qwindowsinputcontext.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qwindowsinputcontext.h"
#include "qwindowscontext.h"
#include "qwindowswindow.h"
#include "qwindowsintegration.h"
#include "qwindowsmousehandler.h"
 
#include <QtCore/qdebug.h>
#include <QtCore/qobject.h>
#include <QtCore/qrect.h>
#include <QtCore/qtextboundaryfinder.h>
 
#include <QtGui/qevent.h>
#include <QtGui/qtextformat.h>
#include <QtGui/qpalette.h>
#include <QtGui/qguiapplication.h>
 
#include <private/qhighdpiscaling_p.h>
 
#include <algorithm>
 
QT_BEGIN_NAMESPACE
 
static inline QByteArray debugComposition(int lParam)
{
    QByteArray str;
    if (lParam & GCS_RESULTSTR)
        str += "RESULTSTR ";
    if (lParam & GCS_COMPSTR)
        str += "COMPSTR ";
    if (lParam & GCS_COMPATTR)
        str += "COMPATTR ";
    if (lParam & GCS_CURSORPOS)
        str += "CURSORPOS ";
    if (lParam & GCS_COMPCLAUSE)
        str += "COMPCLAUSE ";
    if (lParam & CS_INSERTCHAR)
        str += "INSERTCHAR ";
    if (lParam & CS_NOMOVECARET)
        str += "NOMOVECARET ";
    return str;
}
 
// Cancel current IME composition.
static inline void imeNotifyCancelComposition(HWND hwnd)
{
    if (!hwnd) {
        qWarning() << __FUNCTION__ << "called with" << hwnd;
        return;
    }
    const HIMC himc = ImmGetContext(hwnd);
    ImmNotifyIME(himc, NI_COMPOSITIONSTR, CPS_CANCEL, 0);
    ImmReleaseContext(hwnd, himc);
}
 
static inline LCID languageIdFromLocaleId(LCID localeId)
{
    return localeId & 0xFFFF;
}
 
static inline LCID currentInputLanguageId()
{
    return languageIdFromLocaleId(reinterpret_cast<quintptr>(GetKeyboardLayout(0)));
}
 
Q_CORE_EXPORT QLocale qt_localeFromLCID(LCID id); // from qlocale_win.cpp
 
QWindowsInputContext::QWindowsInputContext() :
    m_WM_MSIME_MOUSE(RegisterWindowMessage(L"MSIMEMouseOperation")),
    m_languageId(currentInputLanguageId()),
    m_locale(qt_localeFromLCID(m_languageId))
{
    const quint32 bmpData = 0;
    m_transparentBitmap = CreateBitmap(2, 2, 1, 1, &bmpData);
 
    connect(QGuiApplication::inputMethod(), &QInputMethod::cursorRectangleChanged,
            this, &QWindowsInputContext::cursorRectChanged);
}
 
QWindowsInputContext::~QWindowsInputContext()
{
    if (m_transparentBitmap)
        DeleteObject(m_transparentBitmap);
}
 
bool QWindowsInputContext::hasCapability(Capability capability) const
{
    switch (capability) {
    case QPlatformInputContext::HiddenTextCapability:
        return false; // QTBUG-40691, do not show IME on desktop for password entry fields.
    default:
        break;
    }
    return true;
}
 
void QWindowsInputContext::reset()
{
    if (!m_compositionContext.hwnd)
        return;
    qCDebug(lcQpaInputMethods) << __FUNCTION__;
    if (m_compositionContext.isComposing && !m_compositionContext.focusObject.isNull()) {
        QInputMethodEvent event;
        if (!m_compositionContext.composition.isEmpty())
            event.setCommitString(m_compositionContext.composition);
        QCoreApplication::sendEvent(m_compositionContext.focusObject, &event);
        endContextComposition();
    }
    imeNotifyCancelComposition(m_compositionContext.hwnd);
    doneContext();
}
 
void QWindowsInputContext::setFocusObject(QObject *)
{
    // ### fixme: On Windows 8.1, it has been observed that the Input context
    // remains active when this happens resulting in a lock-up. Consecutive
    // key events still have VK_PROCESSKEY set and are thus ignored.
    if (m_compositionContext.isComposing)
        reset();
    updateEnabled();
}
 
HWND QWindowsInputContext::getVirtualKeyboardWindowHandle() const
{
    return ::FindWindowA("IPTip_Main_Window", nullptr);
}
 
