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tqt3/src/kernel/qinputcontext.cpp

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/****************************************************************************
** $Id: qinputcontext.cpp,v 1.6 2004/06/22 06:47:30 daisuke Exp $
**
** Implementation of TQInputContext class
**
** Copyright (C) 2000-2003 Trolltech AS. All rights reserved.
**
** This file is part of the kernel module of the TQt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.TQPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid TQt Enterprise Edition or TQt Professional Edition
** licenses for Unix/X11 may use this file in accordance with the TQt Commercial
** License Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about TQt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for TQPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/
//#define TQT_NO_IM_PREEDIT_RELOCATION
#include "ntqinputcontext.h"
#ifndef TQT_NO_IM
#include "qplatformdefs.h"
#include "ntqapplication.h"
#include "ntqwidget.h"
#include "ntqpopupmenu.h"
#include <stdlib.h>
#include <limits.h>
class TQInputContextPrivate
{
public:
TQInputContextPrivate()
: holderWidget( 0 ), composingWidget( 0 ), hasFocus( FALSE ),
isComposing( FALSE )
#if !defined(TQT_NO_IM_PREEDIT_RELOCATION)
, preeditString( TQString::null ),
cursorPosition( -1 ), selLength ( 0 )
#endif
{}
TQWidget *holderWidget; // widget to which TQInputContext instance belongs.
TQWidget *composingWidget;
bool hasFocus;
bool isComposing;
void updateComposingState( const TQString &text,
int newCursorPosition, int newSelLength ) {
#if !defined(TQT_NO_IM_PREEDIT_RELOCATION)
preeditString = text;
cursorPosition = newCursorPosition;
selLength = newSelLength;
#endif
}
void resetComposingState() {
isComposing = FALSE;
#if !defined(TQT_NO_IM_PREEDIT_RELOCATION)
preeditString = TQString::null;
cursorPosition = -1;
selLength = 0;
#endif
}
#if !defined(TQT_NO_IM_PREEDIT_RELOCATION)
TQString preeditString;
int cursorPosition;
int selLength;
#endif
};
// UPDATED COMMENT REQUIRED -- 2004-07-08 YamaKen
/*!
\class TQInputContext ntqinputcontext.h
\brief The TQInputContext class abstracts the input method dependent data and composing state.
\ingroup i18n
An input method is responsible to input complex text that cannot
be inputted via simple keymap. It converts a sequence of input
events (typically key events) into a text string through the input
method specific converting process. The class of the processes are
widely ranging from simple finite state machine to complex text
translator that pools a whole paragraph of a text with text
editing capability to perform grammar and semantic analysis.
To abstract such different input method specific intermediate
information, TQt offers the TQInputContext as base class. The
concept is well known as 'input context' in the input method
domain. an input context is created for a text widget in response
to a demand. It is ensured that an input context is prepared for
an input method before input to a text widget.
Multiple input contexts that is belonging to a single input method
may concurrently coexist. Suppose multi-window text editor. Each
text widget of window A and B holds different TQInputContext
instance which contains different state information such as
partially composed text.
\section1 Groups of functions:
\table
\header \i Context \i Functions
\row \i Receiving information \i
x11FilterEvent(),
filterEvent(),
setMicroFocus(),
mouseHandler()
\row \i Sending back composed text \i
sendIMEvent(),
\row \i State change notification \i
setFocus(),
unsetFocus(),
reset()
\row \i Context information \i
identifierName(),
language(),
font(),
isComposing(),
\endtable
\section1 Sharing input context between text widgets
Any input context can be shared between several text widgets to
reduce resource consumption. In ideal case, each text widgets
should be allocated dedicated input context. But some complex
input contexts require slightly heavy resource such as 100
kilobytes of memory. It prevents quite many text widgets from
being used concurrently.
To resolve such problem, we can share an input context. There is
one 'input context holder widget' per text widgets that shares
identical input context. In this model, the holder widget owns the
shared input context. Other text widgets access the input context
via TQApplication::locateICHolderWidget(). But the access
convention is transparently hidden into TQWidget, so developers are
not required to aware of it.
