Run layout validity checks before export

python/core/auto_generated/validity/qgsvaliditycheckcontext.sip.in

@@ -23,9 +23,17 @@ context, containing a reference to the QgsLayout to be checked.
 
 %TypeHeaderCode
 #include "qgsvaliditycheckcontext.h"
+%End
+%ConvertToSubClassCode
+    if ( dynamic_cast<QgsLayoutValidityCheckContext *>( sipCpp ) != NULL )
+      sipType = sipType_QgsLayoutValidityCheckContext;
+    else
+      sipType = 0;
 %End
   public:
 
+    virtual ~QgsValidityCheckContext();
+
 };
 
 class QgsLayoutValidityCheckContext : QgsValidityCheckContext

src/app/CMakeLists.txt

@@ -671,6 +671,7 @@ INCLUDE_DIRECTORIES(
   ${CMAKE_SOURCE_DIR}/src/core/raster
   ${CMAKE_SOURCE_DIR}/src/core/scalebar
   ${CMAKE_SOURCE_DIR}/src/core/symbology
+  ${CMAKE_SOURCE_DIR}/src/core/validity
   ${CMAKE_SOURCE_DIR}/src/gui
   ${CMAKE_SOURCE_DIR}/src/gui/symbology
   ${CMAKE_SOURCE_DIR}/src/gui/attributetable

src/app/layout/qgslayoutdesignerdialog.cpp

@@ -67,6 +67,9 @@
 #include "ui_qgssvgexportoptions.h"
 #include "ui_qgspdfexportoptions.h"
 #include "qgsproxyprogresstask.h"
+#include "qgsvaliditycheckresultswidget.h"
+#include "qgsabstractvaliditycheck.h"
+#include "qgsvaliditycheckcontext.h"
 #include "ui_defaults.h"
 
 #include <QShortcut>
@@ -1835,6 +1838,9 @@ void QgsLayoutDesignerDialog::deleteLayout()
 
 void QgsLayoutDesignerDialog::print()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   if ( containsWmsLayers() )
   {
     showWmsPrintingWarning();
@@ -1941,6 +1947,9 @@ void QgsLayoutDesignerDialog::print()
 
 void QgsLayoutDesignerDialog::exportToRaster()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   if ( containsWmsLayers() )
     showWmsPrintingWarning();
 
@@ -2032,6 +2041,9 @@ void QgsLayoutDesignerDialog::exportToRaster()
 
 void QgsLayoutDesignerDialog::exportToPdf()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   if ( containsWmsLayers() )
   {
     showWmsPrintingWarning();
@@ -2150,6 +2162,9 @@ void QgsLayoutDesignerDialog::exportToPdf()
 
 void QgsLayoutDesignerDialog::exportToSvg()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   if ( containsWmsLayers() )
   {
     showWmsPrintingWarning();
@@ -2406,6 +2421,9 @@ void QgsLayoutDesignerDialog::atlasLast()
 
 void QgsLayoutDesignerDialog::printAtlas()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QgsLayoutAtlas *printAtlas = atlas();
   if ( !printAtlas || !printAtlas->enabled() )
     return;
@@ -2551,6 +2569,9 @@ void QgsLayoutDesignerDialog::printAtlas()
 
 void QgsLayoutDesignerDialog::exportAtlasToRaster()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QgsLayoutAtlas *printAtlas = atlas();
   if ( !printAtlas || !printAtlas->enabled() )
     return;
@@ -2709,6 +2730,9 @@ void QgsLayoutDesignerDialog::exportAtlasToRaster()
 
 void QgsLayoutDesignerDialog::exportAtlasToSvg()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QgsLayoutAtlas *printAtlas = atlas();
   if ( !printAtlas || !printAtlas->enabled() )
     return;
@@ -2877,6 +2901,9 @@ void QgsLayoutDesignerDialog::exportAtlasToSvg()
 
 void QgsLayoutDesignerDialog::exportAtlasToPdf()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QgsLayoutAtlas *printAtlas = atlas();
   if ( !printAtlas || !printAtlas->enabled() )
     return;
@@ -3102,6 +3129,9 @@ void QgsLayoutDesignerDialog::exportAtlasToPdf()
 
 void QgsLayoutDesignerDialog::exportReportToRaster()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QString outputFileName = QgsFileUtils::stringToSafeFilename( mMasterLayout->name() );
 
   QPair<QString, QString> fileNExt = QgsGuiUtils::getSaveAsImageName( this, tr( "Save Report As" ), outputFileName );
@@ -3209,6 +3239,9 @@ void QgsLayoutDesignerDialog::exportReportToRaster()
 
 void QgsLayoutDesignerDialog::exportReportToSvg()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   showSvgExportWarning();
 
   const QString defaultPath = defaultExportPath();
@@ -3337,6 +3370,9 @@ void QgsLayoutDesignerDialog::exportReportToSvg()
 
 void QgsLayoutDesignerDialog::exportReportToPdf()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   const QString defaultPath = defaultExportPath();
 
   QString outputFileName = defaultPath + '/' + QgsFileUtils::stringToSafeFilename( mMasterLayout->name() ) + QStringLiteral( ".pdf" );
@@ -3466,6 +3502,9 @@ void QgsLayoutDesignerDialog::exportReportToPdf()
 
 void QgsLayoutDesignerDialog::printReport()
 {
+  if ( !checkBeforeExport() )
+    return;
+
   QPrintDialog printDialog( printer(), nullptr );
   if ( printDialog.exec() != QDialog::Accepted )
   {
@@ -4409,6 +4448,13 @@ void QgsLayoutDesignerDialog::setLastExportPath( const QString &path ) const
   QgsSettings().setValue( QStringLiteral( "lastLayoutExportDir" ), savePath, QgsSettings::App );
 }
 
+bool QgsLayoutDesignerDialog::checkBeforeExport()
+{
+  QgsLayoutValidityCheckContext context( mLayout );
+  return QgsValidityCheckResultsWidget::runChecks( QgsAbstractValidityCheck::TypeLayoutCheck, &context, tr( "Checking Layout" ),
+         tr( "The layout generated the following warnings. Please review and address these before proceeding with the layout export." ), this );
+}
+
 void QgsLayoutDesignerDialog::updateWindowTitle()
 {
   QString title;

src/app/layout/qgslayoutdesignerdialog.h

@@ -538,6 +538,7 @@ class QgsLayoutDesignerDialog: public QMainWindow, public Ui::QgsLayoutDesignerB
     QString defaultExportPath() const;
     void setLastExportPath( const QString &path ) const;
 
+    bool checkBeforeExport();
 };
 
 #endif // QGSLAYOUTDESIGNERDIALOG_H

src/core/validity/qgsvaliditycheckcontext.h

@@ -34,9 +34,21 @@ class QgsLayout;
  */
 class CORE_EXPORT QgsValidityCheckContext
 {
+
+#ifdef SIP_RUN
+    SIP_CONVERT_TO_SUBCLASS_CODE
+    if ( dynamic_cast<QgsLayoutValidityCheckContext *>( sipCpp ) != NULL )
+      sipType = sipType_QgsLayoutValidityCheckContext;
+    else
+      sipType = 0;
+    SIP_END
+#endif
+
   public:
     // initially nothing in the base class!
 
+    virtual ~QgsValidityCheckContext() = default;
+
 };
 
 /**