The user creates annotation objects and passes all of the mouse actions and user interface events such as change color, line width and font to the annotation DLL. When display is necessary (it's usually the ON_PAINT event), one can call the AnnoUIOnPaint to draw annotation objects on the display device context.
If the user wishes to write his own display routines or use a third party display library, he must process all user interface events such as mouse access separately and he must call the AnnoObjXX functions to create/resize/move objects. In this case, the user must write the frame draw functions, handle mouse cursor changes, etc. These user interface functions are supplied in the AnnoUIXX functions.)