How make minifb window transparent?

Using minifb how do you make make a image transparent? The window option for transparency makes sense, but gives issues as shown below. Besides I was wondering if there was a cleaner way to handle my if mode != 0 && mode != 1 bit. I feel I should be able to utilize the code in the if, but I am not sure how. I use Linux btw so it should be implemented: WindowOptions in minifb - Rust Code Output