How to set alpha for an Assets Color in Swift-CodePudding

I just wanted to know how to change the opacity (alpha) of an asset color I have. When I try this UIColor(named: "something", alpha: 0.4), Xcode complains: Extra argument 'alpha' in call.

Is there any way I can modify the opacity of an asset color programmatically?

CodePudding user response：

Use this extension to get the rgb value from the UIColor

extension UIColor {
    var rgba: (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)
    }
}

Then you can create a new color

let assetColor = UIColor(named: "something")
let (r,g,b,_) = assetColor.rgba
let newColor = UIColor(red:r, green:g, blue:b, alpha: 0.4)

CodePudding user response：

You can add this extension for UIColor and easy to use.

extension UIColor {
    convenience init?(named: String, alpha: CGFloat) {
        if let rgbComponents = UIColor(named: named)?.cgColor.components {
            self.init(red: rgbComponents[0], green: rgbComponents[1], blue: rgbComponents[2], alpha: alpha)
        } else {
            self.init(named: named)
        }
    }
}

Usage:

let colorWithAlpha = UIColor(named: "Assets Color", alpha: 0.5)

CodePudding user response：

You can set color alpha component when you assign color as follows:

button.backgroundColor = .black.withAlphaComponent(0.5)

CodePudding user response：

You can modify asset color from here Select that particular asset color and Drag that opacity indicator in left or right or directly set some values

CodePudding user response：

UIColor, as mentioned by Jasur S., has the withAlphaComponent(_:).

It can be used with any UIColor objects to modify its alpha:

let color = UIColor(named: "something")?.withAlphaComponent(0.5)

Creating custom extensions to cover existing functionality is an arguable good.