Use standaloneMonthName in the printed month's header

Use `standaloneMonthName()` to generate the month name in the printed
month's header, as is done by KOrganizer's date navigator, because
`monthName()` produces inappropriate month names for Slavic
languages in this context.

BUG: 453292

Related: eventviews!68

src/freebusymodel/freeperiodmodel.cpp

@@ -156,7 +156,6 @@ QString FreePeriodModel::stringify(int index) const
     const QString longMonthName = QLocale::system().monthName(startDate.month(), QLocale::LongFormat);
     const QString dayofWeek = QLocale::system().dayName(startDate.dayOfWeek(), QLocale::LongFormat);
 
-    // TODO i18n, ping chusslove
     return ki18nc(
                "@label A time period duration. KLocale is used to format the components. "
                "example: Monday, 12 June, 8:00am to 9:30am",

src/printing/calprintdefaultplugins.cpp

@@ -1412,13 +1412,13 @@ void CalPrintMonth::setDateRange(const QDate &from, const QDate &to)
     CalPrintPluginBase::setDateRange(from, to);
     auto cfg = dynamic_cast<CalPrintMonthConfig *>((QWidget *)mConfigWidget);
     if (cfg) {
+        const QLocale locale;
         cfg->mFromMonth->clear();
-        for (int i = 0; i < 12; ++i) {
-            cfg->mFromMonth->addItem(QLocale().monthName(i + 1, QLocale::LongFormat));
-        }
         cfg->mToMonth->clear();
-        for (int i = 0; i < 12; ++i) {
-            cfg->mToMonth->addItem(QLocale().monthName(i + 1, QLocale::LongFormat));
+        for (int i = 1; i < 13; ++i) {
+            const auto monthName = locale.standaloneMonthName(i, QLocale::LongFormat);
+            cfg->mFromMonth->addItem(monthName);
+            cfg->mToMonth->addItem(monthName);
         }
         cfg->mFromMonth->setCurrentIndex(from.month() - 1);
         cfg->mFromYear->setValue(to.year());
@@ -1446,7 +1446,9 @@ void CalPrintMonth::print(QPainter &p, int width, int height)
     monthBox.setTop(headerBox.bottom() + padding());
 
     do {
-        QString title(i18nc("monthname year", "%1 %2", QLocale::system().monthName(curMonth.month()), QString::number(curMonth.year())));
+        QString title(i18nc("monthname year", "%1 %2",
+                            QLocale::system().standaloneMonthName(curMonth.month(), QLocale::LongFormat),
+                            QString::number(curMonth.year())));
         QDate tmp(fromMonth);
         int weekdayCol = weekdayColumn(tmp.dayOfWeek());
         tmp = tmp.addDays(-weekdayCol);

src/printing/calprintpluginbase.cpp

@@ -636,10 +636,12 @@ void CalPrintPluginBase::drawSmallMonth(QPainter &p, QDate qd, QRect box)
     newFont.setPixelSize(cellHeight);
     p.setFont(newFont);
 
+    const QLocale locale;
+
     // draw the title
     QRect titleBox(box);
     titleBox.setHeight(p.fontMetrics().height());
-    p.drawText(titleBox, Qt::AlignTop | Qt::AlignHCenter, QLocale::system().monthName(month));
+    p.drawText(titleBox, Qt::AlignTop | Qt::AlignHCenter, locale.standaloneMonthName(month));
 
     // draw days of week
     QRect wdayBox(box);
@@ -647,10 +649,10 @@ void CalPrintPluginBase::drawSmallMonth(QPainter &p, QDate qd, QRect box)
     wdayBox.setHeight(int(2 * cellHeight) - int(cellHeight));
 
     for (int col = 0; col < 7; ++col) {
-        QString tmpStr = QLocale::system().dayName(monthDate2.dayOfWeek())[0].toUpper();
+        const auto dayLetter = locale.standaloneDayName(monthDate2.dayOfWeek(), QLocale::ShortFormat)[0].toUpper();
         wdayBox.setLeft(int(box.left() + col * cellWidth));
         wdayBox.setRight(int(box.left() + (col + 1) * cellWidth));
-        p.drawText(wdayBox, Qt::AlignCenter, tmpStr);
+        p.drawText(wdayBox, Qt::AlignCenter, dayLetter);
         monthDate2 = monthDate2.addDays(1);
     }
 
@@ -1271,7 +1273,7 @@ void CalPrintPluginBase::drawMonth(QPainter &p,
     subheaderBox.setHeight(subHeaderHeight());
     QRect borderBox(box);
     borderBox.setTop(subheaderBox.bottom() + 1);
-    drawSubHeaderBox(p, QLocale::system().monthName(dt.month()), subheaderBox);
+    drawSubHeaderBox(p, QLocale().standaloneMonthName(dt.month()), subheaderBox);
     // correct for half the border width
     int correction = (BOX_BORDER_WIDTH /*-1*/) / 2;
     QRect daysBox(borderBox);