How to get RGB values from UIColor?

Question

I\'m creating a color object using the following code.

curView.backgroundColor = [[UIColor alloc] initWithHue:229 saturation:40 brightness:75 alpha:1];


        

Answer 1

Using HandyUIKit makes this really easy:

import HandyUIKit    

let color = UIColor(red: 0.1, green: 0.2, blue: 0.3, alpha: 0.4)

// get any of the rgba values
color.rgba.red    // => 0.1
color.rgba.green  // => 0.2
color.rgba.blue   // => 0.3
color.rgba.alpha  // => 0.4

There is also a similar option to get hsba values:

let color = UIColor(hue: 0.1, saturation: 0.2, brightness: 0.3, alpha: 0.4)

// you can get any of the hsba values, too
color.hsba.hue         // => 0.1
color.hsba.saturation  // => 0.2
color.hsba.brightness  // => 0.3
color.hsba.alpha       // => 0.4

Simply install it using Carthage and you're good to go.

I hope it helps!

Answer 2

const float* colors = CGColorGetComponents( curView.backgroundColor.CGColor );

Thanks. I had to add the const at the start of the line as it was generating a warning.

Answer 3

I wanted to get the background color of the UITableViewStyle "UITableViewStyleGrouped" so in the viewDidAppear: method I added the code:

NSLog(@"%@", self.tableView.backgroundView.backgroundColor);

It did what I anticipated and returned the log:

UIDeviceRGBColorSpace 0.937255 0.937255 0.956863 1

So in short just type in NSLog(@"%@", [UIColor whateverColor]);

Answer 4

Swift 3 version of David Rees answer:

extension UIColor {

    var redValue: CGFloat{
        return cgColor.components! [0]
    }

    var greenValue: CGFloat{
        return cgColor.components! [1]
    }

    var blueValue: CGFloat{
        return cgColor.components! [2]
    }

    var alphaValue: CGFloat{
        return cgColor.components! [3]
    }
}

Answer 5

SWIFT 3 & 4

I found that cgColor.components would not always return 4 color values, so I changed this so it gets them from a CIColor wrapper

extension UIColor {
    var redValue: CGFloat{ return CIColor(color: self).red }
    var greenValue: CGFloat{ return CIColor(color: self).green }
    var blueValue: CGFloat{ return CIColor(color: self).blue }
    var alphaValue: CGFloat{ return CIColor(color: self).alpha }
}

SWIFT 2

extension UIColor {
    var red: CGFloat{ return CGColorGetComponents(self.CGColor)[0] }
    var green: CGFloat{ return CGColorGetComponents(self.CGColor)[1] }
    var blue: CGFloat{ return CGColorGetComponents(self.CGColor)[2] }
    var alpha: CGFloat{ return CGColorGetComponents(self.CGColor)[3] }
}

It's not the most efficient way so I wouldn't go using this where a view will be constantly re-drawn.

Answer 6

In iOS 5 you could use:

CGFloat red = 0.0, green = 0.0, blue = 0.0, alpha =0.0;
[multipliedColor getRed:&red green:&green blue:&blue alpha:&alpha];