Implement support for sup and sub HTML tags.

Aztec.xcodeproj/project.pbxproj

@@ -239,6 +239,10 @@
 		FF7A1C511E5651EA00C4C7C8 /* LineAttachment.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF7A1C501E5651EA00C4C7C8 /* LineAttachment.swift */; };
 		FF7C89B01E3BC52F000472A8 /* NSAttributedString+FontTraits.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF7C89AF1E3BC52F000472A8 /* NSAttributedString+FontTraits.swift */; };
 		FF7EAEC4234D253B007A26E0 /* FontProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF7EAEC3234D253B007A26E0 /* FontProvider.swift */; };
+		FF94935E245738AC0085ABB3 /* SuperscriptStringAttributeConverter.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF94935D245738AC0085ABB3 /* SuperscriptStringAttributeConverter.swift */; };
+		FF949360245740250085ABB3 /* SuperscriptFormatter.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF94935F245740250085ABB3 /* SuperscriptFormatter.swift */; };
+		FF949362245744090085ABB3 /* SubscriptStringAttributeConverter.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF949361245744090085ABB3 /* SubscriptStringAttributeConverter.swift */; };
+		FF949364245744560085ABB3 /* SubscriptFormatter.swift in Sources */ = {isa = PBXBuildFile; fileRef = FF949363245744560085ABB3 /* SubscriptFormatter.swift */; };
 		FFA61E891DF18F3D00B71BF6 /* ParagraphStyle.swift in Sources */ = {isa = PBXBuildFile; fileRef = FFA61E881DF18F3D00B71BF6 /* ParagraphStyle.swift */; };
 		FFA61EC21DF6C1C900B71BF6 /* NSAttributedString+Archive.swift in Sources */ = {isa = PBXBuildFile; fileRef = FFA61EC11DF6C1C900B71BF6 /* NSAttributedString+Archive.swift */; };
 		FFB5D29720BEB21A0038DCFB /* CiteFormatter.swift in Sources */ = {isa = PBXBuildFile; fileRef = FFB5D29620BEB21A0038DCFB /* CiteFormatter.swift */; };
@@ -523,6 +527,10 @@
 		FF7A1C501E5651EA00C4C7C8 /* LineAttachment.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = LineAttachment.swift; sourceTree = "<group>"; };
 		FF7C89AF1E3BC52F000472A8 /* NSAttributedString+FontTraits.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSAttributedString+FontTraits.swift"; sourceTree = "<group>"; };
 		FF7EAEC3234D253B007A26E0 /* FontProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FontProvider.swift; sourceTree = "<group>"; };
+		FF94935D245738AC0085ABB3 /* SuperscriptStringAttributeConverter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SuperscriptStringAttributeConverter.swift; sourceTree = "<group>"; };
+		FF94935F245740250085ABB3 /* SuperscriptFormatter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SuperscriptFormatter.swift; sourceTree = "<group>"; };
+		FF949361245744090085ABB3 /* SubscriptStringAttributeConverter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SubscriptStringAttributeConverter.swift; sourceTree = "<group>"; };
+		FF949363245744560085ABB3 /* SubscriptFormatter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SubscriptFormatter.swift; sourceTree = "<group>"; };
 		FFA61E881DF18F3D00B71BF6 /* ParagraphStyle.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ParagraphStyle.swift; sourceTree = "<group>"; };
 		FFA61EC11DF6C1C900B71BF6 /* NSAttributedString+Archive.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "NSAttributedString+Archive.swift"; sourceTree = "<group>"; };
