It would be nice if CEF were enhanced to support IME-aware applications, so that CJK text can be entered in a more natural form. This includes supporting a positionable IME window and underlining the current composition, as is done in Chrome.

I've attached a patch that adds this support to CEF. We currently use this code in Evernote 4. ime_input.cc and ime_input.h were copied from Chromium as-is (updated one or two include's to point to local files). Changes to web_widget_host_win.cc and web_widget_host.h were copied from Chromium with only minor updates to make them compile for CEF. All source comments were left as-is from Chromium.

Overall, looks good. A few questions:

1. Can you explain the changes to ime_input.[cc|h] that made it necessary to copy these files into CEF instead of using them from their current location in the ui_base target (which is already a dependency of libcef)?

2. It looks like the ViewHostMsg_ImeControl enumeration isn't used in webwidget_host_win.cc. Can it be removed?

3. What is the easiest/simplest way to test this functionality?

Hi Marshall,

1. The only changes I made to ime_input.[cc|h} involved updating a couple of include files to point locally. If their current location is already a dependency of libcef, I must have just missed that completely, so there would be no need to duplicate them.

2. Yes, ViewHostMsg_ImeControl can be removed. I believe it's a hold over from a previous revision of the IME code in Chromium (several changes to IME support were made between revision 66269 and 80310; I must have missed deleting that when I ported to 80310).

3. The easiest way to test this at the moment (assumes Windows 7) is to go to the Region and Language control panel applet. On the Keyboards and Languages tab, press the "Change keyboards..." button. Click "Add" and select "Japanese (Japan)" -> Keyboard -> Japanese and Microsoft IME. Then OK everything. Once you've done that, you should see the language bar in your task bar with EN for English and you're ready to test.

For me, testing usually consists of running a release version of Chrome to determine the "expected" properties/behaviors of CJK text entry and then running CefClient to confirm the expected behavior. The language bar should be set to JP and, say, full-width Katakana for both applications (the language settings appear to be app-specific). There are two primary behaviors I've been testing for:

1. When entering text into a text field or contentEditable area, the current composition (i.e. the words/phrase being composed) should have a thick black underline that identifies it. To complete the composition, you press the spacebar one time (caret should jump to the beginning of the composition). Press the spacebar a second time to pop up the window of suggested completions and use arrows/Enter/etc. to navigate and choose from this list).

2. When entering text into a text field or contentEditable area, the IME editing should occur "in-place" directly over the text field. No matter where you type, this window should always auto-position itself directly beneath your current composition. The "default" IME window should'nt appear at all and is not used.

I don't speak or write any CJK languages, so my testing was to the best of my ability but still fairly minimal. However, the feedback on our product is that it works as expected and is always much preffered to the standard "non-IME aware" application support.

Thanks for the detailed explanation. I'll commit this once I've had a chance to try your instructions and the existing version of ime_input.[cc|h].

Committed as revision 257 with minor changes.