QRectF QWindowsInputContext::keyboardRect() const
{
    if (HWND hwnd = getVirtualKeyboardWindowHandle()) {
        RECT rect;
        if (::GetWindowRect(hwnd, &rect)) {
            return QRectF(rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top);
        }
    }
    return QRectF();
}
 
bool QWindowsInputContext::isInputPanelVisible() const
{
    HWND hwnd = getVirtualKeyboardWindowHandle();
    if (hwnd && ::IsWindowEnabled(hwnd) && ::IsWindowVisible(hwnd))
        return true;
    // check if the Input Method Editor is open
    if (inputMethodAccepted()) {
        if (QWindow *window = QGuiApplication::focusWindow()) {
            if (QWindowsWindow *platformWindow = QWindowsWindow::windowsWindowOf(window)) {
                if (HIMC himc = ImmGetContext(platformWindow->handle()))
                    return ImmGetOpenStatus(himc);
            }
        }
    }
    return false;
}
 
void QWindowsInputContext::showInputPanel()
{
    if (!inputMethodAccepted())
        return;
 
    QWindow *window = QGuiApplication::focusWindow();
    if (!window)
        return;
 
    QWindowsWindow *platformWindow = QWindowsWindow::windowsWindowOf(window);
    if (!platformWindow)
        return;
 
    // Create an invisible 2x2 caret, which will be kept at the microfocus position.
    // It is important for triggering the on-screen keyboard in touch-screen devices,
    // for some Chinese input methods, and for Magnifier's "follow keyboard" feature.
    if (!m_caretCreated && m_transparentBitmap)
        m_caretCreated = CreateCaret(platformWindow->handle(), m_transparentBitmap, 0, 0);
 
    if (m_caretCreated) {
        cursorRectChanged();
        ShowCaret(platformWindow->handle());
    }
}
 
void QWindowsInputContext::hideInputPanel()
{
    if (m_caretCreated) {
        DestroyCaret();
        m_caretCreated = false;
    }
}
 
void QWindowsInputContext::updateEnabled()
{
    if (!QGuiApplication::focusObject())
        return;
    if (QWindowsWindow *platformWindow = QWindowsWindow::windowsWindowOf(QGuiApplication::focusWindow())) {
        const bool accepted = inputMethodAccepted();
        if (QWindowsContext::verbose > 1)
            qCDebug(lcQpaInputMethods) << __FUNCTION__ << platformWindow->window() << "accepted=" << accepted;
        QWindowsInputContext::setWindowsImeEnabled(platformWindow, accepted);
    }
}
 
void QWindowsInputContext::setWindowsImeEnabled(QWindowsWindow *platformWindow, bool enabled)
{
    if (!platformWindow)
        return;
    if (enabled) {
        // Re-enable Windows IME by associating default context.
        ImmAssociateContextEx(platformWindow->handle(), nullptr, IACE_DEFAULT);
    } else {
        // Disable Windows IME by associating 0 context.
        ImmAssociateContext(platformWindow->handle(), nullptr);
    }
}
 
void QWindowsInputContext::update(Qt::InputMethodQueries queries)
{
    if (queries & Qt::ImEnabled)
        updateEnabled();
}
 
void QWindowsInputContext::cursorRectChanged()
{
    QWindow *window = QGuiApplication::focusWindow();
    if (!window)
        return;
 
    qreal factor = QHighDpiScaling::factor(window);
 
    const QInputMethod *inputMethod = QGuiApplication::inputMethod();
    const QRectF cursorRectangleF = inputMethod->cursorRectangle();
    if (!cursorRectangleF.isValid())
        return;
 
    const QRect cursorRectangle =
        QRectF(cursorRectangleF.topLeft() * factor, cursorRectangleF.size() * factor).toRect();
 
    if (m_caretCreated)
        SetCaretPos(cursorRectangle.x(), cursorRectangle.y());
 
    if (!m_compositionContext.hwnd)
        return;
 
    qCDebug(lcQpaInputMethods) << __FUNCTION__<< cursorRectangle;
 
    const HIMC himc = ImmGetContext(m_compositionContext.hwnd);
    if (!himc)
        return;
    // Move candidate list window to the microfocus position.
    COMPOSITIONFORM cf;
    // ### need X-like inputStyle config settings
    cf.dwStyle = CFS_FORCE_POSITION;
    cf.ptCurrentPos.x = cursorRectangle.x();
    cf.ptCurrentPos.y = cursorRectangle.y();
 
    CANDIDATEFORM candf;
    candf.dwIndex = 0;
    candf.dwStyle = CFS_EXCLUDE;
    candf.ptCurrentPos.x = cursorRectangle.x();
    candf.ptCurrentPos.y = cursorRectangle.y() + cursorRectangle.height();
    candf.rcArea.left = cursorRectangle.x();
    candf.rcArea.top = cursorRectangle.y();
    candf.rcArea.right = cursorRectangle.x() + cursorRectangle.width();
    candf.rcArea.bottom = cursorRectangle.y() + cursorRectangle.height();
 
