[canvas] Insure a refreshed canvas due to temporal range changes reflects the last provided range

nirvn · nirvn · commit da23cb6ee09b · 2020-05-10T14:02:11.000+07:00
diff --git a/python/gui/auto_generated/qgsmapcanvas.sip.in b/python/gui/auto_generated/qgsmapcanvas.sip.in
@@ -129,6 +129,13 @@ Check whether images of rendered layers are curerently being cached
 Make sure to remove any rendered images from cache (does nothing if cache is not enabled)
 
 .. versionadded:: 2.4
+%End
+
+    void clearTemporalCache();
+%Docstring
+Make sure to remove any rendered images of temporal-enabled layers from cache (does nothing if cache is not enabled)
+
+.. versionadded:: 3.14
 %End
 
     void waitWhileRendering();
diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -696,16 +696,27 @@ void QgsMapCanvas::rendererJobFinished()
     {
       mLastLayerRenderTime.insert( it.key()->id(), it.value() );
     }
-    if ( mUsePreviewJobs )
+    if ( mUsePreviewJobs && !mTemporalRefreshAfterJob )
       startPreviewJobs();
   }
+  else
+  {
+    mTemporalRefreshAfterJob = false;
+  }
 
   // now we are in a slot called from mJob - do not delete it immediately
   // so the class is still valid when the execution returns to the class
   mJob->deleteLater();
   mJob = nullptr;
 
   emit mapCanvasRefreshed();
+
+  if ( mTemporalRefreshAfterJob )
+  {
+    mTemporalRefreshAfterJob = false;
+    clearTemporalCache();
+    refresh();
+  }
 }
 
 void QgsMapCanvas::previewJobFinished()
@@ -761,28 +772,39 @@ void QgsMapCanvas::setCustomDropHandlers( const QVector<QPointer<QgsCustomDropHa
   mDropHandlers = handlers;
 }
 
-void QgsMapCanvas::setTemporalRange( const QgsDateTimeRange &dateTimeRange )
+void QgsMapCanvas::clearTemporalCache()
 {
-  if ( temporalRange() == dateTimeRange )
-    return;
-
-  mSettings.setTemporalRange( dateTimeRange );
-
   if ( mCache )
   {
-    // we need to discard any previously cached images which have temporal properties enabled, so that these will be updated when
-    // the canvas is redrawn
     const QList<QgsMapLayer *> layerList = mapSettings().layers();
     for ( QgsMapLayer *layer : layerList )
     {
       if ( layer->temporalProperties() && layer->temporalProperties()->isActive() )
         mCache->invalidateCacheForLayer( layer );
     }
   }
+}
+
+void QgsMapCanvas::setTemporalRange( const QgsDateTimeRange &dateTimeRange )
+{
+  if ( temporalRange() == dateTimeRange )
+    return;
+
+  mSettings.setTemporalRange( dateTimeRange );
 
   emit temporalRangeChanged();
 
-  autoRefreshTriggered();
+  if ( !mJob )
+  {
+    // we need to discard any previously cached images which have temporal properties enabled, so that these will be updated when
+    // the canvas is redrawn
+    clearTemporalCache();
+    autoRefreshTriggered();
+  }
+  else
+  {
+    mTemporalRefreshAfterJob = true;
+  }
 }
 
 const QgsDateTimeRange &QgsMapCanvas::temporalRange() const
diff --git a/src/gui/qgsmapcanvas.h b/src/gui/qgsmapcanvas.h
@@ -177,6 +177,12 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
      */
     void clearCache();
 
+    /**
+     * Make sure to remove any rendered images of temporal-enabled layers from cache (does nothing if cache is not enabled)
+     * \since QGIS 3.14
+     */
+    void clearTemporalCache();
+
     /**
      * Blocks until the rendering job has finished.
      *
@@ -1057,6 +1063,9 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
     //! Flag that allows squashing multiple refresh() calls into just one delayed rendering job
     bool mRefreshScheduled = false;
 
+    //! Flag that triggers a refresh after an ongoing rendering job finishes and clear cache for temporal-enabled layers
+    bool mTemporalRefreshAfterJob = false;
+
     //! determines whether user has requested to suppress rendering
     bool mRenderFlag = true;
 
