paiai_ios/PaiAi/PaiaiUIKit/Reusable/Extension/UIKit/UILabelExt.swift

//
//  UILabelExt.swift
//  ExtensionKit
//
//  Created by FFIB on 2017/9/14.
//  Copyright © 2017年 FFIB. All rights reserved.
//

import UIKit


extension UILabel {
    
    //Calcute the single line height according to the font
    public var singleHeight: CGFloat {
        if let attributedString = attributedText {
            return attributedString.size().height
        }else {
            return 0
        }
    }
    
    //Adjust the size according to the designed size
    public func sizeToFit(with designedSize: CGSize) {
        calcuteSize(designedWidth: designedSize.width,
                    designedHeight: designedSize.height)
    }
    
    //Adjust the size according to he required number of rows
    public func sizeToFitWithLine(with designedWidth: CGFloat) {
        calcuteSize(designedWidth: designedWidth,
                    designedHeight: singleHeight * CGFloat(numberOfLines))
    }
    
    private func calcuteSize(designedWidth: CGFloat,
                                 designedHeight: CGFloat) {
        guard let attributedString = attributedText else {
            return
        }
        
        let fitSize = attributedString.boundingRect(with: CGSize(width: designedWidth, height: 10000),
                                                    options: .usesLineFragmentOrigin,
                                                    context: nil)
        
        let finalHeight = min(designedHeight, fitSize.height)
        let fitConstraint = [NSLayoutConstraint(item: self,
                                                attribute: .width,
                                                relatedBy: .equal,
                                                toItem: nil,
                                                attribute: .width,
                                                multiplier: 1,
                                                constant: designedWidth),
                             NSLayoutConstraint(item: self,
                                                attribute: .height,
                                                relatedBy: .equal,
                                                toItem: nil,
                                                attribute: .height,
                                                multiplier: 1,
                                                constant: finalHeight)]
        NSLayoutConstraint.activate(fitConstraint)
    }
    
    
    //if using the storyboard and the nib ,need to call withint the method 'viewDidLayoutSubviews'
    public func setLineSpace(space: CGFloat) {
        guard let str = text else {
            return
        }
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = space
        let attributedString = NSMutableAttributedString(string: str)
        attributedString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle],
                                       range: NSRange(location: 0, length: str.characters.count))
        attributedString.addAttributes([NSAttributedStringKey.font: font],
                                       range: NSRange(location: 0, length: str.characters.count))
        attributedText = attributedString
    }
    
    public func setWordSpace(space: CGFloat) {
        guard let str = text else {
            return
        }
        let attributedString = NSMutableAttributedString(string: str,
                                                         attributes: [NSAttributedStringKey.paragraphStyle : NSMutableParagraphStyle(),
                                                                      NSAttributedStringKey.kern: space])
        attributedString.addAttributes([NSAttributedStringKey.font: font],
                                       range: NSRange(location: 0, length: str.characters.count))
        attributedText = attributedString
    }
    
    public func setSpace(lineSpace: CGFloat,
                  wordSpace: CGFloat) {
        guard let str = text else {
            return
        }
        let paragraphStyle = NSMutableParagraphStyle()
        paragraphStyle.lineSpacing = lineSpace
        let attributedString = NSMutableAttributedString(string: str,
                                                         attributes: [NSAttributedStringKey.kern: wordSpace])
        attributedString.addAttributes([NSAttributedStringKey.paragraphStyle: paragraphStyle],
                                       range: NSRange(location: 0, length: str.characters.count))
        attributedString.addAttributes([NSAttributedStringKey.font: font],
                                       range: NSRange(location: 0, length: str.characters.count))
        attributedText = attributedString
    }
}