Always show WMTS/XYZ layers in preview jobs (to pre-warm cache)

src/core/qgsdataprovider.cpp

@@ -42,7 +42,7 @@ void QgsDataProvider::setListening( bool isListening )
   Q_UNUSED( isListening );
 }
 
-bool QgsDataProvider::renderInPreview( QgsDataProvider::PreviewContext context )
+bool QgsDataProvider::renderInPreview( const PreviewContext &context )
 {
   return context.lastRenderingTimeMs <= context.maxRenderingTimeMs;
 }

src/core/qgsdataprovider.h

@@ -490,7 +490,7 @@ class CORE_EXPORT QgsDataProvider : public QObject
      *
      * \note not available in Python bindings
      */
-    virtual bool renderInPreview( QgsDataProvider::PreviewContext context ); // SIP_SKIP
+    virtual bool renderInPreview( const QgsDataProvider::PreviewContext &context ); // SIP_SKIP
 
   signals:
 

src/providers/wms/qgswmsprovider.cpp

@@ -3199,18 +3199,25 @@ QString QgsWmsProvider::lastErrorFormat()
 QString  QgsWmsProvider::name() const
 {
   return WMS_KEY;
-} //  QgsWmsProvider::name()
+}
 
 
 QString  QgsWmsProvider::description() const
 {
   return WMS_DESCRIPTION;
-} //  QgsWmsProvider::description()
+}
 
 void QgsWmsProvider::reloadData()
 {
 }
 
+bool QgsWmsProvider::renderInPreview( const QgsDataProvider::PreviewContext &context )
+{
+  if ( mSettings.mTiled || mSettings.mXyz )
+    return true;
+
+  return QgsRasterDataProvider::renderInPreview( context );
+}
 
 QVector<QgsWmsSupportedFormat> QgsWmsProvider::supportedFormats()
 {

src/providers/wms/qgswmsprovider.h

@@ -208,6 +208,7 @@ class QgsWmsProvider : public QgsRasterDataProvider
     QString name() const override;
     QString description() const override;
     virtual void reloadData() override;
+    bool renderInPreview( const QgsDataProvider::PreviewContext &context ) override;
 
     static QVector<QgsWmsSupportedFormat> supportedFormats();