creating a bitmap pattern for a window's HBRUSH

Answer 1

You could use CreateHatchBrush for simple inbuilt patterns. To create your own, you use CreatePatternBrush.

To quote from MSDN:

A brush created by using a monochrome (1 bit per pixel) bitmap has the text and background colors of the device context to which it is drawn. Pixels represented by a 0 bit are drawn with the current text color; pixels represented by a 1 bit are drawn with the current background color.

Which is I beleave what you are trying to do?

Answer 2

You get the current back colour of a device context by using GetBkColor. You can get a device context compatible with the window using GetDC. To put it together, use something like this:

HDC dc=GetDC(hWnd);
COLORREF backColour=GetBkColor(dc);

// do something...

ReleaseDC(dc);