Avoid multiple map/legend renders while loading compositions

qgis · Mar 21, 2017 · 77706a6 · 77706a6
1 parent ce3c854
commit 77706a6
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Showing 7 changed files with 68 additions and 36 deletions.
diff --git a/python/core/composer/qgscomposeritem.sip b/python/core/composer/qgscomposeritem.sip
@@ -544,26 +544,28 @@ class QgsComposerItem : QgsComposerObject, QGraphicsRectItem
      */
     void setIsGroupMember( const bool isGroupMember );
 
-    /** Get the number of layers that this item requires for exporting as layers
-     * @returns 0 if this item is to be placed on the same layer as the previous item,
-     * 1 if it should be placed on its own layer, and >1 if it requires multiple export layers
-     * @note this method was added in version 2.4
-     * @see setCurrentExportLayer
-     */
-    int numberExportLayers() const;
 
-    /** Sets the current layer to draw for exporting
-     * @param layerIdx can be set to -1 to draw all item layers, and must be less than numberExportLayers()
-     * @note this method was added in version 2.4
-     * @see numberExportLayers
-     */
-    void setCurrentExportLayer( const int layerIdx = -1 );
 
-    /** Creates an expression context relating to the item's current state. The context includes
-     * scopes for global, project, composition, atlas and item properties.
-     * @note added in QGIS 2.12
-     */
-    QgsExpressionContext createExpressionContext() const;
+
+
+
+
+    virtual int numberExportLayers() const;
+
+
+
+
+
+
+    virtual void setCurrentExportLayer( const int layerIdx = -1 );
+
+
+
+
+
+    virtual QgsExpressionContext createExpressionContext() const;
+    void setUpdatesEnabled( bool enabled );
+    bool updatesEnabled() const;
 
   public slots:
 

diff --git a/python/core/composer/qgscomposermap.sip b/python/core/composer/qgscomposermap.sip
@@ -318,12 +318,6 @@ class QgsComposerMap : QgsComposerItem
      */
     void setAtlasMargin( double margin );
 
-    /** Sets whether updates to the composer map are enabled. */
-    void setUpdatesEnabled( bool enabled );
-
-    /** Returns whether updates to the composer map are enabled. */
-    bool updatesEnabled() const;
-
     /** Get the number of layers that this item requires for exporting as layers
      * @returns 0 if this item is to be placed on the same layer as the previous item,
      * 1 if it should be placed on its own layer, and >1 if it requires multiple export layers

diff --git a/src/core/composer/qgscomposeritem.cpp b/src/core/composer/qgscomposeritem.cpp
@@ -571,6 +571,14 @@ double QgsComposerItem::itemRotation( const PropertyValueType valueType ) const
   return valueType == QgsComposerObject::EvaluatedValue ? mEvaluatedItemRotation : mItemRotation;
 }
 
+void QgsComposerItem::updateItem()
+{
+  if ( !mUpdatesEnabled )
+    return;
+
+  QGraphicsRectItem::update();
+}
+
 void QgsComposerItem::move( double dx, double dy )
 {
   QRectF newSceneRect( pos().x() + dx, pos().y() + dy, rect().width(), rect().height() );

diff --git a/src/core/composer/qgscomposeritem.h b/src/core/composer/qgscomposeritem.h
@@ -432,8 +432,12 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
      */
     double itemRotation( const QgsComposerObject::PropertyValueType valueType = QgsComposerObject::EvaluatedValue ) const;
 
-    //! Updates item, with the possibility to do custom update for subclasses
-    virtual void updateItem() { QGraphicsRectItem::update(); }
+    /**
+     * Updates (redraws) the item, with the possibility to do custom update for subclasses.
+     * Subclasses should check updatesEnabled() to determine whether updates are
+     * currently permitted for the item.
+     */
+    virtual void updateItem();
 
     /** Get item's id (which is not necessarly unique)
      * @returns item id
@@ -524,6 +528,26 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
      */
     virtual QgsExpressionContext createExpressionContext() const override;
 
