Item widgets: clean up treatment of Qt::TextAlignmentRole / CheckStateRole

The item widgets all have an API flaw: getters and setters for the text
alignment deal with int instead of Qt::Alignment.

Deprecate the existing setters and introduce others taking
Qt::Alignment. Store the alignment directly into the item widget (now
that views know how to handle it).

We can't change the getters without cluttering the API, so make that a
Qt 7 change. Users can prepare by forcibly casting the return value to
Qt::Alignment; this is going to work in Qt 6 and 7.

While at it: streamline the handling of Qt::CheckStateRole as well,
avoiding to rely on a pointless Qt::CheckState to int conversion
through QVariant (the setter stores a Qt::CheckState, but the getter
retrieves an int and converts it to a Qt::CheckState).

Task-number: QTBUG-75172
Change-Id: I9f29e818e93cb2dc1d8e042bc320162c2f692112
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

src/widgets/itemviews/qlistwidget.cpp

@@ -934,11 +934,24 @@ QDataStream &operator>>(QDataStream &in, QListWidgetItem &item)
 */
 
 /*!
+    \if defined(qt7)
+
+    \fn Qt::Alignment QListWidgetItem::textAlignment() const
+
+    Returns the text alignment for the list item.
+
+    \else
+
     \fn int QListWidgetItem::textAlignment() const
 
     Returns the text alignment for the list item.
 
-    \sa Qt::AlignmentFlag
+    \note This function returns an int for historical reasons. It will
+    be corrected to return Qt::Alignment in Qt 7.
+
+    \sa Qt::Alignment
+
+    \endif
 */
 
 /*!
@@ -1092,11 +1105,21 @@ void QListWidgetItem::setFlags(Qt::ItemFlags aflags)
 */
 
 /*!
+    \obsolete [6.4] Use the overload that takes a Qt::Alignment argument.
+
     \fn void QListWidgetItem::setTextAlignment(int alignment)
 
     Sets the list item's text alignment to \a alignment.
 
-    \sa Qt::AlignmentFlag
+    \sa Qt::Alignment
+*/
+
+/*!
+    \since 6.4
+
+    \fn void QListWidgetItem::setTextAlignment(Qt::Alignment alignment)
+
+    Sets the list item's text alignment to \a alignment.
 */
 
 /*!

src/widgets/itemviews/qlistwidget.h

@@ -109,10 +109,20 @@ public:
         { return qvariant_cast<QFont>(data(Qt::FontRole)); }
     inline void setFont(const QFont &font);
 
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
     inline int textAlignment() const
         { return data(Qt::TextAlignmentRole).toInt(); }
+#else
+    inline Qt::Alignment textAlignment() const
+    { return qvariant_cast<Qt::Alignment>(data(Qt::TextAlignmentRole)); }
+#endif
+#if QT_DEPRECATED_SINCE(6, 4)
+    QT_DEPRECATED_VERSION_X_6_4("Use the overload taking Qt::Alignment")
     inline void setTextAlignment(int alignment)
         { setData(Qt::TextAlignmentRole, alignment); }
+#endif
+    inline void setTextAlignment(Qt::Alignment alignment)
+        { setData(Qt::TextAlignmentRole, QVariant::fromValue(alignment)); }
 
     inline QBrush background() const
         { return qvariant_cast<QBrush>(data(Qt::BackgroundRole)); }
@@ -125,7 +135,7 @@ public:
         { setData(Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState() const
-        { return static_cast<Qt::CheckState>(data(Qt::CheckStateRole).toInt()); }
+        { return qvariant_cast<Qt::CheckState>(data(Qt::CheckStateRole)); }
     inline void setCheckState(Qt::CheckState state)
         { setData(Qt::CheckStateRole, static_cast<int>(state)); }
 

src/widgets/itemviews/qtablewidget.cpp

@@ -1289,14 +1289,29 @@ void QTableWidgetItem::setFlags(Qt::ItemFlags aflags)
 */
 
 /*!
+    \if defined(qt7)
+
+    \fn Qt::Alignment QTableWidgetItem::textAlignment() const
+
+    Returns the text alignment for the list item.
+
+    \else
+
     \fn int QTableWidgetItem::textAlignment() const
 
     Returns the text alignment for the item's text.
 
