Improved labeling engine interface, now connected with QgsMapRenderer instead of individual layers.

Also fixes #2108.


git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@12174 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

python/core/qgsmaprenderer.sip

@@ -1,4 +1,31 @@
 
+
+/** Labeling engine interface.
+ * \note Added in QGIS v1.4
+ */
+class QgsLabelingEngineInterface
+{
+%TypeHeaderCode
+#include <qgsmaprenderer.h>
+%End
+
+public:
+  virtual ~QgsLabelingEngineInterface();
+
+  //! called when we're going to start with rendering
+  virtual void init() = 0;
+  //! called when starting rendering of a layer
+  virtual int prepareLayer(QgsVectorLayer* layer, int& attrIndex) = 0;
+  //! called for every feature
+  virtual void registerFeature( QgsVectorLayer* layer, QgsFeature& feat ) = 0;
+  //! called when the map is drawn and labels should be placed
+  virtual void drawLabeling( QgsRenderContext& context ) = 0;
+  //! called when we're done with rendering
+  virtual void exit() = 0;
+
+};
+
+
 /**
  * \class QgsMapRenderer
  * \brief Class for rendering map layer set
@@ -114,6 +141,15 @@ class QgsMapRenderer : QObject
     //! Accessor for render context
     QgsRenderContext* rendererContext();
 
+    //! Labeling engine (NULL if there's no custom engine)
+    //! \note Added in QGIS v1.4
+    QgsLabelingEngineInterface* labelingEngine();
+
+    //! Set labeling engine. Previous engine (if any) is deleted.
+    //! Takes ownership of the engine.
+    //! Added in QGIS v1.4
+    void setLabelingEngine(QgsLabelingEngineInterface* iface /Transfer/);
+
   signals:
 
     void drawingProgress(int current, int total);

python/core/qgsrendercontext.sip

@@ -32,6 +32,9 @@ class QgsRenderContext
 
   double rendererScale() const;
 
+  //! Added in QGIS v1.4
+  QgsLabelingEngineInterface* labelingEngine();
+
   //setters
 
   /**Sets coordinate transformation. QgsRenderContext takes ownership and deletes if necessary*/
@@ -44,4 +47,6 @@ class QgsRenderContext
   void setRasterScaleFactor(double factor);
   void setRendererScale( double scale );
   void setPainter(QPainter* p);
+  //! Added in QGIS v1.4
+  void setLabelingEngine(QgsLabelingEngineInterface* iface);
 };

src/core/qgsmaprenderer.cpp

@@ -58,13 +58,16 @@ QgsMapRenderer::QgsMapRenderer()
   mDestCRS = new QgsCoordinateReferenceSystem( GEO_EPSG_CRS_ID, QgsCoordinateReferenceSystem::EpsgCrsId ); //WGS 84
 
   mOutputUnits = QgsMapRenderer::Millimeters;
+
+  mLabelingEngine = NULL;
 }
 
 QgsMapRenderer::~QgsMapRenderer()
 {
   delete mScaleCalculator;
   delete mDistArea;
   delete mDestCRS;
+  delete mLabelingEngine;
 }
 
 
@@ -282,6 +285,10 @@ void QgsMapRenderer::render( QPainter* painter )
     mySameAsLastFlag = false;
   }
 
+  mRenderContext.setLabelingEngine(mLabelingEngine);
+  if ( mLabelingEngine )
+    mLabelingEngine->init();
+
   // know we know if this render is just a repeat of the last time, we 
   // can clear caches if it has changed
   if ( !mySameAsLastFlag )
@@ -572,6 +579,12 @@ void QgsMapRenderer::render( QPainter* painter )
   // make sure progress bar arrives at 100%!
   emit drawingProgress( 1, 1 );
 
+  if ( mLabelingEngine )
+  {
+    mLabelingEngine->drawLabeling( mRenderContext );
+    mLabelingEngine->exit();
+  }
+
   QgsDebugMsg( "Rendering completed in (seconds): " + QString( "%1" ).arg( renderTime.elapsed() / 1000.0 ) );
 
   mDrawing = false;
@@ -1041,3 +1054,11 @@ bool QgsMapRenderer::writeXML( QDomNode & theNode, QDomDocument & theDoc )
 
   return true;
 }
+
+void QgsMapRenderer::setLabelingEngine(QgsLabelingEngineInterface* iface)
+{
+  if (mLabelingEngine)
+    delete mLabelingEngine;
+
+  mLabelingEngine = iface;
+}