    ImmSetCompositionWindow(himc, &cf);
    ImmSetCandidateWindow(himc, &candf);
    ImmReleaseContext(m_compositionContext.hwnd, himc);
}
 
void QWindowsInputContext::invokeAction(QInputMethod::Action action, int cursorPosition)
{
    if (action != QInputMethod::Click || !m_compositionContext.hwnd) {
        QPlatformInputContext::invokeAction(action, cursorPosition);
        return;
    }
 
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << cursorPosition << action;
    if (cursorPosition < 0 || cursorPosition > m_compositionContext.composition.size())
        reset();
 
    // Magic code that notifies Japanese IME about the cursor
    // position.
    const HIMC himc = ImmGetContext(m_compositionContext.hwnd);
    const HWND imeWindow = ImmGetDefaultIMEWnd(m_compositionContext.hwnd);
    const WPARAM mouseOperationCode =
        MAKELONG(MAKEWORD(MK_LBUTTON, cursorPosition == 0 ? 2 : 1), cursorPosition);
    SendMessage(imeWindow, m_WM_MSIME_MOUSE, mouseOperationCode, LPARAM(himc));
    ImmReleaseContext(m_compositionContext.hwnd, himc);
}
 
static inline QString getCompositionString(HIMC himc, DWORD dwIndex)
{
    enum { bufferSize = 256 };
    wchar_t buffer[bufferSize];
    const int length = ImmGetCompositionString(himc, dwIndex, buffer, bufferSize * sizeof(wchar_t));
    return QString::fromWCharArray(buffer,  size_t(length) / sizeof(wchar_t));
}
 
// Determine the converted string range as pair of start/length to be selected.
static inline void getCompositionStringConvertedRange(HIMC himc, int *selStart, int *selLength)
{
    enum { bufferSize = 256 };
    // Find the range of bytes with ATTR_TARGET_CONVERTED set.
    char attrBuffer[bufferSize];
    *selStart = *selLength = 0;
    if (const int attrLength = ImmGetCompositionString(himc, GCS_COMPATTR, attrBuffer, bufferSize)) {
        int start = 0;
        while (start < attrLength && !(attrBuffer[start] & ATTR_TARGET_CONVERTED))
            start++;
        if (start < attrLength) {
            int end = start + 1;
            while (end < attrLength && (attrBuffer[end] & ATTR_TARGET_CONVERTED))
                end++;
            *selStart = start;
            *selLength = end - start;
        }
    }
}
 
enum StandardFormat {
    PreeditFormat,
    SelectionFormat
};
 
static inline QTextFormat standardFormat(StandardFormat format)
{
    QTextCharFormat result;
    switch (format) {
    case PreeditFormat:
        result.setUnderlineStyle(QTextCharFormat::DashUnderline);
        break;
    case SelectionFormat: {
        // TODO: Should be that of the widget?
        const QPalette palette = QGuiApplication::palette();
        const QColor background = palette.text().color();
        result.setBackground(QBrush(background));
        result.setForeground(palette.window());
        break;
    }
    }
    return result;
}
 
bool QWindowsInputContext::startComposition(HWND hwnd)
{
    QObject *fo = QGuiApplication::focusObject();
    if (!fo)
        return false;
    // This should always match the object.
    QWindow *window = QGuiApplication::focusWindow();
    if (!window)
        return false;
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << fo << window << "language=" << m_languageId;
    if (!fo || QWindowsWindow::handleOf(window) != hwnd)
        return false;
    initContext(hwnd, fo);
    startContextComposition();
    return true;
}
 
void QWindowsInputContext::startContextComposition()
{
    if (m_compositionContext.isComposing) {
        qWarning("%s: Called out of sequence.", __FUNCTION__);
        return;
    }
    m_compositionContext.isComposing = true;
    m_compositionContext.composition.clear();
    m_compositionContext.position = 0;
    cursorRectChanged(); // position cursor initially.
    update(Qt::ImQueryAll);
}
 
void QWindowsInputContext::endContextComposition()
{
    if (!m_compositionContext.isComposing) {
        qWarning("%s: Called out of sequence.", __FUNCTION__);
        return;
    }
    m_compositionContext.composition.clear();
    m_compositionContext.position = 0;
    m_compositionContext.isComposing = false;
}
 
