NSImage+TintColor

NSImage+TintColor.swift

import Cocoa

// This will work with Swift 5
extension NSImage {
	func image(with tintColor: NSColor) -> NSImage {
		if self.isTemplate == false {
			return self
		}
		
		let image = self.copy() as! NSImage
		image.lockFocus()
		
		tintColor.set()
		
		let imageRect = NSRect(origin: .zero, size: image.size)
		imageRect.fill(using: .sourceIn)
		
		image.unlockFocus()
		image.isTemplate = false
		
		return image
	}
}

/* Usage

let sourceImage = NSImage(named: NSImage.Name("ImageName"))!
sourceImage.isTemplate = true

let tintColor = NSColor(red: 1.0, green: 0.08, blue: 0.50, alpha: 1.0)
let coloredImage = sourceImage.image(with: tintColor)

imageView.image = coloredImage

*/

.CompositeSourceIn works better for colors with not 100% alpha

Swift 5 needs:

    let imageRect = NSRect(origin: .zero, size: image.size)
    imageRect.fill(using: .sourceAtop)

@Cyberbeni @robinstewart
Thanks for some advices!