[FEATURE] Allow layers to be automatically refreshed at a specified i…

…nterval This allows users to set a timer interval in layer properties for individual layers. These layers will be automatically refreshed at a matching interval. Canvas updates are deferred in order to avoid refreshing multiple times if more than one layer has an auto update interval set. Additionally, logic has been added to skip any auto redraws of the canvas while the canvas is already being redrawn. This avoids issues caused by setting a layer auto refresh to a shorter time than is required to redraw the canvas.
qgis · Feb 12, 2017 · 38f87a6 · 38f87a6 · blazek · Jun 29, 2017
1 parent 9b9d49a
commit 38f87a6
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Showing 14 changed files with 417 additions and 2 deletions.
diff --git a/python/core/qgsmaplayer.sip b/python/core/qgsmaplayer.sip
@@ -603,6 +603,11 @@ class QgsMapLayer : QObject
      */
     bool hasScaleBasedVisibility() const;
 
+    bool hasAutoRefreshEnabled() const;
+    int autoRefreshInterval() const;
+    void setAutoRefreshInterval( int interval );
+    void setAutoRefreshEnabled( bool enabled );
+
   public slots:
 
     /** Event handler for when a coordinate transform fails due to bad vertex error */
@@ -730,6 +735,8 @@ class QgsMapLayer : QObject
      */
     void willBeDeleted();
 
+    void autoRefreshIntervalChanged( int interval );
+
   protected:
     /** Set the extent */
     virtual void setExtent( const QgsRectangle &rect );

diff --git a/src/app/qgsrasterlayerproperties.cpp b/src/app/qgsrasterlayerproperties.cpp
@@ -139,6 +139,8 @@ QgsRasterLayerProperties::QgsRasterLayerProperties( QgsMapLayer* lyr, QgsMapCanv
   // enable or disable Build Pyramids button depending on selection in pyramid list
   connect( lbxPyramidResolutions, SIGNAL( itemSelectionChanged() ), this, SLOT( toggleBuildPyramidsButton() ) );
 
+  connect( mRefreshLayerCheckBox, &QCheckBox::toggled, mRefreshLayerIntervalSpinBox, &QDoubleSpinBox::setEnabled );
+
   // set up the scale based layer visibility stuff....
   mScaleRangeWidget->setMapCanvas( mMapCanvas );
   chkUseScaleDependentRendering->setChecked( lyr->hasScaleBasedVisibility() );
@@ -713,6 +715,10 @@ void QgsRasterLayerProperties::sync()
     leNoDataValue->insert( QLatin1String( "" ) );
   }
 
+  mRefreshLayerCheckBox->setChecked( mRasterLayer->hasAutoRefreshEnabled() );
+  mRefreshLayerIntervalSpinBox->setEnabled( mRasterLayer->hasAutoRefreshEnabled() );
+  mRefreshLayerIntervalSpinBox->setValue( mRasterLayer->autoRefreshInterval() / 1000.0 );
+
   populateTransparencyTable( mRasterLayer->renderer() );
 
   QgsDebugMsg( "populate colormap tab" );
@@ -940,6 +946,9 @@ void QgsRasterLayerProperties::apply()
   mRasterLayer->setMaximumScale( 1.0 / mScaleRangeWidget->minimumScale() );
   mRasterLayer->setMinimumScale( 1.0 / mScaleRangeWidget->maximumScale() );
 
+  mRasterLayer->setAutoRefreshInterval( mRefreshLayerIntervalSpinBox->value() * 1000.0 );
+  mRasterLayer->setAutoRefreshEnabled( mRefreshLayerCheckBox->isChecked() );
+
   //update the legend pixmap
   // pixmapLegend->setPixmap( mRasterLayer->legendAsPixmap() );
   // pixmapLegend->setScaledContents( true );

diff --git a/src/app/qgsvectorlayerproperties.cpp b/src/app/qgsvectorlayerproperties.cpp
@@ -322,6 +322,9 @@ QgsVectorLayerProperties::QgsVectorLayerProperties(
   }
 
   mLayersDependenciesTreeView->setModel( mLayersDependenciesTreeModel.get() );
+
+  connect( mRefreshLayerCheckBox, &QCheckBox::toggled, mRefreshLayerIntervalSpinBox, &QDoubleSpinBox::setEnabled );
+
 } // QgsVectorLayerProperties ctor
 
 
@@ -446,6 +449,10 @@ void QgsVectorLayerProperties::syncToLayer()
 
   mForceRasterCheckBox->setChecked( mLayer->renderer() && mLayer->renderer()->forceRasterRender() );
 
+  mRefreshLayerCheckBox->setChecked( mLayer->hasAutoRefreshEnabled() );
+  mRefreshLayerIntervalSpinBox->setEnabled( mLayer->hasAutoRefreshEnabled() );
+  mRefreshLayerIntervalSpinBox->setValue( mLayer->autoRefreshInterval() / 1000.0 );
+
   // load appropriate symbology page (V1 or V2)
   updateSymbologyPage();
 