What developer should know is only the mapping function
TQApplication::locateICHolderWidget(). It accepts a widget as
argument and returns its holder widget. Default implementation
returns the top-level widget of the widget as reasonable
assumption. But some applications should reimplement the function
to fit application specific usability. See
TQApplication::locateICHolderWidget() for further information.
\section1 Preedit preservation
As described above, input contexts have wide variety of amount of
the state information in accordance with belonging input
method. It is ranging from 2-3 keystrokes of sequence in
deterministic input methods to hundreds of keystrokes with
semantic text refinement in complex input methods such as ordinary
Japanese input method. The difference requires the different reset
policies in losing input focus.
The former simple input method case, users will prefer resetting
the context to back to the neutral state when something
happened. Suppose a web browsing. The user scroll the page by
scrollbar after he or she has typed a half of the valid key
sequence into a text widget. In the case, the input context should
be reset in losing focus when he or she has dragged the
scrollbar. He or she will be confused if the input context is
still preserved until focused back to the text widget because he
or she will restart typing with first key of the sequence as a
habitual operation.
On the other hand, we should choose completely different policy
for the latter complex input method case. Suppose same situation
as above but he or she is using a complex input method. In the
case, he or she will be angry if the input context has been lost
when he or she has dragged the scrollbar because the input context
contained a valuably composed text made up by considerable input
cost. So we should not reset the input context in the case. And
the input context should be preserved until focused back to the
text widget. This behavior is named as 'preedit preservation'.
The two policies can be switched by calling or not calling reset()
in unsetFocus(). Default implementation of unsetFocus() calls
reset() to fit the simple input methods. The implementation is
expressed as 'preedit preservation is disabled'.
\section1 Preedit relocation
Although the most case of the preedit preservation problem for
complex input methods is resolved as described above, there is a
special case. Suppose the case that matches all of the following
conditions.
\list
\i a input focus has been moved from a text widget to another text
widget directly
\i the input context is shared between the two text widgets
\i preedit preservation is enabled for the input context
\endlist
In the case, there are the following two requirements that
contradicts each other. The input context sharing causes it.
\list
\i the input context has to be reset to prepare to input to the
newly focused text widget
\i the input context has to be preserved until focused back to the
previous text widget
\endlist
A intrinsic feature named 'preedit relocation' is available to
compromise the requirements. If the feature is enabled for the
input context, it is simply moved to the new text widget with the
preedit string. The user continues the input on the new text
widget, or relocate it to another text widget. The preedit of
previous text widget is automatically cleared to back to the
neutral state of the widget.
This strange behavior is just a compromise. As described in
previous section, complex input method user should not be exposed
to the risk losing the input context because it contains valuable
long text made up with considerable input cost. The user will
immediately focus back to the previous text widget to continue the
input in the correct text widget if the preedit relocation
occurred. The feature is mainly existing as safety.
The feature properly works even if the focus is moved as
following. Input method developers are not required to be aware of
the relocation protocol since TQInputContext transparently handles
it.
a text widget -> a non-text widget -> another text widget
To enable the preedit relocation feature, the input context class
have to reimplement isPreeditRelocationEnabled() as returns TRUE.
The implementation requires that the preedit preservation is also
enabled since preedit relocation is a special case of the preedit
preservation. If the preedit relocation is disabled, the input
context is simply reset in the relocation case.
\section1 Input context instanciation
\section1 Input method switching
\section1 Text widget implementor's guide
Add following code fragment into createPopupMenu() to add input
method dependent submenus.
\code
#ifndef TQT_NO_IM
TQInputContext *qic = getInputContext();
if ( qic )
qic->addMenusTo( popup );
#endif
\endcode
\sa TQInputContextPlugin, TQInputContextFactory, TQApplication::locateICHolderWidget(), TQApplication::defaultInputMethod()
*/
/*!