 		FFB5D29620BEB21A0038DCFB /* CiteFormatter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CiteFormatter.swift; sourceTree = "<group>"; };
@@ -1004,6 +1012,8 @@
 				F12F585F1EF20394008AE298 /* StrikethroughFormatter.swift */,
 				F12F58601EF20394008AE298 /* TextListFormatter.swift */,
 				F12F58611EF20394008AE298 /* UnderlineFormatter.swift */,
+				FF94935F245740250085ABB3 /* SuperscriptFormatter.swift */,
+				FF949363245744560085ABB3 /* SubscriptFormatter.swift */,
 				FF61909D202481F4004BCD0A /* CodeFormatter.swift */,
 				FFB5D29620BEB21A0038DCFB /* CiteFormatter.swift */,
 			);
@@ -1089,6 +1099,8 @@
 				F15BA6082151501300424120 /* BoldStringAttributeConverter.swift */,
 				F1656FDD2152A6A6009C7E3A /* CiteStringAttributeConverter.swift */,
 				F15BA60C215159A600424120 /* ItalicStringAttributeConverter.swift */,
+				FF94935D245738AC0085ABB3 /* SuperscriptStringAttributeConverter.swift */,
+				FF949361245744090085ABB3 /* SubscriptStringAttributeConverter.swift */,
 				F15BA60E21515C0F00424120 /* UnderlineStringAttributeConverter.swift */,
 			);
 			path = Implementations;
@@ -1587,6 +1599,7 @@
 				F16A2AD520CC437E00BF3A0A /* LineAttachmentToElementConverter.swift in Sources */,
 				B574F4A41FB0CF3B0048F355 /* NSAttributedStringKey+Conversion.swift in Sources */,
 				F12F58631EF20394008AE298 /* AttributeFormatter.swift in Sources */,
+				FF949360245740250085ABB3 /* SuperscriptFormatter.swift in Sources */,
 				F19544051F588F1A00671B73 /* CSSParser.swift in Sources */,
 				599F254E1D8BC9A1002871D6 /* FormatBarDelegate.swift in Sources */,
 				F109873F214FF4C400983B6A /* ElementAttributeConverter.swift in Sources */,
@@ -1630,6 +1643,7 @@
 				F11326B21EF1AA91007FEE9A /* HTMLPre.swift in Sources */,
 				F1098741214FF55F00983B6A /* BoldElementAttributeConverter.swift in Sources */,
 				F17BC8AB1F4E512800398E2B /* AttributedStringSerializer.swift in Sources */,
+				FF949364245744560085ABB3 /* SubscriptFormatter.swift in Sources */,
 				F18986E11EF2040A0060EDBA /* FontFormatter.swift in Sources */,
 				F1FF7D9D201A147B007B0B32 /* Figure.swift in Sources */,
 				FFA61E891DF18F3D00B71BF6 /* ParagraphStyle.swift in Sources */,
@@ -1638,6 +1652,7 @@
 				FF7C89B01E3BC52F000472A8 /* NSAttributedString+FontTraits.swift in Sources */,
 				B5E94D101FE01335000E7C20 /* FigureElementConverter.swift in Sources */,
 				40A2986D1FD61B0C00AEDF3B /* ElementConverter.swift in Sources */,
+				FF949362245744090085ABB3 /* SubscriptStringAttributeConverter.swift in Sources */,
 				F1FF7DA1201A1D3E007B0B32 /* FigcaptionElementConverter.swift in Sources */,
 				F9982CF621877663001E606B /* TextViewPasteboardDelegate.swift in Sources */,
 				F1289FB72155244A001E07C5 /* AttributeType.swift in Sources */,
@@ -1684,6 +1699,7 @@
 				F12F586F1EF20394008AE298 /* PreFormatter.swift in Sources */,
 				F18A1EA921C0586E00F1AA9E /* NSAttributedString+ParagraphRange.swift in Sources */,
 				B5B86D371DA3EC250083DB3F /* NSRange+Helpers.swift in Sources */,
+				FF94935E245738AC0085ABB3 /* SuperscriptStringAttributeConverter.swift in Sources */,
 				F15BA6172151693F00424120 /* BoldCSSAttributeMatcher.swift in Sources */,
 				F1E2323420C18055008DA49F /* FormatterElementConverter.swift in Sources */,
 				F15BA60B2151519C00424120 /* CSSAttributeType.swift in Sources */,

