After an application selects the appropriate font, sets the required text-formatting options, and computes the necessary character width and height values for a string of text, it can begin drawing characters and symbols by calling any of the four text-output functions. Two of these functions, DrawText and TabbedTextOut, are part of Window Manager and found in the library USER.DLL; the remaining two functions are part of GDI and found in the library GDI.DLL. When an application calls one of these functions, the operating system passes the call to the graphics engine, which in turn passes the call to the appropriate device driver. At the device driver level, all of these calls are supported by one or more calls to the driver's own ExtTextOut or TextOut function. An application will achieve the fastest execution by calling the ExtTextOut function, which is quickly converted into an ExtTextOut call for the device. However, there are instances when an application should call one of the other three functions; for example, to draw multiple lines of text within the borders of a specified rectangular region, it is more efficient to call the DrawText function. To create a multicolumn table with justified columns of text, it is more efficient to call the TabbedTextOut function.