How to use hex color 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.withAlphaComponent
method, 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)
Or a combination of the previous methods. There is absolutely no need to use strings.
How can I convert RGB hex string into UIColor in objective-c?
You're close but colorWithRed:green:blue:alpha: expects values ranging from 0.0 to 1.0, so you need to shift the bits right and divide by 255.0f:
CGFloat red = ((baseColor1 & 0xFF0000) >> 16) / 255.0f;
CGFloat green = ((baseColor1 & 0x00FF00) >> 8) / 255.0f;
CGFloat blue = (baseColor1 & 0x0000FF) / 255.0f;
EDIT - Also NSScanner's scanHexInt will skip past 0x in front of a hex string, but I don't think it will skip the # character in front of your hex string. You can add this line to handle that:
[scanner2 setCharactersToBeSkipped:[NSCharacterSet symbolCharacterSet]];
How to create a hex color string UIColor initializer in Swift?
Xcode 9 • Swift 4 or later
extension UIColor {
convenience init?(hexaRGB: String, alpha: CGFloat = 1) {
var chars = Array(hexaRGB.hasPrefix("#") ? hexaRGB.dropFirst() : hexaRGB[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }
case 6: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[0...1]), nil, 16)) / 255,
green: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
alpha: alpha)
}
convenience init?(hexaRGBA: String) {
var chars = Array(hexaRGBA.hasPrefix("#") ? hexaRGBA.dropFirst() : hexaRGBA[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }; fallthrough
case 6: chars.append(contentsOf: ["F","F"])
case 8: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[0...1]), nil, 16)) / 255,
green: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
alpha: .init(strtoul(String(chars[6...7]), nil, 16)) / 255)
}
convenience init?(hexaARGB: String) {
var chars = Array(hexaARGB.hasPrefix("#") ? hexaARGB.dropFirst() : hexaARGB[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }; fallthrough
case 6: chars.append(contentsOf: ["F","F"])
case 8: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
green: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[6...7]), nil, 16)) / 255,
alpha: .init(strtoul(String(chars[0...1]), nil, 16)) / 255)
}
}
if let textColor = UIColor(hexa: "00F") {
print(textColor) // r 0.0 g 0.0 b 1.0 a 1.0
}
if let textColor = UIColor(hexaRGB: "00F") {
print(textColor) // r 0.0 g 0.0 b 1.0 a 1.0
}
UIColor(hexaRGB: "#00F") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGB: "#00F", alpha: 0.5) // r 0.0 g 0.0 b 1.0 a 0.5
UIColor(hexaRGB: "#0000FF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGB: "#0000FF", alpha: 0.5) // r 0.0 g 0.0 b 1.0 a 0.5
UIColor(hexaRGBA: "#0000FFFF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGBA: "#0000FF7F") // r 0.0 g 0.0 b 1.0 a 0.498
UIColor(hexaARGB: "#FF0000FF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaARGB: "#7F0000FF") // r 0.0 g 0.0 b 1.0 a 0.498
How do I convert a UIColor to a 3/4/6/8 digits hexadecimal string in Swift?
