NSAttributedStringBuilder

The NSAttributedStringBuilder is an easy to use attributed string builder with extended modifier support (bold/italic, image, custom spacings etc.) that supports most platforms and can be extended easily.

You can add more functionality by extending AttributedStringBuilding. All extensions of AttributedStringBuilding are available to String, NSAttributedString, UIImage and NSImage which conform to the protocol.

Features

Supports most of NSAttributedString.Key
Flexible composition of strings, images etc.
Configure attributes separately (inspired by AttributeContainer)
Declarative syntax
SwiftUI compatible
Fully covered by unit tests

Installation

CocoaPods

Add the following to your Podfile to integrate NSAttributedStringBuilder into your project:

pod 'NSAttributedStringBuilder-jaeilers', '~> 0.3.0'

Swift Package Manager

If you're using Xcode to manage your dependencies, select your project, Package Dependencies and add the package by entering the url https://github.com/jaeilers/NSAttributedStringBuilder.

For projects with a separate Package.swift, add the dependency to your package manifest:

dependencies: [
    .package(url: "https://github.com/jaeilers/NSAttributedStringBuilder", .upToNextMajor(from: "0.3.0"))
]

Usage

You can compose attributed strings either with result builder or with attributed string concatenation (operator overloading of +). There is no need for additional types:

let attributedString = NSAttributedString {
    "Hello"
        .font(.preferredFont(forTextStyle: .body))
        .italic()
        .foregroundColor(.green)
        .underline()

    Space()

    "World"
        .font(.preferredFont(forTextStyle: .headline))
        .bold()
        .foregroundColor(.orange)
        .kerning(2.0)
        .baselineOffset(-1)
}

// or

let attributedString = "Hello"
    .font(.preferredFont(forTextStyle: .body))
    .italic()
    .foregroundColor(.green)
    .underline()
+ Space()
+ "World"
    .font(.preferredFont(forTextStyle: .headline))
    .bold()
    .foregroundColor(.orange)
    .kerning(2.0)
    .baselineOffset(-1)

Write your attributed strings how you prefer:

let attributedString = NSAttributedString {
    UIImage.checkmark.attributedString()

    Space(.custom(1.0))

    "The quick brown fox jumps over the lazy dog."
        .attributedString()

    Newline()

    UIImage.add.attributedString()
}

// or 

let attributedString = UIImage.checkmark
    .space(.custom(1.0))
    .text("The quick brown fox jumps over the lazy dog.")
    .newline()
    .image(UIImage.add)

You can also configure and reuse your attributes separately from your attributed strings:

let attributes = Attributes()
    .font(.systemFont(ofSize: 16))
    .italic()
    .underline()

let attributedString = NSAttributedString {
    "Hello"
        .addingAttributes(attributes)
        .foregroundColor(.systemBlue)

    Space()

    "World!"
        .addingAttributes(attributes)
        .foregroundColor(.systemTeal)
}

How to add your own modifiers

You can add your own modifiers for missing attributes or combine multiple attributes by extending AttributedStringBuilding. All extensions are automatically available to all types conforming to the protocol (UIImage/NSImage, String & NSAttributedString).

Adding an extension isn't always necessary. If you just want to add an attribute, call addingAttribute(_:value:) to add an attribute to the whole range of the attributed string.

public extension AttributedStringBuilding {

    /// Combine multiple modifiers in one.
    func linebreak(_ breakMode: NSLineBreakMode, strategy: NSParagraphStyle.LineBreakStrategy = .standard) -> NSAttributedString {
        lineBreakMode(breakMode)
            .lineBreakStrategy(strategy)
    }

    /// Add support for another modifier.
    func accessibilityStrikethrough(_ hasStrikethrough: Bool) -> NSAttributedString {
        addingAttribute(.accessibilityStrikethrough, value: NSNumber(value: hasStrikethrough))
    }
}

Other

This project is inspired by ethanhuang13/NSAttributedStringBuilder and svdo/swift-RichString.