Fix symbol icon size and pixelation issues on hidpi screens

python/PyQt6/core/auto_additions/qgscolorramplegendnode.py

@@ -1,6 +1,6 @@
 # The following has been generated automatically from src/core/layertree/qgscolorramplegendnode.h
 try:
-    QgsColorRampLegendNode.__overridden_methods__ = ['data', 'drawSymbol', 'drawSymbolText', 'exportSymbolToJson']
+    QgsColorRampLegendNode.__overridden_methods__ = ['data', 'drawSymbol', 'drawSymbolText', 'exportSymbolToJson', 'invalidateDisplayData']
     QgsColorRampLegendNode.__group__ = ['layertree']
 except (NameError, AttributeError):
     pass

python/PyQt6/core/auto_additions/qgslayertreemodellegendnode.py

@@ -61,13 +61,13 @@
     pass
 try:
     QgsLayerTreeModelLegendNode.__attribute_docs__ = {'dataChanged': 'Emitted on internal data change so the layer tree model can forward the\nsignal to views\n', 'sizeChanged': 'Emitted when the size of this node changes.\n\n.. versionadded:: 3.16\n'}
-    QgsLayerTreeModelLegendNode.__virtual_methods__ = ['flags', 'setData', 'isEmbeddedInParent', 'setEmbeddedInParent', 'userLabel', 'setUserLabel', 'userPatchSize', 'setUserPatchSize', 'setColumnBreak', 'columnBreak', 'isScaleOK', 'invalidateMapBasedData', 'draw', 'drawSymbol', 'exportSymbolToJson', 'drawSymbolText']
+    QgsLayerTreeModelLegendNode.__virtual_methods__ = ['flags', 'setData', 'isEmbeddedInParent', 'setEmbeddedInParent', 'userLabel', 'setUserLabel', 'userPatchSize', 'setUserPatchSize', 'setColumnBreak', 'columnBreak', 'isScaleOK', 'invalidateMapBasedData', 'invalidateDisplayData', 'draw', 'drawSymbol', 'exportSymbolToJson', 'drawSymbolText']
     QgsLayerTreeModelLegendNode.__abstract_methods__ = ['data']
     QgsLayerTreeModelLegendNode.__group__ = ['layertree']
 except (NameError, AttributeError):
     pass
 try:
-    QgsSymbolLegendNode.__overridden_methods__ = ['flags', 'data', 'setData', 'drawSymbol', 'exportSymbolToJson', 'setEmbeddedInParent', 'setUserLabel', 'isScaleOK', 'invalidateMapBasedData']
+    QgsSymbolLegendNode.__overridden_methods__ = ['flags', 'data', 'setData', 'invalidateDisplayData', 'drawSymbol', 'exportSymbolToJson', 'setEmbeddedInParent', 'setUserLabel', 'isScaleOK', 'invalidateMapBasedData']
     QgsSymbolLegendNode.__group__ = ['layertree']
 except (NameError, AttributeError):
     pass
@@ -92,7 +92,7 @@
 except (NameError, AttributeError):
     pass
 try:
-    QgsDataDefinedSizeLegendNode.__overridden_methods__ = ['data', 'draw']
+    QgsDataDefinedSizeLegendNode.__overridden_methods__ = ['data', 'invalidateDisplayData', 'draw']
     QgsDataDefinedSizeLegendNode.__group__ = ['layertree']
 except (NameError, AttributeError):
     pass

python/PyQt6/core/auto_generated/layertree/qgscolorramplegendnode.sip.in

@@ -80,6 +80,8 @@ Constructor for QgsColorRampLegendNode.
 
     virtual QJsonObject exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const;
 
+    virtual void invalidateDisplayData();
+
 
     void setIconSize( QSize size );
 %Docstring

python/PyQt6/core/auto_generated/layertree/qgslayertreemodel.sip.in

@@ -350,6 +350,18 @@ which corresponds exactly to the view's screen properties in which this
 model is used.
 
