This is a very simple tutorial of the source of IMdkit library.
It might be helpful when you want to study these complicated
source code. This tutorial is not completed. Additional contents
will be added in the future.


****************************************************************************


IMConn.c:	
	XIM ims;

	IMOpenIM():	_IMVaToNestedList, _FindModifiers, _GetIMS, 
			ims->methods->setup   : xi18n_setup
			ims->methods->openIM  : xi18n_openIM

	IMCloseIM():	ims->methods->closeIM : xi18n_closeIM

===========================================================
i18nMethod.c:

IMMethodsRec Xi18n_im_methods =
{
    xi18n_setup,	(ParseArgs, _Xi18nInitAttrList, _Xi18nInitExtension)

    xi18n_openIM,	(CheckIMName: 
				1. check trans.
				2. set ims->protocol->methods;
			 SetXi18nSelectionOwner: 
				1. check the root window property for 
				   XIM_SERVERS atom.
				2. insert "@server=im_name" atom to root
				   window property.
				3. create "LOCALES" & "TRANSPORT" atoms.
			 i18n_core->methods.begin ==> Xi18nXBegin

			 _XRegisterFilterByType(
				event=SelectionRequest, window=im_window,
			        func=WaitXSelectionRequest(), data=ims))

    xi18n_closeIM,	(i18n_core->methods.end ==> Xi18nXEnd

			 _XUnregisterFilter(WaitXSelectionRequest())

			 delete "@server=im_name" atom from root window
			 property. )

    xi18n_setIMValues,
    xi18n_getIMValues,
    xi18n_forwardEvent,
    xi18n_commit,
    xi18n_callCallback,
    xi18n_preeditStart,
    xi18n_preeditEnd,
};
ims->methods = Xi18n_im_methods;

===========================================================
i18nAttr.c:	(set the attributes)

IMListOfAttr Default_IMattr[] =
{
    {XNQueryInputStyle, XimType_XIMStyles},
    {(char *) NULL, (CARD16) 0}
};

IMListOfAttr Default_ICattr[] =
{
    {XNInputStyle,              XimType_CARD32},
    {XNClientWindow,            XimType_Window},
    {XNFocusWindow,             XimType_Window},
    {XNFilterEvents,            XimType_CARD32},
    {XNPreeditAttributes,       XimType_NEST},
    {XNStatusAttributes,        XimType_NEST},
    {XNFontSet,                 XimType_XFontSet},
    {XNArea,                    XimType_XRectangle},
    {XNAreaNeeded,              XimType_XRectangle},
    {XNColormap,                XimType_CARD32},
    {XNStdColormap,             XimType_CARD32},
    {XNForeground,              XimType_CARD32},
    {XNBackground,              XimType_CARD32},
    {XNBackgroundPixmap,        XimType_CARD32},
    {XNSpotLocation,            XimType_XPoint},
    {XNLineSpace,               XimType_CARD32},
    {XNPreeditState,            XimType_CARD32},
    {XNSeparatorofNestedList,   XimType_SeparatorOfNestedList},
    {(char *) NULL, (CARD16) NULL}
};

IMExtList Default_Extension[] =
{
    {"XIM_EXT_MOVE", XIM_EXTENSION, XIM_EXT_MOVE},
    {"XIM_EXT_SET_EVENT_MASK", XIM_EXTENSION, XIM_EXT_SET_EVENT_MASK},
    {"XIM_EXT_FORWARD_KEYEVENT", XIM_EXTENSION, XIM_EXT_FORWARD_KEYEVENT},
    {(char *) NULL, (CARD8) NULL, (CARD8) NULL}
};

===========================================================
i18nX.c:

_Xi18nCheckXAddress(): "X/" transport, set i18n_core->methods.

        i18n_core->methods.begin = Xi18nXBegin;
		Create atom: xim_request     = "_XIM_PROTOCOL"
		Create atom: connect_request = "_XIM_XCONNECT"
		_XRegisterFilterByType(event=ClientMessage, window=im_window,
				       func=WaitXConnectMessage(), data=ims)

        i18n_core->methods.end = Xi18nXEnd;
		_XUnregisterFilter(WaitXConnectMessage());

        i18n_core->methods.send = Xi18nXSend;

        i18n_core->methods.wait = Xi18nXWait;

        i18n_core->methods.disconnect = Xi18nXDisconnect;

WaitXConnectMessage:
	if (event->message_type == connect_request)
		ReadXConnectMessage

ReadXConnectMessage:
	check version: major_version = minor_version = 0;

	_XRegisterFilterByType(event=ClientMessage, window=accept_win,
			       func=WaitXIMProtocol, data=ims)

	XSendEvent: to new_client, ClientMessage.

WaitXIMProtocol:
	if (event->vessage_type == xim_request) {
		ReadXIMMessage();
		_Xi18nMessageHandler();
	}

ReadXIMMessage:
	get connect_id from event.

	if (ev->format == 8) {
		check for XIM_CONNECT & set byte_order.

		return the message buf: header + data (length * 4)
			header: CARD8  major_opcode;
				CARD8  minor_opcode;
				CARD16 length;
	}
	else if (ev->format == 32) {
		XGetWindowProperty(from=accept_win);

		return the property data.
	}


===========================================================
i18nPtHdr.c:

_Xi18nMessageHandler:
	XIM_GET_IM_VALUES:	GetIMValuesMessageProc()

GetIMValuesMessageProc:


----------------------------------------------------------------------------
/*
 * Register a filter with the filter machinery by type code.
 */
void
_XRegisterFilterByType(display, window, start_type, end_type,
                       filter, client_data)
    Display *display;
    Window window;
    int start_type;
    int end_type;
    Bool (*filter)(
#if NeedNestedPrototypes
                   Display*, Window, XEvent*, XPointer
#endif
                   );
    XPointer client_data;
----------------------------------------------------------------------------

See X11/imInsClbk.c:	_XimFilterPropertyNotify,
			_XimRegisterIMInstantiateCallback