// Create a list of markup attributes for QInputMethodEvent
// to display the selected part of the intermediate composition
// result differently.
static inline QList<QInputMethodEvent::Attribute>
    intermediateMarkup(int position, int compositionLength,
                       int selStart, int selLength)
{
    QList<QInputMethodEvent::Attribute> attributes;
    if (selStart > 0)
        attributes << QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, 0, selStart,
                                                   standardFormat(PreeditFormat));
    if (selLength)
        attributes << QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, selStart, selLength,
                                                   standardFormat(SelectionFormat));
    if (selStart + selLength < compositionLength)
        attributes << QInputMethodEvent::Attribute(QInputMethodEvent::TextFormat, selStart + selLength,
                                                   compositionLength - selStart - selLength,
                                                   standardFormat(PreeditFormat));
    if (position >= 0)
        attributes << QInputMethodEvent::Attribute(QInputMethodEvent::Cursor, position, selLength ? 0 : 1, QVariant());
    return attributes;
}
 
bool QWindowsInputContext::composition(HWND hwnd, LPARAM lParamIn)
{
    const int lParam = int(lParamIn);
    qCDebug(lcQpaInputMethods) << '>' << __FUNCTION__ << m_compositionContext.focusObject
        << debugComposition(lParam) << " composing=" << m_compositionContext.isComposing;
    if (m_compositionContext.focusObject.isNull() || m_compositionContext.hwnd != hwnd || !lParam)
        return false;
    const HIMC himc = ImmGetContext(m_compositionContext.hwnd);
    if (!himc)
        return false;
 
    QScopedPointer<QInputMethodEvent> event;
    if (lParam & (GCS_COMPSTR | GCS_COMPATTR | GCS_CURSORPOS)) {
        if (!m_compositionContext.isComposing)
            startContextComposition();
        // Some intermediate composition result. Parametrize event with
        // attribute sequence specifying the formatting of the converted part.
        int selStart, selLength;
        m_compositionContext.composition = getCompositionString(himc, GCS_COMPSTR);
        m_compositionContext.position = ImmGetCompositionString(himc, GCS_CURSORPOS, nullptr, 0);
        getCompositionStringConvertedRange(himc, &selStart, &selLength);
        if ((lParam & CS_INSERTCHAR) && (lParam & CS_NOMOVECARET)) {
            // make Korean work correctly. Hope this is correct for all IMEs
            selStart = 0;
            selLength = m_compositionContext.composition.size();
        }
        if (!selLength)
            selStart = 0;
 
        event.reset(new QInputMethodEvent(m_compositionContext.composition,
                                          intermediateMarkup(m_compositionContext.position,
                                                             m_compositionContext.composition.size(),
                                                             selStart, selLength)));
    }
    if (event.isNull())
        event.reset(new QInputMethodEvent);
 
    if (lParam & GCS_RESULTSTR) {
        // A fixed result, return the converted string
        event->setCommitString(getCompositionString(himc, GCS_RESULTSTR));
        if (!(lParam & GCS_DELTASTART))
            endContextComposition();
    }
    const bool result = QCoreApplication::sendEvent(m_compositionContext.focusObject, event.data());
    qCDebug(lcQpaInputMethods) << '<' << __FUNCTION__ << "sending markup="
        << event->attributes().size() << " commit=" << event->commitString()
        << " to " << m_compositionContext.focusObject << " returns " << result;
    update(Qt::ImQueryAll);
    ImmReleaseContext(m_compositionContext.hwnd, himc);
    return result;
}
 
bool QWindowsInputContext::endComposition(HWND hwnd)
{
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << m_endCompositionRecursionGuard << hwnd;
    // Googles Pinyin Input Method likes to call endComposition again
    // when we call notifyIME with CPS_CANCEL, so protect ourselves
    // against that.
    if (m_endCompositionRecursionGuard || m_compositionContext.hwnd != hwnd)
        return false;
    if (m_compositionContext.focusObject.isNull())
        return false;
 
    // QTBUG-58300: Ignore WM_IME_ENDCOMPOSITION when CTRL is pressed to prevent
    // for example the text being cleared when pressing CTRL+A
    if (m_locale.language() == QLocale::Korean
        && QGuiApplication::queryKeyboardModifiers().testFlag(Qt::ControlModifier)) {
        reset();
        return true;
    }
 
    m_endCompositionRecursionGuard = true;
 
    imeNotifyCancelComposition(m_compositionContext.hwnd);
    if (m_compositionContext.isComposing) {
        QInputMethodEvent event;
        QCoreApplication::sendEvent(m_compositionContext.focusObject, &event);
    }
    doneContext();
 