Aztec/Classes/Converters/ElementsToAttributedString/Implementations/GenericElementConverter.swift

@@ -11,7 +11,7 @@ class GenericElementConverter: ElementConverter {
     /// At some point we should modify how the conversion works, so that any supported element never goes through this
     /// converter at all, and this converter is turned into an `UnsupportedElementConverter()` exclusively.
     ///
-    private static let supportedElements: [Element] = [.a, .aztecRootNode, .b, .br, .blockquote, .del, .div, .em, .figure, .figcaption, .h1, .h2, .h3, .h4, .h5, .h6, .hr, .i, .img, .li, .ol, .p, .pre, .s, .span, .strike, .strong, .u, .ul, .video, .code]
+    private static let supportedElements: [Element] = [.a, .aztecRootNode, .b, .br, .blockquote, .del, .div, .em, .figure, .figcaption, .h1, .h2, .h3, .h4, .h5, .h6, .hr, .i, .img, .li, .ol, .p, .pre, .s, .span, .strike, .strong, .u, .ul, .video, .code, .sup, .sub]
 
     // MARK: - Built-in formatter instances
 
@@ -34,6 +34,8 @@ class GenericElementConverter: ElementConverter {
     lazy var unorderedListFormatter = TextListFormatter(style: .unordered, increaseDepth: true)
     lazy var codeFormatter = CodeFormatter()
     lazy var liFormatter = LiFormatter()
+    lazy var superscriptFormatter = SuperscriptFormatter()
+    lazy var subscriptFormatter = SubscriptFormatter()
 
     public lazy var elementFormattersMap: [Element: AttributeFormatter] = {
         return [
@@ -55,7 +57,9 @@ class GenericElementConverter: ElementConverter {
             .p: self.paragraphFormatter,
             .pre: self.preFormatter,
             .code: self.codeFormatter,
-            .li: self.liFormatter
+            .li: self.liFormatter,
+            .sup: self.superscriptFormatter,
+            .sub: self.subscriptFormatter,
         ]
     }()
 

Aztec/Classes/Converters/StringAttributesToAttributes/Implementations/SubscriptStringAttributeConverter.swift

@@ -0,0 +1,48 @@
+import Foundation
+import UIKit
+
+
+/// Converts the subscript style information from string attributes and aggregates it into an
+/// existing array of element nodes.
+///
+open class SubscriptStringAttributeConverter: StringAttributeConverter {
+
+    private let toggler = HTMLStyleToggler(defaultElement: .sub, cssAttributeMatcher: NeverCSSAttributeMatcher())
+
+    public func convert(
+        attributes: [NSAttributedString.Key: Any],
+        andAggregateWith elementNodes: [ElementNode]) -> [ElementNode] {
+
+        var elementNodes = elementNodes
+
+        // We add the representation right away, if it exists... as it could contain attributes beyond just this
+        // style.  The enable and disable methods below can modify this as necessary.
+        //
+        if let representation = attributes[NSAttributedString.Key.subHtmlRepresentation] as? HTMLRepresentation,
+            case let .element(representationElement) = representation.kind {
+
+            elementNodes.append(representationElement.toElementNode())
+        }
+
+        if shouldEnable(for: attributes) {
+            return toggler.enable(in: elementNodes)
+        } else {
+            return toggler.disable(in: elementNodes)
+        }
+    }
+
+    // MARK: - Style Detection
+
+    func shouldEnable(for attributes: [NSAttributedString.Key : Any]) -> Bool {
+        return hasTraits(for: attributes)
+    }
+
+    func hasTraits(for attributes: [NSAttributedString.Key : Any]) -> Bool {
+        guard let baselineOffset = attributes[.baselineOffset] as? NSNumber else {
+                return false
+        }
+
+        return baselineOffset.intValue < 0;
+    }
+}
+

Aztec/Classes/Converters/StringAttributesToAttributes/Implementations/SuperscriptStringAttributeConverter.swift

@@ -0,0 +1,48 @@
+import Foundation
+import UIKit
+
+
+/// Converts the superscript  style information from string attributes and aggregates it into an
+/// existing array of element nodes.
+///
+open class SuperscriptStringAttributeConverter: StringAttributeConverter {
+
+    private let toggler = HTMLStyleToggler(defaultElement: .sup, cssAttributeMatcher: NeverCSSAttributeMatcher())
+
+    public func convert(
+        attributes: [NSAttributedString.Key: Any],
+        andAggregateWith elementNodes: [ElementNode]) -> [ElementNode] {
+
+        var elementNodes = elementNodes
+
+        // We add the representation right away, if it exists... as it could contain attributes beyond just this
+        // style.  The enable and disable methods below can modify this as necessary.
+        //
+        if let representation = attributes[NSAttributedString.Key.supHtmlRepresentation] as? HTMLRepresentation,
+            case let .element(representationElement) = representation.kind {
+
+            elementNodes.append(representationElement.toElementNode())
+        }
+
+        if shouldEnable(for: attributes) {
+            return toggler.enable(in: elementNodes)
+        } else {
+            return toggler.disable(in: elementNodes)
+        }
+    }
+
+    // MARK: - Style Detection
+
+    func shouldEnable(for attributes: [NSAttributedString.Key : Any]) -> Bool {
+        return hasTraits(for: attributes)
+    }
+
+    func hasTraits(for attributes: [NSAttributedString.Key : Any]) -> Bool {
+        guard let baselineOffset = attributes[.baselineOffset] as? NSNumber else {
+                return false
+        }
+
+        return baselineOffset.intValue > 0;
+    }
+}
+

