Elegant & painless Attributed Strings in Swift
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Created by Daniele Margutti - danielemargutti.com

SwiftRichString is a lightweight library which allows to create and manipulate attributed strings easily both in iOS, macOS, tvOS and even watchOS. It provides convenient way to store styles you can reuse in your app's UI lements, allows complex tag-based strings rendering and also includes integration with Interface Builder.

If you manipulate NSAttributedString in Swift, SwiftRichString allows you to keep your code manteniable, readable and easy to evolve.

Features Highlights

Want to know what SwiftRichString can do in your app? Lets take a look to these feature highlights!

1. Easy Styling

The main concept behind this lib is the Style: a style is just a collection of text attributes you can apply to a string. The following example show how to create a style an produce an attributed string with it:

let style = Style {
	$0.font = SystemFonts.AmericanTypewriter.font(size: 25) // just pass a string, one of the SystemFonts or an UIFont
	$0.color = "#0433FF" // you can use UIColor or HEX string!
	$0.underline = (.patternDot, UIColor.red)
	$0.alignment = .center
let attributedText = "Hello World!".set(style: style) // et voilà!

2. Global Styles & Interface Builder Integration

Styles can be also registered globally and reused in your app. Just define your own style and register using Styles.register() function:

let myStyle = Style { // define style's attributes... }
Styles.register("MyStyle", style: style)

Now you can reuse it everything in your app; SwiftRichString exposes a styleName property for the most common text containers and you can set it directly in Interface Builder:

3. Complex Rendering with tag-based strings

SwiftRichString allows you to render complex strings by parsing text's tags: each style will be identified by an unique name (used inside the tag) and you can create a StyleGroup which allows you to encapsulate all of them and reuse as you need (clearly you can register it globally).

// Create your own styles

let normal = Style {
	$0.font = SystemFonts.Helvetica_Light.font(size: 15)
let bold = Style {
	$0.font = SystemFonts.Helvetica_Bold.font(size: 20)
	$0.color = UIColor.red
	$0.backColor = UIColor.yellow
let italic = normal.byAdding {
	$0.traitVariants = .italic

// Create a group which contains your style, each identified by a tag.
let myGroup = StyleGroup(base: normal, ["bold": bold, "italic": italic])
// Use tags in your plain string	
let str = "Hello <bold>Daniele!</bold>. You're ready to <italic>play with us!</italic>"
self.label?.attributedText = str.set(style: myGroup)

That's the result!


Other Libraries You May Like

I'm also working on several other projects you may like. Take a look below:

Library Description
SwiftDate The best way to manage date/timezones in Swift
Hydra Write better async code: async/await & promises
FlowKit A new declarative approach to table/collection managment. Forget datasource & delegates.
SwiftRichString Elegant & Painless NSAttributedString in Swift
SwiftLocation Efficient location manager
SwiftMsgPack Fast/efficient msgPack encoder/decoder



Are you using SwiftRichString 1.x in your project? Don't miss to take a look at Migration section of the documentation. You can still use the 1.x release by using tagged version 1.1.0.

Table Of Contents

Full changelog is available in CHANGELOG.md file.

Other info:


Introduction to Style, StyleGroup, StyleRegEx


The main concept behind SwiftRichString is the use of StyleProtocol as generic container of the attributes you can apply to both String and NSMutableAttributedString. Concrete classes derivated by StyleProtocol are: Style, StyleGroup and StyleRegEx.

Each of these classes can be used as source for styles you can apply to a string, substring or attributed string.

Style: apply style to strings or attributed strings

A Style is a class which encapsulate all the attributes you can apply to a string. The vast majority of the attributes of both AppKit/UIKit are currently available via type-safe properties by this class.