Constructs an input context.
holderWidget is set immediately after this constructor has been
returned on the X11 platform.
*/
TQInputContext::TQInputContext( TQObject *parent )
: TQObject( parent )
{
d = new TQInputContextPrivate;
}
/*!
Destroys the input context.
*/
TQInputContext::~TQInputContext()
{
delete d;
}
#if defined(TQ_WS_X11)
/*!
\internal
Returns the owner of this input context. Ordinary input methods
should not call this function directly to keep platform
independence and flexible configuration possibility.
The return value may differ from focusWidget() if the input
context is shared between several text widgets.
\sa setHolderWidget(), focusWidget()
*/
TQWidget *TQInputContext::holderWidget() const
{
return d->holderWidget;
}
/*!
\internal
Sets the owner of this input context. Ordinary input methods
must not call this function directly.
\sa holderWidget()
*/
void TQInputContext::setHolderWidget( TQWidget *w )
{
d->holderWidget = w;
}
/*!
\internal
Returns the widget that has an input focus for this input
context. Ordinary input methods should not call this function
directly to keep platform independence and flexible configuration
possibility.
The return value may differ from holderWidget() if the input
context is shared between several text widgets.
\sa setFocusWidget(), holderWidget()
*/
TQWidget *TQInputContext::focusWidget() const
{
return d->hasFocus ? d->composingWidget : 0;
}
/*!
\internal
Sets the widget that has an input focus for this input
context. Ordinary input methods must not call this function
directly.
\sa focusWidget()
*/
void TQInputContext::setFocusWidget( TQWidget *w )
{
if ( w ) {
bool isFocusingBack = ( w == d->composingWidget );
bool isPreeditRelocation = ( ! isFocusingBack && isComposing() &&
d->composingWidget );
// invoke sendIMEventInternal() rather than sendIMEvent() to
// avoid altering the composing state
if ( isPreeditRelocation == TRUE ) {
// clear preedit of previously focused text
// widget. preserved preedit may be exist even if
// isPreeditRelocationEnabled() == FALSE.
sendIMEventInternal( TQEvent::IMEnd );
}
d->composingWidget = w; // changes recipient of TQIMEvent
if ( isPreeditRelocation == TRUE ) {
#if !defined(TQT_NO_IM_PREEDIT_RELOCATION)
if ( isPreeditRelocationEnabled() ) {
// copy preedit state to the widget that gaining focus
sendIMEventInternal( TQEvent::IMStart );
sendIMEventInternal( TQEvent::IMCompose, d->preeditString,
d->cursorPosition, d->selLength );
} else
#endif
{
// reset input context when the shared context has
// focused on another text widget
reset();
}
}
}
d->hasFocus = w ? TRUE : FALSE;
}
/*!
\internal
This function is called from TQWidget to keep input state
consistency. Ordinary input method must not call this function
directly.
*/
void TQInputContext::releaseComposingWidget( TQWidget *w )
{
if ( d->composingWidget == w ) {
d->composingWidget = 0;
d->hasFocus = FALSE;
}
}
#endif // TQ_WS_X11
/*!
\internal
This function can be reimplemented in a subclass as returning TRUE
if you want making your input method enable the preedit
relocation. See the description for preedit relocation of
TQInputContext.
/sa TQInputContext
*/
bool TQInputContext::isPreeditRelocationEnabled()
{
return FALSE;
}
/*!
This function indicates whether IMStart event had been sent to the
text widget. It is ensured that an input context can send IMCompose
or IMEnd event safely if this function returned TRUE.
The state is automatically being tracked through sendIMEvent().
\sa sendIMEvent()
*/
bool TQInputContext::isComposing() const
{
return d->isComposing;
}
/*!
This function can be reimplemented in a subclass to filter input
events.
Return TRUE if the \a event has been consumed. Otherwise, the
unfiltered \a event will be forwarded to widgets as ordinary
way. Although the input events have accept() and ignore()
methods, leave it untouched.