@@ -583,6 +590,9 @@ void QgsVectorLayerProperties::apply()
   if ( mLayer->renderer() )
     mLayer->renderer()->setForceRasterRender( mForceRasterCheckBox->isChecked() );
 
+  mLayer->setAutoRefreshInterval( mRefreshLayerIntervalSpinBox->value() * 1000.0 );
+  mLayer->setAutoRefreshEnabled( mRefreshLayerCheckBox->isChecked() );
+
   mOldJoins = mLayer->vectorJoins();
 
   //save variables

diff --git a/src/core/qgsmaplayer.cpp b/src/core/qgsmaplayer.cpp
@@ -83,6 +83,7 @@ QgsMapLayer::QgsMapLayer( QgsMapLayer::LayerType type,
   mScaleBasedVisibility = false;
 
   connect( mStyleManager, &QgsMapLayerStyleManager::currentStyleChanged, this, &QgsMapLayer::styleChanged );
+  connect( &mRefreshTimer, &QTimer::timeout, this, [=] { triggerRepaint( true ); } );
 }
 
 QgsMapLayer::~QgsMapLayer()
@@ -420,6 +421,9 @@ bool QgsMapLayer::readLayerXml( const QDomElement& layerElement, const QgsProjec
   setMinimumScale( layerElement.attribute( QStringLiteral( "minimumScale" ) ).toDouble() );
   setMaximumScale( layerElement.attribute( QStringLiteral( "maximumScale" ) ).toDouble() );
 
+  setAutoRefreshInterval( layerElement.attribute( QStringLiteral( "autoRefreshTime" ), 0 ).toInt() );
+  setAutoRefreshEnabled( layerElement.attribute( QStringLiteral( "autoRefreshEnabled" ), QStringLiteral( "0" ) ).toInt() );
+
   QDomNode extentNode = layerElement.namedItem( QStringLiteral( "extent" ) );
   if ( !extentNode.isNull() )
   {
@@ -537,6 +541,9 @@ bool QgsMapLayer::writeLayerXml( QDomElement& layerElement, QDomDocument& docume
     layerElement.appendChild( QgsXmlUtils::writeRectangle( mExtent, document ) );
   }
 
+  layerElement.setAttribute( QStringLiteral( "autoRefreshTime" ), QString::number( mRefreshTimer.interval() ) );
+  layerElement.setAttribute( QStringLiteral( "autoRefreshEnabled" ), mRefreshTimer.isActive() ? 1 : 0 );
+
   // ID
   QDomElement layerId = document.createElement( QStringLiteral( "id" ) );
   QDomText layerIdText = document.createTextNode( id() );
@@ -857,6 +864,40 @@ bool QgsMapLayer::hasScaleBasedVisibility() const
   return mScaleBasedVisibility;
 }
 
+bool QgsMapLayer::hasAutoRefreshEnabled() const
+{
+  return mRefreshTimer.isActive();
+}
+
+int QgsMapLayer::autoRefreshInterval() const
+{
+  return mRefreshTimer.interval();
+}
+
+void QgsMapLayer::setAutoRefreshInterval( int interval )
+{
+  if ( interval <= 0 )
+  {
+    mRefreshTimer.stop();
+    mRefreshTimer.setInterval( 0 );
+  }
+  else
+  {
+    mRefreshTimer.setInterval( interval );
+  }
+  emit autoRefreshIntervalChanged( mRefreshTimer.isActive() ? mRefreshTimer.interval() : 0 );
+}
+
+void QgsMapLayer::setAutoRefreshEnabled( bool enabled )
+{
+  if ( !enabled )
+    mRefreshTimer.stop();
+  else if ( mRefreshTimer.interval() > 0 )
+    mRefreshTimer.start();
+
+  emit autoRefreshIntervalChanged( mRefreshTimer.isActive() ? mRefreshTimer.interval() : 0 );
+}
+
 void QgsMapLayer::setMinimumScale( double scale )
 {
   mMinScale = scale;

diff --git a/src/core/qgsmaplayer.h b/src/core/qgsmaplayer.h
@@ -53,6 +53,7 @@ class CORE_EXPORT QgsMapLayer : public QObject
     Q_OBJECT
 
     Q_PROPERTY( QString name READ name WRITE setName NOTIFY nameChanged )
+    Q_PROPERTY( int autoRefreshInterval READ autoRefreshInterval WRITE setAutoRefreshInterval NOTIFY autoRefreshIntervalChanged )
 
   public:
 
@@ -646,6 +647,44 @@ class CORE_EXPORT QgsMapLayer : public QObject
      */
     bool hasScaleBasedVisibility() const;
 
