Microsoft KB Archive/152753

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KeybFont.exe - Input Language and Font Matching

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Q152753

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The information in this article applies to:


 * Microsoft Win32 Software Development Kit (SDK)

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SUMMARY
In Windows 95 and Windows NT 4.0 non-Unicode applications, when the input language changes and, as a result, the default character set supported by this language also changes, the script of the current font should also be changed, such as changing the input language from English to Russian. By the same token, when the character set (script) of the font changes, the input language should be changed to match the new script, such as changing from Times New Roman Western script to Times New Roman Cyrillic script. Note that in Windows NT 4.0 Unicode applications, changing the font is not necessary because of support for multicharset fonts. For these applications, the methods described here can be used to detect if a given language is supported by a given font.

The KEYBFONT sample demonstrates the use of WM_INPUTLANGCHANGEREQUEST and WM_INPUTLANGCHANGE messages to match the current font to the input language. If the current font is changed, the list of loaded keyboard drivers is scanned for a match and, if one is found, the font is allowed to change. Otherwise, an error message is displayed and the font does not change. If the input language changes, the scripts of the current font are scanned for a match and, if none is found, an error message is displayed and the input language does not change.

MORE INFORMATION
The following file is available for download from the Microsoft Download Center:

"KeybFont.exe" For additional information about how to download Microsoft Support files, click the article number below to view the article in the Microsoft Knowledge Base:

"Q119591 How to Obtain Microsoft Support Files from Online Services" Microsoft used the most current virus detection software available on the date of posting to scan this file for viruses. Once posted, the file is housed on secure servers that prevent any unauthorized changes to the file.

NOTE: Use the -d option when running Keybfont.exe to decompress the file and recreate the proper directory structure.

The WM_INPUTLANGCHANGEREQUEST message is sent when the user chooses an input language, either with an input language change hotkey (see Control Panel.Keyboard.Language.Switch Languages) or from the language indicator on the system taskbar. This indicator will only be present if more than one keyboard layout has been installed and the indicator is enabled. An application can accept the change by passing the message to the DefWindowProc function, or reject the change, preventing it from taking place, by returning immediately.

In this sample, during WM_INPUTLANGCHANGEREQUEST, the character set of the requested language is compared to the default character set of each font script in the current font family through EnumFontFamilies. If the font is not supported, the function returns immediately, disallowing any language change request.

The WM_INPUTLANGCHANGE message is sent to the top-most affected window after a task's locale has been changed. It should be used to make any application-specific settings, such as changing the current font script, and passed on to the DefWindowProc function to be passed on to any children.

In this sample, during WM_INPUTLANGCHANGE, the script of the current font is changed to match the character set of the language the user has switched to.