How to convert UIColor value to a named color string?

Question

I need to convert UIColor to an NSString of the color name.

I tried:

 NSString *colorString = NSStringFromClass([[UIColor redColor] class]); 

But colorString did not give @"redColor".

Answer 1

The CIColor class contains color values and the color space for which the color values are valid.

https://developer.apple.com/documentation/coreimage/cicolor

// UIColor to NSString
CGColorRef colorRef = [UIColor grayColor].CGColor;  
NSString *colorString = [CIColor colorWithCGColor:colorRef].stringRepresentation;

---

// NSString to UIColor 
CIColor *coreColor = [CIColor colorWithString:@"0.5 0.5 0.5 1.0"];  
UIColor *color = [UIColor colorWithCIColor:coreColor];

-----------------Warning-----------

If You Want Support All Devices The Way Mentioned Above to Convert NSString to UIColor Will Not Work On All Devices.

---

stringRepresentation

Returns a formatted string that specifies the components of the color.

The string representation always has four components—red, green, blue, and alpha.

https://developer.apple.com/documentation/coreimage/cicolor/1437910-stringrepresentation

---

colorWithString:

Creates a color object using the RGBA color component values specified by a string.

https://developer.apple.com/documentation/coreimage/cicolor/1438059-colorwithstring

Answer 2

UIColor *color = value;
const CGFloat *components = CGColorGetComponents(color.CGColor);
NSString *colorAsString = [NSString stringWithFormat:@"%f,%f,%f,%f", components[0], components[1], components[2], components[3]];

Done.

If you want to convert the string back to a UIColor object:

NSArray *components = [colorAsString componentsSeparatedByString:@","];
CGFloat r = [[components objectAtIndex:0] floatValue];
CGFloat g = [[components objectAtIndex:1] floatValue];
CGFloat b = [[components objectAtIndex:2] floatValue];
CGFloat a = [[components objectAtIndex:3] floatValue];
UIColor *color = [UIColor colorWithRed:r green:g blue:b alpha:a];

Are you storing a UIColor object as an attribute in Core Data? If so, check out my answer to this question: Core Data data model: attribute type for UIColor