\a event is currently restricted to TQKeyEvent. But some input
method related events such as TQWheelEvent or TQTabletEvent may be
added in future.
The filtering opportunity is always given to the input context as
soon as possible. It has to be taken place before any other key
event consumers such as eventfilters and accelerators because some
input methods require quite various key combination and
sequences. It often conflicts with accelerators and so on, so we
must give the input context the filtering opportunity first to
ensure all input methods work properly regardless of application
design.
Ordinary input methods require discrete key events to work
properly, so TQt's key compression is always disabled for any input
contexts.
\sa TQKeyEvent, x11FilterEvent()
*/
bool TQInputContext::filterEvent( const TQEvent *event )
{
Q_UNUSED(event);
return FALSE;
}
/*!
\fn void TQInputContext::deletionRequested()
Emit this signal when a fatal error has been caused in the input
context. The input context will be deleted by the owner which is
usually the holder widget.
*/
/*!
\fn void TQInputContext::imEventGenerated( TQObject *receiver, TQIMEvent *e )
\internal
This signal is emitted when the user has sent a TQIMEvent through
sendIMEvent(). Ordinary input methods should not emit this signal
directly.
\a receiver is a platform dependent destination of the \a e.
\sa TQIMEvent, sendIMEvent(), sendIMEventInternal(),
*/
/*!
\internal
Sends a TQIMEvent to the client via imEventGenerated()
signal. Ordinary input method should not call this function
directly.
\sa TQIMEvent, TQIMComposeEvent, sendIMEvent(), imEventGenerated()
*/
void TQInputContext::sendIMEventInternal( TQEvent::Type type,
const TQString &text,
int cursorPosition, int selLength )
{
TQObject *receiver = 0;
TQIMEvent *event = 0;
#if defined(TQ_WS_X11)
receiver = d->composingWidget;
#elif defined(TQ_WS_QWS)
// just a placeholder
#endif
if ( ! receiver )
return;
if ( type == TQEvent::IMStart ) {
tqDebug( "sending IMStart with %d chars to %p",
text.length(), receiver );
event = new TQIMEvent( type, text, cursorPosition );
} else if ( type == TQEvent::IMEnd ) {
tqDebug( "sending IMEnd with %d chars to %p, text=%s",
text.length(), receiver, (const char*)text.local8Bit() );
event = new TQIMEvent( type, text, cursorPosition );
} else if ( type == TQEvent::IMCompose ) {
tqDebug( "sending IMCompose to %p with %d chars, cpos=%d, sellen=%d, text=%s",
receiver, text.length(), cursorPosition, selLength,
(const char*)text.local8Bit() );
event = new TQIMComposeEvent( type, text, cursorPosition, selLength );
}
if ( event )
emit imEventGenerated( receiver, event );
}
/*!
Call this function to send TQIMEvent to the text widget. This
function constructs a TQIMEvent based on the arguments and send it
to the appropriate widget. Ordinary input method should not
reimplement this function.
\a type is either \c TQEvent::IMStart or \c TQEvent::IMCompose or \c
TQEvent::IMEnd. You have to send a \c TQEvent::IMStart to start
composing, then send several \c TQEvent::IMCompose to update the
preedit of the widget, and finalize the composition with sending
\c TQEvent::IMEnd.
\c TQEvent::IMStart should always be sent without arguments as:
\code
sendIMEvent( TQEvent::IMStart )
\endcode
And \c TQEvent::IMCompose can be sent without cursor:
\code
sendIMEvent( TQEvent::IMCompose, TQString( "a text" ) )
\endcode
Or optionally with cursor with \a cursorPosition:
\code
sendIMEvent( TQEvent::IMCompose, TQString( "a text with cursor" ), 12 )
\endcode
Note that \a cursorPosition also specifies microfocus position.