+    /**
+     * Sets whether updates to the item are enabled. If false,
+     * the item will not be redrawn. This can be used to prevent
+     * multiple item updates when many settings for an item are
+     * changed sequentially.
+     * @note added in QGIS 3.0
+     * @see updatesEnabled()
+     */
+    void setUpdatesEnabled( bool enabled ) { mUpdatesEnabled = enabled; }
+
+    /**
+     * Returns whether updates to the item are enabled. If false,
+     * the item will not be redrawn. This can be used to prevent
+     * multiple item updates when many settings for an item are
+     * changed sequentially.
+     * @note added in QGIS 3.0
+     * @see setUpdatesEnabled()
+     */
+    bool updatesEnabled() const { return mUpdatesEnabled; }
+
   public slots:
 
     /** Sets the item rotation
@@ -694,6 +718,12 @@ class CORE_EXPORT QgsComposerItem: public QgsComposerObject, public QGraphicsRec
     // true if composition manages the z value for this item
     bool mCompositionManagesZValue;
 
+    /**
+     * Whether updates to the item are enabled. If false,
+     * the item should not be redrawn.
+     */
+    bool mUpdatesEnabled = true;
+
     /** Refresh item's rotation, considering data defined rotation setting
       *@param updateItem set to false to prevent the item being automatically updated
       *@param rotateAroundCenter set to true to rotate the item around its center rather

diff --git a/src/core/composer/qgscomposerlegend.cpp b/src/core/composer/qgscomposerlegend.cpp
@@ -348,6 +348,9 @@ void QgsComposerLegend::updateLegend()
 
 void QgsComposerLegend::updateItem()
 {
+  if ( !updatesEnabled() )
+    return;
+
   updateFilterByMap( false );
   QgsComposerItem::updateItem();
 }

diff --git a/src/core/composer/qgscomposermap.cpp b/src/core/composer/qgscomposermap.cpp
@@ -1024,7 +1024,7 @@ void QgsComposerMap::refreshMapExtents( const QgsExpressionContext *context )
 
 void QgsComposerMap::updateItem()
 {
-  if ( !mUpdatesEnabled )
+  if ( !updatesEnabled() )
   {
     return;
   }
@@ -1247,6 +1247,8 @@ bool QgsComposerMap::readXml( const QDomElement &itemElem, const QDomDocument &d
     return false;
   }
 
+  setUpdatesEnabled( false );
+
   QString idRead = itemElem.attribute( QStringLiteral( "id" ), QStringLiteral( "not found" ) );
   if ( idRead != QLatin1String( "not found" ) )
   {
@@ -1489,6 +1491,8 @@ bool QgsComposerMap::readXml( const QDomElement &itemElem, const QDomDocument &d
   }
 
   updateBoundingRect();
+  setUpdatesEnabled( true );
+
   emit itemChanged();
   return true;
 }

diff --git a/src/core/composer/qgscomposermap.h b/src/core/composer/qgscomposermap.h
@@ -425,12 +425,6 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
      */
     void setAtlasMargin( double margin ) { mAtlasMargin = margin; }
 
-    //! Sets whether updates to the composer map are enabled.
-    void setUpdatesEnabled( bool enabled ) { mUpdatesEnabled = enabled; }
-
-    //! Returns whether updates to the composer map are enabled.
-    bool updatesEnabled() const { return mUpdatesEnabled; }
-
     /** Get the number of layers that this item requires for exporting as layers
      * @returns 0 if this item is to be placed on the same layer as the previous item,
      * 1 if it should be placed on its own layer, and >1 if it requires multiple export layers
@@ -562,9 +556,6 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
      *  is true. May be overridden by data-defined expression. */
     QString mFollowVisibilityPresetName;
 
-    //! Whether updates to the map are enabled
-    bool mUpdatesEnabled = true;
-
     //! Establishes signal/slot connection for update in case of layer change
     void connectUpdateSlot();