Merge pull request #1380 from Oslandia/mask_renderer

[FEATURE] Inverted polygons renderer

python/core/core.sip

@@ -206,6 +206,7 @@
 %Include symbology-ng/qgssinglesymbolrendererv2.sip
 %Include symbology-ng/qgspointdisplacementrenderer.sip
 %Include symbology-ng/qgsrulebasedrendererv2.sip
+%Include symbology-ng/qgsinvertedpolygonrenderer.sip
 %Include symbology-ng/qgsrendererv2.sip
 %Include symbology-ng/qgsrendererv2registry.sip
 

python/core/symbology-ng/qgsinvertedpolygonrenderer.sip

@@ -0,0 +1,70 @@
+class QgsInvertedPolygonRenderer : public QgsFeatureRendererV2
+{
+%TypeHeaderCode
+#include <qgsinvertedpolygonrenderer.h>
+%End
+  public:
+
+  /** Constructor
+   * @param embeddedRenderer optional embeddedRenderer. If null, a default one will be assigned
+   */
+  QgsInvertedPolygonRenderer( const QgsFeatureRendererV2* embeddedRenderer = 0 );
+  virtual ~QgsInvertedPolygonRenderer();
+
+  /** Used to clone this feature renderer.*/
+  virtual QgsFeatureRendererV2* clone();
+
+  virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+
+  /** Renders a given feature.
+   * This will here collect features. The actual rendering will be postponed to stopRender()
+   * @param feature the feature to render
+   * @param context the rendering context
+   * @param layer the symbol layer to render, if that makes sense
+   * @param selected whether this feature has been selected (this will add decorations)
+   * @param drawVertexMarker whether this feature has vertex markers (in edit mode usually)
+   * @returns true if the rendering was ok
+   */
+  virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
+
+  /**
+   * The actual rendering will take place here.
+   * Features collected during renderFeature() are rendered using the embedded feature renderer
+   */
+  virtual void stopRender( QgsRenderContext& context );
+
+  /** @returns a textual reprensation of the renderer */
+  virtual QString dump() const;
+
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QList<QString> usedAttributes();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual int capabilities();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2List symbols();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsLegendSymbologyList legendSymbologyItems( QSize iconSize );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual bool willRenderFeature( QgsFeature& feat );
+
+  /** Creates a renderer out of an XML, for loading*/
+  static QgsFeatureRendererV2* create( QDomElement& element );
+
+  /** Creates an XML representation of the renderer. Used for saving purpose
+   * @param doc the XML document where to create the XML subtree
+   * @returns the created XML subtree
+   */
+  virtual QDomElement save( QDomDocument& doc );
+
+  /** sets the embedded renderer
+   * @param subRenderer the embedded renderer (will be cloned)
+   */
+  void setEmbeddedRenderer( const QgsFeatureRendererV2* subRenderer );
+  /** @returns the current embedded renderer
+   */
+  const QgsFeatureRendererV2* embeddedRenderer() const;
+};

python/gui/gui.sip

@@ -122,6 +122,7 @@
 %Include symbology-ng/qgscptcitycolorrampv2dialog.sip
 %Include symbology-ng/qgsellipsesymbollayerv2widget.sip
 %Include symbology-ng/qgsgraduatedsymbolrendererv2widget.sip
+%Include symbology-ng/qgsinvertedpolygonrendererwidget.sip
 %Include symbology-ng/qgslayerpropertieswidget.sip
 %Include symbology-ng/qgspenstylecombobox.sip
 %Include symbology-ng/qgspointdisplacementrendererwidget.sip

python/gui/symbology-ng/qgsinvertedpolygonrendererwidget.sip

@@ -0,0 +1,23 @@
+class QgsInvertedPolygonRendererWidget : public QgsRendererV2Widget, private Ui::QgsInvertedPolygonRendererWidgetBase
+{
+%TypeHeaderCode
+#include <qgsinvertedpolygonrendererwidget.h>
+%End
+ public:
+  /** static creation method
+   * @param layer the layer where this renderer is applied
+   * @param style
+   * @param renderer the mask renderer (will take ownership)
+   */
+  static QgsRendererV2Widget* create( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer );
+
+  /** Constructor
+   * @param layer the layer where this renderer is applied
+   * @param style
+   * @param renderer the mask renderer (will take ownership)
+   */
+  QgsInvertedPolygonRendererWidget( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer );
+
+  /** @returns the current feature renderer */
+  virtual QgsFeatureRendererV2* renderer();
+};

src/core/CMakeLists.txt

@@ -36,6 +36,7 @@ SET(QGIS_CORE_SRCS
   symbology-ng/qgscategorizedsymbolrendererv2.cpp
   symbology-ng/qgsgraduatedsymbolrendererv2.cpp
   symbology-ng/qgsrulebasedrendererv2.cpp
+  symbology-ng/qgsinvertedpolygonrenderer.cpp
   symbology-ng/qgsvectorcolorrampv2.cpp
   symbology-ng/qgscptcityarchive.cpp
   symbology-ng/qgsstylev2.cpp
@@ -585,6 +586,7 @@ SET(QGIS_CORE_HDRS
   symbology-ng/qgsrendererv2registry.h
   symbology-ng/qgsrulebasedrendererv2.h
   symbology-ng/qgssinglesymbolrendererv2.h
+  symbology-ng/qgsinvertedpolygonrenderer.h
   symbology-ng/qgsstylev2.h
   symbology-ng/qgssvgcache.h
   symbology-ng/qgssymbollayerv2.h

