NSColor.bestTextColorForBackgroundColor

Author: macmade

ColorSet/Classes/PaletteColorItem.swift

@@ -66,7 +66,7 @@ import ColorSetKit
         rect.fill()
 
         let hsl       = base.hsl()
-        let textColor = ( hsl.lightness >= 0.5 ) ? NSColor.black : NSColor.white
+        let textColor = NSColor.bestTextColorForBackgroundColor( base )
         var p         = NSMakePoint( rect.origin.x + 10, rect.origin.y + 10 )
 
         ( info.name as NSString ).draw( at: p, withAttributes: [ .foregroundColor : textColor, .font : NSFont.systemFont( ofSize: 25, weight: .thin ) ] )

ColorSetKit/NSColor+ColorSetKit.swift

@@ -141,6 +141,26 @@ import Cocoa
         self.init( srgbRed: rgb.0, green: rgb.1, blue: rgb.2, alpha: alpha )
     }
 
+    @objc class func bestTextColorForBackgroundColor( _ background: NSColor ) -> NSColor
+    {
+        return NSColor.bestTextColorForBackgroundColor( background, lightTextColor: NSColor.white, darkTextColor: NSColor.black )
+    }
+    
+    @objc class func bestTextColorForBackgroundColor( _ background: NSColor, lightTextColor: NSColor, darkTextColor: NSColor ) -> NSColor
+    {
+        guard let hsl = background.usingColorSpace( .sRGB )?.hsl() else
+        {
+            return NSColor.textColor
+        }
+        
+        if hsl.hue > 40.0 / 360.0 && hsl.hue < 180.0 / 360.0
+        {
+            return ( hsl.lightness > 0.3 ) ? darkTextColor : lightTextColor
+        }
+        
+        return ( hsl.lightness > 0.5 ) ? darkTextColor : lightTextColor
+    }
+    
     @objc var hexString: String
     {
         let rgb = self.rgb()