FittableFontLabel

UILabel can shrink font size as follows:

label.minimumScaleFactor = 0.3
label.adjustsFontSizeToFitWidth = true
label.numberOfLines = 1

But it won't always work as expected:

Doesn't fit the label height
Big top / bottom margins when the maxFontSize is huge
Not really customisable
...

That's why FittableFontLabel exists:

Make the text fit the label size: width and height if multilines, width only if single lines
Works with one or several lines
Supports attributed string (custom line spacing...)
Customize maxFontSize without using default label font size
Auto-layout compliant
UILabel extension if we want to use UILabel
Customisable from xibs / storyboards when using the UILabel's subclass FittableFontLabel
...

Multilines UILabel:

Multilines UILabel with attributed string (lines spacing):

Single line UILabel:

Usage

let aFittableFontLabel = FittableFontLabel(frame: CGRect(x: 0, y: 0, width: 300, height: 100))
aFittableFontLabel.autoFittableFont = true
aFittableFontLabel.lineBreakMode = .ByWordWrapping
aFittableFontLabel.numberOfLines = 0 // or 1...
aFittableFontLabel.text = "?"
// Change the text, it will always fit the label frame!

Check the sample project for advanced usage.

Note: The label lineBreakMode must be set to NSLineBreakByWordWrapping in order to work.

Installation

iOS 8.0+

CocoaPods Installation

FittableFontLabel is available on CocoaPods. Just add the following to your Podfile:

pod 'FittableFontLabel'

Swift Package Manager

FittableFontLabel is available on SPM. Just add the following to your Package file:

import PackageDescription

let package = Package(
    dependencies: [
        .Package(url: "https://github.com/tbaranes/FittableFontLabel.git", majorVersion: 1)
    ]
)

Manual Installation

Just drag the Source/*.swift files into your project.

UILabel extension

func fontSizeToFit(
		maxFontSize maxFontSize: CGFloat = CGFloat.NaN, 
		minFontScale: CGFloat = 0.1, 
		rectSize: CGSize? = nil)

Adjust the font size to make the current text fit the label frame.

maxFontSize: the biggest font size to use during drawing. The default value is the current font size
minFontScale: the scale factor that determines the smallest font size to use during drawing. The default value is 0.1
rectSize: the size where the text must fit. The default value is the label bounds