When exporting layouts to PDF/SVG, always simplify mask clip paths

This results in much smaller output file sizes, and files which
load much quicker in PDF viewers/editors

Refs qgis#50734
Refs qgis#54788

src/core/layout/qgslayoutexporter.cpp

@@ -552,6 +552,7 @@ QgsLayoutExporter::ExportResult QgsLayoutExporter::exportToPdf( const QString &f
   ( void )contextRestorer;
   mLayout->renderContext().setDpi( settings.dpi );
   mLayout->renderContext().setPredefinedScales( settings.predefinedMapScales );
+  mLayout->renderContext().setMaskSettings( createExportMaskSettings() );
 
   if ( settings.simplifyGeometries )
   {
@@ -777,6 +778,7 @@ QgsLayoutExporter::ExportResult QgsLayoutExporter::exportToPdf( QgsAbstractLayou
 
     iterator->layout()->renderContext().setFlags( settings.flags );
     iterator->layout()->renderContext().setPredefinedScales( settings.predefinedMapScales );
+    iterator->layout()->renderContext().setMaskSettings( createExportMaskSettings() );
 
     if ( settings.simplifyGeometries )
     {
@@ -1026,6 +1028,7 @@ QgsLayoutExporter::ExportResult QgsLayoutExporter::exportToSvg( const QString &f
   mLayout->renderContext().setFlag( QgsLayoutRenderContext::FlagForceVectorOutput, settings.forceVectorOutput );
   mLayout->renderContext().setTextRenderFormat( s.textRenderFormat );
   mLayout->renderContext().setPredefinedScales( settings.predefinedMapScales );
+  mLayout->renderContext().setMaskSettings( createExportMaskSettings() );
 
   if ( settings.simplifyGeometries )
   {
@@ -1911,6 +1914,15 @@ QgsVectorSimplifyMethod QgsLayoutExporter::createExportSimplifyMethod()
   return simplifyMethod;
 }
 
+QgsMaskRenderSettings QgsLayoutExporter::createExportMaskSettings()
+{
+  QgsMaskRenderSettings settings;
+  // this is quite a conservative setting -- I think we could make this more aggressive and get smaller file sizes
+  // without too much loss of quality...
+  settings.setSimplificationTolerance( 0.5 );
+  return settings;
+}
+
 void QgsLayoutExporter::computeWorldFileParameters( double &a, double &b, double &c, double &d, double &e, double &f, double dpi ) const
 {
   if ( !mLayout )

src/core/layout/qgslayoutexporter.h

@@ -779,6 +779,7 @@ class CORE_EXPORT QgsLayoutExporter
     ExportResult handleLayeredExport( const QList<QGraphicsItem *> &items, const std::function<QgsLayoutExporter::ExportResult( unsigned int layerId, const QgsLayoutItem::ExportLayerDetail &layerDetails )> &exportFunc );
 
     static QgsVectorSimplifyMethod createExportSimplifyMethod();
+    static QgsMaskRenderSettings createExportMaskSettings();
     friend class TestQgsLayout;
     friend class TestQgsLayoutExporter;