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February 18, 2020 07:50
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Extension to provide an equivalent opaque UIColor to a UIColor with alpha channel. So: f(r,g,b,a) == (r,g,b,1)
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import UIKit | |
public extension UIColor { | |
var components: (red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) { | |
var red: CGFloat = 0 | |
var green: CGFloat = 0 | |
var blue: CGFloat = 0 | |
var alpha: CGFloat = 0 | |
getRed(&red, green: &green, blue: &blue, alpha: &alpha) | |
return (red, green, blue, alpha) | |
} | |
func opaqueEquivalent(withBackground color: UIColor = .white) -> UIColor { | |
let bColor = color.components | |
let fColor = components | |
let alpha = fColor.alpha | |
func finalChannel(_ fColor: CGFloat, _ bColor: CGFloat) -> CGFloat { | |
(1 - alpha) * bColor + (fColor * alpha) | |
} | |
let newRed = finalChannel(fColor.red, bColor.red) | |
let newGreen = finalChannel(fColor.green, bColor.green) | |
let newBlue = finalChannel(fColor.blue, bColor.blue) | |
return UIColor(red: newRed, green: newGreen, blue: newBlue, alpha: 1.0) | |
} | |
} |
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