src/core/qgsmaprenderer.h

@@ -34,6 +34,31 @@ class QgsScaleCalculator;
 class QgsCoordinateReferenceSystem;
 class QgsDistanceArea;
 class QgsOverlayObjectPositionManager;
+class QgsVectorLayer;
+class QgsFeature;
+
+/** Labeling engine interface.
+ * \note Added in QGIS v1.4
+ */
+class QgsLabelingEngineInterface
+{
+public:
+  virtual ~QgsLabelingEngineInterface() {}
+
+  //! called when we're going to start with rendering
+  virtual void init() = 0;
+  //! called when starting rendering of a layer
+  virtual int prepareLayer(QgsVectorLayer* layer, int& attrIndex) = 0;
+  //! called for every feature
+  virtual void registerFeature( QgsVectorLayer* layer, QgsFeature& feat ) = 0;
+  //! called when the map is drawn and labels should be placed
+  virtual void drawLabeling( QgsRenderContext& context ) = 0;
+  //! called when we're done with rendering
+  virtual void exit() = 0;
+
+};
+
+
 
 /** \ingroup core
  * A non GUI class for rendering a map layer set onto a QPainter.
@@ -146,6 +171,15 @@ class CORE_EXPORT QgsMapRenderer : public QObject
     //! Accessor for render context
     QgsRenderContext* rendererContext() {return &mRenderContext;}
 
+    //! Labeling engine (NULL if there's no custom engine)
+    //! \note Added in QGIS v1.4
+    QgsLabelingEngineInterface* labelingEngine() { return mLabelingEngine; }
+
+    //! Set labeling engine. Previous engine (if any) is deleted.
+    //! Takes ownership of the engine.
+    //! Added in QGIS v1.4
+    void setLabelingEngine(QgsLabelingEngineInterface* iface);
+
   signals:
 
     void drawingProgress( int current, int total );
@@ -232,6 +266,9 @@ class CORE_EXPORT QgsMapRenderer : public QObject
 
     //!Output units
     OutputUnits mOutputUnits;
+
+    //! Labeling engine (NULL by default)
+    QgsLabelingEngineInterface* mLabelingEngine;
 };
 
 #endif

src/core/qgsrendercontext.cpp

@@ -18,7 +18,15 @@
 
 #include "qgsrendercontext.h"
 
-QgsRenderContext::QgsRenderContext(): mPainter( 0 ), mCoordTransform( 0 ), mDrawEditingInformation( false ), mForceVectorOutput( true ), mRenderingStopped( false ), mScaleFactor( 1.0 ), mRasterScaleFactor( 1.0 )
+QgsRenderContext::QgsRenderContext()
+  : mPainter( 0 ),
+    mCoordTransform( 0 ),
+    mDrawEditingInformation( false ),
+    mForceVectorOutput( true ),
+    mRenderingStopped( false ),
+    mScaleFactor( 1.0 ),
+    mRasterScaleFactor( 1.0 ),
+    mLabelingEngine( NULL )
 {
 
 }

src/core/qgsrendercontext.h

@@ -24,6 +24,8 @@
 
 class QPainter;
 
+class QgsLabelingEngineInterface;
+
 /** \ingroup core
  * Contains information about the context of a rendering operation.
  * The context of a rendering operation defines properties such as
@@ -58,6 +60,9 @@ class CORE_EXPORT QgsRenderContext
 
     double rendererScale() const {return mRendererScale;}
 
+    //! Added in QGIS v1.4
+    QgsLabelingEngineInterface* labelingEngine() const { return mLabelingEngine; }
+
     //setters
 
     /**Sets coordinate transformation. QgsRenderContext takes ownership and deletes if necessary*/
@@ -70,6 +75,8 @@ class CORE_EXPORT QgsRenderContext
     void setRasterScaleFactor( double factor ) {mRasterScaleFactor = factor;}
     void setRendererScale( double scale ) {mRendererScale = scale;}
     void setPainter( QPainter* p ) {mPainter = p;}
+    //! Added in QGIS v1.4
+    void setLabelingEngine(QgsLabelingEngineInterface* iface) { mLabelingEngine = iface; }
 
   private:
 
@@ -100,6 +107,9 @@ class CORE_EXPORT QgsRenderContext
 
     /**Map scale*/
     double mRendererScale;
+
+    /**Labeling engine (can be NULL)*/
+    QgsLabelingEngineInterface* mLabelingEngine;
 };
 
