Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
Looks like a bug in Magick++. We will fix in the next point release. In the mean-time, reverse the gamma and white point until we get the bug fixed. Keep in mind that the white point is relative to the QuantumDepth. For Q16 you need to scale the white point for the range 0..65535.