 .. versionadded:: 3.32
+%End
+
+    void setTargetScreenProperties( const QSet< QgsScreenProperties > &properties );
+%Docstring
+Sets all target screen ``properties`` to use when generating icons for
+Qt.DecorationRole data.
+
+This allows icons to be generated at an icon device pixel ratio and DPI
+which corresponds exactly to the view's screen properties in which this
+model is used.
+
+.. versionadded:: 4.2
 %End
 
     QSet< QgsScreenProperties > targetScreenProperties() const;
@@ -395,6 +407,13 @@ progress.
 .. seealso:: :py:func:`hitTestCompleted`
 
 .. versionadded:: 3.32
+%End
+
+    void invalidateDisplayData();
+%Docstring
+Invalidates all cached display data throughout the model.
+
+.. versionadded:: 4.2
 %End
 
   signals:

python/PyQt6/core/auto_generated/layertree/qgslayertreemodellegendnode.sip.in

@@ -150,6 +150,15 @@ Returns whether a forced column break should occur before the node.
 %Docstring
 Notification from model that information from associated map view has
 changed. Default implementation does nothing.
+%End
+
+    virtual void invalidateDisplayData();
+%Docstring
+Invalidates cached display data for the node.
+
+The default implementation does nothing.
+
+.. versionadded:: 4.2
 %End
 
     struct ItemContext
@@ -348,6 +357,7 @@ Constructor for QgsSymbolLegendNode.
 
     virtual bool setData( const QVariant &value, int role );
 
+    virtual void invalidateDisplayData();
 
     virtual QSizeF drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const;
 
@@ -729,6 +739,7 @@ definition of the node's appearance
 
     virtual QVariant data( int role ) const;
 
+    virtual void invalidateDisplayData();
 
     virtual ItemMetrics draw( const QgsLegendSettings &settings, ItemContext &ctx );
 

src/core/layertree/qgscolorramplegendnode.cpp

@@ -114,7 +114,7 @@ QVariant QgsColorRampLegendNode::data( int role ) const
   }
   else if ( role == Qt::DecorationRole )
   {
-    if ( mPixmap.isNull() || mPixmap.size() != mIconSize )
+    if ( mPixmap.isNull() )
     {
       const QFont font = data( Qt::FontRole ).value< QFont >();
 
@@ -126,30 +126,42 @@ QVariant QgsColorRampLegendNode::data( int role ) const
       const QRect minBoundingRect = fm.boundingRect( minLabel );
       const QRect maxBoundingRect = fm.boundingRect( maxLabel );
 
-      const int minLabelWidth = minBoundingRect.width();
-      const int maxLabelWidth = maxBoundingRect.width();
-      const int maxTextWidth = std::max( minLabelWidth, maxLabelWidth );
-      const int labelGapFromRamp = fm.boundingRect( u"x"_s ).width();
-      const int extraAllowance = labelGapFromRamp * 0.4; // extra allowance to avoid text clipping on right
-      QRect labelRect;
+      QgsScreenProperties targetScreen = model() && !model()->targetScreenProperties().isEmpty() ? *model()->targetScreenProperties().begin() : QgsScreenProperties();
+      double devicePixelRatio = 1;
+      if ( targetScreen.isValid() )
+      {
+        devicePixelRatio = targetScreen.devicePixelRatio();
+      }
+
+      const double minLabelWidth = minBoundingRect.width() * devicePixelRatio;
+      const double maxLabelWidth = maxBoundingRect.width() * devicePixelRatio;
+      const double maxTextWidth = std::max( minLabelWidth, maxLabelWidth );
+      const double labelGapFromRamp = fm.boundingRect( u"x"_s ).width() * devicePixelRatio;
+      const double extraAllowance = labelGapFromRamp * 0.4; // extra allowance to avoid text clipping on right
+      QRectF labelRect;
       QSize rampSize;
       switch ( mSettings.orientation() )
       {
         case Qt::Vertical:
-          labelRect = QRect( mIconSize.width() + labelGapFromRamp, 0, maxTextWidth + extraAllowance, mIconSize.height() );
+          labelRect = QRectF( ( mIconSize.width() + labelGapFromRamp ) / devicePixelRatio, 0, ( maxTextWidth + extraAllowance ) / devicePixelRatio, mIconSize.height() / devicePixelRatio );
           mPixmap = QPixmap( mIconSize.width() + maxTextWidth + labelGapFromRamp + extraAllowance, mIconSize.height() );
           rampSize = mIconSize;
           break;
 
