Dim NSImage

NSImageDimming.swift

import Cocoa

extension NSImage {
	
	/// Return dimmed NSImage with level (0.0–1.0)
	func dimmed(_ level: CGFloat) -> NSImage {
		NSImage(size: self.size, flipped: false) { rect in
			let imageRect = NSRect(.zero, self.size)
			
			// Draw image
			self.draw(in: imageRect)
			
			// Draw transparent black color over the image
			NSColor(deviceWhite: 0, alpha: level).set()
			imageRect.fill(using: .sourceAtop)
			
			return true
		}
	}
	
}