+    \note This function returns an int for historical reasons. It will
+    be corrected to return Qt::Alignment in Qt 7.
+
     \sa Qt::Alignment
+
+    \endif
 */
 
 /*!
+    \obsolete [6.4] Use the overload that takes a Qt::Alignment argument.
+
     \fn void QTableWidgetItem::setTextAlignment(int alignment)
 
     Sets the text alignment for the item's text to the \a alignment
@@ -1305,6 +1320,15 @@ void QTableWidgetItem::setFlags(Qt::ItemFlags aflags)
     \sa Qt::Alignment
 */
 
+/*!
+    \since 6.4
+
+    \fn void QTableWidgetItem::setTextAlignment(Qt::Alignment alignment)
+
+    Sets the text alignment for the item's text to the \a alignment
+    specified.
+*/
+
 /*!
     Constructs a table item of the specified \a type that does not belong
     to any table.

src/widgets/itemviews/qtablewidget.h

@@ -133,10 +133,20 @@ public:
         { return qvariant_cast<QFont>(data(Qt::FontRole)); }
     inline void setFont(const QFont &font);
 
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
     inline int textAlignment() const
         { return data(Qt::TextAlignmentRole).toInt(); }
+#else
+    inline Qt::Alignment textAlignment() const
+    { return qvariant_cast<Qt::Alignment>(data(Qt::TextAlignmentRole)); }
+#endif
+#if QT_DEPRECATED_SINCE(6, 4)
+    QT_DEPRECATED_VERSION_X_6_4("Use the overload taking Qt::Alignment")
     inline void setTextAlignment(int alignment)
         { setData(Qt::TextAlignmentRole, alignment); }
+#endif
+    inline void setTextAlignment(Qt::Alignment alignment)
+        { setData(Qt::TextAlignmentRole, QVariant::fromValue(alignment)); }
 
     inline QBrush background() const
         { return qvariant_cast<QBrush>(data(Qt::BackgroundRole)); }
@@ -149,7 +159,7 @@ public:
         { setData(Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState() const
-        { return static_cast<Qt::CheckState>(data(Qt::CheckStateRole).toInt()); }
+        { return qvariant_cast<Qt::CheckState>(data(Qt::CheckStateRole)); }
     inline void setCheckState(Qt::CheckState state)
         { setData(Qt::CheckStateRole, state); }
 

src/widgets/itemviews/qtreewidget.cpp

@@ -1362,17 +1362,44 @@ bool QTreeWidgetItem::isFirstColumnSpanned() const
 */
 
 /*!
+  \if defined(qt7)
+
+  \fn Qt::Alignment QTreeWidgetItem::textAlignment(int column) const
+
+  Returns the text alignment for the label in the given \a column.
+
+  \else
+
   \fn int QTreeWidgetItem::textAlignment(int column) const
 
-  Returns the text alignment for the label in the given \a column
-  (see \l{Qt::AlignmentFlag}).
+  Returns the text alignment for the label in the given \a column.
+
+  \note This function returns an int for historical reasons. It will
+  be corrected to return Qt::Alignment in Qt 7.
+
+  \sa Qt::Alignment
+
+  \endif
 */
 
 /*!
+  \obsolete [6.4] Use the overload that takes a Qt::Alignment argument.
+
   \fn void QTreeWidgetItem::setTextAlignment(int column, int alignment)
 
   Sets the text alignment for the label in the given \a column to
-  the \a alignment specified (see \l{Qt::AlignmentFlag}).
+  the \a alignment specified.
+
+  \sa Qt::Alignment
+*/
+
+/*!
+  \since 6.4
+
+  \fn void QTreeWidgetItem::setTextAlignment(int column, Qt::Alignment alignment)
+
+  Sets the text alignment for the label in the given \a column to
+  the \a alignment specified.
 */
 
 /*!

src/widgets/itemviews/qtreewidget.h

@@ -129,10 +129,20 @@ public:
         { return qvariant_cast<QFont>(data(column, Qt::FontRole)); }
     inline void setFont(int column, const QFont &font);
 
+#if QT_VERSION < QT_VERSION_CHECK(7, 0, 0)
     inline int textAlignment(int column) const
         { return data(column, Qt::TextAlignmentRole).toInt(); }
+#else
+    inline Qt::Alignment textAlignment(int column) const
+    { return qvariant_cast<Qt::Alignment>(data(column, Qt::TextAlignmentRole)); }
+#endif
+#if QT_DEPRECATED_SINCE(6, 4)
+    QT_DEPRECATED_VERSION_X_6_4("Use the overload taking Qt::Alignment")
     inline void setTextAlignment(int column, int alignment)
         { setData(column, Qt::TextAlignmentRole, alignment); }
+#endif
+    inline void setTextAlignment(int column, Qt::Alignment alignment)
+        { setData(column, Qt::TextAlignmentRole, QVariant::fromValue(alignment)); }
 
     inline QBrush background(int column) const
         { return qvariant_cast<QBrush>(data(column, Qt::BackgroundRole)); }
@@ -145,7 +155,7 @@ public:
         { setData(column, Qt::ForegroundRole, brush.style() != Qt::NoBrush ? QVariant(brush) : QVariant()); }
 
     inline Qt::CheckState checkState(int column) const
-        { return static_cast<Qt::CheckState>(data(column, Qt::CheckStateRole).toInt()); }
+        { return qvariant_cast<Qt::CheckState>(data(column, Qt::CheckStateRole)); }
     inline void setCheckState(int column, Qt::CheckState state)
         { setData(column, Qt::CheckStateRole, state); }