface that automatically scales the font-size based on the content.

Usage no npm install needed!

<script type="module">
  import famousAutofontsizesurface from 'https://cdn.skypack.dev/famous-autofontsizesurface';



Surface that automatically scales the font-size based on the content.



View the demo here

Getting started

Install using bower or npm:

bower install famous-autofontsizesurface

npm install famous-autofontsizesurface

Example of how to create a AutoFontSizeSurface:

var AutoFontSizeSurface = require('famous-autofontsizesurface/AutoFontSizeSurface');

var autoFontSizeSurface = new AutoFontSizeSurface({
    fontSizeRange: [10, 18], // allow the font to scale between 10pt and 18pt.
    content: 'Lorem ipsum dolor sit amet, alii ludus persius no eos, cum oblique blandit ea. Est ei iuvaret placerat, ius an eruditi dissentiet philosophia, ex quodsi ancillae delicatissimi eam. Vis ad omnis constituto posidonium, sed verear malorum convenire id. Nam dolore fastidii in, unum euismod concludaturque quo et.',

To change the fontSizeRange afterwards, use:

    fontSizeRange: [8, 16]

To get the in-use fontSizeRange, use:

var fontSizeRange = autoFontSizeSurface.getFontSizeRange();

To get the calculated font-size:

var fontSize = autoFontSizeSurface.getFontSize();

When the calculated font-size changed, the fontSizeChanged event is emitted:

autoFontSizeSurface.on('fontSizeChanged', function (fontSize) {
    console.log('fontsize is now: ' + fontSize);

How it works

AutoFontSizeSurface creates a second hidden Surface in the DOM with a true-size height. This hidden surface is used to calculate the best fitting font-size without affecting the original surface. This calculation is only performed when one of these conditions is met:

  • the size of the surface is changed
  • the content is changed (setContent)
  • the options are changed (setOptions)
  • the surface classes are changed (addClass, removeClass, toggleClass, setClasses)
  • a surface property is changed (setProperties)
  • a surface attribute is changed (setAttributes)
  • when AutoFontSizeSurface.refreshAll() is called


If you like this project and want to support it, show some love and give it a star.

Special thanks to flawk.to for allowing me to share this code with the public.


© 2015 - Hein Rutjes