I've built something like this called "stretchtext" 3 years ago :)

Here is the demo (use the slider displayed after the first blockquote in the article) https://blog.fgribreau.com/2014/05/fr-stretchtext-retour-sur... or click on "[+]" to go deeper.

The code is open-source here: https://github.com/FGRibreau/stretchtext