The metafile can be seen as the identifying tag that is used to describe or specify some type of data or action file. In this sense, the metafile is understood to be the sneak preview of what another file is all about. Several types of metafiles are in common usage today, with the configurations and actual relation to other files varying slightly.
One of the more common examples of the metafile is the Windows Metafile, or WMF. Utilized in Microsoft applications, the WMF is structured with the inclusion of a graphical device interface protocol that makes it possible to present a graphic image. By issuing the command to retrieve the information, the metafile initiates a search and retrieve function and generates the display. Some of the commands involved are a lot like vector graphics statements.
In other instances, the commands may involve the identification and retrieval of stored bitmaps from some location on the hard drive. While it is possible to obtain the information by using the bitmaps that are already built and in place, choosing to go with a metafile like WMF will actually save space and time. This especially true when the bitmap in question is in use by multiple components within the operating system or one of the applications that are open and running.
A second example of the metafile is known as the Computer Graphics Metafile, or CGM. Using standards developed and maintained by the American National Standards Institute, the CGM will function on any type of operating system. This is one advantage over the WMF, which will only work in a Windows environment. The Computer Graphics Metafile will provide all the functionality of the Windows Metafile, which gives users who choose to go with an operating system other than a Microsoft based application the same options and ability to access graphics.
Because of the variance in the type of metafiles in use today, several conversion tools have been developed that make it easy to convert one metafile format into a different type of metafile configuration. These tools can be installed on the hard drive and programmed to automatically execute the conversions, or be used on a case by case basis within a larger network.
