Extending the inputMethodQuery API

Currently, inputMethodQuery() only provides information about the
current paragraph. On some platforms, such as Android, the input method
needs information about the global cursor position, and more of the
surrounding text. Some queries need to pass parameters.

The current inputmethodQuery() implementation does not allow parameters to
be passed. Changing this would require new or modified virtual functions, which
is not possible until Qt 6. Therefore, a completely new mechanism is needed.

Change-Id: Ic64fd90198ade70aa0fa6fa5ad3867dfa7ed763c
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

6 files changed, 56 insertions, 7 deletions

diff --git a/src/widgets/graphicsview/qgraphicsitem.cpp b/src/widgets/graphicsview/qgraphicsitem.cpp
index 2d07e545c8..ae2423400a 100644
--- a/src/widgets/graphicsview/qgraphicsitem.cpp
+++ b/src/widgets/graphicsview/qgraphicsitem.cpp
@@ -10316,7 +10316,7 @@ QVariant QGraphicsTextItem::inputMethodQuery(Qt::InputMethodQuery query) const
     if (query == Qt::ImHints)
         v = int(inputMethodHints());
     else if (dd->control)
-        v = dd->control->inputMethodQuery(query);
+        v = dd->control->inputMethodQuery(query, QVariant());
     if (v.type() == QVariant::RectF)
         v = v.toRectF().translated(-dd->controlOffset());
     else if (v.type() == QVariant::PointF)
diff --git a/src/widgets/widgets/qplaintextedit.cpp b/src/widgets/widgets/qplaintextedit.cpp
index 89374b1c41..d51dce4765 100644
--- a/src/widgets/widgets/qplaintextedit.cpp
+++ b/src/widgets/widgets/qplaintextedit.cpp
@@ -2192,7 +2192,7 @@ QVariant QPlainTextEdit::inputMethodQuery(Qt::InputMethodQuery property) const
         v = QWidget::inputMethodQuery(property);
         break;
     default:
-        v = d->control->inputMethodQuery(property);
+        v = d->control->inputMethodQuery(property, QVariant());
         const QPoint offset(-d->horizontalOffset(), -0);
         if (v.type() == QVariant::RectF)
             v = v.toRectF().toRect().translated(offset);
diff --git a/src/widgets/widgets/qtextedit.cpp b/src/widgets/widgets/qtextedit.cpp
index cc7b44d082..a33ac0817f 100644
--- a/src/widgets/widgets/qtextedit.cpp
+++ b/src/widgets/widgets/qtextedit.cpp
@@ -1717,14 +1717,21 @@ void QTextEdit::scrollContentsBy(int dx, int dy)
 */
 QVariant QTextEdit::inputMethodQuery(Qt::InputMethodQuery property) const
 {
+    return inputMethodQuery(property, QVariant());
+}
+
+/*!\internal
+ */
+QVariant QTextEdit::inputMethodQuery(Qt::InputMethodQuery query, QVariant argument) const
+{
     Q_D(const QTextEdit);
     QVariant v;
-    switch (property) {
+    switch (query) {
     case Qt::ImHints:
-        v = QWidget::inputMethodQuery(property);
+        v = QWidget::inputMethodQuery(query);
         break;
     default:
-        v = d->control->inputMethodQuery(property);
+        v = d->control->inputMethodQuery(query, argument);
         const QPoint offset(-d->horizontalOffset(), -d->verticalOffset());
         if (v.type() == QVariant::RectF)
             v = v.toRectF().toRect().translated(offset);
diff --git a/src/widgets/widgets/qtextedit.h b/src/widgets/widgets/qtextedit.h
index 406d8b2c4b..a283a51b90 100644
--- a/src/widgets/widgets/qtextedit.h
+++ b/src/widgets/widgets/qtextedit.h
@@ -212,6 +212,7 @@ public:
     void print(QPagedPaintDevice *printer) const;
 