src/core/symbology-ng/qgsinvertedpolygonrenderer.cpp

@@ -0,0 +1,367 @@
+/***************************************************************************
+    qgsinvertedpolygonrenderer.cpp
+    ---------------------
+    begin                : April 2014
+    copyright            : (C) 2014 Hugo Mercier / Oslandia
+    email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsinvertedpolygonrenderer.h"
+
+#include "qgssymbolv2.h"
+#include "qgssymbollayerv2utils.h"
+
+#include "qgslogger.h"
+#include "qgsfeature.h"
+#include "qgsvectorlayer.h"
+#include "qgssymbollayerv2.h"
+#include "qgsogcutils.h"
+
+#include <QDomDocument>
+#include <QDomElement>
+
+QgsInvertedPolygonRenderer::QgsInvertedPolygonRenderer( const QgsFeatureRendererV2* subRenderer )
+  : QgsFeatureRendererV2( "invertedPolygonRenderer" )
+{
+  if ( subRenderer ) {
+    setEmbeddedRenderer( subRenderer );
+  }
+  else {
+    mSubRenderer.reset( QgsFeatureRendererV2::defaultRenderer( QGis::Polygon ) );
+  }
+}
+
+QgsInvertedPolygonRenderer::~QgsInvertedPolygonRenderer()
+{
+}
+
+void QgsInvertedPolygonRenderer::setEmbeddedRenderer( const QgsFeatureRendererV2* subRenderer )
+{
+  if ( subRenderer ) {
+    mSubRenderer.reset( const_cast<QgsFeatureRendererV2*>(subRenderer)->clone() );
+  }
+  else {
+    mSubRenderer.reset( 0 );
+  }
+}
+
+const QgsFeatureRendererV2* QgsInvertedPolygonRenderer::embeddedRenderer() const
+{
+  return mSubRenderer.data();
+}
+
+void QgsInvertedPolygonRenderer::startRender( QgsRenderContext& context, const QgsFields& fields )
+{
+  if ( !mSubRenderer ) {
+    return;
+  }
+
+  mSubRenderer->startRender( context, fields );
+  mFeaturesCategoryMap.clear();
+  mFeatureDecorations.clear();
+  mFields = fields;
+
+  // We compute coordinates of the extent which will serve as exterior ring
+  // for the final polygon
+  // It must be computed in the destination CRS if reprojection is enabled.
+  const QgsMapToPixel& mtp( context.mapToPixel() );
+
+  // convert viewport to dest CRS
+  QRect e( context.painter()->viewport() );
+  // add some space to hide borders and tend to infinity
+  e.adjust( -e.width()*10, -e.height()*10, e.width()*10, e.height()*10 );
+  QgsPolyline exteriorRing;
+  exteriorRing << mtp.toMapCoordinates( e.topLeft() );
+  exteriorRing << mtp.toMapCoordinates( e.topRight() );
+  exteriorRing << mtp.toMapCoordinates( e.bottomRight() );
+  exteriorRing << mtp.toMapCoordinates( e.bottomLeft() );
+  exteriorRing << mtp.toMapCoordinates( e.topLeft() );
+
+  mTransform = context.coordinateTransform();
+  // If reprojection is enabled, we must reproject during renderFeature
+  // and act as if there is no reprojection
+  // If we don't do that, there is no need to have a simple rectangular extent
+  // that covers the whole screen
+  // (a rectangle in the destCRS cannot be expressed as valid coordinates in the sourceCRS in general)
+  if (mTransform)
+  {
+    // disable projection
+    context.setCoordinateTransform(0);
+  }
+
+  mExtentPolygon.clear();
+  mExtentPolygon.append(exteriorRing);
+}
+
+bool QgsInvertedPolygonRenderer::renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer, bool selected, bool drawVertexMarker )
+{
+  Q_UNUSED( context );
+
+  // store this feature as a feature to render with decoration if needed
+  if ( selected || drawVertexMarker )
+  {
+    mFeatureDecorations.append( FeatureDecoration( feature, selected, drawVertexMarker, layer) );
+  }
+
+  // Features are grouped by category of symbols (returned by symbol(s)ForFeature)
+  // This way, users can have multiple inverted polygon fills for a layer,
+  // for instance, with rule based renderer and different symbols
+  // that have transparency.
+  //
+  // In order to assign a unique category to a set of symbols
+  // during each rendering session (between startRender() and stopRender()), 
+  // we build an unique id as a QByteArray that is the concatenation
+  // of each symbol's memory address.
+  // The only assumption made here is that symbol(s)ForFeature will
+  // always return the same address for the same symbol(s) shared amongst
+  // different features.
+  // This QByteArray can then be used as a key for a QMap where the list of
+  // features for this category is stored
+  QByteArray catId;
+  if ( capabilities() & MoreSymbolsPerFeature ) {
+    QgsSymbolV2List syms( mSubRenderer->symbolsForFeature( feature ) );
+    foreach ( QgsSymbolV2* sym, syms )
+    {
+      // append the memory address
+      catId.append( reinterpret_cast<const char*>(&sym), sizeof(sym) );
+    }
+  }
+  else
+  {
+    QgsSymbolV2* sym = mSubRenderer->symbolForFeature( feature );
+    if (sym) {
+      catId.append( reinterpret_cast<const char*>(&sym), sizeof(sym) );
+    }
+  }
+
+  if ( catId.isEmpty() )
+  {
+    return false;
+  }
+
+  // We build here a "reversed" geometry of all the polygons
+  //
+  // The final geometry is a multipolygon F, with :
+  // * the first polygon of F having the current extent as its exterior ring
+  // * each polygon's exterior ring is added as interior ring of the first polygon of F
+  // * each polygon's interior ring is added as new polygons in F
+  //
+  // No validity check is done, on purpose, it will be very slow and painting
+  // operations do not need geometries to be valid
+  if ( ! mFeaturesCategoryMap.contains(catId) )
+  {
+    // the exterior ring must be a square in the destination CRS
+    CombinedFeature cFeat;
+    cFeat.multiPolygon.append( mExtentPolygon );
+    // store the first feature
+    cFeat.feature = feature;
+    mFeaturesCategoryMap.insert( catId, cFeat );
+  }
+
+  // update the gometry