+    /**
+     * Returns true if auto refresh is enabled for the layer.
+     * @note added in QGIS 3.0
+     * @see autoRefreshInterval()
+     * @see setAutoRefreshEnabled()
+     */
+    bool hasAutoRefreshEnabled() const;
+
+    /**
+     * Returns the auto refresh interval (in milliseconds). Note that
+     * auto refresh is only active when hasAutoRefreshEnabled() is true.
+     * @note added in QGIS 3.0
+     * @see autoRefreshEnabled()
+     * @see setAutoRefreshInterval()
+     */
+    int autoRefreshInterval() const;
+
+    /**
+     * Sets the auto refresh interval (in milliseconds) for the layer. This
+     * will cause the layer to be automatically redrawn on a matching interval.
+     * Note that auto refresh must be enabled by calling setAutoRefreshEnabled().
+     *
+     * Note that auto refresh triggers deferred repaints of the layer. Any map
+     * canvas must be refreshed separately in order to view the refreshed layer.
+     * @note added in QGIS 3.0
+     * @see autoRefreshInterval()
+     * @see setAutoRefreshEnabled()
+     */
+    void setAutoRefreshInterval( int interval );
+
+    /**
+     * Sets whether auto refresh is enabled for the layer.
+     * @note added in QGIS 3.0
+     * @see hasAutoRefreshEnabled()
+     * @see setAutoRefreshInterval()
+     */
+    void setAutoRefreshEnabled( bool enabled );
+
   public slots:
 
     //! Event handler for when a coordinate transform fails due to bad vertex error
@@ -786,6 +825,13 @@ class CORE_EXPORT QgsMapLayer : public QObject
      */
     void willBeDeleted();
 
+    /**
+     * Emitted when the auto refresh interval changes.
+     * @see setAutoRefreshInterval()
+     * @note added in QGIS 3.0
+     */
+    void autoRefreshIntervalChanged( int interval );
+
   protected:
     //! Set the extent
     virtual void setExtent( const QgsRectangle &rect );
@@ -920,6 +966,10 @@ class CORE_EXPORT QgsMapLayer : public QObject
 
     //! Manager of multiple styles available for a layer (may be null)
     QgsMapLayerStyleManager* mStyleManager;
+
+    //! Timer for triggering automatic refreshes of the layer
+    QTimer mRefreshTimer;
+
 };
 
 Q_DECLARE_METATYPE( QgsMapLayer* )

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
@@ -164,7 +164,7 @@ QgsVectorLayer::QgsVectorLayer( const QString& vectorLayerPath,
     setDataSource( vectorLayerPath, baseName, providerKey, loadDefaultStyleFlag );
   }
 
-  connect( this, &QgsVectorLayer::selectionChanged, this, [=]{ emit repaintRequested(); } );
+  connect( this, &QgsVectorLayer::selectionChanged, this, [=] { emit repaintRequested(); } );
   connect( QgsProject::instance()->relationManager(), &QgsRelationManager::relationsLoaded, this, &QgsVectorLayer::onRelationsLoaded );
 
   // Default simplify drawing settings

diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -176,6 +176,8 @@ QgsMapCanvas::QgsMapCanvas( QWidget * parent )
   QPixmap zoomPixmap = QPixmap(( const char ** )( zoom_in ) );
   mZoomCursor = QCursor( zoomPixmap, 7, 7 );
 
+  connect( &mAutoRefreshTimer, &QTimer::timeout, this, &QgsMapCanvas::autoRefreshTriggered );
+
   setInteractive( false );
 
   refresh();
@@ -297,6 +299,7 @@ void QgsMapCanvas::setLayers( const QList<QgsMapLayer*>& layers )
   {
     disconnect( layer, &QgsMapLayer::repaintRequested, this, &QgsMapCanvas::layerRepaintRequested );
     disconnect( layer, &QgsMapLayer::crsChanged, this, &QgsMapCanvas::layerCrsChange );
+    disconnect( layer, &QgsMapLayer::autoRefreshIntervalChanged, this, &QgsMapCanvas::updateAutoRefreshTimer );
     if ( QgsVectorLayer* vlayer = qobject_cast<QgsVectorLayer *>( layer ) )
     {
       disconnect( vlayer, &QgsVectorLayer::selectionChanged, this, &QgsMapCanvas::selectionChangedSlot );
@@ -309,17 +312,18 @@ void QgsMapCanvas::setLayers( const QList<QgsMapLayer*>& layers )
   {
     connect( layer, &QgsMapLayer::repaintRequested, this, &QgsMapCanvas::layerRepaintRequested );
     connect( layer, &QgsMapLayer::crsChanged, this, &QgsMapCanvas::layerCrsChange );
+    connect( layer, &QgsMapLayer::autoRefreshIntervalChanged, this, &QgsMapCanvas::updateAutoRefreshTimer );
     if ( QgsVectorLayer* vlayer = qobject_cast<QgsVectorLayer *>( layer ) )
     {
       connect( vlayer, &QgsVectorLayer::selectionChanged, this, &QgsMapCanvas::selectionChangedSlot );
     }
   }
-
   updateDatumTransformEntries();
 
