LeadKit/Sources/Extensions/String/String+SizeCalculation.swift

83 lines
2.9 KiB
Swift

//
// Copyright (c) 2017 Touch Instinct
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
import UIKit
/**
* Struct for holding result of string size calculation
*/
public struct StringSizeCalculationResult {
public let size: CGSize
public let fontLineHeight: CGFloat?
}
public extension StringSizeCalculationResult {
var height: CGFloat { return size.height }
var width: CGFloat { return size.width }
var numberOfLines: UInt? {
if let lineHeight = fontLineHeight {
let lineHeightRounded = Double(lineHeight).roundValue(withPersicion: 2)
let heightRounded = Double(height).roundValue(withPersicion: 2)
let numberOfLines = ceil(heightRounded / lineHeightRounded)
return UInt(numberOfLines)
}
return nil
}
}
public extension String {
/**
method which calculates string size based on given character attributes and (optional) max width and height
- parameter attributes: dictionary with string character attributes
- parameter maxWidth: maximum width of text
- parameter maxHeight: maximum height of text
- returns: string size calculation result
*/
func size(withAttributes attributes: [NSAttributedStringKey: AnyObject]?,
maxWidth: CGFloat = CGFloat.greatestFiniteMagnitude,
maxHeight: CGFloat = CGFloat.greatestFiniteMagnitude) -> StringSizeCalculationResult {
let size = self.boundingRect(with: CGSize(width: maxWidth, height: maxHeight),
options: [.usesLineFragmentOrigin, .usesFontLeading],
attributes: attributes,
context: nil).size
let fontLineHeight = (attributes?[NSAttributedStringKey.font] as? UIFont)?.lineHeight
return StringSizeCalculationResult(size: size, fontLineHeight: fontLineHeight)
}
}