Draw border of certain color around colored UIImage in tab bar - ios

Question

In order to understand my problem I will start with a short description of my goal:
In the center of my tab bar I deliberately use a usually too big image (a circle) which extends over the tab bar (the tab bar's background color is white) so it laps over the top border of the tab bar. Since all UITabBarItems' default color is a light gray (apparently it is neither UIColor.lightGray nor .darkGray) and I would like to change the color of this (and only this) UITabBarItem (or rather the image considering this is the only thing which can be seen of this UITabBarItem) to white I've used the following extension/function which works fine:
extension UIImage {
func tabBarImageWithCustomTint(tintColor: UIColor) -> UIImage {
UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)
let context: CGContext = UIGraphicsGetCurrentContext()!
context.translateBy(x: 0, y: self.size.height)
context.scaleBy(x: 1.0, y: -1.0)
context.setBlendMode(CGBlendMode(rawValue: 1)!)
let rect: CGRect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
context.clip(to: rect, mask: self.cgImage!)
tintColor.setFill()
context.fill(rect)
var newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
newImage = newImage.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
return newImage
}
}
Link to question where I found this extension
As both the tint color of the image and the background color of the tab bar are white, I would now like to add a border of red color to the now white image. Luckily, I managed to find another question on stackoverflow which answered this question (although I must add that I am not entirely content with this extension because it leaves a very small space between the UIImage and the border):
extension UIImage {
func roundedImageWithBorder(width: CGFloat, color: UIColor) -> UIImage? {
let square = CGSize(width: min(size.width, size.height) + width * 2, height: min(size.width, size.height) + width * 2)
let imageView = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: square))
imageView.contentMode = .center
imageView.image = self
imageView.layer.cornerRadius = square.width/2
imageView.layer.masksToBounds = true
imageView.layer.borderWidth = width
imageView.layer.borderColor = color.cgColor
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, scale)
guard let context = UIGraphicsGetCurrentContext() else { return nil }
imageView.layer.render(in: context)
let result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return result
}
}
My problem now is if I use the function consecutively like this...:
let tabRecordButton = UIImage(named: "circle").tabBarImageWithCustomTint(tintColor: .white).roundedImageWithBorder(width: 1, color: .red)
..., the border is drawn but the UITabBarItem's tint color goes back to this default gray aforementioned (not even the border is red).
So my question: Is there a way I can do both, i.e. color the image white and the border red in my UITabBar?

Answer 1

You have to add this line result = result.withRenderingMode(UIImageRenderingMode.alwaysOriginal) in your second extension as well, if you omit this line then your image will take the tint from your tabBar, that is your original issue
replace your roundedImageWithBorder extension method implementation with this one
func roundedImageWithBorder(width: CGFloat, color: UIColor) -> UIImage? {
let square = CGSize(width: min(size.width, size.height) + width * 2, height: min(size.width, size.height) + width * 2)
let imageView = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: square))
imageView.contentMode = .center
imageView.image = self
imageView.layer.cornerRadius = square.width/2
imageView.layer.masksToBounds = true
imageView.layer.borderWidth = width
imageView.layer.borderColor = color.cgColor
UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, false, scale)
guard let context = UIGraphicsGetCurrentContext() else { return nil }
imageView.layer.render(in: context)
var result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
result = result?.withRenderingMode(UIImageRenderingMode.alwaysOriginal)
return result
}
Testing
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.tabBarItem.selectedImage = UIImage(named: "icono-menu")?.tabBarImageWithCustomTint(tintColor: UIColor.magenta).roundedImageWithBorder(width: 1, color: UIColor.blue)
self.tabBarController?.tabBar.tintColor = UIColor.red //note that the tintColor of the tabBar is red
}
Result