         case Qt::Horizontal:
-          labelRect
-            = QRect( 0, mIconSize.height() + labelGapFromRamp, std::max( mIconSize.width(), minLabelWidth + maxLabelWidth + labelGapFromRamp ), std::max( minBoundingRect.height(), maxBoundingRect.height() ) + extraAllowance );
-          mPixmap = QPixmap( std::max( mIconSize.width(), minLabelWidth + maxLabelWidth + labelGapFromRamp ), mIconSize.height() + maxTextWidth + labelGapFromRamp + extraAllowance );
+          labelRect = QRectF(
+            0,
+            ( mIconSize.height() + labelGapFromRamp ) / devicePixelRatio,
+            std::max( static_cast<double>( mIconSize.width() ), minLabelWidth + maxLabelWidth + labelGapFromRamp ) / devicePixelRatio,
+            ( std::max( minBoundingRect.height() * devicePixelRatio, maxBoundingRect.height() * devicePixelRatio ) + extraAllowance ) / devicePixelRatio
+          );
+          mPixmap = QPixmap( std::max( static_cast< double >( mIconSize.width() ), minLabelWidth + maxLabelWidth + labelGapFromRamp ), mIconSize.height() + maxTextWidth + labelGapFromRamp + extraAllowance );
           rampSize = QSize( labelRect.width(), mIconSize.height() );
           break;
       }
 
       mPixmap.fill( Qt::transparent );
+      mPixmap.setDevicePixelRatio( devicePixelRatio );
 
       QPixmap pix;
 
@@ -170,6 +182,8 @@ QVariant QgsColorRampLegendNode::data( int role ) const
         pix.fill( Qt::transparent );
       }
 
+      pix.setDevicePixelRatio( devicePixelRatio );
+
       QPainter p( &mPixmap );
       p.drawPixmap( 0, 0, pix );
       p.setFont( font );
@@ -538,3 +552,10 @@ QJsonObject QgsColorRampLegendNode::exportSymbolToJson( const QgsLegendSettings
 
   return json;
 }
+
+void QgsColorRampLegendNode::invalidateDisplayData()
+{
+  mPixmap = QPixmap();
+  const int iconSize = QgsLayerTreeModel::scaleIconSize( 16 );
+  mIconSize = mSettings.orientation() == Qt::Vertical ? QSize( iconSize, iconSize * 6 ) : QSize( iconSize * 6, iconSize );
+}

src/core/layertree/qgscolorramplegendnode.h

@@ -82,6 +82,7 @@ class CORE_EXPORT QgsColorRampLegendNode : public QgsLayerTreeModelLegendNode
     QSizeF drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const override;
     QSizeF drawSymbolText( const QgsLegendSettings &settings, ItemContext *ctx, QSizeF symbolSize ) const override;
     QJsonObject exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const override;
+    void invalidateDisplayData() override;
 
     /**
      * Set the icon \a size, which controls how large the ramp will render in a layer tree widget.

src/core/layertree/qgslayertreemodel.cpp

@@ -801,6 +801,12 @@ void QgsLayerTreeModel::addTargetScreenProperties( const QgsScreenProperties &pr
   mTargetScreenProperties.insert( properties );
 }
 
+void QgsLayerTreeModel::setTargetScreenProperties( const QSet<QgsScreenProperties> &properties )
+{
+  mTargetScreenProperties = properties;
+  invalidateDisplayData();
+}
+
 QSet<QgsScreenProperties> QgsLayerTreeModel::targetScreenProperties() const
 {
   return mTargetScreenProperties;
@@ -822,6 +828,41 @@ bool QgsLayerTreeModel::hitTestInProgress() const
   return static_cast< bool >( mHitTestTask );
 }
 