Creating a Style instance is pretty simple; using a builder pattern approach the init class require a callback where the self instance is passed and allows you to configure your properties by keeping the code clean and readable:

let style = Style {
	$0.font = SystemFonts.Helvetica_Bold.font(size: 20)
	$0.color = UIColor.green
	// ... set any other attribute

let attrString = "Some text".set(style: style) // attributed string

StyleGroup: Apply styles for tag-based complex string

Style instances are anonymous; if you want to use a style instance to render a tag-based plain string you need to include it inside a StyleGroup. You can consider a StyleGroup as a container of Styles (but, in fact, thanks to the conformance to a common StyleProtocol's protocol your group may contains other sub-groups too).

let bodyStyle: Style = ...
let h1Style: Style = ...
let h2Style: Style = ...
let group = StyleGroup(base: bodyStyle, ["h1": h1Style, "h2": h2Style])

let attrString = "Some <h1>text</h1>, <h2>welcome here</h2>".set(style: group)

The following code defines a group where:

  • we have defined a base style. Base style is the style applied to the entire string and can be used to provide a base ground of styles you want to apply to the string.
  • we have defined two other styles named h1 and h2; these styles are applied to the source string when parser encounter some text enclosed by these tags.

StyleRegEx: Apply styles via regular expressions

StyleRegEx allows you to define a style which is applied when certain regular expression is matched inside the target string/attributed string.

let emailPattern = "([A-Za-z0-9_\\-\\.\\+])+\\@([A-Za-z0-9_\\-\\.])+\\.([A-Za-z]+)"
let style = StyleRegEx(pattern: emailPattern) {
	$0.color = UIColor.red
	$0.backColor = UIColor.yellow
let attrString = "My email is hello@danielemargutti.com and my website is http://www.danielemargutti.com".(style: style!)

The result is this:

String & Attributed String concatenation

SwiftRichString allows you to simplify string concatenation by providing custom + operator between String,AttributedString (typealias of NSMutableAttributedString) and Style.

This a an example:

let body: Style = Style { ... }
let big: Style = Style { ... }
let attributed: AttributedString = "hello ".set(style: body)

// the following code produce an attributed string by
// concatenating an attributed string and two plain string
// (one styled and another plain).
let attStr = attributed + "\(username)!".set(style:big) + ". You are welcome!"

You can also use + operator to add a style to a plain or attributed string:

// This produce an attributed string concatenating a plain
// string with an attributed string created via + operator
// between a plain string and a style
let attStr = "Hello" + ("\(username)" + big)

Apply styles to String & Attributed String

Both String and Attributed String (aka NSMutableAttributedString) has a come convenience methods you can use to create an manipulate attributed text easily via code:

Strings Instance Methods

  • set(style: String, range: NSRange? = nil): apply a globally registered style to the string (or a substring) by producing an attributed string.
  • set(styles: [String], range: NSRange? = nil): apply an ordered sequence of globally registered styles to the string (or a substring) by producing an attributed string.
  • set(style: StyleProtocol, range: NSRange? = nil): apply an instance of Style or StyleGroup (to render tag-based text) to the string (or a substring) by producting an attributed string.
  • set(styles: [StyleProtocol], range: NSRange? = nil): apply a sequence of Style/StyleGroup instance in order to produce a single attributes collection which will be applied to the string (or substring) to produce an attributed string.

Some examples:

// apply a globally registered style named MyStyle to the entire string
let a1: AttributedString = "Hello world".set(style: "MyStyle")

// apply a style group to the entire string
// commonStyle will be applied to the entire string as base style
// styleH1 and styleH2 will be applied only for text inside that tags.
let styleH1: Style = ...
let styleH2: Style = ...
let styleGroup = StyleGroup(base: commonStyle, ["h1" : styleH1, "h2" : styleH2])
let a2: AttributedString = "Hello <h1>world</h1>, <h2>welcome here</h2>".set(style: styleGroup)

// Apply a style defined via closure to a portion of the string
let a3 = "Hello Guys!".set(Style({ $0.font = SystemFonts.Helvetica_Bold.font(size: 20) }), range: NSMakeRange(0,4))

AttributedString Instance Methods

Similar methods are also available to attributed strings.

