add setCalendar function in qdatetimeaxis class

src/charts/axis/cartesianchartaxis.cpp

@@ -76,6 +76,7 @@ void CartesianChartAxis::createItems(int count)
             if (labelsEditable())
                 dateTimeLabel->setEditable(true);
             dateTimeLabel->setFormat(static_cast<QDateTimeAxis*>(axis())->format());
+            dateTimeLabel->setCalendar(static_cast<QDateTimeAxis *>(axis())->calendar());
 #endif
         } else {
             label = new QGraphicsTextItem(this);
@@ -285,6 +286,17 @@ void CartesianChartAxis::setDateTimeLabelsFormat(const QString &format)
 #endif
 }
 
+void CartesianChartAxis::setDateTimeLabelsCalendar(const QCalendar &calendar) {
+  if (max() <= min() || layout().size() < 1 ||
+      axis()->type() != QAbstractAxis::AxisTypeDateTime) {
+    return;
+  }
+#if QT_CONFIG(charts_datetime_axis)
+  for (int i = 0; i < layout().size(); i++)
+    static_cast<DateTimeAxisLabel *>(labelItems().at(i))->setCalendar(calendar);
+#endif
+}
+
 void CartesianChartAxis::handleArrowPenChanged(const QPen &pen)
 {
     foreach (QGraphicsItem *item, arrowItems())

src/charts/axis/cartesianchartaxis_p.h

@@ -37,6 +37,8 @@ class Q_CHARTS_PRIVATE_EXPORT CartesianChartAxis : public ChartAxisElement
     QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const override;
 
     void setDateTimeLabelsFormat(const QString &format);
+
+    void setDateTimeLabelsCalendar(const QCalendar &calendar);
 
 protected:
     void setGeometry(const QRectF &size) override { Q_UNUSED(size);}

src/charts/axis/datetimeaxis/datetimeaxislabel.cpp

@@ -15,7 +15,7 @@ DateTimeAxisLabel::DateTimeAxisLabel(QGraphicsItem *parent) :
 void DateTimeAxisLabel::finishEditing()
 {
     QDateTime oldDateTime = m_dateTime;
-    QDateTime newDateTime = QDateTime::fromString(document()->toPlainText(), m_format);
+    QDateTime newDateTime = QDateTime::fromString(document()->toPlainText(), m_format, m_calendar);
     if (newDateTime.isValid() && newDateTime != m_dateTime) {
         m_dateTime = newDateTime;
         emit dateTimeChanged(oldDateTime, newDateTime);
@@ -49,10 +49,14 @@ void DateTimeAxisLabel::setFormat(const QString &format)
     m_format.replace(QChar::fromLatin1('\n'), QChar::fromLatin1(' '));
 }
 
+void DateTimeAxisLabel::setCalendar(const QCalendar &calendar) {
+  m_calendar = calendar;
+}
+
 void DateTimeAxisLabel::setInitialEditValue()
 {
     m_dateTimeBeforeEdit = m_dateTime;
-    setHtml(m_dateTime.toString(m_format));
+    setHtml(m_dateTime.toString(m_format, m_calendar));
 }
 
 void DateTimeAxisLabel::keyPressEvent(QKeyEvent *event)

src/charts/axis/datetimeaxis/datetimeaxislabel_p.h

@@ -15,6 +15,7 @@
 
 #include <private/editableaxislabel_p.h>
 
+#include <QtCore/qcalendar.h>
 #include <QtCore/qdatetime.h>
 
 QT_BEGIN_NAMESPACE
@@ -30,11 +31,13 @@ class Q_CHARTS_PRIVATE_EXPORT DateTimeAxisLabel : public EditableAxisLabel
     QDateTime value() const;
     void setValue(const QDateTime &value);
     void setFormat(const QString &format);
+    void setCalendar(const QCalendar &calendar);
 
 private:
     QDateTime m_dateTime;
     QDateTime m_dateTimeBeforeEdit;
     QString m_format;
+    Calendar m_calendar;
 
     void setInitialEditValue() override;
     void finishEditing() override;

src/charts/axis/datetimeaxis/qdatetimeaxis.cpp

@@ -245,6 +245,19 @@ QString QDateTimeAxis::format() const
     return d->m_format;
 }
 
+void QDateTimeAxis::setCalendar(QCalendar calendar) {
+  Q_D(QDateTimeAxis);
+  if (d->axisItem())
+    static_cast<CartesianChartAxis *>(d->axisItem())
+        ->setDateTimeLabelsCalendar(calendar);
+  // emit formatChanged(format); TODO
+}
+
+QCalendar QDateTimeAxis::calendar() const {
+  Q_D(const QDateTimeAxis);
+  return d->m_calendar;
+}
+
 /*!
   Sets the number of tick marks on the axis to \a count.
 */
@@ -284,6 +297,7 @@ QDateTimeAxisPrivate::QDateTimeAxisPrivate(QDateTimeAxis *q)
       m_tickCount(5)
 {
     m_format = QStringLiteral("dd-MM-yyyy\nh:mm");
+    m_calendar = QCalendar(QCalendar::System::Gregorian);
 }
 
 QDateTimeAxisPrivate::~QDateTimeAxisPrivate()

src/charts/axis/datetimeaxis/qdatetimeaxis.h

@@ -8,6 +8,7 @@
 
 QT_BEGIN_NAMESPACE
 class QDateTime;
+class QCalendar;
 QT_END_NAMESPACE
 
 QT_BEGIN_NAMESPACE
@@ -42,6 +43,9 @@ class Q_CHARTS_EXPORT QDateTimeAxis : public QAbstractAxis
     void setFormat(QString format);
     QString format() const;
 
+    void setCalendar(QCalendar calendar);
+    QCalendar calendar() const;
+
     //ticks handling
     void setTickCount(int count);
     int tickCount() const;

src/charts/axis/datetimeaxis/qdatetimeaxis_p.h

@@ -49,6 +49,7 @@ class Q_CHARTS_PRIVATE_EXPORT QDateTimeAxisPrivate : public QAbstractAxisPrivate
     qreal m_max;
     int m_tickCount;
     QString m_format;
+    QCalendar m_calendar;
     Q_DECLARE_PUBLIC(QDateTimeAxis)
 };