text.swift

import SwiftUI

public extension Text {
	init(_ attributedString: NSAttributedString) {
		if #available(iOS 15.0, *) {
			self.init(AttributedString(attributedString))
		} else {
			self.init("") // initial, empty Text

			// scan the attributed string for distinctly attributed regions
			attributedString.enumerateAttributes(in: NSRange(location: 0, length: attributedString.length),
																					 options: []) { (attrs, range, _) in
				let string = attributedString.attributedSubstring(from: range).string
				var text = Text(string)

				// then, read applicable attributes and apply them to the Text

				if let font = attrs[.font] as? UIFont {
					// this takes care of the majority of formatting - text size, font family,
					// font weight, if it's italic, etc.
					text = text.font(.init(font))
				}

				if let color = attrs[.foregroundColor] as? UIColor {
					text = text.foregroundColor(color.asColor())
				}

				if let kern = attrs[.kern] as? CGFloat {
					text = text.kerning(kern)
				}

				if #available(iOS 14.0, *) {
					if let tracking = attrs[.tracking] as? CGFloat {
						text = text.tracking(tracking)
					}
				}

				if let strikethroughStyle = attrs[.strikethroughStyle] as? NSNumber,
					 strikethroughStyle != 0 {
					if let strikethroughColor = (attrs[.strikethroughColor] as? UIColor) {
						text = text.strikethrough(true, color: Color(strikethroughColor))
					} else {
						text = text.strikethrough(true)
					}
				}

				if let underlineStyle = attrs[.underlineStyle] as? NSNumber,
					 underlineStyle != 0 {
					if let underlineColor = (attrs[.underlineColor] as? UIColor) {
						text = text.underline(true, color: Color(underlineColor))
					} else {
						text = text.underline(true)
					}
				}

				if let baselineOffset = attrs[.baselineOffset] as? NSNumber {
					text = text.baselineOffset(CGFloat(baselineOffset.floatValue))
				}

				// append the newly styled subtext to the rest of the text
				self = self + text
			}
		}
	}
}