如何在iOS的C＃中为固定背景图像上的颜色设置颜色的透明度级别？

Question

I would like to have these 2 things in my iOS game:

(A) One background image of a car as the background image of the game. This background image has the RED color. (I already know how to do this part A).

(B) Next, I want to draw a GREEN rectangle on the TOP of that background image of the car. But, I need to set some level of transparency for that GREEN rectangle so that the GREEN rectangle is 50% clear (or transparent) in order for viewers to be able to see the part of the car behind that GREEN rectangle. This transparency is what I don't know how to implement yet.

Would you please show me how to write the code for part (B) in C# for iOS ?

( I am using C# with Xamarin to write code, and unfortunately, I can't understand Objective-C or Swift .)

Thank you very much.

Answer 1

很简单，您可以在图像上添加UIView，将其背景颜色设置为绿色，并将其Alpha设置为介于0和1之间的某个值。