Mac 32 bit color depth?

[Wayne Landsman <landsman(at)mpb.gsfc.nasa.gov>]

I have a simple program that tries to reset the default value of
!P.COLOR for the current (Mac, Win or X) device using the following
code:

device, get_visual_depth=depth
!P.Color = 256L^(depth/8) - 1

I am told that this fails on IDL V5.4 on a Mac since
device,/get_visual_depth returns a value of 32 (whereas !P.COLOR is
256L^24 -1).   Can other Mac users verify this?      What is the meaning
of a 32 bit  visual depth?

Thanks,  --Wayne

Wayne
Landsman
landsman@mpb.gsfc.nasa.gov