Active Input Method Manager Overview

Active Input Method Manager (Active IMM) provides limited Far Eastern input support on non-Far East versions of Microsoft® Windows® 95 and Microsoft Windows NT® 4.0. This technology will change after Microsoft Internet Explorer 5 is released.

Note This technology is not meant as a replacement for the Win32® Input Method Manager (IMM) API and it only offers limited IMM support. Windows NT 5.0 will provide complete cross-language input support.

The following topics are covered in this article:

• Prerequisites and Requirements
• Key Terms
• Supporting Active IMM

Prerequisites and Requirements

This documentation assumes a familiarity with the Win32 IMM API and Input Method Editors (IMEs). For more information on the Win32 IMM API, see the documentation in the Microsoft Platform Software Development Kit (SDK).  For more information on IMEs, see the Microsoft Windows NT Device Driver Kit.

Key Terms

The following topics are key terms in understanding the Active Input Method Manager API.

Input Method Manager

The Input Method Manager (IMM) is a component in the Windows system that provides a connection between the application and Input Method Editors (IME) used primarily to input East Asian characters. The IMM also manages the installation of IMEs. IMEs are implemented as one of a number of keyboard layouts. IMM support is only available in the Far Eastern versions of Windows 95 and Windows NT 4.0. Because NT 5.0 contains cross-language version IMM support, it does not require Active IMM. Therefore, Active IMM is disabled for Windows NT 5.0 and later.

Active Input Method Manager

The Active Input Method Manager (Active IMM) is an ActiveX® object that provides limited IMM service on non-Far East language versions of Windows and Windows NT 4.0 platforms. Conventional IMM service was available only on Far Eastern Windows and Windows NT 4.0. Active IMM can be installed on any language version of these two platforms. Active IMM will provide limited IMM service for supporting clients only for these platforms. On Far East language versions of Windows NT 4.0 and Windows 95, Active IMM simply works as a wrapper to the native IMM system.

The Active IMEs are also implemented as keyboard layouts, but they are only accessible when an Active IMM client application has the focus. Applications that are not Active IMM-aware remain unaware of the Active IME keyboard layouts. Microsoft has developed a limited number of Far Eastern Active IMEs that make use of the Active IMM, including Japanese, Korean, simplified Chinese, and traditional Chinese Active IMEs.

Supporting Active IMM

To support Active IMM, client applications are required to follow these steps:

1. Call CoCreateInstance to create an instance of the Active Input Method Manager Object.
2. Obtain a pointer to the IActiveIMMApp interface.
3. Obtain a pointer to the IActiveIMMMessagePumpOwner interface, if the client application owns the message pump.
4. Call the IActiveIMMApp::Activate method to start the Active IMM service.

   Client applications should call the IActiveIMMApp::Activate method on each thread they want to enable or disable support for Active IMEs on.

5. Call the IActiveIMMMessagePumpOwner::Start method, if the client application owns the message pump.
6. Call the IActiveIMMApp::OnDefWindowProc method instead of calling DefWindowProc. Only call DefWindowProc if the return value of IActiveIMMApp::OnDefWindowProc indicates the call wasn't handled.
7. Call the IActiveIMMMessagePumpOwner::OnTranslateMessage method instead of calling TranslateMessage. Only call TranslateMessage if the return value indicates the call wasn't handled.
8. Optional. Call IActiveIMMApp::FilterClientWindows to limit which window classes allow Active IME interaction. This is particularly useful to prevent interaction with component windows (such as Win32 Common Controls) that do not support Active IMEs.
9. Call the Active IMM methods instead of using the Win32 IMM APIs.