   QgsDebugMsg( "Layers have changed, refreshing" );
   emit layersChanged();
 
+  updateAutoRefreshTimer();
   refresh();
 }
 
@@ -1674,7 +1678,40 @@ void QgsMapCanvas::layerRepaintRequested( bool deferred )
     refresh();
 }
 
+void QgsMapCanvas::autoRefreshTriggered()
+{
+  if ( mJob )
+  {
+    // canvas is currently being redrawn, so we skip this auto refresh
+    // otherwise we could get stuck in the situation where an auto refresh is triggered
+    // too often to allow the canvas to ever finish rendering
+    return;
+  }
 
+  refresh();
+}
+
+void QgsMapCanvas::updateAutoRefreshTimer()
+{
+  // min auto refresh interval stores the smallest interval between layer auto refreshes. We automatically
+  // trigger a map refresh on this minimum interval
+  int minAutoRefreshInterval = -1;
+  Q_FOREACH ( QgsMapLayer* layer, mSettings.layers() )
+  {
+    if ( layer->hasAutoRefreshEnabled() && layer->autoRefreshInterval() > 0 )
+      minAutoRefreshInterval = minAutoRefreshInterval > 0 ? qMin( layer->autoRefreshInterval(), minAutoRefreshInterval ) : layer->autoRefreshInterval();
+  }
+
+  if ( minAutoRefreshInterval > 0 )
+  {
+    mAutoRefreshTimer.setInterval( minAutoRefreshInterval );
+    mAutoRefreshTimer.start();
+  }
+  else
+  {
+    mAutoRefreshTimer.stop();
+  }
+}
 
 QgsMapTool* QgsMapCanvas::mapTool()
 {

diff --git a/src/gui/qgsmapcanvas.h b/src/gui/qgsmapcanvas.h
@@ -616,6 +616,10 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
 
     void layerRepaintRequested( bool deferred );
 
+    void autoRefreshTriggered();
+
+    void updateAutoRefreshTimer();
+
   private:
     /// this class is non-copyable
 
@@ -706,6 +710,8 @@ class GUI_EXPORT QgsMapCanvas : public QGraphicsView
 
     QCursor mZoomCursor;
 
+    QTimer mAutoRefreshTimer;
+
     //! Force a resize of the map canvas item
     //! @note added in 2.16
     void updateMapSize();

diff --git a/src/ui/qgsrasterlayerpropertiesbase.ui b/src/ui/qgsrasterlayerpropertiesbase.ui
@@ -420,6 +420,52 @@
                  </layout>
                 </widget>
                </item>
+               <item>
+                <layout class="QHBoxLayout" name="horizontalLayout_3">
+                 <item>
+                  <widget class="QCheckBox" name="mRefreshLayerCheckBox">
+                   <property name="text">
+                    <string>Refresh layer at interval (seconds)</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <widget class="QDoubleSpinBox" name="mRefreshLayerIntervalSpinBox">
+                   <property name="toolTip">
+                    <string>Higher values result in more simplification</string>
+                   </property>
+                   <property name="decimals">
+                    <number>2</number>
+                   </property>
+                   <property name="minimum">
+                    <double>0.000000000000000</double>
+                   </property>
+                   <property name="maximum">
+                    <double>100000000000000000000.000000000000000</double>
+                   </property>
+                   <property name="singleStep">
+                    <double>5.000000000000000</double>
+                   </property>
+                   <property name="value">
+                    <double>10.000000000000000</double>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <spacer name="horizontalSpacer_6">
+                   <property name="orientation">
+                    <enum>Qt::Horizontal</enum>
+                   </property>
+                   <property name="sizeHint" stdset="0">
+                    <size>
+                     <width>40</width>
+                     <height>20</height>
+                    </size>
+                   </property>
+                  </spacer>
+                 </item>
+                </layout>
+               </item>
                <item>
                 <spacer name="verticalSpacer_3">
                  <property name="orientation">
@@ -2242,6 +2288,8 @@ p, li { white-space: pre-wrap; }
   <tabstop>grpSRS</tabstop>
   <tabstop>mCrsSelector</tabstop>
   <tabstop>chkUseScaleDependentRendering</tabstop>
+  <tabstop>mRefreshLayerCheckBox</tabstop>
+  <tabstop>mRefreshLayerIntervalSpinBox</tabstop>
   <tabstop>scrollArea</tabstop>
   <tabstop>mBandRenderingGrpBx</tabstop>
   <tabstop>mRenderTypeComboBox</tabstop>