+  CombinedFeature& cFeat = mFeaturesCategoryMap[catId];
+  QgsMultiPolygon multi;
+  QgsGeometry* geom = feature.geometry();
+  if ( !geom )
+  {
+    return false;
+  }
+  if ( (geom->wkbType() == QGis::WKBPolygon) ||
+       (geom->wkbType() == QGis::WKBPolygon25D) ) {
+    multi.append(geom->asPolygon() );
+  }
+  else if ( (geom->wkbType() == QGis::WKBMultiPolygon) ||
+            (geom->wkbType() == QGis::WKBMultiPolygon25D) ) {
+    multi = geom->asMultiPolygon();
+  }
+
+  for ( int i = 0; i < multi.size(); i++ ) {
+    // add the exterior ring as interior ring to the first polygon
+    if ( mTransform ) {
+      QgsPolyline new_ls;
+      QgsPolyline& old_ls = multi[i][0];
+      for ( int k = 0; k < old_ls.size(); k++ ) {
+        new_ls.append( mTransform->transform( old_ls[k] ) );
+      }
+      cFeat.multiPolygon[0].append( new_ls );
+    }
+    else
+    {
+      cFeat.multiPolygon[0].append( multi[i][0] );
+    }
+    // add interior rings as new polygons
+    for ( int j = 1; j < multi[i].size(); j++ ) {
+      QgsPolygon new_poly;
+      if ( mTransform ) {
+        QgsPolyline new_ls;
+        QgsPolyline& old_ls = multi[i][j];
+        for ( int k = 0; k < old_ls.size(); k++ ) {
+          new_ls.append( mTransform->transform( old_ls[k] ) );
+        }
+        new_poly.append( new_ls );
+      }
+      else
+      {
+        new_poly.append( multi[i][j] );
+      }
+
+      cFeat.multiPolygon.append( new_poly );
+    }
+  }
+  return true;
+}
+
+void QgsInvertedPolygonRenderer::stopRender( QgsRenderContext& context )
+{
+  if ( !mSubRenderer ) {
+    return;
+  }
+
+  for ( FeatureCategoryMap::iterator cit = mFeaturesCategoryMap.begin(); cit != mFeaturesCategoryMap.end(); ++cit)
+  {
+    QgsFeature feat( cit.value().feature );
+    feat.setGeometry( QgsGeometry::fromMultiPolygon( cit.value().multiPolygon ) );
+    mSubRenderer->renderFeature( feat, context );
+  }
+
+  // when no features are visible, we still have to draw the exterior rectangle
+  // warning: when sub renderers have more than one possible symbols,
+  // there is no way to choose a correct one, because there is no attribute here
+  // in that case, nothing will be rendered
+  if ( mFeaturesCategoryMap.isEmpty() )
+  {
+    // empty feature with default attributes
+    QgsFeature feat( mFields );
+    feat.setGeometry( QgsGeometry::fromPolygon( mExtentPolygon ) );
+    mSubRenderer->renderFeature( feat, context );
+  }
+
+  // draw feature decorations
+  foreach (FeatureDecoration deco, mFeatureDecorations )
+  {
+    mSubRenderer->renderFeature( deco.feature, context, deco.layer, deco.selected, deco.drawMarkers );
+  }
+
+  mSubRenderer->stopRender( context );
+
+  if ( mTransform )
+  {
+    // restore the coordinate transform if needed
+    context.setCoordinateTransform( mTransform );
+  }
+}
+
+QString QgsInvertedPolygonRenderer::dump() const
+{
+  if ( !mSubRenderer ) {
+    return "INVERTED: NULL";
+  }
+  return "INVERTED [" + mSubRenderer->dump() + "]";
+}
+
+QgsFeatureRendererV2* QgsInvertedPolygonRenderer::clone()
+{
+  if ( mSubRenderer.isNull() )
+  {
+    return new QgsInvertedPolygonRenderer( 0 );
+  }
+  // else
+  return new QgsInvertedPolygonRenderer( mSubRenderer->clone() );
+}
+
+QgsFeatureRendererV2* QgsInvertedPolygonRenderer::create( QDomElement& element )
+{
+  QgsInvertedPolygonRenderer* r = new QgsInvertedPolygonRenderer();
+  //look for an embedded renderer <renderer-v2>
+  QDomElement embeddedRendererElem = element.firstChildElement( "renderer-v2" );
+  if ( !embeddedRendererElem.isNull() )
+  {
+    r->setEmbeddedRenderer( QgsFeatureRendererV2::load( embeddedRendererElem ) );
+  }
+  return r;
+}
+
+QDomElement QgsInvertedPolygonRenderer::save( QDomDocument& doc )
+{
+  QDomElement rendererElem = doc.createElement( RENDERER_TAG_NAME );
+  rendererElem.setAttribute( "type", "invertedPolygonRenderer" );
+
+  if ( mSubRenderer )
+  {
+    QDomElement embeddedRendererElem = mSubRenderer->save( doc );
+    rendererElem.appendChild( embeddedRendererElem );
+  }
+
+  return rendererElem;
+}
+
+QgsSymbolV2* QgsInvertedPolygonRenderer::symbolForFeature( QgsFeature& feature )
+{
+  if ( !mSubRenderer ) {
+    return 0;
+  }
+  return mSubRenderer->symbolForFeature( feature );
+}
+
+QgsSymbolV2List QgsInvertedPolygonRenderer::symbolsForFeature( QgsFeature& feature )
+{
+  if ( !mSubRenderer ) {
+    return QgsSymbolV2List();
+  }
+  return mSubRenderer->symbolsForFeature( feature );
+}
+
+QgsSymbolV2List QgsInvertedPolygonRenderer::symbols()
+{
+  if ( !mSubRenderer ) {
+    return QgsSymbolV2List();
+  }
+  return mSubRenderer->symbols();
+}
+
+int QgsInvertedPolygonRenderer::capabilities()
+{
+  if ( !mSubRenderer ) {
+    return 0;
+  }
+  return mSubRenderer->capabilities();
+}
+
+QList<QString> QgsInvertedPolygonRenderer::usedAttributes()
+{
+  if ( !mSubRenderer ) {
+    return QList<QString>();
+  }
+  return mSubRenderer->usedAttributes();
+}
+
+QgsLegendSymbologyList QgsInvertedPolygonRenderer::legendSymbologyItems( QSize iconSize )
+{
+  if ( !mSubRenderer ) {
+    return QgsLegendSymbologyList();
+  }
+  return mSubRenderer->legendSymbologyItems( iconSize );
+}
+
+QgsLegendSymbolList QgsInvertedPolygonRenderer::legendSymbolItems( double scaleDenominator, QString rule )
+{
+  if ( !mSubRenderer ) {
+    return QgsLegendSymbolList();
+  }
+  return mSubRenderer->legendSymbolItems( scaleDenominator, rule );
+}
+
+bool QgsInvertedPolygonRenderer::willRenderFeature( QgsFeature& feat )
+{
+  if ( !mSubRenderer ) {
+    return false;
+  }
+  return mSubRenderer->willRenderFeature( feat );
+}

