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

Answer 1

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.

Answer 2

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

Answer 3

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;
 }

Answer 4

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

Answer 5

CGContextSetFillColorWithColor(context,[[UIColor colorWithRed:(255/255.f) green:(0/255.f) blue: (0/255.f) alpha:1] CGColor]);

Answer 6

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.