There are three categories of methods:

  • set methods replace any existing attributes already set on target.
  • add add attributes defined by style/styles list to the target
  • remove remove attributes defined from the receiver string.

Each of this method alter the receiver instance of the attributed string and also return the same instance in output (so chaining is allowed).


  • add(style: String, range: NSRange? = nil): add to existing style of string/substring a globally registered style with given name.
  • add(styles: [String], range: NSRange? = nil): add to the existing style of string/substring a style which is the sum of ordered sequences of globally registered styles with given names.
  • add(style: StyleProtocol, range: NSRange? = nil): append passed style instance to string/substring by altering the receiver attributed string.
  • add(styles: [StyleProtocol], range: NSRange? = nil): append passed styles ordered sequence to string/substring by altering the receiver attributed string.


  • set(style: String, range: NSRange? = nil): replace any existing style inside string/substring with the attributes defined inside the globally registered style with given name.
  • set(styles: [String], range: NSRange? = nil): replace any existing style inside string/substring with the attributes merge of the ordered sequences of globally registered style with given names.
  • set(style: StyleProtocol, range: NSRange? = nil): replace any existing style inside string/substring with the attributes of the passed style instance.
  • set(styles: [StyleProtocol], range: NSRange? = nil): replace any existing style inside string/substring with the attributes of the passed ordered sequence of styles.


  • removeAttributes(_ keys: [NSAttributedStringKey], range: NSRange): remove attributes specified by passed keys from string/substring.
  • remove(_ style: StyleProtocol): remove attributes specified by the style from string/substring.


let a = "hello".set(style: styleA)
let b = "world!".set(style: styleB)
let ab = (a + b).add(styles: [coupondStyleA,coupondStyleB]).remove([.foregroundColor,.font])

Fonts & Colors in Style

All colors and fonts you can set for a Style are wrapped by FontConvertible and ColorConvertible protocols.

SwiftRichString obviously implements these protocols for UIColor/NSColor, UIFont/NSFont but also for String. For Fonts this mean you can assign a font by providing directly its PostScript name and it will be translated automatically to a valid instance:

let firaLight: UIFont = "FiraCode-Light".font(ofSize: 14)
let style = Style {
	$0.font = "Jura-Bold"
	$0.size = 24

On UIKit you can also use the SystemFonts enum to pick from a type-safe auto-complete list of all available iOS fonts:

let font1 = SystemFonts.Helvetica_Light.font(size: 15)
let font2 = SystemFonts.Avenir_Black.font(size: 24)

For Color this mean you can create valid color instance from HEX strings:

let color: UIColor = "#0433FF".color
let style = Style {
	$0.color = "#0433FF"

Clearly you can still pass instances of both colors/fonts.

Derivating a Style

Sometimes you may need to infer properties of a new style from an existing one. In this case you can use byAdding() function of Style to produce a new style with all the properties of the receiver and the chance to configure additional/replacing attributes.

let initialStyle = Style {
	$0.font = SystemFonts.Helvetica_Light.font(size: 15)
	$0.alignment = right

// The following style contains all the attributes of initialStyle
// but also override the alignment and add a different foreground color.
let subStyle = bold.byAdding {
	$0.alignment = center
	$0.color = UIColor.red

The StyleManager

Register globally available styles

Styles can be created as you need or registered globally to be used once you need. This second approach is strongly suggested because allows you to theme your app as you need and also avoid duplication of the code.

To register a Style or a StyleGroup globally you need to assign an unique identifier to it and call register() function via Styles shortcut (which is equal to call StylesManager.shared).

In order to keep your code type-safer you can use a non-instantiable struct to keep the name of your styles, then use it to register style:

// Define a struct with your styles names
public struct StyleNames {
	public static let body: String = "body"
	public static let h1: String = "h1"
	public static let h2: String = "h2"
	private init { }

Then you can:

let bodyStyle: Style = ...
Styles.register(StyleNames.body, bodyStyle)

Now you can use it everywhere inside the app; you can apply it to a text just using its name:

let text = "hello world".set(StyleNames.body)

or you can assign body string to the styledText via Interface Builder designable property.