Here's an extension for UIColor
that can provide hexStrings in many formats including 3, 4, 6, and 8 digit forms:
extension UIColor {
enum HexFormat {
case RGB
case ARGB
case RGBA
case RRGGBB
case AARRGGBB
case RRGGBBAA
}
enum HexDigits {
case d3, d4, d6, d8
}
func hexString(_ format: HexFormat = .RRGGBBAA) -> String {
let maxi = [.RGB, .ARGB, .RGBA].contains(format) ? 16 : 256
func toI(_ f: CGFloat) -> Int {
return min(maxi - 1, Int(CGFloat(maxi) * f))
}
var r: CGFloat = 0
var g: CGFloat = 0
var b: CGFloat = 0
var a: CGFloat = 0
self.getRed(&r, green: &g, blue: &b, alpha: &a)
let ri = toI(r)
let gi = toI(g)
let bi = toI(b)
let ai = toI(a)
switch format {
case .RGB: return String(format: "#%X%X%X", ri, gi, bi)
case .ARGB: return String(format: "#%X%X%X%X", ai, ri, gi, bi)
case .RGBA: return String(format: "#%X%X%X%X", ri, gi, bi, ai)
case .RRGGBB: return String(format: "#%02X%02X%02X", ri, gi, bi)
case .AARRGGBB: return String(format: "#%02X%02X%02X%02X", ai, ri, gi, bi)
case .RRGGBBAA: return String(format: "#%02X%02X%02X%02X", ri, gi, bi, ai)
}
}
func hexString(_ digits: HexDigits) -> String {
switch digits {
case .d3: return hexString(.RGB)
case .d4: return hexString(.RGBA)
case .d6: return hexString(.RRGGBB)
case .d8: return hexString(.RRGGBBAA)
}
}
}
Examples
print(UIColor.red.hexString(.d3)) // #F00
print(UIColor.red.hexString(.d4)) // #F00F
print(UIColor.red.hexString(.d6)) // #FF0000
print(UIColor.red.hexString(.d8)) // #FF0000FF
print(UIColor.green.hexString(.RGB)) // #0F0
print(UIColor.green.hexString(.ARGB)) // #F0F0
print(UIColor.green.hexString(.RGBA)) // #0F0F
print(UIColor.green.hexString(.RRGGBB)) // #00FF00
print(UIColor.green.hexString(.AARRGGBB)) // #FF00FF00
print(UIColor.green.hexString(.RRGGBBAA)) // #00FF00FF
print(UIColor(red: 0.25, green: 0.5, blue: 0.75, alpha: 0.3333).hexString()) // #4080c055
How to convert HEX RGB color codes to UIColor?
In some code of mine, I use 2 different functions:
void SKScanHexColor(NSString * hexString, float * red, float * green, float * blue, float * alpha) {
NSString *cleanString = [hexString stringByReplacingOccurrencesOfString:@"#" withString:@""];
if([cleanString length] == 3) {
cleanString = [NSString stringWithFormat:@"%@%@%@%@%@%@",
[cleanString substringWithRange:NSMakeRange(0, 1)],[cleanString substringWithRange:NSMakeRange(0, 1)],
[cleanString substringWithRange:NSMakeRange(1, 1)],[cleanString substringWithRange:NSMakeRange(1, 1)],
[cleanString substringWithRange:NSMakeRange(2, 1)],[cleanString substringWithRange:NSMakeRange(2, 1)]];
}
if([cleanString length] == 6) {
cleanString = [cleanString stringByAppendingString:@"ff"];
}
unsigned int baseValue;
[[NSScanner scannerWithString:cleanString] scanHexInt:&baseValue];
if (red) { *red = ((baseValue >> 24) & 0xFF)/255.0f; }
if (green) { *green = ((baseValue >> 16) & 0xFF)/255.0f; }
if (blue) { *blue = ((baseValue >> 8) & 0xFF)/255.0f; }
if (alpha) { *alpha = ((baseValue >> 0) & 0xFF)/255.0f; }
}
And then I use it like this:
UIColor * SKColorFromHexString(NSString * hexString) {
float red, green, blue, alpha;
SKScanHexColor(hexString, &red, &green, &blue, &alpha);
return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}
If you prefer to use this as a UIColor
category, then it's just a matter of altering a few lines:
+ (UIColor *) colorFromHexString:(NSString *)hexString {
NSString *cleanString = [hexString stringByReplacingOccurrencesOfString:@"#" withString:@""];
if([cleanString length] == 3) {
cleanString = [NSString stringWithFormat:@"%@%@%@%@%@%@",
[cleanString substringWithRange:NSMakeRange(0, 1)],[cleanString substringWithRange:NSMakeRange(0, 1)],
[cleanString substringWithRange:NSMakeRange(1, 1)],[cleanString substringWithRange:NSMakeRange(1, 1)],
[cleanString substringWithRange:NSMakeRange(2, 1)],[cleanString substringWithRange:NSMakeRange(2, 1)]];
}
if([cleanString length] == 6) {
cleanString = [cleanString stringByAppendingString:@"ff"];
}
unsigned int baseValue;
[[NSScanner scannerWithString:cleanString] scanHexInt:&baseValue];
float red = ((baseValue >> 24) & 0xFF)/255.0f;
float green = ((baseValue >> 16) & 0xFF)/255.0f;
float blue = ((baseValue >> 8) & 0xFF)/255.0f;
float alpha = ((baseValue >> 0) & 0xFF)/255.0f;
return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}
This will handle strings like "#abc", "#abcdef31", etc.
