Add basic support for hit test without calling getMap

Author: pblottiere

src/server/services/wms/qgswmsgetlegendgraphics.cpp

@@ -127,13 +127,33 @@ namespace QgsWms
       throw QgsBadRequestException( QgsServiceException::QGIS_INVALID_PARAMETER_VALUE,
                                     QStringLiteral( "BBOX parameter cannot be combined with RULE." ) );
     }
+
+    if ( ! parameters.bbox().isEmpty() && parameters.bboxAsRectangle().isEmpty() )
+    {
+      throw QgsBadRequestException( QgsServiceException::QGIS_INVALID_PARAMETER_VALUE,
+                                    parameters[QgsWmsParameter::BBOX] );
+    }
   }
 
   QgsLayerTreeModel *legendModel( const QgsWmsRenderContext &context, QgsLayerTree &tree )
   {
     const QgsWmsParameters parameters = context.parameters();
-
     std::unique_ptr<QgsLayerTreeModel> model( new QgsLayerTreeModel( &tree ) );
+
+    if ( context.scaleDenominator() > 0 )
+    {
+      model->setLegendFilterByScale( context.scaleDenominator() );
+    }
+
+    // content based legend
+    if ( ! parameters.bbox().isEmpty() )
+    {
+      QgsRenderer renderer( context );
+      const QgsRenderer::HitTest symbols = renderer.symbols();
+
+      // TODO
+    }
+
     return model.release();
   }
 

src/server/services/wms/qgswmsrenderer.cpp

@@ -249,6 +249,36 @@ namespace QgsWms
     r->stopRender( context );
   }
 
+  QgsRenderer::HitTest QgsRenderer::symbols()
+  {
+    // check size
+    checkMaximumWidthHeight();
+
+    // init layer restorer before doing anything
+    std::unique_ptr<QgsLayerRestorer> restorer;
+    restorer.reset( new QgsLayerRestorer( mContext.layers() ) );
+
+    // configure layers
+    QgsMapSettings mapSettings;
+    QList<QgsMapLayer *> layers = mContext.layersToRender();
+    configureLayers( layers, &mapSettings );
+
+    // create the output image and the painter
+    std::unique_ptr<QPainter> painter;
+    std::unique_ptr<QImage> image( createImage() );
+
+    // configure map settings (background, DPI, ...)
+    configureMapSettings( image.get(), mapSettings );
+
+    // add layers to map settings
+    mapSettings.setLayers( layers );
+
+    // run hit tests
+    HitTest symbols;
+    runHitTest( mapSettings, symbols );
+
+    return symbols;
+  }
 
   QByteArray QgsRenderer::getPrint()
   {
@@ -385,7 +415,7 @@ namespace QgsWms
     std::unique_ptr<QImage> image( new QImage() );
     configureMapSettings( image.get(), mapSettings );
 
-    // add layers to map settings (revert order for the rendering)
+    // add layers to map settings
     mapSettings.setLayers( layers );
 
     // configure layout
@@ -751,7 +781,7 @@ namespace QgsWms
     // configure map settings (background, DPI, ...)
     configureMapSettings( image.get(), mapSettings );
 
-    // add layers to map settings (revert order for the rendering)
+    // add layers to map settings
     mapSettings.setLayers( layers );
 
     // rendering step for layers

src/server/services/wms/qgswmsrenderer.h

@@ -83,6 +83,8 @@ namespace QgsWms
       typedef QSet<QString> SymbolSet;
       typedef QHash<QgsVectorLayer *, SymbolSet> HitTest;
 
+      HitTest symbols();
+
       /**
        * Returns the map as an image (or NULLPTR in case of error). The caller takes ownership
       of the image object). If an instance to existing hit test structure is passed, instead of rendering