Defer style creation on demand

Sometimes you may need to return a particular style used only in small portion of your app; while you can still set it directly you can also defer its creation in StylesManager.

By implementing onDeferStyle() callback you have an option to create a new style once required: you will receive the identifier of the style.

Styles.onDeferStyle = { name in
	if name == "MyStyle" {
		let normal = Style {
			$0.font = SystemFonts.Helvetica_Light.font(size: 15)
		let bold = Style {
			$0.font = SystemFonts.Helvetica_Bold.font(size: 20)
			$0.color = UIColor.red
			$0.backColor = UIColor.yellow
		let italic = normal.byAdding {
			$0.traitVariants = .italic
		return (StyleGroup(base: normal, ["bold": bold, "italic": italic]), true)
	return (nil,false)

The following code return a valid style for myStyle identifier and cache it; if you don't want to cache it just return false along with style instance.

Now you can use your style to render, for example, a tag based text into an UILabel: just set the name of the style to use.

Assign style using Interface Builder

SwiftRichString can be used also via Interface Builder.

  • UILabel
  • UITextView
  • UITextField

has three additional properties:

  • styleName: String (available via IB): you can set it to render the text already set via Interface Builder with a style registered globally before the parent view of the UI control is loaded.
  • style: StyleProtocol: you can set it to render the text of the control with an instance of style instance.
  • styledText: String: use this property, instead of attributedText to set a new text for the control and render it with already set style. You can continue to use attributedText and set the value using .set() functions of String/AttributedString.

Assigned style can be a Style, StyleGroup or StyleRegEx:

  • if style is a Style the entire text of the control is set with the attributes defined by the style.
  • if style is a StyleGroup a base attribute is set (if base is valid) and other attributes are applied once each tag is found.
  • if style is a StyleRegEx a base attribute is set (if base is valid) and the attribute is applied only for matches of the specified pattern.

Typically you will set the style of a label via Style Name (styleName) property in IB and update the content of the control by setting the styledText:

// use `styleName` set value to update a text with the style
self.label?.styledText = "Another text to render" // text is rendered using specified `styleName` value.

Otherwise you can set values manually:

// manually set the an attributed string
self.label?.attributedText = (self.label?.text ?? "").set(myStyle)

// manually set the style via instance
self.label?.style = myStyle
self.label?.styledText = "Updated text"

Properties available via Style class

The following properties are available:

