135 lines
4.8 KiB
Swift
135 lines
4.8 KiB
Swift
//
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// NSAttributedString+NetNewsWire.swift
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// NetNewsWire
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//
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// Created by Nate Weaver on 2020-04-07.
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// Copyright © 2020 Ranchero Software. All rights reserved.
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//
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#if canImport(AppKit)
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import AppKit
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typealias Font = NSFont
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typealias FontDescriptor = NSFontDescriptor
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typealias Color = NSColor
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private let boldTrait = NSFontDescriptor.SymbolicTraits.bold
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private let italicTrait = NSFontDescriptor.SymbolicTraits.italic
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private let monoSpaceTrait = NSFontDescriptor.SymbolicTraits.monoSpace
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#else
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import UIKit
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typealias Font = UIFont
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typealias FontDescriptor = UIFontDescriptor
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typealias Color = UIColor
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private let boldTrait = UIFontDescriptor.SymbolicTraits.traitBold
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private let italicTrait = UIFontDescriptor.SymbolicTraits.traitItalic
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private let monoSpaceTrait = UIFontDescriptor.SymbolicTraits.traitMonoSpace
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#endif
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extension NSAttributedString {
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/// Adds a font and color to an attributed string.
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///
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/// Additionally converts super-/subscript runs to super-/subscripted font variants
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/// and converts bold text to heavy if the base font is semibold.
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///
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/// - Parameters:
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/// - baseFont: The font to add.
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/// - color: The color to add.
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func adding(font baseFont: Font, color: Color? = nil) -> NSAttributedString {
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let mutable = self.mutableCopy() as! NSMutableAttributedString
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let fullRange = NSRange(location: 0, length: mutable.length)
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if let color = color {
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mutable.addAttribute(.foregroundColor, value: color as Any, range: fullRange)
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}
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let size = baseFont.pointSize
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let baseDescriptor = baseFont.fontDescriptor
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let baseSymbolicTraits = baseDescriptor.symbolicTraits
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let baseTraits = baseDescriptor.object(forKey: .traits) as! [FontDescriptor.TraitKey: Any]
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let baseWeight = baseTraits[.weight] as! Font.Weight
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mutable.enumerateAttribute(.font, in: fullRange, options: []) { (font: Any?, range: NSRange, stop: UnsafeMutablePointer<ObjCBool>) in
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guard let font = font as? Font else { return }
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var newSymbolicTraits = baseSymbolicTraits
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let symbolicTraits = font.fontDescriptor.symbolicTraits
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if symbolicTraits.contains(italicTrait) {
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newSymbolicTraits.insert(italicTrait)
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}
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if symbolicTraits.contains(monoSpaceTrait) {
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newSymbolicTraits.insert(monoSpaceTrait)
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}
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#if canImport(AppKit)
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var descriptor = baseDescriptor.withSymbolicTraits(newSymbolicTraits)
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#else
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var descriptor = baseDescriptor.withSymbolicTraits(newSymbolicTraits)!
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#endif
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if symbolicTraits.contains(boldTrait) {
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// If the base font is semibold (as timeline titles are), make the "bold"
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// text heavy for better contrast.
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if baseWeight == .semibold {
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let traits: [FontDescriptor.TraitKey: Any] = [.weight: Font.Weight.heavy]
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let attributes: [FontDescriptor.AttributeName: Any] = [.traits: traits]
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descriptor = descriptor.addingAttributes(attributes)
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}
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}
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let newFont = Font(descriptor: descriptor, size: size)
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mutable.addAttribute(.font, value: newFont as Any, range: range)
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}
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// make sup/sub smaller. `Key("NSSupeScript")` is used here because `.superscript`
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// isn't defined in UIKit.
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let superscriptAttribute = Key("NSSuperScript")
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mutable.enumerateAttributes(in: fullRange, options: []) { (attributes: [Key : Any], range: NSRange, stop: UnsafeMutablePointer<ObjCBool>) in
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guard let superscript = attributes[superscriptAttribute] as? Int else {
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return
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}
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if superscript != 0 {
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let font = mutable.attribute(.font, at: range.location, effectiveRange: nil) as! Font
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// There's some discrepancy here: The raw value of AppKit's .typeIdentifier is UIKit's .featureIdentifier,
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// and AppKit's .selectorIdentifier is UIKit's .typeIdentifier
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#if canImport(AppKit)
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let features: [FontDescriptor.FeatureKey: Any] = [.typeIdentifier: kVerticalPositionType, .selectorIdentifier: superscript > 0 ? kSuperiorsSelector : kInferiorsSelector]
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#else
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let features: [FontDescriptor.FeatureKey: Any] = [.featureIdentifier: kVerticalPositionType, .typeIdentifier: superscript > 0 ? kSuperiorsSelector : kInferiorsSelector]
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#endif
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let attributes: [FontDescriptor.AttributeName: Any] = [.featureSettings: [features]]
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let descriptor = font.fontDescriptor.addingAttributes(attributes)
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let newFont = Font(descriptor: descriptor, size: font.pointSize)
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let newAttributes: [NSAttributedString.Key: Any] = [
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.font: newFont as Any,
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superscriptAttribute: 0,
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]
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mutable.addAttributes(newAttributes, range: range)
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}
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}
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return mutable.copy() as! NSAttributedString
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}
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/// Creates an attributed string from HTML.
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convenience init(html: String) {
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let data = html.data(using: .utf8)!
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let options: [NSAttributedString.DocumentReadingOptionKey: Any] = [.characterEncoding: String.Encoding.utf8.rawValue, .documentType: NSAttributedString.DocumentType.html]
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try! self.init(data: data, options: options, documentAttributes: nil)
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}
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}
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