Is there function to convert UIColor to Hue Saturation Brightness?

Question

i can set uicolor with RGB values:

[UIColor colorWithRed:0.53 green:0.37 blue:0.11 alpha:1.00]; 

i can set uicolor with hsb values:

[UIColor colorWithHue:0.10 saturation:0.16 brightness:0.13 alpha:1.00]; 

i also could convert it back to RGB:

CGFloat* colors = CGColorGetComponents(Color1.CGColor); 

But how i can get HSB from uicolor?

Answer 1

Use the UIColor method: getHue:saturation:brightness:alpha:

From the Apple docs:
"Returns the components that make up the color in the HSB color space."

- (BOOL)getHue:(CGFloat *)hue saturation:(CGFloat *)saturation brightness:(CGFloat *)brightness alpha:(CGFloat *)alpha 

Example:

UIColor *testColor = [UIColor colorWithRed:0.53 green:0.37 blue:0.11 alpha:1.00];  CGFloat hue; CGFloat saturation; CGFloat brightness; CGFloat alpha; BOOL success = [testColor getHue:&hue saturation:&saturation brightness:&brightness alpha:&alpha]; NSLog(@"success: %i hue: %0.2f, saturation: %0.2f, brightness: %0.2f, alpha: %0.2f", success, hue, saturation, brightness, alpha); 

NSLog output:

success: 1 hue: 0.10, saturation: 0.79, brightness: 0.53, alpha: 1.00

Here is a corrected version of the method provided by @WhiteTiger:

// Test values CGFloat red = 0.53; CGFloat green = 0.37; CGFloat blue = 0.11;  CGFloat hue = 0; CGFloat saturation = 0; CGFloat brightness = 0;  CGFloat minRGB = MIN(red, MIN(green,blue)); CGFloat maxRGB = MAX(red, MAX(green,blue));  if (minRGB==maxRGB) {     hue = 0;     saturation = 0;     brightness = minRGB; } else {     CGFloat d = (red==minRGB) ? green-blue : ((blue==minRGB) ? red-green : blue-red);     CGFloat h = (red==minRGB) ? 3 : ((blue==minRGB) ? 1 : 5);     hue = (h - d/(maxRGB - minRGB)) / 6.0;     saturation = (maxRGB - minRGB)/maxRGB;     brightness = maxRGB; } NSLog(@"hue: %0.2f, saturation: %0.2f, value: %0.2f", hue, saturation, brightness); 

NSLog output:

hue: 0.10, saturation: 0.79, value: 0.53

Answer 2

Here is a nice way of using Swift features (extensions, computed properties and tuples) to do the same thing in just a few lines of code.

extension UIColor {   var hsba: (h: CGFloat, s: CGFloat, b: CGFloat, a: CGFloat) {     var hsba: (h: CGFloat, s: CGFloat, b: CGFloat, a: CGFloat) = (0, 0, 0, 0)     self.getHue(&(hsba.h), saturation: &(hsba.s), brightness: &(hsba.b), alpha: &(hsba.a))     return hsba   } } 

Swift 3.2 / 4 minor update

Swift 3.2 / 4 enforced a new warning triggered with the previous code because you were modifying the hsba variable several times within the same call to getHue

Simultaneous accesses to parameter 'hsba', but modification requires exclusive access; consider copying to a local variable.

extension UIColor {     var hsba: (h: CGFloat, s: CGFloat, b: CGFloat, a: CGFloat) {         var h: CGFloat = 0, s: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0         self.getHue(&h, saturation: &s, brightness: &b, alpha: &a)         return (h: h, s: s, b: b, a: a)     } }