Or optionally with selection text:
\code
sendIMEvent( TQEvent::IMCompose, TQString( "a text with selection" ), 12, 9 )
\endcode
\a cursorPosition and \a selLength must be within the \a text. The
\a cursorPosition also specifies microfocus position in the case:
\c TQEvent::IMEnd can be sent without arguments to terminate the
composition with null string:
\code
sendIMEvent( TQEvent::IMEnd )
\endcode
Or optionally accepts \a text to commit a string:
\code
sendIMEvent( TQEvent::IMEnd, TQString( "a text" ) )
\endcode
\sa TQIMEvent, TQIMComposeEvent, setMicroFocus()
*/
void TQInputContext::sendIMEvent( TQEvent::Type type, const TQString &text,
int cursorPosition, int selLength )
{
#if defined(TQ_WS_X11)
if ( !focusWidget() )
return;
#endif
if ( type == TQEvent::IMStart ) {
sendIMEventInternal( type, text, cursorPosition, selLength );
d->isComposing = TRUE;
} else if ( type == TQEvent::IMEnd ) {
d->resetComposingState();
sendIMEventInternal( type, text, cursorPosition, selLength );
} else if ( type == TQEvent::IMCompose ) {
d->updateComposingState( text, cursorPosition, selLength );
sendIMEventInternal( type, text, cursorPosition, selLength );
}
}
/*!
This function can be reimplemented in a subclass to detect
that the input context has been focused on.
The input context will receive input events through
x11FilterEvent() and filterEvent() after setFocus() until
unsetFocus() has been called.
an input context is ensured that setFocus() is called exactly once
until unsetFocus() has been called even if preedit relocation has
occurred. This means that an input focus will survive between
several widgets that sharing the input context.
On the X11 platform, focusWidget is already set before this
function has been called.
\sa unsetFocus()
*/
void TQInputContext::setFocus()
{
}
/*!
This function can be reimplemented in a subclass to detect
that the input context has lost the focus.
an input context is ensured that unsetFocus() is not called during
preedit relocation. This means that an input focus will survive
between several widgets that sharing the input context.
Default implementation that calls reset() is sufficient for simple
input methods. You can override this function to alter the
behavior. For example, most Japanese input contexts should not be
reset on losing focus. The context sometimes contains a whole
paragraph and has minutes of lifetime different to ephemeral one
in other languages. The piled input context should be survived
until focused again since Japanese user naturally expects so.
On the X11 platform, focusWidget is valid until this function has
been returned.
\sa setFocus()
*/
void TQInputContext::unsetFocus()
{
reset();
}
/*!
This function can be implemented in a subclass to handle
microfocus changes.
'microfocus' stands for the input method focus point in the
preedit (XIM "spot" point) for complex language input handling. It
can be used to place auxiliary GUI widgets such as candidate
selection window.
\a x, \a y, \a w and \a h represents the position and size of the
cursor in the preedit string. \a f is the font on the location of
the cursor.
*/
void TQInputContext::setMicroFocus( int x, int y, int w, int h, TQFont *f )
{
Q_UNUSED(x);
Q_UNUSED(y);
Q_UNUSED(w);
Q_UNUSED(h);
Q_UNUSED(f);
}
/*!
This function can be reimplemented in a subclass to handle mouse
presses/releases/doubleclicks/moves within the preedit text. You
can use the function to implement mouse-oriented user interface
such as text selection or popup menu for candidate selection.
The parameter \a x is the offset within the string that was sent
with the IMCompose event. The alteration boundary of \a x is
ensured as character boundary of preedit string accurately.
\a type is either \c TQEvent::MouseButtonPress or \c
TQEvent::MouseButtonRelease or \c TQEvent::MouseButtonDblClick or \c
TQEvent::MouseButtonMove. Refer \a button and \a state to determine
what operation has performed.
The method interface is imported from
TQWSInputMethod::mouseHandler() of TQt/Embedded 2.3.7 and extended
for desktop system.