Aztec/Classes/Extensions/NSAttributedStringKey+Aztec.swift

@@ -53,4 +53,12 @@ public extension NSAttributedString.Key {
     /// Key used to store citeHTMLRepresentations, by our CiteFormatter.
     ///
     static let citeHtmlRepresentation = NSAttributedString.Key("Cite.htmlRepresentation")
+
+    /// Key used to store Sup Tag Metadata, by our SupFormatter.
+    ///
+    static let supHtmlRepresentation = NSAttributedString.Key("Sup.htmlRepresentation")
+
+    /// Key used to store Sub Tag Metadata, by our SupFormatter.
+    ///
+    static let subHtmlRepresentation = NSAttributedString.Key("Sub.htmlRepresentation")
 }

Aztec/Classes/Formatters/Base/StandardAttributeFormatter.swift

@@ -11,12 +11,15 @@ class StandardAttributeFormatter: AttributeFormatter {
 
     let htmlRepresentationKey: NSAttributedString.Key
 
+    let needsToMatchValue: Bool
+
     // MARK: - Init
 
-    init(attributeKey: NSAttributedString.Key, attributeValue: Any, htmlRepresentationKey: NSAttributedString.Key) {
+    init(attributeKey: NSAttributedString.Key, attributeValue: Any, htmlRepresentationKey: NSAttributedString.Key, needsToMatchValue: Bool = false) {
         self.attributeKey = attributeKey
         self.attributeValue = attributeValue
         self.htmlRepresentationKey = htmlRepresentationKey
+        self.needsToMatchValue = needsToMatchValue
     }
 
     func applicationRange(for range: NSRange, in text: NSAttributedString) -> NSRange {
@@ -43,7 +46,16 @@ class StandardAttributeFormatter: AttributeFormatter {
 
     func present(in attributes: [NSAttributedString.Key: Any]) -> Bool {
         let enabled = attributes[attributeKey] != nil
-        return enabled
+        if (!needsToMatchValue) {
+            return enabled
+        }
+
+        if let value = attributes[attributeKey] as? NSObject,
+            let attributeValue = attributeValue as? NSObject {
+            return value.isEqual(attributeValue)
+        }
+
+        return false
     }
 }
 

Aztec/Classes/Formatters/Implementations/SubscriptFormatter.swift

@@ -0,0 +1,32 @@
+import UIKit
+
+class SubscriptFormatter: StandardAttributeFormatter {
+
+    init() {
+        super.init(attributeKey: .baselineOffset,
+                   attributeValue: NSNumber(-4),
+                   htmlRepresentationKey: .subHtmlRepresentation)
+    }
+
+    override func apply(to attributes: [NSAttributedString.Key: Any], andStore representation: HTMLRepresentation?) -> [NSAttributedString.Key: Any] {
+        var resultingAttributes = super.apply(to: attributes, andStore: representation)
+        guard let currentFont = attributes[.font] as? UIFont else {
+            return resultingAttributes
+        }
+        let font = UIFont(descriptor: currentFont.fontDescriptor, size: currentFont.pointSize - 2)
+        resultingAttributes[.font] = font
+        return resultingAttributes
+    }
+
+    override func remove(from attributes: [NSAttributedString.Key: Any]) -> [NSAttributedString.Key: Any] {
+        var resultingAttributes = super.remove(from: attributes)
+
+        guard let currentFont = attributes[.font] as? UIFont else {
+            return resultingAttributes
+        }
+        let font = UIFont(descriptor: currentFont.fontDescriptor, size: currentFont.pointSize + 2)
+        resultingAttributes[.font] = font
+
+        return resultingAttributes
+    }
+}

