QLineEdit - made mouse interactions commit preedit

Simplifying input context mouse handling rules by making
the editor in charge when text gets committed and selected.

This includes:
 - Allowing selection to start on top of preedit. Commits once a
   single character gets selected
 - Double click to commit preedit before selecting a word.
 - Only sending events to input context that happen on top of preedit.
 - Committing preedit when a mouse press happens outside of it,
   allowing to move cursor to click position.

Change-Id: I9dab00ea3445055ffd0d7cae540a1197c5748509
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

src/widgets/widgets/qlineedit.cpp

@@ -1388,6 +1388,9 @@ bool QLineEdit::event(QEvent * e)
 void QLineEdit::mousePressEvent(QMouseEvent* e)
 {
     Q_D(QLineEdit);
+
+    d->mousePressPos = e->pos();
+
     if (d->sendMouseEventToInputContext(e))
         return;
     if (e->button() == Qt::RightButton)
@@ -1410,7 +1413,6 @@ void QLineEdit::mousePressEvent(QMouseEvent* e)
 #ifndef QT_NO_DRAGANDDROP
     if (!mark && d->dragEnabled && d->control->echoMode() == Normal &&
          e->button() == Qt::LeftButton && d->control->inSelection(e->pos().x())) {
-        d->dndPos = e->pos();
         if (!d->dndTimer.isActive())
             d->dndTimer.start(QApplication::startDragTime(), this);
     } else
@@ -1425,20 +1427,28 @@ void QLineEdit::mousePressEvent(QMouseEvent* e)
 void QLineEdit::mouseMoveEvent(QMouseEvent * e)
 {
     Q_D(QLineEdit);
-    if (d->sendMouseEventToInputContext(e))
-        return;
 
     if (e->buttons() & Qt::LeftButton) {
 #ifndef QT_NO_DRAGANDDROP
         if (d->dndTimer.isActive()) {
-            if ((d->dndPos - e->pos()).manhattanLength() > QApplication::startDragDistance())
+            if ((d->mousePressPos - e->pos()).manhattanLength() > QApplication::startDragDistance())
                 d->drag();
         } else
 #endif
         {
-            d->control->moveCursor(d->xToPos(e->pos().x()), true);
+            if (d->control->composeMode()) {
+                int startPos = d->xToPos(d->mousePressPos.x());
+                int currentPos = d->xToPos(e->pos().x());
+                if (startPos != currentPos)
+                    d->control->setSelection(startPos, currentPos - startPos);
+
+            } else {
+                d->control->moveCursor(d->xToPos(e->pos().x()), true);
+            }
         }
     }
+
+    d->sendMouseEventToInputContext(e);
 }
 
 /*! \reimp
@@ -1478,12 +1488,43 @@ void QLineEdit::mouseReleaseEvent(QMouseEvent* e)
 void QLineEdit::mouseDoubleClickEvent(QMouseEvent* e)
 {
     Q_D(QLineEdit);
-    if (d->sendMouseEventToInputContext(e))
-        return;
+
     if (e->button() == Qt::LeftButton) {
-        d->control->selectWordAtPos(d->xToPos(e->pos().x()));
+        int position = d->xToPos(e->pos().x());
+
+        // exit composition mode
+        if (d->control->composeMode()) {
+            int preeditPos = d->control->cursor();
+            int posInPreedit = position - d->control->cursor();
+            int preeditLength = d->control->preeditAreaText().length();
+            bool positionOnPreedit = false;
+
+            if (posInPreedit >= 0 && posInPreedit <= preeditLength)
+                positionOnPreedit = true;
+
+            int textLength = d->control->end();
+            d->control->commitPreedit();
+            int sizeChange = d->control->end() - textLength;
+
+            if (positionOnPreedit) {
+                if (sizeChange == 0)
+                    position = -1; // cancel selection, word disappeared
+                else
+                    // ensure not selecting after preedit if event happened there
+                    position = qBound(preeditPos, position, preeditPos + sizeChange);
+            } else if (position > preeditPos) {
+                // adjust positions after former preedit by how much text changed
+                position += (sizeChange - preeditLength);
+            }
+        }
+
+        if (position >= 0)
+            d->control->selectWordAtPos(position);
+
         d->tripleClickTimer.start(QApplication::doubleClickInterval(), this);
         d->tripleClick = e->pos();
+    } else {
+        d->sendMouseEventToInputContext(e);
     }
 }
 

src/widgets/widgets/qlineedit_p.cpp

@@ -259,19 +259,15 @@ bool QLineEditPrivate::sendMouseEventToInputContext( QMouseEvent *e )
     if ( control->composeMode() ) {
         int tmp_cursor = xToPos(e->pos().x());
         int mousePos = tmp_cursor - control->cursor();
-        if ( mousePos < 0 || mousePos > control->preeditAreaText().length() ) {
+        if ( mousePos < 0 || mousePos > control->preeditAreaText().length() )
             mousePos = -1;
-            // don't send move events outside the preedit area
-            if ( e->type() == QEvent::MouseMove )
-                return true;
-        }
 
         QInputContext *qic = q->inputContext();
-        if ( qic )
+        if (qic && mousePos >= 0) {
             // may be causing reset() in some input methods
             qic->mouseHandler(mousePos, e);
-        if (!control->preeditAreaText().isEmpty())
             return true;
+        }
     }
 #else
     Q_UNUSED(e);

src/widgets/widgets/qlineedit_p.h

@@ -137,8 +137,8 @@ public:
 #ifndef QT_NO_COMPLETER
     void _q_completionHighlighted(QString);
 #endif
+    QPoint mousePressPos;
 #ifndef QT_NO_DRAGANDDROP
-    QPoint dndPos;
     QBasicTimer dndTimer;
     void drag();
 #endif

src/widgets/widgets/qwidgetlinecontrol.cpp

@@ -164,6 +164,31 @@ void QWidgetLineControl::paste(QClipboard::Mode clipboardMode)
 
 #endif // !QT_NO_CLIPBOARD
 
+/*!
+    \internal
+
+    Exits preedit mode and commits parts marked as tentative commit
+*/
+void QWidgetLineControl::commitPreedit()
+{
+    if (!composeMode())
+        return;
+
+    qApp->inputPanel()->reset();
+
+    if (!m_tentativeCommit.isEmpty()) {
+        internalInsert(m_tentativeCommit);
+        m_tentativeCommit.clear();
+        finishChange(-1, true/*not used, not documented*/, false);
+    }
+
+    m_preeditCursor = 0;
+    setPreeditArea(-1, QString());
+    m_textLayout.clearAdditionalFormats();
+    updateDisplayText(/*force*/ true);
+}
+
+
 /*!
     \internal
 
@@ -259,6 +284,8 @@ void QWidgetLineControl::clear()
 */
 void QWidgetLineControl::setSelection(int start, int length)
 {
+    commitPreedit();
+
     if(start < 0 || start > (int)m_text.length()){
         qWarning("QWidgetLineControl::setSelection: Invalid start position");
         return;
@@ -394,6 +421,8 @@ bool QWidgetLineControl::fixup() // this function assumes that validate currentl
 */
 void QWidgetLineControl::moveCursor(int pos, bool mark)
 {
+    commitPreedit();
+
     if (pos != m_cursor) {
         separate();
         if (m_maskData)

src/widgets/widgets/qwidgetlinecontrol_p.h

@@ -234,6 +234,7 @@ public:
         m_tentativeCommit.clear();
         internalSetText(txt, -1, false);
     }
+    void commitPreedit();
 
     QString displayText() const { return m_textLayout.text(); }