Unlike an embedded window, an extended window displays a bitmap (up to 256 colors) only when the user clicks a hot spot. You can move, maximize, or resize an extended bitmap window independent of the main Viewer window. An extended bitmap window remains displayed even when you change topics, so you can examine the picture displayed in the window while you are looking at other topics. Extended windows also have scroll bars so that you can scroll large bitmaps vertically or horizontally.
Each bitmap displayed in an extended window is contained in a separate file, which must be in Windows DIB format. Bitmap files can reside in one of two locations:
In a normal MS-DOS directory (typically, a subdirectory of the project directory). Unless you specify otherwise, bitmap files are stored in this way.
As part of the file system associated with the .MVB file. See “Storing Bitmap Files Within a Title,” later in this chapter, for more information.