Dynamic Text Resizing in Swift
Oct 18, 2019 Update: You can now find a complete solution including an example app at https://github.com/joncardasis/FontFit.
✨ Updated: May 26, 2018 ✨
Creating a great user experience lies in making every interaction feel nature and intended to the user. In a recent project, to make interactions feel more catered, I needed a UILabel to have it’s text scale to fit its bounds to the best extent that it can.
And so began my challenge.
There isn’t a simple cut-and-dry answer for this problem. Many developers run a while loop and keep upsizing the font size until it has the maximum fit. I wanted a faster method.
The implementation I ended up with was to leverage String’s boundingRect method. This method draws text with special attributes and will then return the size of the content. Perfect.
Using this I was able to create a base model of the text with a set font and then find a scalar between the results of boundingRect and the content size of the UILabel frame. Voila! I had a proper scaling font sizes.
Usage 📱
The implementation can be extended for any UI element (such as UITextField). A simple call to the new fitTextToBounds() function is all that is needed:
Source Code 🚀
Update May 26, 2018: I’ve created a more robust solution for determining dynamic font sizing. The previous source code can still be found here.
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