src/core/symbology-ng/qgsinvertedpolygonrenderer.h

@@ -0,0 +1,151 @@
+/***************************************************************************
+    qgsinvertedpolygonrenderer.h
+    ---------------------
+    begin                : April 2014
+    copyright            : (C) 2014 Hugo Mercier / Oslandia
+    email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#ifndef QGSINVERTEDPOLYGONRENDERER_H
+#define QGSINVERTEDPOLYGONRENDERER_H
+
+#include "qgis.h"
+#include "qgsrendererv2.h"
+#include "qgssymbolv2.h"
+#include "qgsexpression.h"
+#include "qgsfeature.h"
+#include "qgsgeometry.h"
+#include <QScopedPointer>
+
+/**
+ * QgsInvertedPolygonRenderer is a polygon-only feature renderer used to
+ * display features inverted, where the exterior is turned to an interior
+ * and where the exterior theoretically spans the entire plane, allowing
+ * to mask the surroundings of some features.
+ *
+ * It is designed on top of another feature renderer, which is called "embedded"
+ * Most of the methods are then only proxies to the embedded renderer.
+ * 
+ * Features are collected to form one "inverted" polygon
+ * during renderFeature() and rendered on stopRender().
+ */
+class CORE_EXPORT QgsInvertedPolygonRenderer : public QgsFeatureRendererV2
+{
+  public:
+
+  /** Constructor
+   * @param embeddedRenderer optional embeddedRenderer. If null, a default one will be assigned
+   */
+  QgsInvertedPolygonRenderer( const QgsFeatureRendererV2* embeddedRenderer = 0 );
+  virtual ~QgsInvertedPolygonRenderer();
+
+  /** Used to clone this feature renderer.*/
+  virtual QgsFeatureRendererV2* clone();
+
+  virtual void startRender( QgsRenderContext& context, const QgsFields& fields );
+
+  /** Renders a given feature.
+   * This will here collect features. The actual rendering will be postponed to stopRender()
+   * @param feature the feature to render
+   * @param context the rendering context
+   * @param layer the symbol layer to render, if that makes sense
+   * @param selected whether this feature has been selected (this will add decorations)
+   * @param drawVertexMarker whether this feature has vertex markers (in edit mode usually)
+   * @returns true if the rendering was ok
+   */
+  virtual bool renderFeature( QgsFeature& feature, QgsRenderContext& context, int layer = -1, bool selected = false, bool drawVertexMarker = false );
+
+  /**
+   * The actual rendering will take place here.
+   * Features collected during renderFeature() are rendered using the embedded feature renderer
+   */
+  virtual void stopRender( QgsRenderContext& context );
+
+  /** @returns a textual reprensation of the renderer */
+  virtual QString dump() const;
+
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QList<QString> usedAttributes();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual int capabilities();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2List symbols();
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2* symbolForFeature( QgsFeature& feature );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsLegendSymbologyList legendSymbologyItems( QSize iconSize );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual QgsLegendSymbolList legendSymbolItems( double scaleDenominator = -1, QString rule = "" );
+  /** Proxy that will call this method on the embedded renderer. */
+  virtual bool willRenderFeature( QgsFeature& feat );
+
+  /** Creates a renderer out of an XML, for loading*/
+  static QgsFeatureRendererV2* create( QDomElement& element );
+
+  /** Creates an XML representation of the renderer. Used for saving purpose
+   * @param doc the XML document where to create the XML subtree
+   * @returns the created XML subtree
+   */
+  virtual QDomElement save( QDomDocument& doc );
+
+  /** sets the embedded renderer
+   * @param subRenderer the embedded renderer (will be cloned)
+   */
+  void setEmbeddedRenderer( const QgsFeatureRendererV2* subRenderer );
+  /** @returns the current embedded renderer
+   */
+  const QgsFeatureRendererV2* embeddedRenderer() const;
+
+ private:
+  /** Private copy constructor. @see clone() */
+  QgsInvertedPolygonRenderer( const QgsInvertedPolygonRenderer& );
+  /** Private assignment operator. @see clone() */
+  QgsInvertedPolygonRenderer& operator=( const QgsInvertedPolygonRenderer& );
+
+  /** Embedded renderer */
+  QScopedPointer<QgsFeatureRendererV2> mSubRenderer;
+
+  /** Structure where the reversed geometry is built during renderFeature */
+  struct CombinedFeature
+  {
+    QgsMultiPolygon multiPolygon; //< the final combined geometry
+    QgsFeature feature;           //< one feature (for attriute-based rendering)
+  };
+  typedef QMap< QByteArray, CombinedFeature > FeatureCategoryMap;
+  /** where features are stored, based on their symbol category */
+  FeatureCategoryMap mFeaturesCategoryMap;
+
+  /** the polygon used as exterior ring that covers the current extent */
+  QgsPolygon mExtentPolygon;
+
+  /** the current coordinate transform (or null) */
+  const QgsCoordinateTransform* mTransform;
+
+  /** fields of each feature*/
+  QgsFields mFields;
+
+  /** Class used to represent features that must be rendered
+      with decorations (selection, vertex markers)
+  */
+  struct FeatureDecoration
+  {
+    QgsFeature feature;
+    bool selected;
+    bool drawMarkers;
+    int layer;
+  FeatureDecoration( QgsFeature& a_feature, bool a_selected, bool a_drawMarkers, int a_layer ) :
+    feature(a_feature),selected(a_selected), drawMarkers(a_drawMarkers), layer(a_layer) {}
+  };
+  QList<FeatureDecoration> mFeatureDecorations;
+};
+
+
+#endif // QGSMASKRENDERERV2_H

src/core/symbology-ng/qgsrendererv2registry.cpp

@@ -20,6 +20,7 @@
 #include "qgsgraduatedsymbolrendererv2.h"
 #include "qgsrulebasedrendererv2.h"
 #include "qgspointdisplacementrenderer.h"
+#include "qgsinvertedpolygonrenderer.h"
 
 QgsRendererV2Registry::QgsRendererV2Registry()
 {
@@ -44,6 +45,10 @@ QgsRendererV2Registry::QgsRendererV2Registry()
   addRenderer( new QgsRendererV2Metadata( "pointDisplacement",
                                           QObject::tr( "Point displacement" ),
                                           QgsPointDisplacementRenderer::create ) );
+
+  addRenderer( new QgsRendererV2Metadata( "invertedPolygonRenderer",
+                                          QObject::tr( "Inverted polygons" ),
+                                          QgsInvertedPolygonRenderer::create ) );
 }
 