*/
void TQInputContext::mouseHandler( int x, TQEvent::Type type,
TQt::ButtonState button,
TQt::ButtonState state )
{
Q_UNUSED(x);
Q_UNUSED(button);
Q_UNUSED(state);
// Default behavior for simple ephemeral input contexts. Some
// complex input contexts should not be reset here.
if ( type == TQEvent::MouseButtonPress ||
type == TQEvent::MouseButtonDblClick )
reset();
}
/*!
Returns the font of the current input widget
*/
TQFont TQInputContext::font() const
{
if ( !focusWidget() )
return TQApplication::font(); //### absolutely last resort
return focusWidget()->font();
}
/*!
This function can be reimplemented in a subclass to reset the
state of the input method.
This function is called by several widgets to reset input
state. For example, a text widget call this function before
inserting a text to make widget ready to accept a text.
Default implementation is sufficient for simple input method. You
can override this function to reset external input method engines
in complex input method. In the case, call TQInputContext::reset()
to ensure proper termination of inputting.
You must not send any TQIMEvent except empty IMEnd event using
TQInputContext::reset() at reimplemented reset(). It will break
input state consistency.
*/
void TQInputContext::reset()
{
if ( isComposing() )
sendIMEvent( TQEvent::IMEnd );
}
/*!
This function must be implemented in any subclasses to return the
identifier name of the input method.
Return value is the name to identify and specify input methods for
the input method switching mechanism and so on. The name has to be
consistent with TQInputContextPlugin::keys(). The name has to
consist of ASCII characters only.
There are two different names with different responsibility in the
input method domain. This function returns one of them. Another
name is called 'display name' that stands for the name for
endusers appeared in a menu and so on.
\sa TQInputContextPlugin::keys(), TQInputContextPlugin::displayName()
*/
TQString TQInputContext::identifierName()
{
return "";
}
/*!
This function must be implemented in any subclasses to return a
language code (e.g. "zh_CN", "zh_TW", "zh_HK", "ja", "ko", ...)
of the input context. If the input context can handle multiple
languages, return the currently used one. The name has to be
consistent with TQInputContextPlugin::language().
This information will be used by language tagging feature in
TQIMEvent. It is required to distinguish unified han characters
correctly. It enables proper font and character code
handling. Suppose CJK-awared multilingual web browser
(that automatically modifies fonts in CJK-mixed text) and XML editor
(that automatically inserts lang attr).
\sa TQInputContextPlugin::language()
*/
TQString TQInputContext::language()
{
return "";
}
/*!
This function can be reimplemented in a subclass to provide input
method dependent popup menus. Return 0 if the menus are
unnecessary.
Ownership of the object and children are transferred to the
caller, and the result must not be called
setAutoDelete(). TQInputContextMenu::title is used for label text
of the popup menu as submenu.
\sa addMenusTo()
*/
TQPtrList<TQInputContextMenu> *TQInputContext::menus()
{
return 0;
}
/*!
Appends input method dependent submenus into \a popup. A separator
is also inserted into \a popup if \a action is InsertSeparator.
This is an utility function only for convenience in limited
situation. This function is used by input context owner such as
text widgets to add the submenus to its own context menu. If you
want to insert the submenus in more flexible way, use
TQInputContext::menus() manually. \a popup is not restricted to
context menu of a text widget. For example, the owner may be a
input method menu of TQtopia taskbar in TQt/Embedded platform.
\sa menus(), TQInputContextMenu::Action
*/
void TQInputContext::addMenusTo( TQPopupMenu *popup, TQInputContextMenu::Action action )
{
if ( ! popup )
return;
TQPtrList<TQInputContextMenu> *imMenus = menus();
if ( imMenus ) {
if ( action == TQInputContextMenu::InsertSeparator )
popup->insertSeparator();
for ( TQPtrList<TQInputContextMenu>::Iterator it = imMenus->begin();
it != imMenus->end();
++it ) {
TQInputContextMenu *imMenu = *it;
popup->insertItem( imMenu->title, imMenu->popup );
}
imMenus->clear();
delete imMenus;
}
}
#endif //Q_NO_IM
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