 #endif

src/core/qgsvectorlayer.cpp

@@ -109,8 +109,7 @@ QgsVectorLayer::QgsVectorLayer( QString vectorLayerPath,
     mVertexMarkerOnlyForSelection( false ),
     mFetching( false ),
     mRendererV2( NULL ),
-    mUsingRendererV2( false ),
-    mLabelingEngine( NULL )
+    mUsingRendererV2( false )
 {
   mActions = new QgsAttributeAction;
 
@@ -686,7 +685,7 @@ void QgsVectorLayer::drawRendererV2( QgsRenderContext& rendererContext, bool lab
       mRendererV2->renderFeature( fet, rendererContext );
 
     if ( labeling )
-      mLabelingEngine->registerFeature( this, fet );
+      rendererContext.labelingEngine()->registerFeature( this, fet );
   }
 
   mRendererV2->stopRender( rendererContext );
@@ -725,7 +724,7 @@ void QgsVectorLayer::drawRendererV2Levels( QgsRenderContext& rendererContext, bo
     features[sym].append( fet );
 
     if ( labeling )
-      mLabelingEngine->registerFeature( this, fet );
+      rendererContext.labelingEngine()->registerFeature( this, fet );
   }
 
   // find out the order
@@ -799,10 +798,10 @@ bool QgsVectorLayer::draw( QgsRenderContext& rendererContext )
     }
 
     bool labeling = FALSE;
-    if ( mLabelingEngine )
+    if ( rendererContext.labelingEngine() )
     {
       int attrIndex;
-      if ( mLabelingEngine->prepareLayer( this, attrIndex ) )
+      if ( rendererContext.labelingEngine()->prepareLayer( this, attrIndex ) )
       {
         if ( !attributes.contains( attrIndex ) )
           attributes << attrIndex;
@@ -859,10 +858,10 @@ bool QgsVectorLayer::draw( QgsRenderContext& rendererContext )
     QgsAttributeList attributes = mRenderer->classificationAttributes();
 
     bool labeling = FALSE;
-    if ( mLabelingEngine )
+    if ( rendererContext.labelingEngine() )
     {
       int attrIndex;
-      if ( mLabelingEngine->prepareLayer( this, attrIndex ) )
+      if ( rendererContext.labelingEngine()->prepareLayer( this, attrIndex ) )
       {
         if ( !attributes.contains( attrIndex ) )
           attributes << attrIndex;
@@ -934,9 +933,9 @@ bool QgsVectorLayer::draw( QgsRenderContext& rendererContext )
         //double scale = rendererContext.scaleFactor() /  markerScaleFactor;
         drawFeature( rendererContext, fet, &marker );
 
-        if ( labeling && mLabelingEngine )
+        if ( labeling )
         {
-          mLabelingEngine->registerFeature( this, fet );
+          rendererContext.labelingEngine()->registerFeature( this, fet );
         }
 
         ++featureCount;
@@ -2256,12 +2255,6 @@ bool QgsVectorLayer::hasLabelsEnabled( void ) const
   return mLabelOn;
 }
 
-void QgsVectorLayer::setLabelingEngine( QgsLabelingEngineInterface* engine )
-{
-  mLabelingEngine = engine;
-}
-
-
 bool QgsVectorLayer::startEditing()
 {
   if ( !mDataProvider )

src/core/qgsvectorlayer.h

@@ -53,17 +53,6 @@ typedef QList<int> QgsAttributeList;
 typedef QSet<int> QgsFeatureIds;
 typedef QSet<int> QgsAttributeIds;
 
-class QgsLabelingEngineInterface
-{
-  public:
-    virtual ~QgsLabelingEngineInterface() {}
-    virtual int prepareLayer( QgsVectorLayer* layer, int& attrIndex ) = 0;
-    virtual void registerFeature( QgsVectorLayer* layer, QgsFeature& feat ) = 0;
-    //void calculateLabeling() = 0;
-    //void drawLabeling(QgsRenderContext& context) = 0;
-};
-
-
 
 /** \ingroup core
  * Vector layer backed by a data source provider.
@@ -362,9 +351,6 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
     /** Label is on */
     bool hasLabelsEnabled( void ) const;
 
-    /** Assign a custom labeling engine with layer. Added in v1.4 */
-    void setLabelingEngine( QgsLabelingEngineInterface* engine );
-
     /** Returns true if the provider is in editing mode */
     virtual bool isEditable() const;
 
@@ -747,9 +733,6 @@ class CORE_EXPORT QgsVectorLayer : public QgsMapLayer
     /** Label */
     QgsLabel *mLabel;
 
-    QgsLabelingEngineInterface* mLabelingEngine;
-
-
     /** Display labels */
     bool mLabelOn;