 QgsRendererV2Registry::~QgsRendererV2Registry()

src/gui/CMakeLists.txt

@@ -20,6 +20,7 @@ symbology-ng/qgssinglesymbolrendererv2widget.cpp
 symbology-ng/qgscategorizedsymbolrendererv2widget.cpp
 symbology-ng/qgsgraduatedsymbolrendererv2widget.cpp
 symbology-ng/qgsrulebasedrendererv2widget.cpp
+symbology-ng/qgsinvertedpolygonrendererwidget.cpp
 symbology-ng/qgsrendererv2propertiesdialog.cpp
 symbology-ng/qgsstylev2managerdialog.cpp
 symbology-ng/qgssymbollevelsv2dialog.cpp
@@ -231,6 +232,7 @@ symbology-ng/qgscategorizedsymbolrendererv2widget.h
 symbology-ng/qgsdatadefinedsymboldialog.h
 symbology-ng/qgsgraduatedsymbolrendererv2widget.h
 symbology-ng/qgsrulebasedrendererv2widget.h
+symbology-ng/qgsinvertedpolygonrendererwidget.h
 symbology-ng/qgsrendererv2widget.h
 symbology-ng/qgsrendererv2propertiesdialog.h
 symbology-ng/qgsstylev2managerdialog.h

src/gui/symbology-ng/qgsinvertedpolygonrendererwidget.cpp

@@ -0,0 +1,132 @@
+/***************************************************************************
+    qgsinvertedpolygonrendererwidget.cpp
+    ---------------------
+    begin                : April 2014
+    copyright            : (C) 2014 Hugo Mercier / Oslandia
+    email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#include "qgsinvertedpolygonrendererwidget.h"
+#include "qgsinvertedpolygonrenderer.h"
+#include "qgsrendererv2registry.h"
+
+#include "qgssymbolv2.h"
+
+#include "qgslogger.h"
+#include "qgsvectorlayer.h"
+
+QgsRendererV2Widget* QgsInvertedPolygonRendererWidget::create( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer )
+{
+  return new QgsInvertedPolygonRendererWidget( layer, style, renderer );
+}
+
+QgsInvertedPolygonRendererWidget::QgsInvertedPolygonRendererWidget( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer )
+    : QgsRendererV2Widget( layer, style )
+{
+  if ( !layer ) {
+    return;
+  }
+
+  // the renderer only applies to polygon vector layers
+  if ( layer->wkbType() != QGis::WKBPolygon &&
+       layer->wkbType() != QGis::WKBPolygon25D &&
+       layer->wkbType() != QGis::WKBMultiPolygon &&
+       layer->wkbType() != QGis::WKBMultiPolygon25D )
+  {
+    //setup blank dialog
+    mRenderer.reset( 0 );
+    QGridLayout* layout = new QGridLayout( this );
+    QLabel* label = new QLabel( tr( "The inverted polygon renderer only applies to polygon and multipolygon layers. \n"
+                                    "'%1' is not a polygon layer and then cannot be displayed" )
+                                .arg( layer->name() ), this );
+    layout->addWidget( label );
+    return;
+  }
+  setupUi( this );
+
+  // try to recognize the previous renderer
+  // (null renderer means "no previous renderer")
+  if ( !renderer )
+  {
+    // a new renderer
+    mRenderer.reset( new QgsInvertedPolygonRenderer() );
+  }
+  else if ( renderer && renderer->type() != "invertedPolygonRenderer" )
+  {
+    // an existing renderer, but not an inverted renderer
+    // create an inverted renderer, with the existing renderer embedded
+    mRenderer.reset( new QgsInvertedPolygonRenderer( renderer ) );
+  }
+  else
+  {
+    // an existing inverted renderer
+    mRenderer.reset( static_cast<QgsInvertedPolygonRenderer*>(renderer) );
+  }
+
+  int currentEmbeddedIdx = 0;
+  //insert possible renderer types
+  QStringList rendererList = QgsRendererV2Registry::instance()->renderersList();
+  QStringList::const_iterator it = rendererList.constBegin();
+  int idx = 0;
+  mRendererComboBox->blockSignals( true );
+  for ( ; it != rendererList.constEnd(); ++it, ++idx )
+  {
+    if (( *it != "invertedPolygonRenderer" ) && //< an inverted renderer cannot contain another inverted renderer
+        ( *it != "pointDisplacement" ))         //< an inverted renderer can only contain a polygon renderer
+    {
+      QgsRendererV2AbstractMetadata* m = QgsRendererV2Registry::instance()->rendererMetadata( *it );
+      mRendererComboBox->addItem( m->icon(), m->visibleName(), /* data */ *it );
+      const QgsFeatureRendererV2* embeddedRenderer = mRenderer->embeddedRenderer();
+      if ( embeddedRenderer && embeddedRenderer->type() == m->name() )
+      {
+        // store the combo box index of the current renderer
+        currentEmbeddedIdx = idx;
+      }
+    }
+  }
+  mRendererComboBox->blockSignals( false );
+
+  int oldIdx = mRendererComboBox->currentIndex();
+  mRendererComboBox->setCurrentIndex( currentEmbeddedIdx );
+  if ( oldIdx == currentEmbeddedIdx )
+  {
+    // force update
+    on_mRendererComboBox_currentIndexChanged( currentEmbeddedIdx );
+  }
+}
+
+QgsFeatureRendererV2* QgsInvertedPolygonRendererWidget::renderer()
+{
+  if ( mRenderer && mEmbeddedRendererWidget )
+  {
+    QgsFeatureRendererV2* embeddedRenderer = mEmbeddedRendererWidget->renderer();
+    if ( embeddedRenderer )
+    {
+      mRenderer->setEmbeddedRenderer( embeddedRenderer->clone() );
+    }
+  }
+  return mRenderer.data();
+}
+
+void QgsInvertedPolygonRendererWidget::on_mRendererComboBox_currentIndexChanged( int index )
+{
+  QString rendererId = mRendererComboBox->itemData( index ).toString();
+  QgsRendererV2AbstractMetadata* m = QgsRendererV2Registry::instance()->rendererMetadata( rendererId );
+  if ( m )
+  {
+    mEmbeddedRendererWidget.reset( m->createRendererWidget( mLayer, mStyle, const_cast<QgsFeatureRendererV2*>(mRenderer->embeddedRenderer())->clone() ) );
+
+    if ( mLayout->count() > 1 ) {
+      // remove the current renderer widget
+      mLayout->takeAt( 1 );
+    }
+    mLayout->addWidget( mEmbeddedRendererWidget.data() );
+  }
+}
+