+void QgsLayerTreeModel::invalidateDisplayData()
+{
+  std::function< void( QgsLayerTreeNode * ) > invalidateNode;
+  invalidateNode = [this, &invalidateNode]( QgsLayerTreeNode *node ) {
+    if ( !node )
+      return;
+
+    switch ( node->nodeType() )
+    {
+      case QgsLayerTreeNode::NodeLayer:
+      {
+        auto layerNode = qobject_cast< QgsLayerTreeLayer * >( node );
+        const QList<QgsLayerTreeModelLegendNode *> legendNodes = layerLegendNodes( layerNode );
+        for ( QgsLayerTreeModelLegendNode *legendNode : legendNodes )
+        {
+          legendNode->invalidateDisplayData();
+        }
+
+        break;
+      }
+
+      case QgsLayerTreeNode::NodeGroup:
+      case QgsLayerTreeNode::NodeCustom:
+        break;
+    }
+
+    const QList<QgsLayerTreeNode *> children = node->children();
+    for ( QgsLayerTreeNode *childNode : children )
+    {
+      invalidateNode( childNode );
+    }
+  };
+  invalidateNode( mRootNode );
+}
+
 void QgsLayerTreeModel::nodeWillAddChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo )
 {
   beginInsertRows( node2index( node ), indexFrom, indexTo );

src/core/layertree/qgslayertreemodel.h

@@ -302,6 +302,16 @@ class CORE_EXPORT QgsLayerTreeModel : public QAbstractItemModel
      */
     void addTargetScreenProperties( const QgsScreenProperties &properties );
 
+    /**
+     * Sets all target screen \a properties to use when generating icons for Qt::DecorationRole data.
+     *
+     * This allows icons to be generated at an icon device pixel ratio and DPI which
+     * corresponds exactly to the view's screen properties in which this model is used.
+     *
+     * \since QGIS 4.2
+     */
+    void setTargetScreenProperties( const QSet< QgsScreenProperties > &properties );
+
     /**
      * Returns the target screen properties to use when generating icons.
      *
@@ -342,6 +352,13 @@ class CORE_EXPORT QgsLayerTreeModel : public QAbstractItemModel
      */
     bool hitTestInProgress() const;
 
+    /**
+     * Invalidates all cached display data throughout the model.
+     *
+     * \since QGIS 4.2
+     */
+    void invalidateDisplayData();
+
   signals:
 
     /**

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -668,6 +668,11 @@ bool QgsSymbolLegendNode::setData( const QVariant &value, int role )
   return true;
 }
 
+void QgsSymbolLegendNode::invalidateDisplayData()
+{
+  mPixmap = QPixmap();
+}
+
 QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const
 {
   QgsSymbol *s = mCustomSymbol ? mCustomSymbol.get() : mItem.symbol();
@@ -1513,6 +1518,11 @@ QVariant QgsDataDefinedSizeLegendNode::data( int role ) const
   return QVariant();
 }
 
+void QgsDataDefinedSizeLegendNode::invalidateDisplayData()
+{
+  mImage = QImage();
+}
+
 QgsLayerTreeModelLegendNode::ItemMetrics QgsDataDefinedSizeLegendNode::draw( const QgsLegendSettings &settings, QgsLayerTreeModelLegendNode::ItemContext &ctx )
 {
   // setup temporary render context if none specified

src/core/layertree/qgslayertreemodellegendnode.h

@@ -183,6 +183,15 @@ class CORE_EXPORT QgsLayerTreeModelLegendNode : public QObject
     */
     virtual void invalidateMapBasedData() {}
 
+    /**
+     * Invalidates cached display data for the node.
+     *
+     * The default implementation does nothing.
+     *
+     * \since QGIS 4.2
+     */
+    virtual void invalidateDisplayData() {}
+
     struct ItemContext
     {
         Q_NOWARN_DEPRECATED_PUSH //because of deprecated members
@@ -426,7 +435,7 @@ class CORE_EXPORT QgsSymbolLegendNode : public QgsLayerTreeModelLegendNode
     Qt::ItemFlags flags() const override;
     QVariant data( int role ) const override;
     bool setData( const QVariant &value, int role ) override;
-
+    void invalidateDisplayData() override;
     QSizeF drawSymbol( const QgsLegendSettings &settings, ItemContext *ctx, double itemHeight ) const override;
 
