#162 Support IMM

[yybbwc]

hello.Is there a plan to support input methods?
https://github.com/mercury233/irrlicht/commit/0cea1bc534b22a2265491cf656fe0065b1c5483e
Something like what's done in this project.
If Irrlicht doesn't support input methods, then Chinese users won't be able to input text in Irrlicht. Am I wrong in my understanding?

[Michael Zeilfelder]

You are probably correct. Thought strangely we do have a few Chinese users, not sure how they do it. I've never seen that patch or that Irrlicht clone. On first view I don't like the copy-paste changes in that patch too much as they break the interface instead of extending it and keeping downward compatibility. That's fine to do for your own project, but a pretty bad thing for a library. Can't say much about the changes they do with key-input without spending some time on that. Bit interesting on first view, but maybe conflicts with using keys as gaming keys (you don't want to have to hit 2 keys to get one event in games)? But really have to test it to know more.

Thanks for making me aware about the patch.

[yybbwc]

是时候支持输入法了，但考虑到难度，还是只支持windows系统上的输入法吧。

It's time to support input methods, but considering the difficulty, let's just focus on supporting input methods on the Windows system for now.

        irr::gui::IGUIElement* ele = dev->getGUIEnvironment()->getFocus();
        if (!ele || (ele->getType() != irr::gui::EGUIET_EDIT_BOX) || !ele->isEnabled())
        {
            HIMC hIMC = ImmGetContext(hWnd);
            if (hIMC)
            {
                ImmNotifyIME(hIMC, NI_COMPOSITIONSTR, CPS_COMPLETE, 0);
                ImmReleaseContext(hWnd, hIMC);
            }
            ImmAssociateContextEx(hWnd, NULL, 0);
        }
        else {
            ImmAssociateContextEx(hWnd, NULL, IACE_DEFAULT);
    }

    case WM_IME_STARTCOMPOSITION:
        {
            dev = getDeviceFromHWnd(hWnd);
            irr::gui::IGUIElement* ele = dev->getGUIEnvironment()->getFocus();
            if (!ele)
                break;
            irr::core::position2di pos = ele->getAbsolutePosition().UpperLeftCorner;
            COMPOSITIONFORM CompForm = { CFS_POINT, { pos.X, pos.Y + ele->getAbsolutePosition().getHeight() } };
            HIMC hIMC = ImmGetContext(hWnd);
            ImmSetCompositionWindow(hIMC, &CompForm);
            ImmReleaseContext(hWnd, hIMC);
        }
        break;

    case WM_IME_CHAR:
        event.EventType = irr::EET_KEY_INPUT_EVENT;
        event.KeyInput.PressedDown = true;
#ifdef _UNICODE
        event.KeyInput.Char = wParam;
#else
        BYTE ch[3];
        if (wParam >> 8) {
            ch[0] = wParam >> 8;
            ch[1] = wParam & 0xff;
            ch[2] = 0;
        } else {
            ch[0] = wParam;
            ch[1] = 0;
        }
        WORD unicodeChar;
        MultiByteToWideChar(
            KEYBOARD_INPUT_CODEPAGE,
            MB_PRECOMPOSED, // default
            (LPCSTR)ch,
            sizeof(wParam),
            (WCHAR*)&unicodeChar,
            1);
        event.KeyInput.Char = unicodeChar;
#endif
        event.KeyInput.Key = irr::KEY_ACCEPT;
        event.KeyInput.Shift = 0;
        event.KeyInput.Control = 0;
        dev = getDeviceFromHWnd(hWnd);
        if (dev)
            dev->postEventFromUser(event);
        return 0;

[yybbwc]

@cutealien 不考虑在windows上支持输入法吗？你看，这代码很短，也很简单

Not planning to support input methods on Windows? Look, the code is short and simple.

[Michael Zeilfelder]

I haven't even found time yet to look at this ... (I spend my spare-time yesterday on the other bug you reported, I'm not doing Irrlicht round-the-clock or even every evening). And nothing is ever simple, especially when you have to make things work for all users insteads of just one application.

My first thoughts on a very quick view go like this:
- It mixes device abstraction code (Irrlicht device) with gui. Maybe can't be avoided (hard to tell without spending a lot more time on it), but it's definitely not a good sign. Usually that means there is one layer of abstraction missing to separate those. Just a very simple example where this goes wrong is that some Irrlicht users compile the engine without IRR_COMPILE_WITH_GUI.
- It adds new events for key-input, what happens with the old ones? Will users now get 2 events for every key? Then this patch breaks basically every game out there using Irrlicht. So this is likely something which users have to be able to enable/disable
- Does it work fullscreen? As it the main way Irrlicht games are coded right now? Have to test.

But main problem is simply that's it's not that high up on my todo list currently - got too many half-finished open tasks already where I started and then another thing came in between and I looked at that etc. - got like half a dozen half-finished todo's at the moment.

But don't get me wrong. I'm glad this is on the feature list and people who urgently need this can just put it in their local version of the engine for now .