src/gui/symbology-ng/qgsinvertedpolygonrendererwidget.h

@@ -0,0 +1,60 @@
+/***************************************************************************
+    qgsinvertedpolygonrendererwidget.h
+    ---------------------
+    begin                : April 2014
+    copyright            : (C) 2014 Hugo Mercier / Oslandia
+    email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#ifndef QGSINVERTEDPOLYGONRENDERERWIDGET_H
+#define QGSINVERTEDPOLYGONRENDERERWIDGET_H
+
+#include "ui_qgsinvertedpolygonrendererwidgetbase.h"
+#include "qgsinvertedpolygonrenderer.h"
+#include "qgsrendererv2widget.h"
+
+class QMenu;
+
+/**
+ * A widget used represent options of a QgsInvertedPolygonRenderer
+ */
+class GUI_EXPORT QgsInvertedPolygonRendererWidget : public QgsRendererV2Widget, private Ui::QgsInvertedPolygonRendererWidgetBase
+{
+  Q_OBJECT
+
+ public:
+  /** static creation method
+   * @param layer the layer where this renderer is applied
+   * @param style
+   * @param renderer the mask renderer (will take ownership)
+   */
+  static QgsRendererV2Widget* create( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer );
+
+  /** Constructor
+   * @param layer the layer where this renderer is applied
+   * @param style
+   * @param renderer the mask renderer (will take ownership)
+   */
+  QgsInvertedPolygonRendererWidget( QgsVectorLayer* layer, QgsStyleV2* style, QgsFeatureRendererV2* renderer );
+
+  /** @returns the current feature renderer */
+  virtual QgsFeatureRendererV2* renderer();
+
+ protected:
+  /** the mask renderer */
+  QScopedPointer<QgsInvertedPolygonRenderer> mRenderer;
+  /** the widget used to represent the mask's embedded renderer */
+  QScopedPointer<QgsRendererV2Widget> mEmbeddedRendererWidget;
+
+ private slots:
+  void on_mRendererComboBox_currentIndexChanged( int index );
+};
+
+
+#endif // QGSMASKRENDERERV2WIDGET_H

src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp

@@ -23,6 +23,7 @@
 #include "qgsgraduatedsymbolrendererv2widget.h"
 #include "qgsrulebasedrendererv2widget.h"
 #include "qgspointdisplacementrendererwidget.h"
+#include "qgsinvertedpolygonrendererwidget.h"
 
 #include "qgsapplication.h"
 #include "qgslogger.h"
@@ -66,6 +67,7 @@ static void _initRendererWidgetFunctions()
   _initRenderer( "graduatedSymbol", QgsGraduatedSymbolRendererV2Widget::create, "rendererGraduatedSymbol.png" );
   _initRenderer( "RuleRenderer", QgsRuleBasedRendererV2Widget::create );
   _initRenderer( "pointDisplacement", QgsPointDisplacementRendererWidget::create );
+  _initRenderer( "invertedPolygonRenderer", QgsInvertedPolygonRendererWidget::create );
   initialized = true;
 }
 

src/ui/qgsinvertedpolygonrendererwidgetbase.ui

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>QgsInvertedPolygonRendererWidgetBase</class>
+ <widget class="QWidget" name="QgsInvertedPolygonRendererWidgetBase">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>390</width>
+    <height>79</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QVBoxLayout" name="mLayout">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <item>
+      <widget class="QLabel" name="mRendererLabel">
+       <property name="text">
+        <string>Sub renderer:</string>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="QComboBox" name="mRendererComboBox"/>
+     </item>
+    </layout>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

tests/src/core/CMakeLists.txt

@@ -121,3 +121,4 @@ ADD_QGIS_TEST(vectorlayercachetest testqgsvectorlayercache.cpp )
 ADD_QGIS_TEST(spatialindextest testqgsspatialindex.cpp)
 ADD_QGIS_TEST(gradienttest testqgsgradients.cpp )
 ADD_QGIS_TEST(shapebursttest testqgsshapeburst.cpp )
+ADD_QGIS_TEST(invertedpolygontest testqgsinvertedpolygonrenderer.cpp )

tests/src/core/testqgsinvertedpolygonrenderer.cpp

@@ -0,0 +1,152 @@
+/***************************************************************************
+     testqgsinvertedpolygonrenderer.cpp
+     --------------------------------------
+    Date                 : 23 may 2014
+    Copyright            : (C) 2014 by Hugo Mercier / Oslandia
+    Email                : hugo dot mercier at oslandia dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+#include <QtTest>
+#include <QObject>
+#include <QString>
+#include <QStringList>
+#include <QObject>
+#include <QApplication>
+#include <QFileInfo>
+#include <QDir>
+#include <QDesktopServices>
+
+#include <iostream>
+//qgis includes...
+#include <qgsmaprenderer.h>
+#include <qgsmaplayer.h>
+#include <qgsvectorlayer.h>
+#include <qgsapplication.h>
+#include <qgsproviderregistry.h>
+#include <qgsmaplayerregistry.h>
+//qgis test includes
+#include "qgsrenderchecker.h"
+
+/** \ingroup UnitTests
+ * This is a unit test for the different renderers for vector layers.
+ */
+class TestQgsInvertedPolygon: public QObject
+{
+    Q_OBJECT;
+  private slots:
+    void initTestCase();// will be called before the first testfunction is executed.
+    void cleanupTestCase();// will be called after the last testfunction was executed.
+    void init() {};// will be called before each testfunction is executed.
+    void cleanup() {};// will be called after every testfunction.
+
+    void singleSubRenderer();
+    void graduatedSubRenderer();
+
+  private:
+    bool mTestHasError;
+    bool setQml( QString qmlFile );
+    bool imageCheck( QString theType );
+    QgsMapSettings mMapSettings;
+    QgsVectorLayer * mpPolysLayer;
+    QString mTestDataDir;
+    QString mReport;
+};
+
+
+void TestQgsInvertedPolygon::initTestCase()
+{
+  mTestHasError = false;
+  // init QGIS's paths - true means that all path will be inited from prefix
+  QgsApplication::init();
+  QgsApplication::initQgis();
+  QgsApplication::showSettings();
+
+  QString myDataDir( TEST_DATA_DIR ); //defined in CmakeLists.txt
+  mTestDataDir = myDataDir + QDir::separator();
+
+  //
+  //create a poly layer that will be used in all tests...
+  //
+  QString myPolysFileName = mTestDataDir + "polys.shp";
+  QFileInfo myPolyFileInfo( myPolysFileName );
+  mpPolysLayer = new QgsVectorLayer( myPolyFileInfo.filePath(),
+                                     myPolyFileInfo.completeBaseName(), "ogr" );
+  QgsVectorSimplifyMethod simplifyMethod;
+  simplifyMethod.setSimplifyHints( QgsVectorSimplifyMethod::NoSimplification );
+  mpPolysLayer->setSimplifyMethod( simplifyMethod );
+
+  // Register the layer with the registry
+  QgsMapLayerRegistry::instance()->addMapLayers(
+    QList<QgsMapLayer *>() << mpPolysLayer );
+
+  mMapSettings.setLayers( QStringList() << mpPolysLayer->id() );
+  mReport += "<h1>Inverted Polygon Renderer Tests</h1>\n";
+}
+
+void TestQgsInvertedPolygon::cleanupTestCase()
+{
+  QString myReportFile = QDir::tempPath() + QDir::separator() + "qgistest.html";
+  QFile myFile( myReportFile );
+  if ( myFile.open( QIODevice::WriteOnly | QIODevice::Append ) )
+  {
+    QTextStream myQTextStream( &myFile );
+    myQTextStream << mReport;
+    myFile.close();
+  }
+}
+
+void TestQgsInvertedPolygon::singleSubRenderer()
+{
+  mReport += "<h2>Inverted polygon renderer, single sub renderer test</h2>\n";
+  QVERIFY( setQml( "inverted_polys_single.qml" ) );
+  QVERIFY( imageCheck( "inverted_polys_single" ) );
+}
+
+void TestQgsInvertedPolygon::graduatedSubRenderer()
+{
+  mReport += "<h2>Inverted polygon renderer, graduated sub renderer test</h2>\n";
+  QVERIFY( setQml( "inverted_polys_graduated.qml" ) );
+  QVERIFY( imageCheck( "inverted_polys_graduated" ) );
+}
+
+//
+// Private helper functions not called directly by CTest
+//
+
+bool TestQgsInvertedPolygon::setQml( QString qmlFile )
+{
+  //load a qml style and apply to our layer
+  //the style will correspond to the renderer
+  //type we are testing
+  bool myStyleFlag = false;
+  QString myFileName = mTestDataDir + qmlFile;
+  QString error = mpPolysLayer->loadNamedStyle( myFileName, myStyleFlag );
+  if ( !myStyleFlag )
+  {
+    qDebug( "%s", error.toLocal8Bit().constData() );
+    return false;
+  }
+  return myStyleFlag;
+}
+
+bool TestQgsInvertedPolygon::imageCheck( QString theTestType )
+{
+  //use the QgsRenderChecker test utility class to
+  //ensure the rendered output matches our control image
+  mMapSettings.setExtent( mpPolysLayer->extent() );
+  QgsRenderChecker myChecker;
+  myChecker.setControlName( "expected_" + theTestType );
+  myChecker.setMapSettings( mMapSettings );
+  bool myResultFlag = myChecker.runTest( theTestType );
+  mReport += myChecker.report();
+  return myResultFlag;
+}
+
+QTEST_MAIN( TestQgsInvertedPolygon )
+#include "moc_testqgsinvertedpolygonrenderer.cxx"