size CGFloat font size in points
font FontConvertible font used in text
color ColorConvertible foreground color of the text
backColor ColorConvertible background color of the text
underline (NSUnderlineStyle?,ColorConvertible?) underline style and color (if color is nil foreground is used)
strikethrough (NSUnderlineStyle?,ColorConvertible?) strikethrough style and color (if color is nil foreground is used)
baselineOffset Float character’s offset from the baseline, in point
paragraph NSMutableParagraphStyle paragraph attributes
lineSpacing CGFloat distance in points between the bottom of one line fragment and the top of the next
paragraphSpacingBefore CGFloat distance between the paragraph’s top and the beginning of its text content
paragraphSpacingAfter CGFloat space (measured in points) added at the end of the paragraph
alignment NSTextAlignment text alignment of the receiver
firstLineHeadIndent CGFloat distance (in points) from the leading margin of a text container to the beginning of the paragraph’s first line.
headIndent CGFloat The distance (in points) from the leading margin of a text container to the beginning of lines other than the first.
tailIndent CGFloat this value is the distance from the leading margin, If 0 or negative, it’s the distance from the trailing margin.
lineBreakMode LineBreak mode that should be used to break lines
minimumLineHeight CGFloat minimum height in points that any line in the receiver will occupy regardless of the font size or size of any attached graphic
maximumLineHeight CGFloat maximum height in points that any line in the receiver will occupy regardless of the font size or size of any attached graphic
baseWritingDirection NSWritingDirection initial writing direction used to determine the actual writing direction for text
lineHeightMultiple CGFloat natural line height of the receiver is multiplied by this factor (if positive) before being constrained by minimum and maximum line height
hyphenationFactor Float threshold controlling when hyphenation is attempted
ligatures Ligatures Ligatures cause specific character combinations to be rendered using a single custom glyph that corresponds to those characters
speaksPunctuation Bool Enable spoken of all punctuation in the text
speakingLanguage String The language to use when speaking a string (value is a BCP 47 language code string).
speakingPitch Double Pitch to apply to spoken content
speakingPronunciation String
shouldQueueSpeechAnnouncement Bool Spoken text is queued behind, or interrupts, existing spoken content
headingLevel HeadingLevel Specify the heading level of the text
numberCase NumberCase "Configuration for the number case, also known as ""figure style"""
numberSpacing NumberSpacing "Configuration for number spacing, also known as ""figure spacing"""
fractions Fractions Configuration for displyaing a fraction
superscript Bool Superscript (superior) glpyh variants are used, as in footnotes_.
subscript Bool Subscript (inferior) glyph variants are used: v_.
ordinals Bool Ordinal glyph variants are used, as in the common typesetting of 4th.
scientificInferiors Bool Scientific inferior glyph variants are used: H_O
smallCaps Set<SmallCaps> Configure small caps behavior.
stylisticAlternates StylisticAlternates Different stylistic alternates available for customizing a font.
contextualAlternates ContextualAlternates Different contextual alternates available for customizing a font.
kerning Kerning Tracking to apply.
traitVariants TraitVariant Describe trait variants to apply to the font

Migration from 1.x

SwiftRichString is a complete rewrite of the library. While some inner concept are the same, in order to keep the code cleaner and simpler I've made some important changes.

  • A StyleProtocol is now a common entry point for every style definition; both Style and StyleGroup are conform to this protocol which is the central repository to make actions on text (in 1.x String and AttributedString act directly to parse text).
  • Style some properties of the class has a different (but quite equal) name, changed to better reflect the purpose of the attribute. Some attributes like underline or striketought are now tuple of elements instead of different properties.
  • Style are now anonymous; you don't need to assign a name to a style; only if you need to parse tag-based text you need to group used styles in a StyleGroup instance where you define the name/id of each tag.
  • There is not any parseTag function; just pass the StyleGroup as parameter to render a text and the tag-based parsing will be done automatically.
  • There is not any default style; StyleGroup implements a base style used to render common attributes of your text. You can also use Styles to register globally available StyleProtocol instances and use them in your app.
  • In order to simplify our APIs some init methods of Style are now removed. You should not miss them, but let me know via PR in case.


SwiftRichString is compatible with Swift 4.x. All Apple platforms are supported:

  • iOS 8.0+
  • macOS 10.10+
  • watchOS 2.0+
  • tvOS 11.0+


Install via CocoaPods

CocoaPods is a dependency manager for Objective-C, which automates and simplifies the process of using 3rd-party libraries like SwiftRichString in your projects. You can install it with the following command:

$ sudo gem install cocoapods

CocoaPods 1.0.1+ is required to build SwiftRichString.

Install via Podfile

To integrate SwiftRichString into your Xcode project using CocoaPods, specify it in your Podfile:

source 'https://github.com/CocoaPods/Specs.git'
platform :ios, '8.0'

target 'TargetName' do
pod 'SwiftRichString'

Then, run the following command:

$ pod install


Carthage is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.

You can install Carthage with Homebrew using the following command:

$ brew update
$ brew install carthage

To integrate SwiftRichString into your Xcode project using Carthage, specify it in your Cartfile:

github "malcommac/SwiftRichString"

Run carthage to build the framework and drag the built SwiftRichString.framework into your Xcode project.


Issues and pull requests are welcome! Contributors are expected to abide by the Contributor Covenant Code of Conduct.


SwiftRichString is available under the MIT license. See the LICENSE file for more info.

Daniele Margutti: hello@danielemargutti.com, @danielemargutti