# SwiftRichString **Repository Path**: szlsay/SwiftRichString ## Basic Information - **Project Name**: SwiftRichString - **Description**: No description available - **Primary Language**: Swift - **License**: MIT - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2021-06-11 - **Last Updated**: 2021-09-24 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README

Elegant Attributed String composition in Swift sauce

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 elements, allows complex tag-based strings rendering and also includes integration with Interface Builder. ## Main Features | | Features Highlights | |--- |--------------------------------------------------------------------------------- | | 🦄 | Easy styling and typography managment with coincise declarative syntax | | 🏞 | Attach local images (lazy/static) and remote images inside text | | 🧬 | Fast & high customizable XML/HTML tagged string rendering | | 🌟 | Apply text transforms within styles | | 📐 | Native support for iOS 11 Dynamic Type | | 🖇 | Support for Swift 5.1's function builder to compose strings | | ⏱ | Compact code base with no external dependencies. | | 🐦 | Fully made in Swift 5 from Swift ❥ lovers | ### Easy Styling ```swift 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! ``` ### XML/HTML tag based rendering 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 `StyleXML` (was `StyleGroup`) which allows you to encapsulate all of them and reuse as you need (clearly you can register it globally). ```swift // 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 } let myGroup = StyleXML(base: normal, ["bold": bold, "italic": italic]) let str = "Hello Daniele!. You're ready to play with us!" self.label?.attributedText = str.set(style: myGroup) ``` That's the result!

## Documentation - [Introduction to `Style`, `StyleXML` & `StyleRegEx`](#styleStyleXML) - [String & Attributed String concatenation](#concatenation) - [Apply styles to `String` & `Attributed String`](#manualstyling) - [Fonts & Colors in `Style`](#fontscolors) - [Derivating a `Style`](#derivatingstyle) - [Support Dynamic Type](#dynamictype) - [Render XML tagged strings](#customizexmlstrings) - [Customize XML rendering: react to tag's attributes and unknown tags](#xmlstrings) - [Custom text transforms](#texttransforms) - [Local & Remote Images inside text](#images) - [The `StyleManager`](#stylemanager) - [Register globally available styles](#globalregister) - [Defer style creation on demand](#defer) - [Assign style using Interface Builder](#ib) - [All properties of `Style`](#props) Other info: - [Requirements](#requirements) - [Installation](#installation) - [Contributing](#contributing) - [Copyright](#copyright) ## Introduction to `Style`, `StyleXML`, `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`, `StyleXML` 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: ```swift 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 ``` ### `StyleXML`: 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 `StyleXML`. You can consider a `StyleXML` 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). ```swift let bodyStyle: Style = ... let h1Style: Style = ... let h2Style: Style = ... let group = StyleXML(base: bodyStyle, ["h1": h1Style, "h2": h2Style]) let attrString = "Some

text

welcome here

".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. ```swift 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: ```swift 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: ```swift // 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) ``` Finally you can concatente strings using function builders: ```swift let bold = Style { ... } let italic = Style { ... } let attributedString = AttributedString.composing { "hello".set(style: bold) "world".set(style: italic) } ``` ## 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 `StyleXML` (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`/`StyleXML` 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: ```swift // 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 StyleXML = StyleXML(base: commonStyle, ["h1" : styleH1, "h2" : styleH2]) let a2: AttributedString = "Hello

