feat: add hidpi rounding policy option to setting dialog

app/main.cpp

@@ -5,6 +5,7 @@
 #include "mainwindow.h"
 
 #include "playlistmanager.h"
+#include "settings.h"
 
 #include <QApplication>
 #include <QCommandLineParser>
@@ -19,6 +20,8 @@
 
 int main(int argc, char *argv[])
 {
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Settings::instance()->hiDpiScaleFactorBehavior());
+
     QApplication a(argc, argv);
 #if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     a.setAttribute(Qt::ApplicationAttribute::AA_UseHighDpiPixmaps);

app/settings.cpp

@@ -68,6 +68,13 @@ Settings::WindowSizeBehavior Settings::initWindowSizeBehavior() const
     return QEnumHelper::fromString<WindowSizeBehavior>(result, WindowSizeBehavior::Auto);
 }
 
+Qt::HighDpiScaleFactorRoundingPolicy Settings::hiDpiScaleFactorBehavior() const
+{
+    QString result = m_qsettings->value("hidpi_scale_factor_behavior", "PassThrough").toString();
+
+    return QEnumHelper::fromString<Qt::HighDpiScaleFactorRoundingPolicy>(result, Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+}
+
 void Settings::setStayOnTop(bool on)
 {
     m_qsettings->setValue("stay_on_top", on);
@@ -92,6 +99,12 @@ void Settings::setInitWindowSizeBehavior(WindowSizeBehavior wsb)
     m_qsettings->sync();
 }
 
+void Settings::setHiDpiScaleFactorBehavior(Qt::HighDpiScaleFactorRoundingPolicy hidpi)
+{
+    m_qsettings->setValue("hidpi_scale_factor_behavior", QEnumHelper::toString(hidpi));
+    m_qsettings->sync();
+}
+
 Settings::Settings()
     : QObject(qApp)
 {

app/settings.h

@@ -16,19 +16,19 @@ public:
         Close,
         Maximize,
     };
-    Q_ENUM(DoubleClickBehavior);
+    Q_ENUM(DoubleClickBehavior)
 
     enum MouseWheelBehavior {
         Zoom,
         Switch,
     };
-    Q_ENUM(MouseWheelBehavior);
+    Q_ENUM(MouseWheelBehavior)
 
     enum WindowSizeBehavior {
         Auto,
         Maximized,
     };
-    Q_ENUM(WindowSizeBehavior);
+    Q_ENUM(WindowSizeBehavior)
 
     static Settings *instance();
 
@@ -36,11 +36,13 @@ public:
     DoubleClickBehavior doubleClickBehavior() const;
     MouseWheelBehavior mouseWheelBehavior() const;
     WindowSizeBehavior initWindowSizeBehavior() const;
+    Qt::HighDpiScaleFactorRoundingPolicy hiDpiScaleFactorBehavior() const;
 
     void setStayOnTop(bool on);
     void setDoubleClickBehavior(DoubleClickBehavior dcb);
     void setMouseWheelBehavior(MouseWheelBehavior mwb);
     void setInitWindowSizeBehavior(WindowSizeBehavior wsb);
+    void setHiDpiScaleFactorBehavior(Qt::HighDpiScaleFactorRoundingPolicy hidpi);
 
 private:
     Settings();

app/settingsdialog.cpp

@@ -17,6 +17,7 @@ SettingsDialog::SettingsDialog(QWidget *parent)
     , m_doubleClickBehavior(new QComboBox)
     , m_mouseWheelBehavior(new QComboBox)
     , m_initWindowSizeBehavior(new QComboBox)
+    , m_hiDpiRoundingPolicyBehavior(new QComboBox)
 {
     this->setWindowTitle(tr("Settings"));
 
@@ -38,6 +39,13 @@ SettingsDialog::SettingsDialog(QWidget *parent)
         { Settings::WindowSizeBehavior::Maximized, tr("Maximized") }
     };
 
