🎨Basic Color Terms-you should know!

🙂🙂Color is the most important element of art. If you are a designer, then you must do research on color.

1️⃣ Hue 2️⃣ Saturation 3️⃣ Tint 4️⃣ Tone 5️⃣ Shade

original source : https://stackoverflow.com/questions/24263007/how-to-use-hex-colour-values

#ffffff are actually 3 color components in hexadecimal notation - red ff, green ff and blue ff. You can write hexadecimal notation in Swift using 0x prefix, e.g 0xFF

To simplify the conversion, let's create an initializer that takes integer (0 - 255) values:

extension UIColor {   convenience init(red: Int, green: Int, blue: Int) {       assert(red >= 0 && red <= 255, "Invalid red component")       assert(green >= 0 && green <= 255, "Invalid green component")       assert(blue >= 0 && blue <= 255, "Invalid blue component")       self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)   }   convenience init(rgb: Int) {       self.init(           red: (rgb >> 16) & 0xFF,           green: (rgb >> 8) & 0xFF,           blue: rgb & 0xFF       )   } }

Usage:

let color = UIColor(red: 0xFF, green: 0xFF, blue: 0xFF) let color2 = UIColor(rgb: 0xFFFFFF)

How to get alpha?

Depending on your use case, you can simply use the native UIColor.withAlphaComponentmethod, e.g.

let semitransparentBlack = UIColor(rgb: 0x000000).withAlphaComponent(0.5)

Or you can add an additional (optional) parameter to the above methods:

convenience init(red: Int, green: Int, blue: Int, a: CGFloat = 1.0) {    self.init(        red: CGFloat(red) / 255.0,        green: CGFloat(green) / 255.0,        blue: CGFloat(blue) / 255.0,        alpha: a    ) } convenience init(rgb: Int, a: CGFloat = 1.0) {    self.init(        red: (rgb >> 16) & 0xFF,        green: (rgb >> 8) & 0xFF,        blue: rgb & 0xFF,        a: a    ) }

(we cannot name the parameter alpha because of a name collision with the existing initializer).

Called as:

let color = UIColor(red: 0xFF, green: 0xFF, blue: 0xFF, a: 0.5) let color2 = UIColor(rgb: 0xFFFFFF, a: 0.5)

To get the alpha as an integer 0-255, we can

convenience init(red: Int, green: Int, blue: Int, a: Int = 0xFF) {    self.init(        red: CGFloat(red) / 255.0,        green: CGFloat(green) / 255.0,        blue: CGFloat(blue) / 255.0,        alpha: CGFloat(a) / 255.0    ) } // let's suppose alpha is the first component (ARGB) convenience init(argb: Int) {    self.init(        red: (argb >> 16) & 0xFF,        green: (argb >> 8) & 0xFF,        blue: argb & 0xFF,        a: (argb >> 24) & 0xFF    ) }

Called as

let color = UIColor(red: 0xFF, green: 0xFF, blue: 0xFF, a: 0xFF) let color2 = UIColor(argb: 0xFFFFFFFF)

UIColorをRGBじゃなくてhexで指定したい人へ。

Swift adventures : Utiliser UIColor

Maintenant que vous savez ce que je pense de Swift et/ou à quoi servent les opérateurs “?” et “!”, je vais vous parler d’un sujet un peu plus simple ou un peu plus léger que d’habitude : L’utilisation et la création des couleurs en Swift.

Pour ceux qui développait déjà en Objective-C, UIColor existant déjà dans ce langage, je vais essayer de comparer les deux façons de faire pour que vous voyez…