How to initialize UIColor from RGB values properly?

Question

I am working on an iPhone application which uses various colors. When user selects the particular color button I set drawing color accordingly. I am getting the color for so

Answer 1

Here is a method that you can easily turn into a category on UIColor that will allow you to specify a color based on RGBA values of 0 - 255.

+ (UIColor *)colorFromRGBAWithRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha {
    return [UIColor colorWithRed:red/255.0 green:green/255.0 blue:blue/255.0 alpha:alpha/255.0];
}

If you make it a UIColor category extension, you can use it like so:

UIColor *myAwesomeColor = [UIColor colorFromRGBAWithRed:48 green:119 blue:167 alpha:255];

Answer 2

You got several options

Code

CGFloat red = 16.0;
CGFloat green = 97.0;
CGFloat blue = 5.0;
CGFloat alpha = 255.0;
UIColor *color = [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:(alpha/255.0)];

Color picker plugin for Interface Builder

There's a nice color picker from Panic which works well with IB: http://panic.com/~wade/picker/

Xcode plugin

This one gives you a GUI for choosing colors: http://www.youtube.com/watch?v=eblRfDQM0Go

Pods and libraries

There's a nice pod named MPColorTools: https://github.com/marzapower/MPColorTools

Answer 3

(ContentView.Layer.BorderColor) //CG Object
   = UIColor.LightGray.CGColor; 

Answer 4

In Swift you can easily set your Background-Color for example of a cell like this:

cell.backgroundColor = UIColor.init(red: 14.0/255.0, green: 114.0/255.0, blue: 199.0/255.0, alpha: 1)

:-)

Answer 5

Pragmatic approach with Swift.

extension UIColor {

   convenience init(rgbColorCodeRed red: Int, green: Int, blue: Int, alpha: CGFloat) {

     let redPart: CGFloat = CGFloat(red) / 255
     let greenPart: CGFloat = CGFloat(green) / 255
     let bluePart: CGFloat = CGFloat(blue) / 255

     self.init(red: redPart, green: greenPart, blue: bluePart, alpha: alpha)

   }
}

Answer 6

The values are in the 0.0 to 1.0 range.

E.g. divide by 255., but remember the decimal dot so you get floating point division and not integer division.

Like

selectedColor = [UIColor colorWithRed:14.0/255.0 green:114.0/255.0 blue:199.0/255.0 alpha:1];