needsimprovement.swift

   func adjRed(inout pixel:Pixel, by:Int) {
        let redDiff = Int(pixel.red) - avgRed
        if (redDiff > 0) {
            pixel.red = UInt8(max(0,min(255, avgRed + redDiff * by)))
        }
    }

    func adjGreen(inout pixel:Pixel, by:Int) {
        let greenDiff = Int(pixel.green) - avgGreen
        if (greenDiff > 0) {
            pixel.green = UInt8(max(0,min(255, avgGreen + greenDiff * by)))
        }
    }

    func adjBlue(inout pixel:Pixel, by:Int) {
        let blueDiff = Int(pixel.blue) - avgBlue
        if (blueDiff > 0) {
            pixel.blue = UInt8(max(0,min(255, avgBlue + blueDiff * by)))
        }
    }

    
    func adj(inout pixel:Pixel, color:String, by:Int) {
 
        switch color {
            case "Red":
                adjRed(&pixel, by:by);
            case "Green":
                adjGreen(&pixel, by:by);
            case "Blue":
                adjBlue(&pixel, by:by);
            
            default:
                print("Invalid color")
        }
    }
    
    func adj(colorIn:String, by:Int) {
        
        // Load iterate pixels of the image.
        for y in 0..<height {
            for x in 0..<width {
                let index = y * width + x
                var pixel = myRGBA.pixels[index]
  
                adj(&pixel, color:colorIn, by:by);
                myRGBA.pixels[index] = pixel

        

            }
        }
    }