Store previous layer rendering time in canvas, not map layer

python/core/qgsmaplayer.sip

@@ -916,7 +916,6 @@ Time stamp of data source in the moment when data/metadata were loaded by provid
  :rtype: bool
 %End
 
-
   public slots:
 
     void setMinimumScale( double scale );

python/core/qgsmaprendererjob.sip

@@ -137,10 +137,18 @@ List of errors that happened during the rendering job - available when the rende
 
     int renderingTime() const;
 %Docstring
-Find out how long it took to finish the job (in milliseconds)
+ Returns the total time it took to finish the job (in milliseconds).
+.. seealso:: layerRenderingTime()
  :rtype: int
 %End
 
+    QMap< QString, int > layerRenderingTime() const;
+%Docstring
+ Returns the render time (in ms) per layer, by layer ID.
+.. versionadded:: 3.0
+ :rtype: QMap< str, int >
+%End
+
     const QgsMapSettings &mapSettings() const;
 %Docstring
  Return map settings with which this job was started.
@@ -179,6 +187,7 @@ emitted when asynchronous rendering is finished (or canceled).
 
 
 
+
 };
 
 

src/core/qgsmaplayer.h

@@ -882,25 +882,6 @@ class CORE_EXPORT QgsMapLayer : public QObject
      */
     bool isRefreshOnNotifyEnabled() const { return mIsRefreshOnNofifyEnabled; }
 
-///@cond PRIVATE
-#ifndef SIP_RUN
-
-    /**
-     * Set last rendering time.
-     *
-     * \note not available in Python bindings
-     */
-    void setLastRenderingTime( double time ) { mLastRenderingTime = time; }
-
-    /**
-     * Get last rendering time.
-     *
-     * \note not available in Python bindings
-     */
-    double lastRenderingTime() const { return mLastRenderingTime; }
-#endif
-///@endcond
-
   public slots:
 
     /**
@@ -1240,7 +1221,6 @@ class CORE_EXPORT QgsMapLayer : public QObject
     //! Renderer for 3D views
     QgsAbstract3DRenderer *m3DRenderer = nullptr;
 
-    double mLastRenderingTime = 0.0;
 };
 
 Q_DECLARE_METATYPE( QgsMapLayer * )

src/core/qgsmaprenderercustompainterjob.cpp

@@ -265,10 +265,6 @@ void QgsMapRendererCustomPainterJob::doRender()
       job.renderer->render();
 
       job.renderingTime = layerTime.elapsed();
-      if ( job.layer )
-      {
-        job.layer->setLastRenderingTime( job.renderingTime );
-      }
     }
 
     if ( job.img )

src/core/qgsmaprendererjob.cpp

@@ -242,13 +242,6 @@ LayerRenderJobs QgsMapRendererJob::prepareJobs( QPainter *painter, QgsLabelingEn
       continue;
     }
 
-    if ( ( mSettings.flags() & QgsMapSettings::RenderPreviewJob ) &&
-         !ml->dataProvider()->renderInPreview( ml->lastRenderingTime(), MAXIMUM_LAYER_PREVIEW_TIME_MS ) )
-    {
-      QgsDebugMsgLevel( "Layer not rendered because it does not match the renderInPreview criterion", 3 );
-      continue;
-    }
-
     QgsRectangle r1 = mSettings.visibleExtent(), r2;
     QgsCoordinateTransform ct;
 
@@ -419,8 +412,10 @@ void QgsMapRendererJob::cleanupJobs( LayerRenderJobs &jobs )
       delete job.renderer;
       job.renderer = nullptr;
     }
-  }
 
+    if ( job.layer )
+      mLayerRenderingTime.insert( job.layer->id(), job.renderingTime );
+  }
 
   jobs.clear();
 }

src/core/qgsmaprendererjob.h

@@ -199,9 +199,18 @@ class CORE_EXPORT QgsMapRendererJob : public QObject
      */
     void setCache( QgsMapRendererCache *cache );
 
-    //! Find out how long it took to finish the job (in milliseconds)
+    /**
+     * Returns the total time it took to finish the job (in milliseconds).
+     * \see layerRenderingTime()
+     */
     int renderingTime() const { return mRenderingTime; }
 
+    /**
+     * Returns the render time (in ms) per layer, by layer ID.
+     * \since QGIS 3.0
+     */
+    QMap< QString, int > layerRenderingTime() const { return mLayerRenderingTime; }
+
     /**
      * Return map settings with which this job was started.
      * \returns A QgsMapSettings instance with render settings
@@ -239,6 +248,9 @@ class CORE_EXPORT QgsMapRendererJob : public QObject
 
     int mRenderingTime = 0;
 
+    //! Render time (in ms) per layer, by layer ID
+    QMap< QString, int > mLayerRenderingTime;
+
     /**
      * Prepares the cache for storing the result of labeling. Returns false if
      * the render cannot use cached labels and should not cache the result.

src/core/qgsmaprendererparalleljob.cpp

@@ -270,10 +270,6 @@ void QgsMapRendererParallelJob::renderLayerStatic( LayerRenderJob &job )
     QgsDebugMsg( "Caught unhandled unknown exception" );
   }
   job.renderingTime = t.elapsed();
-  if ( job.layer )
-  {
-    job.layer->setLastRenderingTime( job.renderingTime );
-  }
   QgsDebugMsgLevel( QString( "job %1 end [%2 ms] (layer %3)" ).arg( reinterpret_cast< quint64 >( &job ), 0, 16 ).arg( job.renderingTime ).arg( job.layer ? job.layer->id() : QString() ), 2 );
 }
 

src/gui/qgsmapcanvas.cpp

@@ -611,6 +611,8 @@ void QgsMapCanvas::rendererJobFinished()
     p.end();
 
     mMap->setContent( img, imageRect( img, mSettings ) );
+
+    mLastLayerRenderTime = mJob->layerRenderingTime();
     if ( mUsePreviewJobs )
       startPreviewJobs();
   }
@@ -2268,6 +2270,21 @@ void QgsMapCanvas::startPreviewJob( int number )
   jobSettings.setFlag( QgsMapSettings::DrawLabeling, false );
   jobSettings.setFlag( QgsMapSettings::RenderPreviewJob, true );
 
+  // truncate preview layers to fast layers
+  const QList<QgsMapLayer *> layers = jobSettings.layers();
+  QList< QgsMapLayer * > previewLayers;
+  for ( QgsMapLayer *layer : layers )
+  {
+    if ( !layer->dataProvider()->renderInPreview( mLastLayerRenderTime.value( layer->id() ), MAXIMUM_LAYER_PREVIEW_TIME_MS ) )
+    {
+      QgsDebugMsgLevel( QString( "Layer %1 not rendered because it does not match the renderInPreview criterion %2" ).arg( layer->id() ).arg( mLastLayerRenderTime.value( layer->id() ) ), 3 );
+      continue;
+    }
+
+    previewLayers << layer;
+  }
+  jobSettings.setLayers( previewLayers );
+
   QgsMapRendererQImageJob *job = new QgsMapRendererSequentialJob( jobSettings );
   mPreviewJobs.append( job );
   connect( job, &QgsMapRendererJob::finished, this, &QgsMapCanvas::previewJobFinished );

src/gui/qgsmapcanvas.h

@@ -1000,6 +1000,8 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
 
     bool mUsePreviewJobs = false;
 
+    QMap< QString, int > mLastLayerRenderTime;
+
     /**
      * Force a resize of the map canvas item
      * \since QGIS 2.16