tests/testdata/inverted_polys_graduated.qml

@@ -0,0 +1,228 @@
+<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
+<qgis version="2.3.0-Master" minimumScale="1" maximumScale="1e+08" simplifyDrawingHints="1" minLabelScale="1" maxLabelScale="1e+08" simplifyDrawingTol="1" simplifyMaxScale="1" hasScaleBasedVisibilityFlag="0" simplifyLocal="1" scaleBasedLabelVisibilityFlag="0">
+  <renderer-v2 type="invertedPolygonRenderer">
+    <renderer-v2 attr="Name" symbollevels="0" type="categorizedSymbol">
+      <categories>
+        <category symbol="0" value="Dam" label="Dam"/>
+        <category symbol="1" value="Lake" label="Lake"/>
+      </categories>
+      <symbols>
+        <symbol alpha="1" type="fill" name="0">
+          <layer pass="0" class="ShapeburstFill" locked="0">
+            <prop k="blur_radius" v="0"/>
+            <prop k="color1" v="0,0,255,255"/>
+            <prop k="color2" v="0,255,0,255"/>
+            <prop k="color_type" v="0"/>
+            <prop k="discrete" v="0"/>
+            <prop k="distance_map_unit_scale" v="0,0"/>
+            <prop k="distance_unit" v="MM"/>
+            <prop k="ignore_rings" v="0"/>
+            <prop k="max_distance" v="5"/>
+            <prop k="offset" v="0,0"/>
+            <prop k="offset_map_unit_scale" v="0,0"/>
+            <prop k="offset_unit" v="MM"/>
+            <prop k="shapeburst_color" v="27,54,212,255"/>
+            <prop k="shapeburst_color2" v="255,255,255,0"/>
+            <prop k="use_whole_shape" v="0"/>
+          </layer>
+        </symbol>
+        <symbol alpha="1" type="fill" name="1">
+          <layer pass="0" class="ShapeburstFill" locked="0">
+            <prop k="blur_radius" v="0"/>
+            <prop k="color1" v="0,0,255,255"/>
+            <prop k="color2" v="0,255,0,255"/>
+            <prop k="color_type" v="0"/>
+            <prop k="discrete" v="0"/>
+            <prop k="distance_map_unit_scale" v="0,0"/>
+            <prop k="distance_unit" v="MM"/>
+            <prop k="ignore_rings" v="0"/>
+            <prop k="max_distance" v="5"/>
+            <prop k="offset" v="0,0"/>
+            <prop k="offset_map_unit_scale" v="0,0"/>
+            <prop k="offset_unit" v="MM"/>
+            <prop k="shapeburst_color" v="110,194,217,255"/>
+            <prop k="shapeburst_color2" v="255,255,255,0"/>
+            <prop k="use_whole_shape" v="0"/>
+          </layer>
+        </symbol>
+      </symbols>
+      <rotation/>
+      <sizescale scalemethod="area"/>
+    </renderer-v2>
+  </renderer-v2>
+  <customproperties>
+    <property key="labeling" value="pal"/>
+    <property key="labeling/addDirectionSymbol" value="false"/>
+    <property key="labeling/angleOffset" value="0"/>
+    <property key="labeling/blendMode" value="0"/>
+    <property key="labeling/bufferBlendMode" value="0"/>
+    <property key="labeling/bufferColorA" value="255"/>
+    <property key="labeling/bufferColorB" value="255"/>
+    <property key="labeling/bufferColorG" value="255"/>
+    <property key="labeling/bufferColorR" value="255"/>
+    <property key="labeling/bufferDraw" value="false"/>
+    <property key="labeling/bufferJoinStyle" value="64"/>
+    <property key="labeling/bufferNoFill" value="false"/>
+    <property key="labeling/bufferSize" value="1"/>
+    <property key="labeling/bufferSizeInMapUnits" value="false"/>
+    <property key="labeling/bufferSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/bufferSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/bufferTransp" value="0"/>
+    <property key="labeling/centroidWhole" value="false"/>
+    <property key="labeling/decimals" value="3"/>
+    <property key="labeling/displayAll" value="false"/>
+    <property key="labeling/dist" value="0"/>
+    <property key="labeling/distInMapUnits" value="false"/>
+    <property key="labeling/distMapUnitMaxScale" value="0"/>
+    <property key="labeling/distMapUnitMinScale" value="0"/>
+    <property key="labeling/enabled" value="false"/>
+    <property key="labeling/fieldName" value=""/>
+    <property key="labeling/fontBold" value="true"/>
+    <property key="labeling/fontCapitals" value="0"/>
+    <property key="labeling/fontFamily" value="Ubuntu"/>
+    <property key="labeling/fontItalic" value="true"/>
+    <property key="labeling/fontLetterSpacing" value="0"/>
+    <property key="labeling/fontLimitPixelSize" value="false"/>
+    <property key="labeling/fontMaxPixelSize" value="10000"/>
+    <property key="labeling/fontMinPixelSize" value="3"/>
+    <property key="labeling/fontSize" value="11"/>
+    <property key="labeling/fontSizeInMapUnits" value="false"/>
+    <property key="labeling/fontSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/fontSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/fontStrikeout" value="false"/>
+    <property key="labeling/fontUnderline" value="false"/>
+    <property key="labeling/fontWeight" value="75"/>
+    <property key="labeling/fontWordSpacing" value="0"/>
+    <property key="labeling/formatNumbers" value="false"/>
+    <property key="labeling/isExpression" value="false"/>
+    <property key="labeling/labelOffsetInMapUnits" value="true"/>
