feature: High-quality dictionary icons in toolbar (#1750)

* better procedure of image scaling and size choosing
* allow user to set toolbar icon size via qt style sheet

---------

Co-authored-by: shenleban tongying <shenlebantongying@gmail.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

src/dict/dictionary.cc

@@ -271,27 +271,13 @@ bool Class::loadIconFromFile( QString const & _filename, bool isFullName )
     if ( !img.isNull() ) {
       // Load successful
 
-      //some icon is very large ,will crash the application.
-      img = img.scaledToWidth( 64 );
+
       // Apply the color key
 #if ( QT_VERSION >= QT_VERSION_CHECK( 6, 0, 0 ) )
       img.setAlphaChannel( img.createMaskFromColor( QColor( 192, 192, 192 ).rgb(), Qt::MaskOutColor ) );
 #endif
 
-      // Transform it to be square
-      int max = img.width() > img.height() ? img.width() : img.height();
-
-      QImage result( max, max, QImage::Format_ARGB32 );
-      result.fill( 0 ); // Black transparent
-
-      QPainter painter( &result );
-      painter.setRenderHint( QPainter::RenderHint::Antialiasing );
-      painter.drawImage( QPoint( img.width() == max ? 0 : ( max - img.width() ) / 2,
-                                 img.height() == max ? 0 : ( max - img.height() ) / 2 ),
-                         img );
-
-      painter.end();
-
+      auto result    = img.scaled( { iconSize, iconSize }, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation );
       dictionaryIcon = QIcon( QPixmap::fromImage( result ) );
 
       return !dictionaryIcon.isNull();
@@ -307,18 +293,10 @@ bool Class::loadIconFromText( QString iconUrl, QString const & text )
   QImage img( iconUrl );
 
   if ( !img.isNull() ) {
-    int iconSize = 64;
-    //some icon is very large ,will crash the application.
-    img = img.scaledToWidth( iconSize );
-    QImage result( iconSize, iconSize, QImage::Format_ARGB32 );
-    result.fill( 0 ); // Black transparent
-    int max = img.width() > img.height() ? img.width() : img.height();
+    QImage result = img.scaled( { iconSize, iconSize }, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation );
 
     QPainter painter( &result );
-    painter.setRenderHint( QPainter::RenderHint::Antialiasing );
-    painter.drawImage( QPoint( img.width() == max ? 0 : ( max - img.width() ) / 2,
-                               img.height() == max ? 0 : ( max - img.height() ) / 2 ),
-                       img );
+    painter.setRenderHints( QPainter::Antialiasing | QPainter::TextAntialiasing );
     painter.setCompositionMode( QPainter::CompositionMode_SourceAtop );
 
     QFont font = painter.font();

src/dict/dictionary.hh

@@ -316,11 +316,12 @@ protected:
   bool synonymSearchEnabled;
   string dictionaryName;
   std::optional< bool > metadata_enable_fts = std::nullopt;
-
   // Load user icon if it exist
   // By default set icon to empty
   virtual void loadIcon() noexcept;
 
+  const int iconSize = 64;
+
   // Load icon from filename directly if isFullName == true
   // else treat filename as name without extension
   bool loadIconFromFile( QString const & filename, bool isFullName = false );

src/ui/dictionarybar.cc

@@ -4,6 +4,7 @@
 #include <QMenu>
 #include <QContextMenuEvent>
 #include <QProcess>
+#include <QStyle>
 
 
 using std::vector;
@@ -18,6 +19,13 @@ DictionaryBar::DictionaryBar( QWidget * parent,
   editDictionaryCommand( _editDictionaryCommand ),
   maxDictionaryRefsInContextMenu( maxDictionaryRefsInContextMenu_ )
 {
+
+  auto iconWidth  = this->size().width();
+  auto iconHeight = this->size().height();
+
+  normalIconSize = { std::max( iconWidth, iconHeight ), std::max( iconWidth, iconHeight ) };
+
+
   setObjectName( "dictionaryBar" );
 
   maxDictionaryRefsAction =
@@ -72,14 +80,24 @@ void DictionaryBar::setDictionaries( vector< sptr< Dictionary::Class > > const &
     dictActions.append( action );
   }
 
-  setDictionaryIconSize( 21 );
 
   setUpdatesEnabled( true );
 }
 
-void DictionaryBar::setDictionaryIconSize( int extent )
+void DictionaryBar::setDictionaryIconSize( IconSize size )
 {
-  setIconSize( QSize( extent, extent ) );
+  switch ( size ) {
+    case IconSize::Small: {
+      auto smallSize = QApplication::style()->pixelMetric( QStyle::PM_SmallIconSize );
+      setIconSize( { smallSize, smallSize } );
+      break;
+    }
+
+    case IconSize::Normal: {
+      setIconSize( normalIconSize );
+      break;
+    }
+  }
 }
 
 void DictionaryBar::contextMenuEvent( QContextMenuEvent * event )
@@ -87,6 +105,7 @@ void DictionaryBar::contextMenuEvent( QContextMenuEvent * event )
   showContextMenu( event );
 }
 
+
 void DictionaryBar::showContextMenu( QContextMenuEvent * event, bool extended )
 {
   QMenu menu( this );

src/ui/dictionarybar.hh

@@ -34,7 +34,14 @@ public:
   {
     return mutedDictionaries;
   }
-  void setDictionaryIconSize( int extent );
+
+  enum class IconSize {
+    Small,
+    Normal,
+    // TODO: implement something to have an Large option
+  };
+
+  void setDictionaryIconSize( IconSize size );
 
 signals:
 
@@ -69,6 +76,8 @@ private:
   QList< QAction * > dictActions;
   QAction * maxDictionaryRefsAction;
 
+  QSize normalIconSize; // cache icon size set by stylesheet provided by user
+
 protected:
 
   void contextMenuEvent( QContextMenuEvent * event );

src/ui/mainwindow.cc

@@ -1655,11 +1655,8 @@ void MainWindow::updateDictionaryBar()
 
     dictionaryBar.setDictionaries( grp->dictionaries );
 
-    int extent = useSmallIconsInToolbarsAction.isChecked() ?
-      QApplication::style()->pixelMetric( QStyle::PM_SmallIconSize ) :
-      QApplication::style()->pixelMetric( QStyle::PM_ToolBarIconSize );
-
-    dictionaryBar.setDictionaryIconSize( extent );
+    dictionaryBar.setDictionaryIconSize( useSmallIconsInToolbarsAction.isChecked() ? DictionaryBar::IconSize::Small :
+                                                                                     DictionaryBar::IconSize::Normal );
   }
 }
 

src/ui/scanpopup.cc

@@ -1110,9 +1110,8 @@ void ScanPopup::on_goForwardButton_clicked() const
 
 void ScanPopup::setDictionaryIconSize()
 {
-  int extent = cfg.usingSmallIconsInToolbars ? QApplication::style()->pixelMetric( QStyle::PM_SmallIconSize ) :
-                                               QApplication::style()->pixelMetric( QStyle::PM_ToolBarIconSize );
-  dictionaryBar.setDictionaryIconSize( extent );
+  dictionaryBar.setDictionaryIconSize( cfg.usingSmallIconsInToolbars ? DictionaryBar::IconSize::Small :
+                                                                       DictionaryBar::IconSize::Normal );
 }
 
 void ScanPopup::setGroupByName( QString const & name ) const