Creating a UIImage from a UIColor to use as a background image for UIButton

Question

I m creating a colored image like this   CGRect rect   CGRectMake 0  0  1  1   UIGraphicsBeginImageContext rect size   CGContextRef context   UIGraphicsGetCurrentContext    CGContextSetFillColorWithColor context                                       UIColor redColor  CGColor          UIColor colorWithRed 222  255 green 227  255 blue  229  255 alpha 1  CGColor     CGContextFillRect context  rect   UIImage  img   UIGraphicsGetImageFromCurrentImageContext    UIGraphicsEndImageContext      and then use it as the background image of a button    resultButton setBackgroundImage img forState UIControlStateNormal     This works great using the redColor  however I want to use an RGB color  as shown in the commented line   When I use the RGB color  the buttons background isn t changed   What am I missing

User · Answer

CGContextSetFillColorWithColor context   UIColor colorWithRed  255 255 f  green  0 255 f  blue   0 255 f  alpha 1  CGColor

User · Answer

I created a category around UIButton to be able to set the background color of the button and set the state  You might find this useful    implementation  UIButton  ButtonMagic   -  void setBackgroundColor  UIColor   backgroundColor forState  UIControlState state        self setBackgroundImage  UIButton imageFromColor backgroundColor  forState state         UIImage   imageFromColor  UIColor   color       CGRect rect   CGRectMake 0  0  1  1       UIGraphicsBeginImageContext rect size       CGContextRef context   UIGraphicsGetCurrentContext        CGContextSetFillColorWithColor context   color CGColor        CGContextFillRect context  rect       UIImage  image   UIGraphicsGetImageFromCurrentImageContext        UIGraphicsEndImageContext        return image      This will be part of a set of helper categories I m open sourcing this month   Swift 2 2  extension UIImage   static func fromColor color  UIColor  - gt  UIImage       let rect   CGRect x  0  y  0  width  1  height  1      UIGraphicsBeginImageContext rect size      let context   UIGraphicsGetCurrentContext       CGContextSetFillColorWithColor context  color CGColor      CGContextFillRect context  rect      let img   UIGraphicsGetImageFromCurrentImageContext       UIGraphicsEndImageContext       return img         Swift 3 0   extension UIImage       static func from color  UIColor  - gt  UIImage           let rect   CGRect x  0  y  0  width  1  height  1          UIGraphicsBeginImageContext rect size          let context   UIGraphicsGetCurrentContext           context  setFillColor color cgColor          context  fill rect          let img   UIGraphicsGetImageFromCurrentImageContext           UIGraphicsEndImageContext           return img            Use as  let img   UIImage from color   black

User · Answer

Are you using ARC  The problem here is that you don t have a reference to the UIColor object that you re trying to apply  the CGColor is backed by that UIColor  but ARC will deallocate the UIColor before you have a chance to use the CGColor    The clearest solution is to have a local variable pointing to your UIColor with the objc precise lifetime attribute    You can read more about this exact case on this article about UIColor and short ARC lifetimes or get more details about the objc precise lifetime attribute

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I suppose that 255 in 227  255 is perceived as an integer and divide is always return 0

User · Answer

Add the dots to all values     UIColor colorWithRed 222  255  green 227  255  blue  229  255  alpha 1  CGColor       Otherwise  you are dividing float by int

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Xamarin iOS solution   public UIImage CreateImageFromColor           var imageSize   new CGSize 30  30        var imageSizeRectF   new CGRect 0  0  30  30        UIGraphics BeginImageContextWithOptions imageSize  false  0        var context   UIGraphics GetCurrentContext         var red   new CGColor 255  0  0        context SetFillColor red        context FillRect imageSizeRectF        var image   UIGraphics GetImageFromCurrentImageContext         UIGraphics EndImageContext         return image

User · Answer

Your code works fine  You can verify the RGB colors with Iconfactory s xScope  Just compare it to  UIColor whiteColor

[ios] Creating a UIImage from a UIColor to use as a background image for UIButton

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