+    static QList< QPair<Qt::HighDpiScaleFactorRoundingPolicy, QString> > _hidpi_options {
+        { Qt::HighDpiScaleFactorRoundingPolicy::Round, tr("Round (Integer scaling)", "This option means round up for .5 and above") },
+        { Qt::HighDpiScaleFactorRoundingPolicy::Ceil, tr("Ceil (Integer scaling)", "This option means always round up") },
+        { Qt::HighDpiScaleFactorRoundingPolicy::Floor, tr("Floor (Integer scaling)", "This option means always round down") },
+        { Qt::HighDpiScaleFactorRoundingPolicy::PassThrough, tr("Follow system (Fractional scaling)", "This option means don't round") }
+    };
+
     QStringList dcbDropDown;
     for (const QPair<Settings::DoubleClickBehavior, QString> & dcOption : _dc_options) {
         dcbDropDown.append(dcOption.second);
@@ -53,10 +61,16 @@ SettingsDialog::SettingsDialog(QWidget *parent)
         iwsbDropDown.append(iwsOption.second);
     }
 
+    QStringList hidpiDropDown;
+    for (const QPair<Qt::HighDpiScaleFactorRoundingPolicy, QString> & hidpiOption : _hidpi_options) {
+        hidpiDropDown.append(hidpiOption.second);
+    }
+
     settingsForm->addRow(tr("Stay on top when start-up"), m_stayOnTop);
     settingsForm->addRow(tr("Double-click behavior"), m_doubleClickBehavior);
     settingsForm->addRow(tr("Mouse wheel behavior"), m_mouseWheelBehavior);
     settingsForm->addRow(tr("Default window size"), m_initWindowSizeBehavior);
+    settingsForm->addRow(tr("HiDPI scale factor rounding policy"), m_hiDpiRoundingPolicyBehavior);
 
     m_stayOnTop->setChecked(Settings::instance()->stayOnTop());
     m_doubleClickBehavior->setModel(new QStringListModel(dcbDropDown));
@@ -68,6 +82,14 @@ SettingsDialog::SettingsDialog(QWidget *parent)
     m_initWindowSizeBehavior->setModel(new QStringListModel(iwsbDropDown));
     Settings::WindowSizeBehavior iwsb = Settings::instance()->initWindowSizeBehavior();
     m_initWindowSizeBehavior->setCurrentIndex(static_cast<int>(iwsb));
+    m_hiDpiRoundingPolicyBehavior->setModel(new QStringListModel(hidpiDropDown));
+    Qt::HighDpiScaleFactorRoundingPolicy hidpi = Settings::instance()->hiDpiScaleFactorBehavior();
+    for (int i = 0; i < _hidpi_options.count(); i++) {
+        if (_hidpi_options.at(i).first == hidpi) {
+            m_hiDpiRoundingPolicyBehavior->setCurrentIndex(i);
+            break;
+        }
+    }
 
     connect(m_stayOnTop, &QCheckBox::stateChanged, this, [ = ](int state){
         Settings::instance()->setStayOnTop(state == Qt::Checked);
@@ -85,6 +107,10 @@ SettingsDialog::SettingsDialog(QWidget *parent)
         Settings::instance()->setInitWindowSizeBehavior(_iws_options.at(index).first);
     });
 
+    connect(m_hiDpiRoundingPolicyBehavior, QOverload<int>::of(&QComboBox::currentIndexChanged), this, [ = ](int index){
+        Settings::instance()->setHiDpiScaleFactorBehavior(_hidpi_options.at(index).first);
+    });
+
     adjustSize();
     setWindowFlag(Qt::WindowContextHelpButtonHint, false);
 }

app/settingsdialog.h

@@ -26,6 +26,7 @@ private:
     QComboBox * m_doubleClickBehavior = nullptr;
     QComboBox * m_mouseWheelBehavior = nullptr;
     QComboBox * m_initWindowSizeBehavior = nullptr;
+    QComboBox * m_hiDpiRoundingPolicyBehavior = nullptr;
 };
 
 #endif // SETTINGSDIALOG_H