Fix huge legend item size when symbol uses map unit sizes (fix #13979)

Add unit test

Author: nyalldawson

src/core/layertree/qgslayertreemodellegendnode.cpp

@@ -362,15 +362,15 @@ QSizeF QgsSymbolV2LegendNode::drawSymbol( const QgsLegendSettings& settings, Ite
   //Consider symbol size for point markers
   double height = settings.symbolSize().height();
   double width = settings.symbolSize().width();
-  double size = 0;
+
   //Center small marker symbols
   double widthOffset = 0;
   double heightOffset = 0;
 
   if ( QgsMarkerSymbolV2* markerSymbol = dynamic_cast<QgsMarkerSymbolV2*>( s ) )
   {
     // allow marker symbol to occupy bigger area if necessary
-    size = QgsSymbolLayerV2Utils::convertToPainterUnits( context, markerSymbol->size(), s->outputUnit(), s->mapUnitScale() ) / context.scaleFactor();
+    double size = QgsSymbolLayerV2Utils::convertToPainterUnits( context, markerSymbol->size(), markerSymbol->sizeUnit(), markerSymbol->sizeMapUnitScale() ) / context.scaleFactor();
     height = size;
     width = size;
     if ( width < settings.symbolSize().width() )

tests/src/core/testqgslegendrenderer.cpp

@@ -110,6 +110,7 @@ class TestQgsLegendRenderer : public QObject
 
     void testBasic();
     void testBigMarker();
+    void testMapUnits();
     void testLongSymbolText();
     void testThreeColumns();
     void testFilterByMap();
@@ -290,6 +291,42 @@ void TestQgsLegendRenderer::testBigMarker()
   QVERIFY( _verifyImage( testName, mReport ) );
 }
 
+void TestQgsLegendRenderer::testMapUnits()
+{
+  QString testName = "legend_mapunits";
+
+  QgsMarkerSymbolV2* sym = new QgsMarkerSymbolV2();
+  sym->setColor( Qt::red );
+  sym->setSize( 100 );
+  sym->setSizeUnit( QgsSymbolV2::MapUnit );
+  QgsCategorizedSymbolRendererV2* catRenderer = dynamic_cast<QgsCategorizedSymbolRendererV2*>( mVL3->rendererV2() );
+  QVERIFY( catRenderer );
+  catRenderer->updateCategorySymbol( 0, sym );
+
+  sym = new QgsMarkerSymbolV2();
+  sym->setColor( Qt::green );
+  sym->setSize( 300 );
+  sym->setSizeUnit( QgsSymbolV2::MapUnit );
+  catRenderer->updateCategorySymbol( 1, sym );
+
+  sym = new QgsMarkerSymbolV2();
+  sym->setColor( Qt::blue );
+  sym->setSize( 5 );
+  sym->setSizeUnit( QgsSymbolV2::MM );
+  catRenderer->updateCategorySymbol( 2, sym );
+
+  QgsLayerTreeGroup* root = new QgsLayerTreeGroup();
+  root->addLayer( mVL3 );
+  QgsLayerTreeModel legendModel( root );
+
+  QgsLegendSettings settings;
+  _setStandardTestFont( settings );
+  settings.setMmPerMapUnit( 0.1 );
+  settings.setMapScale( 1000 );
+  _renderLegend( testName, &legendModel, settings );
+  QVERIFY( _verifyImage( testName, mReport ) );
+}
+
 void TestQgsLegendRenderer::testLongSymbolText()
 {
   QString testName = "legend_long_symbol_text";