I've been using this macro in Objective-C:
#define RGBA(r, g, b, a) [UIColor colorWithRed:(r)/255.0 green:(g)/255.0 blue:(b)/255.0 alpha:(a)]
I am trying to figure out how I can get the closest thing possible in swift. Any ideas?
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How about making a function that wraps around Swift's syntax for creating a color, if it's too long for you?Justin Johns– Justin Johns2014-06-13 23:05:45 +00:00Commented Jun 13, 2014 at 23:05
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4In Swift, Apple has decided that macros make debugging harder. They want you to use a function instead.CrimsonChris– CrimsonChris2014-06-13 23:08:15 +00:00Commented Jun 13, 2014 at 23:08
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ok, so no more macros. I see. thanks for the inputzumzum– zumzum2014-06-13 23:11:50 +00:00Commented Jun 13, 2014 at 23:11
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3 Answers
An extension on UIColor is a valid option.
extension UIColor {
convenience init(_ r: Double, _ g: Double, _ b: Double, _ a: Double) {
self.init(red: r/255, green: g/255, blue: b/255, alpha: a)
}
}
Usage
let white = UIColor(255.0, 255.0, 255.0, 1.0)
answered Jun 13, 2014 at 23:21
Gabriele Petronella
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3 Comments
zumzum
This works thanks. Will this be visible to other classes now?, also, why did you add the "_" before each parameter in the function call?
Gabriele Petronella
the
_ allows you to skip the parameter names when calling the methods.
Pichirichi
It might be just a swift 2.0 issue but you need to add CGFloat convert on the double values other wise you'll get an error that a double is not convertible to CGFloat
In the global scope provide:
func RGBA (r:CGFloat, g:CGFloat, b:CGFloat, a:CGFloat) {
return UIColor (red: r/255.0, green: g/255.0, blue: b/255.0, alpha: a)
}
and then use it with:
var theColor : UIColor = RGBA (255, 255, 0, 1)
3 Comments
zumzum
I'll try this. I am not 100% sure I understand it, could you provide the full answer in code? thank you
GoZoner
Yes, but check out the Apple documentation for UIColor, specifically the init() functions with their Swift calling convention.
zumzum
So I added what you suggested: func RGBA (r:Int, g:Int, b:Int, a:Int) -> UIColor { return UIColor(red:r/255.0,green:g/255.0,blue:b/255.0,alpha:a) } and also added the Return type -> UIColor. Compiler gave me an error saying: "Could not find an overload for '/' that accepts the supplied arguments. The initializer in UIColor cannot take in Int, so I went ahead and changed the "Int" to "CGFloat" and it worked. I will mark @Gabriele Petronella's answer correct as it worked as is. Thank you.
What I did is to create a class method that returns the #define.
Example:
.h file
#define RGBA(r, g, b, a) [UIColor colorWithRed:(r)/255.0 green:(g)/255.0 blue:(b)/255.0 alpha:(a)]
+ (UIColor*)RGBA:(CGFloat)r g:(CGFloat)g b:(CGFloat)b a:(CGFloat)a;
.m file
+ (UIColor*)RGBA:(CGFloat)r g:(CGFloat)g b:(CGFloat)b a:(CGFloat)a { return RGBA(r, g, b, a); }
