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Q10837: INFO: A Discussion of Windows Fonts

Article: Q10837
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly _IK kbSDKWin16
Last Modified: 27-JUN-1999

3.00 3.10
WINDOWS
kbprg


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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) 3.1 
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SUMMARY
=======

The following discussion on Windows fonts describes how they are defined and why
they are necessary.

MORE INFORMATION
================

How Default Fonts Are Assigned
------------------------------

At the API level, Windows version 3.0 defines six stock fonts. Each of these
fonts has a logical description. At Windows 3.0 boot time, GDI constructs the
logical description of these fonts in the following manner:

1. During its initialization, GDI calls an internal function, InitFonts(), which
  is responsible for physically loading three basic fonts. Under a typical
  Windows 3.0 installation, the names of the font files for these fonts are
  listed in the [boot] section of the SYSTEM.ini file. For example, this
  section (in part) resembles the following:

     fixedfon.fon=vgafix.fon
     oemfonts.fon=vgaoem.fon
     fonts.fon=vgasys.fon

  The system font is loaded first. GDI first checks the WIN.ini file in the
  [windows] section for the key name SystemFont=<file>, where
  <file> is a name of a bitmap font (such as HELV.FON). If GDI finds this
  keyname, it will attempt to load the specified file as thesystem font.
  Changing this value is one method the user can use to customize the system
  font. NOTE: If you change SystemFont=<font> you *must* also have the
  line fonts.fon=<font> in the [windows] section of the SYSTEM.INI file.
  Otherwise, Windows will not load properly.

  If GDI does not find this key name, it attempts to load the system font from a
  file called FONTS.fon using the GDI function AddFontResource. Notice that on
  typical installations of Windows 3.0, there is no file called FONTS.fon.
  AddFontResource calls LoadLibrary to load the specified file. If the file is
  not found, LoadLibrary will search the SYSTEM.ini file (in the [boot]
  section) for a redirection of the file. As shown above, the [boot] section of
  SYSTEM.ini for a VGA system contains the following:

     fonts.fon=vgasys.fon

  This line indicates that the system font should be loaded from the file
  VGASYS.fon, which resides in the system directory.

2. Once the system font is physically loaded, GDI attempts to load a fixed-pitch
  font. GDI examines the [boot] section of the SYSTEM.ini file and extracts the
  filename from the fixedfon.fon= field. If no file is specified, the system
  font (loaded in step 1) is substituted for the system fixed-pitch font.

3. Next, the terminal font is loaded. GDI attempts to load the file OEMFONTS.fon
  (via AddFontResource). This file may be redirected in the same manner as the
  system font in step 1.

4. Later during its initialization, GDI gets the module handle of DISPLAY. Using
  the module handle, it does a FindResource() on the resource string "fonts",
  which is an array of three LOGFONT structures that have been defined by the
  display driver manufacturer. This is the resource that is included in the
  display driver's .RC file with the line:

     fonts   oembin  PRELOAD         fonts.bin

  Once this resource is found, GDI steps through the array of LOGFONTS and calls
  CreateFontIndirect to create the stock font objects:

     OEM_FIXED_FONT
     ANSI_FIXED_FONT
     ANSI_VAR_FONT

  These logical font definitions can be thought of as recommendations for a
  particular display by the display driver. In general, these logical font
  descriptions will map to one of the physical fonts loaded initially by GDI.

  However, when an application selects one of these stock fonts, the font mapper
  selects the closest matching font from a list of available physical fonts in
  the system. This list contains the initial system fonts that were loaded by
  GDI, in addition to other fonts that may have been loaded at a later time.
  Therefore, there is no guarantee that a given stock font will necessarily map
  to one of the three initial fonts loaded by GDI.

5. Once these three stock fonts have been defined, GDI defines the stock font
  SYSTEM_FONT. GDI does this by opening the system font file loaded in step 1
  and builds a logical font structure that exactly matches the physical
  characteristics of the physical font. This is to ensure that the font mapper
  will select this physical font when the SYSTEM_FONT stock font is requested.

6. Finally, the logical description of the device default font
  (DEVICE_DEFAULT_FONT) is defined. This font is defined to be the same as the
  SYSTEM_FONT.

Why These Fonts Are Necessary
-----------------------------

There are two reasons for having these six stock fonts. One reason is to provide
an OEM font that displays well at 10 pitch on the machine. This font is also
used to determine the height of dialog boxes. The second reason is to provide
ANSI fonts that are based on proposed standards (device-independent) and match
Microsoft's virtual-key definitions.

Please note that all of these fonts are required. The display driver must include
the three logical fonts (described above) or GDI will not initialize properly.

Additional query words: 3.00 3.10

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Keywords          : kb16bitonly _IK kbSDKWin16 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1
Issue type        : kbinfo

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