NetNewsWire/Shared/Favicons/ColorHash.swift

73 lines
1.9 KiB
Swift

//
// ColorHash.swift
// ColorHash
//
// Created by Atsushi Nagase on 11/25/15.
// Copyright © 2015 LittleApps Inc. All rights reserved.
//
// Original Project: https://github.com/ngs/color-hash.swift
import Foundation
#if os(iOS) || os(tvOS)
import UIKit
#elseif os(watchOS)
import WatchKit
#elseif os(OSX)
import AppKit
#endif
public class ColorHash {
public static let defaultLS = [CGFloat(0.45), CGFloat(0.6), CGFloat(0.75)]
let seed = CGFloat(131.0)
let seed2 = CGFloat(137.0)
let maxSafeInteger = 9007199254740991.0 / CGFloat(137.0)
let full = CGFloat(360.0)
public private(set) var str: String
public private(set) var brightness: [CGFloat]
public private(set) var saturation: [CGFloat]
public init(_ str: String, _ saturation: [CGFloat] = defaultLS, _ brightness: [CGFloat] = defaultLS) {
self.str = str
self.saturation = saturation
self.brightness = brightness
}
public var bkdrHash: CGFloat {
var hash = CGFloat(0)
for char in "\(str)x" {
if let scl = String(char).unicodeScalars.first?.value {
if hash > maxSafeInteger {
hash = hash / seed2
}
hash = hash * seed + CGFloat(scl)
}
}
return hash
}
public var HSB: (CGFloat, CGFloat, CGFloat) {
var hash = CGFloat(bkdrHash)
let H = hash.truncatingRemainder(dividingBy: (full - 1.0)) / full
hash /= full
let S = saturation[Int((full * hash).truncatingRemainder(dividingBy: CGFloat(saturation.count)))]
hash /= CGFloat(saturation.count)
let B = brightness[Int((full * hash).truncatingRemainder(dividingBy: CGFloat(brightness.count)))]
return (H, S, B)
}
#if os(iOS) || os(tvOS) || os(watchOS)
public var color: UIColor {
let (H, S, B) = HSB
return UIColor(hue: H, saturation: S, brightness: B, alpha: 1.0)
}
#elseif os(OSX)
public var color: NSColor {
let (H, S, B) = HSB
return NSColor(hue: H, saturation: S, brightness: B, alpha: 1.0)
}
#endif
}