     QJsonObject exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context ) const override;
@@ -833,7 +842,7 @@ class CORE_EXPORT QgsDataDefinedSizeLegendNode : public QgsLayerTreeModelLegendN
     ~QgsDataDefinedSizeLegendNode() override;
 
     QVariant data( int role ) const override;
-
+    void invalidateDisplayData() override;
     ItemMetrics draw( const QgsLegendSettings &settings, ItemContext &ctx ) override;
 
 #ifdef SIP_RUN

src/core/maprenderer/qgsmaprendererjob.cpp

@@ -1181,13 +1181,12 @@ LabelRenderJob QgsMapRendererJob::prepareLabelingJob( QPainter *painter, QgsLabe
     return job;
 
   // if we can use the cache, let's do it and avoid rendering!
-  bool hasCache = canUseLabelCache && mCache && mCache->hasCacheImage( LABEL_CACHE_ID );
+  bool hasCache = canUseLabelCache && mCache && mCache->hasCacheImage( LABEL_CACHE_ID ) && mCache->cacheImage( LABEL_CACHE_ID ).devicePixelRatio() == mSettings.devicePixelRatio();
   if ( hasCache )
   {
     job.cached = true;
     job.complete = true;
     job.img = new QImage( mCache->cacheImage( LABEL_CACHE_ID ) );
-    Q_ASSERT( job.img->devicePixelRatio() == mSettings.devicePixelRatio() );
     job.context.setPainter( nullptr );
   }
   else

src/core/symbology/qgssymbollayerutils.cpp

@@ -1172,7 +1172,7 @@ QPixmap QgsSymbolLayerUtils::colorRampPreviewPixmap( QgsColorRamp *ramp, QSize s
         const QPen pen( ramp->color( static_cast< double >( i ) / size.width() ) );
         painter.setPen( pen );
         const int x = flipDirection ? size.width() - i - 1 : i;
-        painter.drawLine( x, 0 + padding, x, size.height() - 1 - padding );
+        painter.drawLine( QLineF( x, 0 + padding, x, size.height() - 1 - padding ) );
       }
       break;
     }
@@ -1184,7 +1184,7 @@ QPixmap QgsSymbolLayerUtils::colorRampPreviewPixmap( QgsColorRamp *ramp, QSize s
         const QPen pen( ramp->color( static_cast< double >( i ) / size.height() ) );
         painter.setPen( pen );
         const int y = flipDirection ? size.height() - i - 1 : i;
-        painter.drawLine( 0 + padding, y, size.width() - 1 - padding, y );
+        painter.drawLine( QLineF( 0 + padding, y, size.width() - 1 - padding, y ) );
       }
       break;
     }

src/gui/layertree/qgslayertreeview.cpp

@@ -24,6 +24,7 @@
 #include "qgslayertreeviewdefaultactions.h"
 #include "qgsmaplayer.h"
 #include "qgsmessagebar.h"
+#include "qgsscreenhelper.h"
 
 #include <QApplication>
 #include <QContextMenuEvent>
@@ -96,7 +97,9 @@ void QgsLayerTreeViewBase::setLayerTreeModel( QgsLayerTreeModel *model )
 
   mLayerTreeModel = model;
 
-  mLayerTreeModel->addTargetScreenProperties( QgsScreenProperties( screen() ) );
+  mLayerTreeModel->setTargetScreenProperties( { QgsScreenProperties( screen() ) } );
+  auto screenHelper = new QgsScreenHelper( this );
+  connect( screenHelper, &QgsScreenHelper::screenDpiChanged, this, [this] { mLayerTreeModel->setTargetScreenProperties( { QgsScreenProperties( screen() ) } ); } );
 
   connect( mLayerTreeModel->rootGroup(), &QgsLayerTreeNode::expandedChanged, this, &QgsLayerTreeViewBase::onExpandedChanged );