NSAttributedString_ext.swift

extension String {
    func attributed(attributes: [NSAttributedString.Key: Any]? = nil, font: UIFont? = nil, color: UIColor? = nil, base: CGFloat? = nil, lineHeight: CGFloat? = nil) -> NSAttributedString {
        var atb = attributes ?? [:]
        if let v = base { atb[.baselineOffset] = v }
        if let v = font { atb[.font] = v }
        if let v = color { atb[.foregroundColor] = v }
        if let v = lineHeight {
            let ps = NSMutableParagraphStyle()
            ps.lineBreakMode = .byTruncatingTail
            ps.minimumLineHeight = v
            ps.maximumLineHeight = v
            atb[.paragraphStyle] = ps
        }
        return NSMutableAttributedString(string: self, attributes: atb)
    }

    func imageAttributed(attributes: [NSAttributedString.Key: Any]? = nil, width: CGFloat? = nil, height: CGFloat? = nil, base: CGFloat? = nil) -> NSAttributedString {
        guard let image = UIImage(named: self) else { return NSAttributedString() }
        return image.attributed(attributes: attributes, width: width, height: height, base: base)
    }
}

extension UIImage {
    func attributed(attributes: [NSAttributedString.Key: Any]? = nil, width: CGFloat? = nil, height: CGFloat? = nil, base: CGFloat? = nil) -> NSAttributedString {
        var rc = CGRect(origin: .zero, size: size)
        if let v = width, height == nil && size.width > 0 { rc.size.width = v; rc.size.height = size.height / size.width * v }
        if let v = height, width == nil && size.height > 0 { rc.size.height = v; rc.size.width = size.width / size.height * v }
        if let w = width, let h = height { rc.size = CGSize(width: w, height: h) }
        let attach = NSTextAttachment()
        attach.image = self
        attach.bounds = rc
        let s = NSMutableAttributedString(attachment: attach)
        var atb = attributes ?? [:]
        if let v = base { atb[.baselineOffset] = v }
        s.addAttributes(atb, range: NSRange(location: 0, length: 1))
        return s
    }
}

func + (left: NSAttributedString?, right: NSAttributedString) -> NSAttributedString {
    guard let v = left else { return NSMutableAttributedString(attributedString: right) }
    let s = v as? NSMutableAttributedString ?? NSMutableAttributedString(attributedString: v)
    s.append(right)
    return s
}

func += (left: inout NSAttributedString?, right: NSAttributedString) {
    guard let v = left else { left = NSMutableAttributedString(attributedString: right); return }
    let s = v as? NSMutableAttributedString ?? NSMutableAttributedString(attributedString: v)
    s.append(right)
    left = s
}