    m_endCompositionRecursionGuard = false;
    return true;
}
 
void QWindowsInputContext::initContext(HWND hwnd, QObject *focusObject)
{
    if (m_compositionContext.hwnd)
        doneContext();
    m_compositionContext.hwnd = hwnd;
    m_compositionContext.focusObject = focusObject;
 
    update(Qt::ImQueryAll);
    m_compositionContext.isComposing = false;
    m_compositionContext.position = 0;
}
 
void QWindowsInputContext::doneContext()
{
    if (!m_compositionContext.hwnd)
        return;
    m_compositionContext.hwnd = nullptr;
    m_compositionContext.composition.clear();
    m_compositionContext.position = 0;
    m_compositionContext.isComposing = false;
    m_compositionContext.focusObject = nullptr;
}
 
bool QWindowsInputContext::handleIME_Request(WPARAM wParam,
                                             LPARAM lParam,
                                             LRESULT *result)
{
    switch (int(wParam)) {
    case IMR_RECONVERTSTRING: {
        const int size = reconvertString(reinterpret_cast<RECONVERTSTRING *>(lParam));
        if (size < 0)
            return false;
        *result = size;
    }
        return true;
    case IMR_CONFIRMRECONVERTSTRING:
        return true;
    default:
        break;
    }
    return false;
}
 
void QWindowsInputContext::handleInputLanguageChanged(WPARAM wparam, LPARAM lparam)
{
    const LCID newLanguageId = languageIdFromLocaleId(WORD(lparam));
    if (newLanguageId == m_languageId)
        return;
    const LCID oldLanguageId = m_languageId;
    m_languageId = newLanguageId;
    m_locale = qt_localeFromLCID(m_languageId);
    emitLocaleChanged();
 
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << Qt::hex << Qt::showbase
        << oldLanguageId  << "->" << newLanguageId << "Character set:"
        << DWORD(wparam) << Qt::dec << Qt::noshowbase << m_locale;
}
 
int QWindowsInputContext::reconvertString(RECONVERTSTRING *reconv)
{
    QObject *fo = QGuiApplication::focusObject();
    if (!fo)
        return false;
 
    const QVariant surroundingTextV = QInputMethod::queryFocusObject(Qt::ImSurroundingText, QVariant());
    if (!surroundingTextV.isValid())
        return -1;
    const QString surroundingText = surroundingTextV.toString();
    const int memSize = int(sizeof(RECONVERTSTRING))
        + (surroundingText.length() + 1) * int(sizeof(ushort));
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << " reconv=" << reconv
        << " surroundingText=" << surroundingText << " size=" << memSize;
    // If memory is not allocated, return the required size.
    if (!reconv)
        return surroundingText.isEmpty() ? -1 : memSize;
 
    const QVariant posV = QInputMethod::queryFocusObject(Qt::ImCursorPosition, QVariant());
    const int pos = posV.isValid() ? posV.toInt() : 0;
    // Find the word in the surrounding text.
    QTextBoundaryFinder bounds(QTextBoundaryFinder::Word, surroundingText);
    bounds.setPosition(pos);
    if (bounds.position() > 0 && !(bounds.boundaryReasons() & QTextBoundaryFinder::StartOfItem))
        bounds.toPreviousBoundary();
    const int startPos = bounds.position();
    bounds.toNextBoundary();
    const int endPos = bounds.position();
    qCDebug(lcQpaInputMethods) << __FUNCTION__ << " boundary=" << startPos << endPos;
    // Select the text, this will be overwritten by following IME events.
    QList<QInputMethodEvent::Attribute> attributes;
    attributes << QInputMethodEvent::Attribute(QInputMethodEvent::Selection, startPos, endPos-startPos, QVariant());
    QInputMethodEvent selectEvent(QString(), attributes);
    QCoreApplication::sendEvent(fo, &selectEvent);
 
    reconv->dwSize = DWORD(memSize);
    reconv->dwVersion = 0;
 
    reconv->dwStrLen = DWORD(surroundingText.size());
    reconv->dwStrOffset = sizeof(RECONVERTSTRING);
    reconv->dwCompStrLen = DWORD(endPos - startPos); // TCHAR count.
    reconv->dwCompStrOffset = DWORD(startPos) * sizeof(ushort); // byte count.
    reconv->dwTargetStrLen = reconv->dwCompStrLen;
    reconv->dwTargetStrOffset = reconv->dwCompStrOffset;
    auto *pastReconv = reinterpret_cast<ushort *>(reconv + 1);
    std::copy(surroundingText.utf16(), surroundingText.utf16() + surroundingText.size(),
              QT_MAKE_UNCHECKED_ARRAY_ITERATOR(pastReconv));
    return memSize;
}
 
QT_END_NAMESPACE