It would help if you told us which language you are using, both for coding the DLL, and whether it's DBC or DBPro ...
If it's C++, and you are coding for DBPro, and you are using my Interface library, then you can do something like this:
#include <DBPro.hpp>
void BitmapCommand(int Bitmap)
{
int SaveBitmap = DBPro::CurrentBitmap();
DBPro::SetCurrentBitmap(Bitmap);
DBPro::LockPixels();
char* Ptr = DBPro::GetPixelsPointer();
// Manipulate the pixel data
DBPro::UnlockPixels();
DBPro::SetCurrentBitmap(SaveBitmap);
}
*** Coming soon - Network Plug-in - Check my site for info ***
For free Plug-ins, source and the Interface library for Visual C++ 6, .NET and now for Dev-C++
http://www.matrix1.demon.co.uk