feat: auto dark reader mode that sync with system theme

src/article_maker.cc

@@ -15,6 +15,7 @@
 #include <QFile>
 #include <QTextDocumentFragment>
 #include <QUrl>
+#include <QStyleHints>
 
 #include "fmt/core.h"
 #include "fmt/compile.h"
@@ -151,7 +152,22 @@ std::string ArticleMaker::makeHtmlHeader( QString const & word, QString const &
   result += R"(<script src="qrc:///scripts/gd-builtin.js"></script>)";
   result += R"(<script src="qrc:///scripts/mark.min.js"></script>)";
 
+  /// Handling Dark reader mode.
+
+  bool darkReaderModeEnabled = false;
+
   if ( GlobalBroadcaster::instance()->getPreference()->darkReaderMode == Config::Dark::On ) {
+    darkReaderModeEnabled = true;
+  }
+
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 5, 0 )
+  if ( GlobalBroadcaster::instance()->getPreference()->darkReaderMode == Config::Dark::Auto
+       && QGuiApplication::styleHints()->colorScheme() == Qt::ColorScheme::Dark ) {
+    darkReaderModeEnabled = true;
+  }
+#endif
+
+  if ( darkReaderModeEnabled ) {
     //only enable this darkmode on modern style.
     if ( cfg.displayStyle == "modern" ) {
       result += R"(<link href="qrc:///article-style-darkmode.css"  media="all" rel="stylesheet" type="text/css">)";

src/config.hh

@@ -32,7 +32,7 @@ namespace Config {
 enum class Dark : std::uint8_t {
   Off = 0,
   On  = 1,
-  // TODO: Auto = 2,
+  Auto = 2,
 };
 
 /// Dictionaries which are temporarily disabled via the dictionary bar.
@@ -428,7 +428,13 @@ struct Preferences
   // Appearances
 
   Dark darkMode       = Dark::Off;
-  Dark darkReaderMode = Dark::Off;
+  Dark darkReaderMode =
+#if defined( Q_OS_MACOS )
+    Dark::Auto;
+#else
+    Dark::Off;
+#endif
+
   QString addonStyle;
   QString displayStyle; // Article Display style (Which also affect interface style on windows)
 

src/ui/mainwindow.cc

@@ -36,6 +36,8 @@
 #include <QThreadPool>
 #include <QSslConfiguration>
 #include <QStyleFactory>
+#include <QStyleHints>
+
 #include "weburlrequestinterceptor.hh"
 #include "folding.hh"
 
@@ -61,6 +63,7 @@
   #include <windows.h>
 #endif
 
+#include <QGuiApplication>
 #include <QWebEngineSettings>
 #include <QProxyStyle>
 
@@ -2321,6 +2324,7 @@ void MainWindow::editPreferences()
         || cfg.preferences.collapseBigArticles != p.collapseBigArticles
         || cfg.preferences.articleSizeLimit != p.articleSizeLimit
         || cfg.preferences.alwaysExpandOptionalParts != p.alwaysExpandOptionalParts // DSL format's special feature
+        || p.darkReaderMode == Config::Dark::Auto // We cannot know if a reload is needed, just do it regardless.
       );
 
     // This line must be here because the components below require cfg's value to reconfigure
@@ -2336,6 +2340,15 @@ void MainWindow::editPreferences()
       if ( needReload ) {
         view.reload();
       }
+
+#if QT_VERSION >= QT_VERSION_CHECK( 6, 5, 0 )
+      if ( cfg.preferences.darkReaderMode == Config::Dark::Auto ) {
+        connect( QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged, &view, &ArticleView::reload );
+      }
+      else {
+        disconnect( QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged, &view, &ArticleView::reload );
+      }
+#endif
     }
 
     audioPlayerFactory.setPreferences( cfg.preferences );

src/ui/preferences.cc

@@ -189,6 +189,8 @@ Preferences::Preferences( QWidget * parent, Config::Class & cfg_ ):
     ui.darkMode->setCurrentIndex( i );
   }
 
+  ui.darkReaderMode->addItem( tr( "Auto" ), QVariant::fromValue( Config::Dark::Auto ) );
+  ui.darkReaderMode->setItemData( 0, tr( "Auto does nothing on some systems." ), Qt::ToolTipRole );
   ui.darkReaderMode->addItem( tr( "On" ), QVariant::fromValue( Config::Dark::On ) );
   ui.darkReaderMode->addItem( tr( "Off" ), QVariant::fromValue( Config::Dark::Off ) );