String Dimension Provider

StringDimensionProvider.swift

//
//  StringDimensionProvider.swift
//
//  Created by steve on 2019-07-11.
//  Copyright © 2019 Steven Thompson. All rights reserved.
//

//
//  StringHeightProvider.swift
//
//  Created by steve on 2019-07-11.
//  Copyright © 2019 Steven Thompson. All rights reserved.
//

import UIKit

final class StringDimensionProvider {
    static let shared = StringDimensionProvider()
    private init() { }
    private let label = UILabel()
    
    func computeHeight(
        with text: String?,
        font: UIFont,
        maxWidth: CGFloat,
        maxLineCount: Int = 1
    ) -> CGFloat {
        if text.isEmptyOrNil { return 0 }
        label.text = text
        label.font = font
        label.preferredMaxLayoutWidth = maxWidth
        label.numberOfLines = maxLineCount
        return label.intrinsicContentSize.height
    }
    
    func computeHeight(
        with attributedText: NSAttributedString?,
        maxWidth: CGFloat = .infinity,
        numberOfLines: Int = 1
    ) -> CGFloat {
        if attributedText.isEmptyOrNil { return 0 }
        label.attributedText = attributedText
        label.preferredMaxLayoutWidth = maxWidth
        label.numberOfLines = numberOfLines
        return label.intrinsicContentSize.height
    }
    
    func computeSize(
        with attributedText: NSAttributedString?,
        maxWidth: CGFloat = .infinity,
        numberOfLines: Int = 1
    ) -> CGSize {
        if attributedText.isEmptyOrNil { return .zero }
        label.numberOfLines = numberOfLines
        label.attributedText = attributedText
        label.preferredMaxLayoutWidth = maxWidth
        return .init(
            width: label.intrinsicContentSize.width,
            height: label.intrinsicContentSize.height
        )
    }
    
    func computeHeight(
        with attributedList: [(NSAttributedString?, Int)],
        maxWidth: CGFloat
    ) -> CGFloat {
        var result: CGFloat = 0
        attributedList.forEach { arg in
            let (str, numberOfLines) = arg
            result += computeHeight(
                with: str,
                maxWidth: maxWidth,
                numberOfLines: numberOfLines
            )
        }
        return result
    }
    
    func isTruncated(
        with attributedText: NSAttributedString?,
        maxWidth: CGFloat,
        numberOfLines: Int = 1
    ) -> Bool {
       let containedHeight = computeHeight(
        with: attributedText,
        maxWidth: maxWidth,
        numberOfLines: numberOfLines
       )
        let uncontainedHeight = computeHeight(
            with: attributedText,
            maxWidth: maxWidth,
            numberOfLines: .zero
        )
        return uncontainedHeight > containedHeight
    }
}