build: raise minimum Qt version to 6.8 and drop pre-6.8 fallbacks

CMakeLists.txt

@@ -20,7 +20,7 @@ set (CMAKE_AUTOUIC ON)
 
 find_package(QT NAMES Qt6 REQUIRED COMPONENTS Core)
 
-set (QT_MINIMUM_VERSION "6.5")
+set (QT_MINIMUM_VERSION "6.8")
 
 find_package(Qt${QT_VERSION_MAJOR} ${QT_MINIMUM_VERSION} REQUIRED
     COMPONENTS Widgets Svg SvgWidgets LinguistTools

app/graphicsscene.cpp

@@ -21,17 +21,12 @@
 
 static const QColor& ColorSchemaToTextForeground(Qt::ColorScheme colorScheme) {
     // YYC MARK:
-    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
-    // theme (lower than Qt 6.7), we should only support light mode.
+    // If we are using Windows 10 and lower system, we should only support light mode.
     // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
 #if defined(Q_OS_WIN)
-#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
-    colorScheme = Qt::ColorScheme::Light;
-#else
     if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
         colorScheme = Qt::ColorScheme::Light;
     }
-#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
 #endif // defined(Q_OS_WIN)
 
     switch (colorScheme) {
@@ -164,11 +159,9 @@ void GraphicsScene::showSvg(const QString &filepath)
     this->clear();
     QGraphicsSvgItem * svgItem = new QGraphicsSvgItem();
     QSvgRenderer * render = new QSvgRenderer(svgItem);
-#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
     if (Settings::instance()->svgTiny12Only()) {
         render->setOptions(QtSvg::Tiny12FeaturesOnly);
     }
-#endif // QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
     render->load(filepath);
     svgItem->setSharedRenderer(render);
     this->addItem(svgItem);

app/graphicsview.cpp

@@ -57,7 +57,6 @@ void GraphicsView::showFileFromPath(const QString &filePath)
         } else if (!imageReader.canRead()) {
             showText(tr("Image data is invalid or currently unsupported"));
         } else {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
             QImage && img = imageReader.read();
             if (img.isNull()) {
                 showText(tr("Image data is invalid or currently unsupported"));
@@ -68,15 +67,6 @@ void GraphicsView::showFileFromPath(const QString &filePath)
                 img.setDevicePixelRatio(devicePixelRatioF());
                 showImage(img);
             }
-#else
-            QPixmap && pixmap = QPixmap::fromImageReader(&imageReader);
-            if (pixmap.isNull()) {
-                showText(tr("Image data is invalid or currently unsupported"));
-            } else {
-                pixmap.setDevicePixelRatio(devicePixelRatioF());
-                showImage(pixmap);
-            }
-#endif // QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
         }
     }
 }
@@ -366,17 +356,12 @@ QTransform GraphicsView::resetScale(const QTransform & orig)
 
 void GraphicsView::updateStyle(Qt::ColorScheme colorScheme) {
     // YYC MARK:
-    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
-    // theme (lower than Qt 6.7), we should only support light mode.
+    // If we are using Windows 10 and lower system, we should only support light mode.
     // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
 #if defined(Q_OS_WIN)
-#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
-    colorScheme = Qt::ColorScheme::Light;
-#else
     if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
         colorScheme = Qt::ColorScheme::Light;
     }
-#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
 #endif // defined(Q_OS_WIN)
 
     switch (colorScheme) {

app/mainwindow.cpp

@@ -257,11 +257,7 @@ void MainWindow::galleryCurrent(bool fromFileWatcher)
 
 QStringList MainWindow::supportedImageFormats()
 {
-    QStringList formatFilters {
-#if QT_VERSION < QT_VERSION_CHECK(6, 8, 0)
-        QStringLiteral("*.jfif")
-#endif // QT_VERSION < QT_VERSION_CHECK(6, 8, 0)
-    };
+    QStringList formatFilters;
     for (const QByteArray &item : QImageReader::supportedImageFormats()) {
         formatFilters.append(QStringLiteral("*.") % QString::fromLocal8Bit(item));
     }

app/navigatorview.cpp

@@ -43,17 +43,12 @@ void NavigatorView::updateMainViewportRegion()
 
 void NavigatorView::updateStyle(Qt::ColorScheme colorScheme) {
     // YYC MARK:
-    // If we are using Windows 10 and lower system or Qt which do not support "Windows 11"
-    // theme (lower than Qt 6.7), we should only support light mode.
+    // If we are using Windows 10 and lower system, we should only support light mode.
     // Because Qt's dark-mode-aware "Windows 11" theme is only well-supported on Windows 11.
 #if defined(Q_OS_WIN)
-#if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
-    colorScheme = Qt::ColorScheme::Light;
-#else
     if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows11) {
         colorScheme = Qt::ColorScheme::Light;
     }
-#endif // QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
 #endif // defined(Q_OS_WIN)
 
     switch (colorScheme) {

app/settingsdialog.cpp

@@ -98,27 +98,19 @@ SettingsDialog::SettingsDialog(QWidget *parent)
     Qt::HighDpiScaleFactorRoundingPolicy hidpi = settings->hiDpiScaleFactorBehavior();
     ui->m_hiDpiRoundingPolicyBehavior->setCurrentIndex(HIDPI_OPTIONS.to_index(hidpi));
 
-#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
-# define QCHECKBOX_CHECKSTATECHANGED QCheckBox::checkStateChanged
-# define QT_CHECKSTATE Qt::CheckState
-#else
-# define QCHECKBOX_CHECKSTATECHANGED QCheckBox::stateChanged
-# define QT_CHECKSTATE int
-#endif // QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
-
-    connect(ui->m_showNavigatorView, &QCHECKBOX_CHECKSTATECHANGED, this, [ = ](QT_CHECKSTATE state){
+    connect(ui->m_showNavigatorView, &QCheckBox::checkStateChanged, this, [ = ](Qt::CheckState state){
         Settings::instance()->setShowNavigatorView(state == Qt::Checked);
     });
 
-    connect(ui->m_useLightCheckerboard, &QCHECKBOX_CHECKSTATECHANGED, this, [ = ](QT_CHECKSTATE state){
+    connect(ui->m_useLightCheckerboard, &QCheckBox::checkStateChanged, this, [ = ](Qt::CheckState state){
         Settings::instance()->setUseLightCheckerboard(state == Qt::Checked);
     });
 
-    connect(ui->m_loopGallery, &QCHECKBOX_CHECKSTATECHANGED, this, [ = ](QT_CHECKSTATE state){
+    connect(ui->m_loopGallery, &QCheckBox::checkStateChanged, this, [ = ](Qt::CheckState state){
         Settings::instance()->setLoopGallery(state == Qt::Checked);
     });
 
-    connect(ui->m_svgTiny12Only, &QCHECKBOX_CHECKSTATECHANGED, this, [ = ](QT_CHECKSTATE state){
+    connect(ui->m_svgTiny12Only, &QCheckBox::checkStateChanged, this, [ = ](Qt::CheckState state){
         Settings::instance()->setSvgTiny12Only(state == Qt::Checked);
     });