• OpenCV => master
• Operating System / Platform => Windows 64 Bit
• Compiler => mingw64 / 7.2.0

Detailed description

regression after: 11eafca

the cvConvertImage() calls were removed.
while code was added to adapt the colorspace, there is no more depth conversion to CV_8U

Steps to reproduce

//Mat m(400,400,CV_32FC3,Scalar(1.0));
Mat m(400,400,CV_16U,Scalar(255));
imshow("win",m);
waitKey();

leading to:

OpenCV(4.0.0-pre) Error: Assertion failed (dst.data == (uchar*)dst_ptr) in cvShowImage, file C:\p\opencv\modules\highgui\src\window_w32.cpp, line 1230

apart from the windows version (tried here), others will be affected:

• window_w32.cpp
• window_cocoa.mm
• window_gtk.cpp
• window_QT.cpp