OS X help needed

[John W. Eaton]

We have the following code to get the number of bits per pixel for the 
current display on OS X systems:

#if defined (HAVE_CARBON_CGDISPLAYBITSPERPIXEL)

      *dp = CGDisplayBitsPerPixel (display);

#else

      /* FIXME: This will only work for MacOS > 10.5.  For earlier versions
         this code is not needed (use CGDisplayBitsPerPixel instead).  */

      CGDisplayModeRef mode = CGDisplayCopyDisplayMode (display);
      CFStringRef pixelEncoding = CGDisplayModeCopyPixelEncoding (mode);

      if (CFStringCompare (pixelEncoding, CFSTR (IO32BitDirectPixels), 
0) == 0)
        *dp = 32;
      else if (CFStringCompare (pixelEncoding,
                                CFSTR (IO16BitDirectPixels), 0) == 0)
        *dp = 16;
      else
        *dp = 8;

#endif

But now I see that the function CGDisplayModeCopyPixelEncoding has been 
deprecated for OS X 10.11.  Is there a replacement?  It doesn't have to 
be a direct replacement for this function, we just need some way to get 
a value for the number of bits per pixel for the display.

jwe