How to make a rectangle in Graphics in a transparent colour?

Question

I\'m trying to paint a rectangle on my application in a red shade but I need to make it sort of transparent so that the component under it will still show. However I still want

Answer 1

int alpha = 127; // 50% transparent
Color myColour = new Color(255, value, value, alpha);

See the Color constructors that take 4 arguments (of either int or float) for further details.