93 lines
3.4 KiB
Swift
93 lines
3.4 KiB
Swift
/*
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* DynamicColor
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*
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* Copyright 2015-present Yannick Loriot.
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* http://yannickloriot.com
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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*/
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#if os(iOS) || os(tvOS) || os(watchOS)
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import UIKit
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#elseif os(OSX)
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import AppKit
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#endif
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// MARK: CIE L*a*b* Color Space
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public extension DynamicColor {
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/**
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Initializes and returns a color object using CIE XYZ color space component values with an observer at 2° and a D65 illuminant.
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Notes that values out of range are clipped.
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- parameter L: The lightness, specified as a value from 0 to 100.0.
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- parameter a: The red-green axis, specified as a value from -128.0 to 127.0.
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- parameter b: The yellow-blue axis, specified as a value from -128.0 to 127.0.
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- parameter alpha: The opacity value of the color object, specified as a value from 0.0 to 1.0. Default to 1.0.
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*/
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convenience init(L: CGFloat, a: CGFloat, b: CGFloat, alpha: CGFloat = 1) {
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let clippedL = clip(L, 0, 100)
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let clippedA = clip(a, -128, 127)
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let clippedB = clip(b, -128, 127)
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let normalized = { (c: CGFloat) -> CGFloat in
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pow(c, 3) > 0.008856 ? pow(c, 3) : (c - 16 / 116) / 7.787
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}
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let preY = (clippedL + 16) / 116
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let preX = clippedA / 500 + preY
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let preZ = preY - clippedB / 200
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let X = 95.05 * normalized(preX)
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let Y = 100 * normalized(preY)
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let Z = 108.9 * normalized(preZ)
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self.init(X: X, Y: Y, Z: Z, alpha: alpha)
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}
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// MARK: - Getting the L*a*b* Components
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/**
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Returns the Lab (lightness, red-green axis, yellow-blue axis) components.
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It is based on the CIE XYZ color space with an observer at 2° and a D65 illuminant.
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Notes that L values are between 0 to 100.0, a values are between -128 to 127.0 and b values are between -128 to 127.0.
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- returns: The L*a*b* components as a tuple (L, a, b).
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*/
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final func toLabComponents() -> (L: CGFloat, a: CGFloat, b: CGFloat) {
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let normalized = { (c: CGFloat) -> CGFloat in
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c > 0.008856 ? pow(c, 1.0 / 3) : 7.787 * c + 16.0 / 116
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}
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let xyz = toXYZComponents()
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let normalizedX = normalized(xyz.X / 95.05)
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let normalizedY = normalized(xyz.Y / 100)
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let normalizedZ = normalized(xyz.Z / 108.9)
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let L = roundDecimal(116 * normalizedY - 16, precision: 1000)
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let a = roundDecimal(500 * (normalizedX - normalizedY), precision: 1000)
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let b = roundDecimal(200 * (normalizedY - normalizedZ), precision: 1000)
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return (L: L, a: a, b: b)
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}
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}
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