How to convert UIColor to HEX and display in NSLog
Swift 5:
func hexStringFromColor(color: UIColor) -> String {
let components = color.cgColor.components
let r: CGFloat = components?[0] ?? 0.0
let g: CGFloat = components?[1] ?? 0.0
let b: CGFloat = components?[2] ?? 0.0
let hexString = String.init(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))
print(hexString)
return hexString
}
func colorWithHexString(hexString: String) -> UIColor {
var colorString = hexString.trimmingCharacters(in: .whitespacesAndNewlines)
colorString = colorString.replacingOccurrences(of: "#", with: "").uppercased()
print(colorString)
let alpha: CGFloat = 1.0
let red: CGFloat = self.colorComponentFrom(colorString: colorString, start: 0, length: 2)
let green: CGFloat = self.colorComponentFrom(colorString: colorString, start: 2, length: 2)
let blue: CGFloat = self.colorComponentFrom(colorString: colorString, start: 4, length: 2)
let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
return color
}
func colorComponentFrom(colorString: String, start: Int, length: Int) -> CGFloat {
let startIndex = colorString.index(colorString.startIndex, offsetBy: start)
let endIndex = colorString.index(startIndex, offsetBy: length)
let subString = colorString[startIndex..<endIndex]
let fullHexString = length == 2 ? subString : "\(subString)\(subString)"
var hexComponent: UInt32 = 0
guard Scanner(string: String(fullHexString)).scanHexInt32(&hexComponent) else {
return 0
}
let hexFloat: CGFloat = CGFloat(hexComponent)
let floatValue: CGFloat = CGFloat(hexFloat / 255.0)
print(floatValue)
return floatValue
}
How to use
let red = CGFloat(30.0)
let green = CGFloat(171.0)
let blue = CGFloat(13.0)
let alpha = CGFloat(1.0)
let color = UIColor(red: CGFloat(red/255.0), green: CGFloat(green/255.0), blue: CGFloat(blue / 255.0), alpha: alpha)
let colorCode = self.hexStringFromColor(color: color)
print(colorCode)
let resultColor = self.colorWithHexString(hexString: colorCode)
print(resultColor)
Objective-C:
- (NSString *)hexStringFromColor:(UIColor *)color {
const CGFloat *components = CGColorGetComponents(color.CGColor);
CGFloat r = components[0];
CGFloat g = components[1];
CGFloat b = components[2];
return [NSString stringWithFormat:@"#%02lX%02lX%02lX",
lroundf(r * 255),
lroundf(g * 255),
lroundf(b * 255)];
}
After getting hex code string, Call below method to get UIColor
- (UIColor *) colorWithHexString: (NSString *) hexString
{
NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];
NSLog(@"colorString :%@",colorString);
CGFloat alpha, red, blue, green;
// #RGB
alpha = 1.0f;
red = [self colorComponentFrom: colorString start: 0 length: 2];
green = [self colorComponentFrom: colorString start: 2 length: 2];
blue = [self colorComponentFrom: colorString start: 4 length: 2];
return [UIColor colorWithRed: red green: green blue: blue alpha: alpha];
}
- (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length {
NSString *substring = [string substringWithRange: NSMakeRange(start, length)];
NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];
unsigned hexComponent;
[[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];
return hexComponent / 255.0;
}
How to use
// ( R = 30, G = 171, B = 13)?
CGFloat red = 30.0;
CGFloat green = 171.0;
CGFloat blue = 13.0;
CGFloat alpha = 255.0
UIColor *color = [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:(alpha/255.0)];
NSString *colorCode = [self hexStringFromColor:color];
NSLog(@"Color Code: %@", colorCode);
UIColor *resultColor = [self colorWithHexString:colorCode];
How can I get a hex string from UIColor or from rgb
Use this method :
- (NSString *)hexStringForColor:(UIColor *)color {
const CGFloat *components = CGColorGetComponents(color.CGColor);
CGFloat r = components[0];
CGFloat g = components[1];
CGFloat b = components[2];
NSString *hexString=[NSString stringWithFormat:@"%02X%02X%02X", (int)(r * 255), (int)(g * 255), (int)(b * 255)];
return hexString;
}
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