Why does GetObject return an BITMAP with null bmBits?

Question

Context: I\'m trying to take a screenshot of another window to feed it into OpenCV. I found some code on the web that should be able to convert a BITMAP to something OpenCV can

Answer 1

The bmBits member is non-null for DIB sections. For device-dependent bitmaps (such as the one you're creating), the bmBits is not set because the pixels are on the video card, not in main memory.

In your example, you need to change CreateCompatibleBitmap to CreateDIBSection if you want direct access to the bits.