I will soon add some functions to the extension to manipulate alpha and other colors.
In the meantime, you can increase a bitmap's alpha by blitting onto it another bitmap with "ADD" option. ADD adds the values of each channel (A, R, G, B) separately for each pixel:
Code:
-- AS_bitmap is the target Area Select bitmap
alpha_bitmap = reaper.JS_LICE_CreateBitmap(true, 1, 1)
reaper.JS_LICE_Clear(alpha_bitmap, 0xFF000000) -- This value will added to ASbm
reaper.JS_LICE_ScaledBlit(AS_bitmap, 0, 0, w, h, alpha_bitmap, 0, 0, 1, 1, 1, "ADD")
I only discovered this trick today, after experimenting with the blitting modes. My previous examples would have been better if I used this.
"MUL" mode can be used to lower the brightness of each channel separately.
I'm not quite sure yet what "HSVADJ" and "MASK" do on a bitwise level.