It's FAR too expensive to construct a QgsSettings object for every sy…

…mbol node, especially for complex

projects. So only read the valid size ranges once, and store them for subsequent use

(cherry picked from commit da51a5a)

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

@@ -257,6 +257,9 @@ and allowing interaction with the symbol / renderer.
 %End
   public:
 
+    static double MINIMUM_SIZE;
+    static double MAXIMUM_SIZE;
+
     QgsSymbolLegendNode( QgsLayerTreeLayer *nodeLayer, const QgsLegendSymbolItem &item, QObject *parent /TransferThis/ = 0 );
 %Docstring
 Constructor for QgsSymbolLegendNode.

src/app/options/qgsoptions.cpp

@@ -38,6 +38,7 @@
 #include "qgsexpressioncontextutils.h"
 #include "qgslocaldefaultsettings.h"
 #include "qgsnumericformatwidget.h"
+#include "qgslayertreemodellegendnode.h"
 
 #include "qgsattributetablefiltermodel.h"
 #include "qgslocalizeddatapathregistry.h"
@@ -1570,6 +1571,8 @@ void QgsOptions::saveOptions()
 
   mSettings->setValue( QStringLiteral( "/qgis/legendsymbolMinimumSize" ), mLegendSymbolMinimumSizeSpinBox->value() );
   mSettings->setValue( QStringLiteral( "/qgis/legendsymbolMaximumSize" ), mLegendSymbolMaximumSizeSpinBox->value() );
+  QgsSymbolLegendNode::MINIMUM_SIZE = mLegendSymbolMinimumSizeSpinBox->value();
+  QgsSymbolLegendNode::MAXIMUM_SIZE = mLegendSymbolMaximumSizeSpinBox->value();
 
   mSettings->setValue( QStringLiteral( "/qgis/defaultLegendGraphicResolution" ), mLegendGraphicResolutionSpinBox->value() );
   mSettings->setValue( QStringLiteral( "/qgis/mapTipsDelay" ), mMapTipsDelaySpinBox->value() );

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -242,6 +242,9 @@ QSizeF QgsLayerTreeModelLegendNode::drawSymbolText( const QgsLegendSettings &set
 
 // -------------------------------------------------------------------------
 
+double QgsSymbolLegendNode::MINIMUM_SIZE = -1.0;
+double QgsSymbolLegendNode::MAXIMUM_SIZE = -1.0;
+
 QgsSymbolLegendNode::QgsSymbolLegendNode( QgsLayerTreeLayer *nodeLayer, const QgsLegendSymbolItem &item, QObject *parent )
   : QgsLayerTreeModelLegendNode( nodeLayer, parent )
   , mItem( item )
@@ -250,9 +253,14 @@ QgsSymbolLegendNode::QgsSymbolLegendNode( QgsLayerTreeLayer *nodeLayer, const Qg
   const int iconSize = QgsLayerTreeModel::scaleIconSize( 16 );
   mIconSize = QSize( iconSize, iconSize );
 
-  QgsSettings settings;
-  mSymbolMinimumSize = settings.value( "/qgis/legendsymbolMinimumSize", 0.5 ).toDouble();
-  mSymbolMaximumSize = settings.value( "/qgis/legendsymbolMaximumSize", 20.0 ).toDouble();
+  if ( MINIMUM_SIZE < 0 )
+  {
+    // it's FAR too expensive to construct a QgsSettings object for every symbol node, especially for complex
+    // projects. So only read the valid size ranges once, and store them for subsequent use
+    QgsSettings settings;
+    MINIMUM_SIZE = settings.value( "/qgis/legendsymbolMinimumSize", 0.5 ).toDouble();
+    MAXIMUM_SIZE = settings.value( "/qgis/legendsymbolMaximumSize", 20.0 ).toDouble();
+  }
 
   updateLabel();
   connect( qobject_cast<QgsVectorLayer *>( nodeLayer->layer() ), &QgsVectorLayer::symbolFeatureCountMapChanged, this, &QgsSymbolLegendNode::updateLabel );
@@ -287,7 +295,7 @@ QSize QgsSymbolLegendNode::minimumIconSize( QgsRenderContext *context ) const
     // unusued width, height variables
     double width = 0.0;
     double height = 0.0;
-    std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), mSymbolMinimumSize, mSymbolMaximumSize, context, width, height ) );
+    std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), MINIMUM_SIZE, MAXIMUM_SIZE, context, width, height ) );
     minSz = QgsImageOperation::nonTransparentImageRect(
               QgsSymbolLayerUtils::symbolPreviewPixmap( symbol ? symbol.get() : mItem.symbol(), QSize( largeIconSize, largeIconSize ), 0,
                   context ).toImage(),
@@ -298,7 +306,7 @@ QSize QgsSymbolLegendNode::minimumIconSize( QgsRenderContext *context ) const
   {
     double width = 0.0;
     double height = 0.0;
-    std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), mSymbolMinimumSize, mSymbolMaximumSize, context, width, height ) );
+    std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), MINIMUM_SIZE, MAXIMUM_SIZE, context, width, height ) );
     minSz = QgsImageOperation::nonTransparentImageRect(
               QgsSymbolLayerUtils::symbolPreviewPixmap( symbol ? symbol.get() : mItem.symbol(), QSize( minSz.width(), largeIconSize ), 0,
                   context ).toImage(),
@@ -468,7 +476,7 @@ QVariant QgsSymbolLegendNode::data( int role ) const
         // unusued width, height variables
         double width = 0.0;
         double height = 0.0;
-        std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), mSymbolMinimumSize, mSymbolMaximumSize, context.get(), width, height ) );
+        std::unique_ptr<QgsSymbol> symbol( QgsSymbolLayerUtils::restrictedSizeSymbol( mItem.symbol(), MINIMUM_SIZE, MAXIMUM_SIZE, context.get(), width, height ) );
         pix = QgsSymbolLayerUtils::symbolPreviewPixmap( symbol ? symbol.get() : mItem.symbol(), mIconSize, 0, context.get() );
 
         if ( !mTextOnSymbolLabel.isEmpty() && context )
@@ -1307,3 +1315,4 @@ void QgsDataDefinedSizeLegendNode::cacheImage() const
     mImage = mSettings->collapsedLegendImage( *context );
   }
 }
+

src/core/layertree/qgslayertreemodellegendnode.h

@@ -307,9 +307,11 @@ class CORE_EXPORT QgsSymbolLegendNode : public QgsLayerTreeModelLegendNode
 {
     Q_OBJECT
 
-
   public:
 
+    static double MINIMUM_SIZE;
+    static double MAXIMUM_SIZE;
+
     /**
      * Constructor for QgsSymbolLegendNode.
      * \param nodeLayer layer node
@@ -489,8 +491,6 @@ class CORE_EXPORT QgsSymbolLegendNode : public QgsLayerTreeModelLegendNode
     bool mSymbolUsesMapUnits;
 
     QSize mIconSize;
-    double mSymbolMinimumSize = 0.5;
-    double mSymbolMaximumSize = 20.0;
 
     QString mTextOnSymbolLabel;
     QgsTextFormat mTextOnSymbolTextFormat;