world

welcome here

".set(style: StyleXML) // 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** - `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** - `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. **Remove** - `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. Example: ```swift 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: ```swift 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: ```swift 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: ```swift 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. ```swift 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 } ``` ### Conforming to `Dynamic Type` To support your fonts/text to dynammically scale based on the users preffered content size, you can implement style's `dynamicText` property. UIFontMetrics properties are wrapped inside `DynamicText` class. ```swift let style = Style { $0.font = UIFont.boldSystemFont(ofSize: 16.0) $0.dynamicText = DynamicText { $0.style = .body $0.maximumSize = 35.0 $0.traitCollection = UITraitCollection(userInterfaceIdiom: .phone) } } ``` ## Render XML/HTML tagged strings SwiftRichString is also able to parse and render xml tagged strings to produce a valid `NSAttributedString` instance. This is particularly useful when you receive dynamic strings from remote services and you need to produce a rendered string easily. In order to render an XML string you need to create a compisition of all styles you are planning to render in a single `StyleXML` instance and apply it to your source string as just you made for a single `Style`. For example: ```swift // The base style is applied to the entire string let baseStyle = Style { $0.font = UIFont.boldSystemFont(ofSize: self.baseFontSize * 1.15) $0.lineSpacing = 1 $0.kerning = Kerning.adobe(-20) } let boldStyle = Style { $0.font = UIFont.boldSystemFont(ofSize: self.baseFontSize) $0.dynamicText = DynamicText { $0.style = .body $0.maximumSize = 35.0 $0.traitCollection = UITraitCollection(userInterfaceIdiom: .phone) } } let italicStyle = Style { $0.font = UIFont.italicSystemFont(ofSize: self.baseFontSize) } // A group container includes all the style defined. let groupStyle = StyleXML.init(base: baseStyle, ["b" : boldStyle, "i": italicStyle]) // We can render our string let bodyHTML = "Hello world!, my name is Daniele" self.textView?.attributedText = bodyHTML.set(style: group) ``` ## Customize XML rendering: react to tag's attributes and unknown tags You can also add custom attributes to your tags and render it as you prefer: you need to provide a croncrete implementation of `XMLDynamicAttributesResolver` protocol and assign it to the `StyleXML`'s `.xmlAttributesResolver` property. The protocol will receive two kind of events: - `applyDynamicAttributes(to attributedString: inout AttributedString, xmlStyle: XMLDynamicStyle)` is received when parser encounter an existing style with custom attributes. Style is applied and event is called so you can make further customizations. - `func styleForUnknownXMLTag(_ tag: String, to attributedString: inout AttributedString, attributes: [String: String]?)` is received when a unknown (not defined in `StyleXML`'s styles) tag is received. You can decide to ignore or perform customizations. The following example is used to override text color for when used for any known tag: ```swift // First define our own resolver for attributes open class MyXMLDynamicAttributesResolver: XMLDynamicAttributesResolver { public func applyDynamicAttributes(to attributedString: inout AttributedString, xmlStyle: XMLDynamicStyle) { let finalStyleToApply = Style() xmlStyle.enumerateAttributes { key, value in switch key { case "color": // color support finalStyleToApply.color = Color(hexString: value) default: break } } attributedString.add(style: finalStyleToApply) } } // Then set it to our's StyleXML instance before rendering text. let groupStyle = StyleXML.init(base: baseStyle, ["b" : boldStyle, "i": italicStyle]) groupStyle.xmlAttributesResolver = MyXMLDynamicAttributesResolver() ``` The following example define the behaviour for a non known tag called `rainbow`. Specifically it alter the string by setting a custom color for each letter of the source string. ```swift open class MyXMLDynamicAttributesResolver: XMLDynamicAttributesResolver { public override func styleForUnknownXMLTag(_ tag: String, to attributedString: inout AttributedString, attributes: [String : String]?) { super.styleForUnknownXMLTag(tag, to: &attributedString, attributes: attributes) if tag == "rainbow" { let colors = UIColor.randomColors(attributedString.length) for i in 0..` tag with url linking. ```swift let sourceHTML = "My webpage is really cool. Take a look here" let styleBase = Style({ $0.font = UIFont.boldSystemFont(ofSize: 15) }) let styleBold = Style({ $0.font = UIFont.boldSystemFont(ofSize: 20) $0.color = UIColor.blue }) let groupStyle = StyleXML.init(base: styleBase, ["b" : styleBold]) self.textView?.attributedText = sourceHTML.set(style: groupStyle) ``` The result is this:

where the `b` tag's blue color was overriden by the color tag attributes and the link in 'here' is clickable. ## Custom Text Transforms Sometimes you want to apply custom text transforms to your string; for example you may want to make some text with a given style uppercased with current locale. In order to provide custom text transform in `Style` instances just set one or more `TextTransform` to your `Style`'s `.textTransforms` property: ```swift let allRedAndUppercaseStyle = Style({ $0.font = UIFont.boldSystemFont(ofSize: 16.0) $0.color = UIColor.red $0.textTransforms = [ .uppercaseWithLocale(Locale.current) ] }) let text = "test".set(style: allRedAndUppercaseStyle) // will become red and uppercased (TEST) ``` While `TextTransform` is an enum with a predefined set of transform you can also provide your own function which have a `String` as source and another `String` as destination: ```swift let markdownBold = Style({ $0.font = UIFont.boldSystemFont(ofSize: 16.0) $0.color = UIColor.red $0.textTransforms = [ .custom({ return "**\($0)**" }) ] }) ``` All text transforms are applied in the same ordered you set in `textTransform` property. ## Local & Remote Images inside text SwiftRichString supports local and remote attached images along with attributed text. You can create an attributed string with an image with a single line: ```swift // You can specify the bounds of the image, both for size and the location respecting the base line of the text. let localTextAndImage = AttributedString(image: UIImage(named: "rocket")!, bounds: CGRect(x: 0, y: -20, width: 25, height: 25)) // You can also load a remote image. If you not specify bounds size is the original size of the image. let remoteTextAndImage = AttributedString(imageURL: "http://...") // You can now compose it with other attributed or simple string let finalString = "...".set(style: myStyle) + remoteTextAndImage + " some other text" ``` Images can also be loaded by rending an XML string by using the `img` tag (with `named` tag for local resource and `url` for remote url). `rect` parameter is optional and allows you to specify resize and relocation of the resource. ```swift let taggedText = """ Some text and this image: This other is loaded from remote URL: """ self.textView?.attributedText = taggedText.set(style: ...) ``` This is the result:

Sometimes you may want to provide these images lazily. In order to do it just provide a custom implementation of the `imageProvider` callback in `StyleXML` instance: ```swift let xmlText = "- has done!" let xmlStyle = StyleXML(base: { /// some attributes for base style }) // This method is called when a new `img` tag is found. It's your chance to // return a custom image. If you return `nil` (or you don't implement this method) // image is searched inside any bundled `xcasset` file. xmlStyle.imageProvider = { (imageName, attributes) in switch imageName { case "check": // create & return your own image default: // ... } } self.textView?.attributedText = xmlText.set(style: x) ``` ## 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 `StyleXML` 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: ```swift // 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: ```swift 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: ```swift 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. ```swift 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 (StyleXML(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.