The WGL4 Character Set
Traditionally, a font has been designed to contain all the glyphs required by a single codepage. However, Microsoft has now defined a character set standard which includes characters required by Western, Central, and Eastern European writing systems, as well as characters required by Greek and Turkish. This "PanEuropean" character set contains 652 characters and is called WGL4: Windows Glyph List 4. WGL4 takes advantage of the ability of Windows 95 to address characters according to their Unicode Double-Byte character codes using API extensions.
Note WGL4 fonts are not required under Windows 95. Windows 95 will continue to support fonts which worked under Windows 3.1.
The WGL4 character set covers several codepages: 1250, 1251, 1252, 1253, and 1254. A user can load a single WGL4 font, and change codepages as needed. Previously, a user desiring to switch from English to Cyrillic to Greek while typing would have to choose three different fonts: first typing in Times New Roman, then in Times New Roman Cyrillic, and then in Times New Roman Greek.
Microsoft is supporting font developers as they create new WGL4 fonts. Windows 95 will also enable font developers to create fonts for large character sets other than WGL4, and users will be able to access all the glyphs as long as the associated characters exist in codepages supported by Windows 95.
The WGL4 character set is listed in Chapter 4 of the TrueType 1.0 Font File Specification (available on MSDN). The character set is compared to Win 3.1 ANSI, UGL, and Macintosh character sets.