Also, I noticed that converting mute_overlay_mode=
196608 decimal value to hexadecimal gives the 5-digit number 30000, which in this case is equal to the alpha of 1.00.
Converting mute_overlay_mode=
131072 decimal value to hexadecimal gives the 5-digit number 20000, which in this case is equal to the alpha of 0.00.
I cannot figure out how these 5-digit hex values relate to alpha values. Do they deal with alpha only or do they also encode the blend mode?
I am way in over my head, but it's fun!
EDIT: After some messing about it looks like setting the value of mute_overlay_mode in .ReaperTheme to 196608 or 131072 does not affect the blend mode and only changes the alpha value.
I can see this by keeping the Theme development/tweaker open and refreshing the theme after changing the values in .ReaperTheme. The Theme development/tweaker reads the new values from .ReaperTheme which is handy for understanding things.
So the question that remains is how are alpha values encoded/transcoded between decimal (e.g. 196608) and hexadecimal (e.g. 30000) and float (e.g. 1.00)? And how would one reverse engineer what the alpha value of, say, 0.75 is in decimal to be able to type it into .ReaperTheme?