     QVariant inputMethodQuery(Qt::InputMethodQuery property) const;
+    Q_INVOKABLE QVariant inputMethodQuery(Qt::InputMethodQuery query, QVariant argument) const;
 
 public Q_SLOTS:
     void setFontPointSize(qreal s);
diff --git a/src/widgets/widgets/qwidgettextcontrol.cpp b/src/widgets/widgets/qwidgettextcontrol.cpp
index 06b513f3e0..98f85e681b 100644
--- a/src/widgets/widgets/qwidgettextcontrol.cpp
+++ b/src/widgets/widgets/qwidgettextcontrol.cpp
@@ -2024,7 +2024,7 @@ void QWidgetTextControlPrivate::inputMethodEvent(QInputMethodEvent *e)
         emit q->microFocusChanged();
 }
 
-QVariant QWidgetTextControl::inputMethodQuery(Qt::InputMethodQuery property) const
+QVariant QWidgetTextControl::inputMethodQuery(Qt::InputMethodQuery property, QVariant argument) const
 {
     Q_D(const QWidgetTextControl);
     QTextBlock block = d->cursor.block();
@@ -2043,6 +2043,47 @@ QVariant QWidgetTextControl::inputMethodQuery(Qt::InputMethodQuery property) con
         return QVariant(); // No limit.
     case Qt::ImAnchorPosition:
         return QVariant(d->cursor.anchor() - block.position());
+    case Qt::ImAbsolutePosition:
+        return QVariant(d->cursor.position());
+    case Qt::ImTextAfterCursor:
+    {
+        int maxLength = argument.isValid() ? argument.toInt() : 1024;
+        QTextCursor tmpCursor = d->cursor;
+        int localPos = d->cursor.position() - block.position();
+        QString result = block.text().mid(localPos);
+        while (result.length() < maxLength) {
+            int currentBlock = tmpCursor.blockNumber();
+            tmpCursor.movePosition(QTextCursor::NextBlock);
+            if (tmpCursor.blockNumber() == currentBlock)
+                break;
+            result += QLatin1Char('\n') + tmpCursor.block().text();
+        }
+        return QVariant(result);
+    }
+    case Qt::ImTextBeforeCursor:
+    {
+        int maxLength = argument.isValid() ? argument.toInt() : 1024;
+        QTextCursor tmpCursor = d->cursor;
+        int localPos = d->cursor.position() - block.position();
+        int numBlocks = 0;
+        int resultLen = localPos;
+        while (resultLen < maxLength) {
+            int currentBlock = tmpCursor.blockNumber();
+            tmpCursor.movePosition(QTextCursor::PreviousBlock);
+            if (tmpCursor.blockNumber() == currentBlock)
+                break;
+            numBlocks++;
+            resultLen += tmpCursor.block().length();
+        }
+        QString result;
+        while (numBlocks) {
+            result += tmpCursor.block().text() + QLatin1Char('\n');
+            tmpCursor.movePosition(QTextCursor::NextBlock);
+            --numBlocks;
+        }
+        result += block.text().mid(0,localPos);
+        return QVariant(result);
+    }
     default:
         return QVariant();
     }
diff --git a/src/widgets/widgets/qwidgettextcontrol_p.h b/src/widgets/widgets/qwidgettextcontrol_p.h
index 847371e194..0c76355ca1 100644
--- a/src/widgets/widgets/qwidgettextcontrol_p.h
+++ b/src/widgets/widgets/qwidgettextcontrol_p.h
@@ -239,7 +239,7 @@ public:
 
     void setFocus(bool focus, Qt::FocusReason = Qt::OtherFocusReason);
 
-    virtual QVariant inputMethodQuery(Qt::InputMethodQuery property) const;
+    virtual QVariant inputMethodQuery(Qt::InputMethodQuery property, QVariant argument) const;
 
     virtual QMimeData *createMimeDataFromSelection() const;
     virtual bool canInsertFromMimeData(const QMimeData *source) const;