Aztec/Classes/Formatters/Implementations/SuperscriptFormatter.swift

@@ -0,0 +1,32 @@
+import UIKit
+
+class SuperscriptFormatter: StandardAttributeFormatter {
+
+    init() {
+        super.init(attributeKey: .baselineOffset,
+                   attributeValue: NSNumber(4),
+                   htmlRepresentationKey: .supHtmlRepresentation)
+    }
+
+    override func apply(to attributes: [NSAttributedString.Key: Any], andStore representation: HTMLRepresentation?) -> [NSAttributedString.Key: Any] {
+        var resultingAttributes = super.apply(to: attributes, andStore: representation)
+        guard let currentFont = attributes[.font] as? UIFont else {
+            return resultingAttributes
+        }
+        let font = UIFont(descriptor: currentFont.fontDescriptor, size: currentFont.pointSize - 2)
+        resultingAttributes[.font] = font
+        return resultingAttributes
+    }
+
+    override func remove(from attributes: [NSAttributedString.Key: Any]) -> [NSAttributedString.Key: Any] {
+        var resultingAttributes = super.remove(from: attributes)
+
+        guard let currentFont = attributes[.font] as? UIFont else {
+            return resultingAttributes
+        }
+        let font = UIFont(descriptor: currentFont.fontDescriptor, size: currentFont.pointSize + 2)
+        resultingAttributes[.font] = font
+
+        return resultingAttributes
+    }
+}

Aztec/Classes/Libxml2/DOM/Data/Element.swift

@@ -30,7 +30,7 @@ public struct Element: RawRepresentable, Hashable {
     public static var mergeableBlockLevelElements = Set<Element>([.blockquote, .div, .figure, .figcaption, .h1, .h2, .h3, .h4, .h5, .h6, .hr, .li, .ol, .ul, .p, .pre])
 
     /// List of style HTML elements that can be merged together when they are sibling to each other
-    public static var mergeableStyleElements = Set<Element>([.i, .em, .b, .strong, .strike, .u, .code, .cite, .a])
+    public static var mergeableStyleElements = Set<Element>([.i, .em, .b, .strong, .strike, .u, .code, .cite, .a, .sup, .sub])
 
     /// List of block level elements that can be merged but only when they have a single children that is also mergeable
     ///
@@ -106,6 +106,8 @@ extension Element {
     public static let span = Element("span")
     public static let strike = Element("strike")
     public static let strong = Element("strong")
+    public static let sub = Element("sub")
+    public static let sup = Element("sup")
     public static let table = Element("table")
     public static let tbody = Element("tbody")
     public static let td = Element("td")

Aztec/Classes/Libxml2/DOM/Logic/CSS/CSSAttributeMatcher.swift

@@ -3,3 +3,9 @@ import Foundation
 public protocol CSSAttributeMatcher {
     func check(_ cssAttribute: CSSAttribute) -> Bool
 }
+
+open class NeverCSSAttributeMatcher: CSSAttributeMatcher {
+    public func check(_ cssAttribute: CSSAttribute) -> Bool {
+        return false
+    }
+}

Aztec/Classes/NSAttributedString/Conversions/AttributedStringParser.swift

@@ -27,6 +27,8 @@ class AttributedStringParser {
         BoldStringAttributeConverter(),
         ConditionalItalicStringAttributeConverter(),
         UnderlineStringAttributeConverter(),
+        SuperscriptStringAttributeConverter(),
+        SubscriptStringAttributeConverter(),
     ]
 
     // MARK: - Attachment Converters

CHANGELOG.md

@@ -1,3 +1,7 @@
+1.19.0
+-------
+* Add support for the sup and sub HTML tags.
+
 1.18.0
 -------
 * Added an option to not colapse whitespaces when saving the HTML.

Example/Example/SampleContent/content.html

@@ -10,12 +10,13 @@ <h2>Character Styles</h2>
 
 Bold: <strong>Bold text</strong><br/>
 Italic: <em>Italic text</em><br/>
+This is superscript<sup>(1)</sup> and this is subscript<sub>(2)</sub><br/>
 Underline: <u>Underlined text</u><br/>
 Strikethrough: <del>Strikethrough</del><br/>
 Colors: <span style="color: royalblue;">Royal Blue by name</span> <span style="color: #ff0000;">Red by hex</span><br/><br/>
 Underline with CSS: <span style="text-decoration: underline;">Alternative underline text</span><br/>
 Links: <a href="http://www.wordpress.com">I'm a link!</a><br/> <a href="http://www.wordpress.com" target="_blank">Open in new window link!</a> <br/>
-Code: <code>print("Hello world")</code>
+Code: <code>print("Hello world")</code> <br/>
 
 <hr/>