Input Method Editors (IME)
An Input Method Editor (IME) is a software component that enables a user to input text in a language that can't be represented easily on a standard QWERTY keyboard. This is typically due to the number of characters in the user's written language, such as the various East Asian languages.
Instead of each single character appearing on a single keyboard key, a user types combinations of keys that are interpreted by the IME. The IME generates either the character that matches the set of key strokes or a list of candidate characters to choose from. The selected character is then inserted into the edit control that the user is interacting with.
IMEs can support both hardware keyboards and on-screen or touch keyboards.
Your app doesn't need to interact directly with the IME. The IME is built into the system, just as the touch keyboard is. If your app has text input, and you intend to support text input in languages that require an IME, you should test the end-to-end customer experience for text entry. This lets you fix any issues, such as adjusting your UI so it isn't occluded by the touch keyboard or IME candidate window.
Creating an IME
To enable a great input experience for all users, Microsoft produces IMEs that ship in-box for a variety of languages.
In addition to the in-box IMEs, you can build your own custom IMEs that users can install and use just like an in-box IME.
All IMEs run in the Windows system, which is hardened to stop malicious IMEs and to improve the security and user experience of all IMEs.
Custom IMEs can link to the default touch keyboard and use its layout so that end users can use their IME with the touch keyboard. However, you cannot provide your own independent touch keyboard and certain functions of in-box IMEs for touch keyboards are not available to custom IMEs.
Requirements for IMEs
A third-party IME must meet these requirements:
- Must be digitally signed
- Must be Text Services Framework (TSF) aware, with appropriate IME flags set correctly
- Must follow the guidelines described in Input Method Editor (IME) requirements and Design and code Windows apps
A third-party IME that doesn't meet these requirements is blocked from running.
Legacy custom IMEs can run in desktop apps, but are blocked in Windows apps.
Also, Windows Defender removes malicious IMEs from the system. Because of this, it's important that you familiarize yourself with the IME coding requirements. For more info, see Input Method Editor (IME) requirements.
Design guidelines for IMEs
Read the Input Method Editor (IME) requirements for more details on best practices and design guidelines for IMEs. In general, all IME UIs need to:
- Follow the UX guidelines for Windows Runtime apps
- Avoid modal experiences and only show the IME window when needed
- include icons that are black and white only