Fix invalid values for @map_extent_width/height (fix #15672)

Author: nyalldawson

src/core/qgsexpressioncontext.cpp

@@ -779,8 +779,8 @@ QgsExpressionContextScope* QgsExpressionContextUtils::mapSettingsScope( const Qg
   scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_id", "canvas", true ) );
   scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_rotation", mapSettings.rotation(), true ) );
   scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_scale", mapSettings.scale(), true ) );
-  scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_extent_width", mapSettings.extent().width(), true ) );
-  scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_extent_height", mapSettings.extent().height(), true ) );
+  scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_extent_width", mapSettings.visibleExtent().width(), true ) );
+  scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_extent_height", mapSettings.visibleExtent().height(), true ) );
   QgsGeometry centerPoint = QgsGeometry::fromPoint( mapSettings.visibleExtent().center() );
   scope->addVariable( QgsExpressionContextScope::StaticVariable( "map_extent_center", QVariant::fromValue( centerPoint ), true ) );
 

tests/src/core/testqgs25drenderer.cpp

@@ -146,6 +146,7 @@ bool TestQgs25DRenderer::imageCheck( const QString& theTestType )
   //use the QgsRenderChecker test utility class to
   //ensure the rendered output matches our control image
   mMapSettings.setExtent( mpPolysLayer->extent() );
+  mMapSettings.setOutputSize( QSize( 400, 400 ) );
   mMapSettings.setOutputDpi( 96 );
   QgsExpressionContext context;
   context << QgsExpressionContextUtils::mapSettingsScope( mMapSettings );