Uicolor Not Working With Rgba Values

UIColor not working with RGBA values

RGB values for UIColor are between 0 and 1 (see the documentation "specified as a value from 0.0 to 1.0")

You need to divide your numbers by 255:

passwordTextField.textColor = UIColor(red: CGFloat(202.0/255.0), green: CGFloat(228.0/255.0), blue: CGFloat(230.0/255.0), alpha: CGFloat(1.0))

Another thing, you don't need to create CGFloats:

passwordTextField.textColor = UIColor(red:202.0/255.0, green:228.0/255.0, blue:230.0/255.0, alpha:1.0)

UIColor(r: g: b:) not working properly

The RGB values range from 0.0 to 1.0, not 0 to 255.

Why does only the built-in UIColors work here?

This should work for you:

func switchColor(data: UInt32) {
    guard let contents = backgroundGeometry.firstMaterial?.diffuse.contents else {
        fatalError("First material is nil") // If this really can be empty, just replace this with return
    }

    switch data {
    case 1..<200:
        contents = UIColor(red: 242/255, green: 90/255, blue: 90/255, alpha: 1)
    case 200..<400:
        contents = UIColor(red: 252/255, green: 162/255, blue: 115/255, alpha: 1)
    case 400..<600:
        contents = UIColor(red: 244/255, green: 235/255, blue: 99/255, alpha: 1)
    case 600..<800:
        contents = UIColor(red: 110/255, green: 195/255, blue: 175/255, alpha: 1)
    case 800..<1000:
        contents = UIColor(red: 91/255, green: 118/255, blue: 211/255, alpha: 1)
    default:
        contents = .green
    }
}

The maximum value of a color is 1.0, not 255. Therefore you need to divide the values.

How convert RGBA to UIColor and back

Welcome!

The issue is that you use two different color spaces:

• When converting from RGBA to UIColor, you assume the RGBA values are in Display P3 (UIColor(displayP3Red:...).
• But the CGContext you create with the "device RGB" color space, which is an sRGB color space as far as I know.

If you'd use the init(red:, green:, blue:, alpha:) initializer of UIColor it should work.

How do I create a UIColor from RGBA?

Your values are incorrect, you need to divide each color value by 255.0.

[UIColor colorWithRed:66.0f/255.0f
                green:79.0f/255.0f
                 blue:91.0f/255.0f
                alpha:1.0f];

The docs state:

+ (UIColor *)colorWithRed:(CGFloat)red
                    green:(CGFloat)green
                     blue:(CGFloat)blue
                    alpha:(CGFloat)alpha

Parameters

red
The red component of the color object, specified as a value from 0.0 to 1.0.

green
The green component of the color object, specified as a value from 0.0 to 1.0.

blue
The blue component of the color object, specified as a value from 0.0 to 1.0.

alpha
The opacity value of the color object, specified as a value from 0.0 to 1.0.

Reference here.

Objective-c HTML-RGB color not correct in UIColor

Simply divide all you color values by 255:

[UIColor colorWithRed:235/255.0f green:242/255.0f blue:212/255.0f alpha:1]

UIColor doesn't work with it's own properties

I believe your problem is that grayColor is not defined with a colorspace that's compatible with the getRed:green:blue:alpha: method. You can verify this by initializing the rgba values to something impossible for a color and noting that they are not changed by the call, which matches the documented return behavior. Or, replace grayColor with something that explicitly includes colors, such as cyanColor and the getRed:green:blue:alpha: method works.

Here's a bit of code to demonstrate:

float r = 5.0,g = 6.0,b = 7.0,a = 8.0, w = 3.0, a2 = 4.0;
UIColor *aaa = [UIColor grayColor];
[aaa getRed:&r green:&g blue:&b alpha:&a];
[aaa getWhite:&w alpha:&a2];

(On OS X there are methods for converting between colorspaces but I'm not seeing iOS equivalents.)

Swift - Custom color not applying to barTintColor

You need to give color by dividing them by 255, the syntax is like this.

init(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat)

Each of the ones that take a CGFloat take a value between 0.0 and 1.0, referring to either the complete absence of, or the maximum amount of that color component respectively. So, this means that even if you have pure RGB values in decimal or hexadecimal format, you will have to divide them by decimal 255 to get the amount to input here.

let customRedColor = UIColor(red: 255/255.0 , green: 0, blue: 13/255.0, alpha: 1.0)
//or Direct
let customRedColor = UIColor(red: 1.0 , green: 0, blue: 0.05, alpha: 1.0)
self.navigationController?.navigationBar.barTintColor = customRedColor

UIColor Components

The values aren't zero, they're just printing that way since you're printing a CGFloat as a Float. To fix it:

NSLog("%f, %f, %f, %f", Float(red1), Float(green1), Float(blue1), Float(alpha1))

or

NSLog("%@, %@, %@, %@", red1, green1, blue1, alpha1)

or

println("\(red1), \(green1), \(blue1), \(alpha1)")

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