QDate::toStdSysDays is needlessly behind __cpp_lib_chrono >= 201907L

scwx-qt/source/scwx/qt/ui/animation_dock_widget.cpp

@@ -1,6 +1,7 @@
 #include "animation_dock_widget.hpp"
 #include "ui_animation_dock_widget.h"
 
+#include <scwx/qt/util/time.hpp>
 #include <scwx/util/logger.hpp>
 
 #include <QTimer>
@@ -65,7 +66,7 @@ AnimationDockWidget::AnimationDockWidget(QWidget* parent) :
    ui->dateEdit->setDate(currentDate);
    ui->timeEdit->setTime(currentTime);
    ui->dateEdit->setMaximumDate(currentDateTime.date());
-   p->selectedDate_ = currentDate.toStdSysDays();
+   p->selectedDate_ = util::SysDays(currentDate);
    p->selectedTime_ =
       std::chrono::seconds(currentTime.msecsSinceStartOfDay() / 1000);
 
@@ -129,7 +130,7 @@ void AnimationDockWidgetImpl::ConnectSignals()
       {
          if (date.isValid())
          {
-            selectedDate_ = date.toStdSysDays();
+            selectedDate_ = util::SysDays(date);
             emit self_->DateTimeChanged(selectedDate_ + selectedTime_);
          }
       });

scwx-qt/source/scwx/qt/util/time.cpp

@@ -0,0 +1,24 @@
+#include <scwx/qt/util/time.hpp>
+
+namespace scwx
+{
+namespace qt
+{
+namespace util
+{
+
+std::chrono::sys_days SysDays(const QDate& date)
+{
+   using namespace std::chrono;
+   using sys_days             = time_point<system_clock, days>;
+   constexpr auto julianEpoch = sys_days {-4713y / November / 24d};
+   constexpr auto unixEpoch   = sys_days {1970y / January / 1d};
+   constexpr auto offset      = std::chrono::days(julianEpoch - unixEpoch);
+
+   return std::chrono::sys_days(std::chrono::days(date.toJulianDay()) +
+                                julianEpoch);
+}
+
+} // namespace util
+} // namespace qt
+} // namespace scwx

scwx-qt/source/scwx/qt/util/time.hpp

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <chrono>
+
+#include <QDateTime>
+
+namespace scwx
+{
+namespace qt
+{
+namespace util
+{
+
+/**
+ * @brief Convert QDate to std::chrono::sys_days.
+ *
+ * @param [in] date Date to convert
+ *
+ * @return Days
+ */
+std::chrono::sys_days SysDays(const QDate& date);
+
+} // namespace util
+} // namespace qt
+} // namespace scwx