+    <property key="labeling/labelOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/labelOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/labelPerPart" value="false"/>
+    <property key="labeling/leftDirectionSymbol" value="&lt;"/>
+    <property key="labeling/limitNumLabels" value="false"/>
+    <property key="labeling/maxCurvedCharAngleIn" value="20"/>
+    <property key="labeling/maxCurvedCharAngleOut" value="-20"/>
+    <property key="labeling/maxNumLabels" value="2000"/>
+    <property key="labeling/mergeLines" value="false"/>
+    <property key="labeling/minFeatureSize" value="0"/>
+    <property key="labeling/multilineAlign" value="0"/>
+    <property key="labeling/multilineHeight" value="1"/>
+    <property key="labeling/namedStyle" value="Bold Italic"/>
+    <property key="labeling/obstacle" value="true"/>
+    <property key="labeling/placeDirectionSymbol" value="0"/>
+    <property key="labeling/placement" value="0"/>
+    <property key="labeling/placementFlags" value="0"/>
+    <property key="labeling/plussign" value="false"/>
+    <property key="labeling/preserveRotation" value="true"/>
+    <property key="labeling/previewBkgrdColor" value="#ffffff"/>
+    <property key="labeling/priority" value="5"/>
+    <property key="labeling/quadOffset" value="4"/>
+    <property key="labeling/reverseDirectionSymbol" value="false"/>
+    <property key="labeling/rightDirectionSymbol" value=">"/>
+    <property key="labeling/scaleMax" value="10000000"/>
+    <property key="labeling/scaleMin" value="1"/>
+    <property key="labeling/scaleVisibility" value="false"/>
+    <property key="labeling/shadowBlendMode" value="6"/>
+    <property key="labeling/shadowColorB" value="0"/>
+    <property key="labeling/shadowColorG" value="0"/>
+    <property key="labeling/shadowColorR" value="0"/>
+    <property key="labeling/shadowDraw" value="false"/>
+    <property key="labeling/shadowOffsetAngle" value="135"/>
+    <property key="labeling/shadowOffsetDist" value="1"/>
+    <property key="labeling/shadowOffsetGlobal" value="true"/>
+    <property key="labeling/shadowOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/shadowOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/shadowOffsetUnits" value="1"/>
+    <property key="labeling/shadowRadius" value="1.5"/>
+    <property key="labeling/shadowRadiusAlphaOnly" value="false"/>
+    <property key="labeling/shadowRadiusMapUnitMaxScale" value="0"/>
+    <property key="labeling/shadowRadiusMapUnitMinScale" value="0"/>
+    <property key="labeling/shadowRadiusUnits" value="1"/>
+    <property key="labeling/shadowScale" value="100"/>
+    <property key="labeling/shadowTransparency" value="30"/>
+    <property key="labeling/shadowUnder" value="0"/>
+    <property key="labeling/shapeBlendMode" value="0"/>
+    <property key="labeling/shapeBorderColorA" value="255"/>
+    <property key="labeling/shapeBorderColorB" value="128"/>
+    <property key="labeling/shapeBorderColorG" value="128"/>
+    <property key="labeling/shapeBorderColorR" value="128"/>
+    <property key="labeling/shapeBorderWidth" value="0"/>
+    <property key="labeling/shapeBorderWidthMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeBorderWidthMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeBorderWidthUnits" value="1"/>
+    <property key="labeling/shapeDraw" value="false"/>
+    <property key="labeling/shapeFillColorA" value="255"/>
+    <property key="labeling/shapeFillColorB" value="255"/>
+    <property key="labeling/shapeFillColorG" value="255"/>
+    <property key="labeling/shapeFillColorR" value="255"/>
+    <property key="labeling/shapeJoinStyle" value="64"/>
+    <property key="labeling/shapeOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeOffsetUnits" value="1"/>
+    <property key="labeling/shapeOffsetX" value="0"/>
+    <property key="labeling/shapeOffsetY" value="0"/>
+    <property key="labeling/shapeRadiiMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeRadiiMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeRadiiUnits" value="1"/>
+    <property key="labeling/shapeRadiiX" value="0"/>
+    <property key="labeling/shapeRadiiY" value="0"/>
+    <property key="labeling/shapeRotation" value="0"/>
+    <property key="labeling/shapeRotationType" value="0"/>
+    <property key="labeling/shapeSVGFile" value=""/>
+    <property key="labeling/shapeSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeSizeType" value="0"/>
+    <property key="labeling/shapeSizeUnits" value="1"/>
+    <property key="labeling/shapeSizeX" value="0"/>
+    <property key="labeling/shapeSizeY" value="0"/>
+    <property key="labeling/shapeTransparency" value="0"/>
+    <property key="labeling/shapeType" value="0"/>
+    <property key="labeling/textColorA" value="255"/>
+    <property key="labeling/textColorB" value="0"/>
+    <property key="labeling/textColorG" value="0"/>
+    <property key="labeling/textColorR" value="0"/>
+    <property key="labeling/textTransp" value="0"/>
+    <property key="labeling/upsidedownLabels" value="0"/>
+    <property key="labeling/wrapChar" value=""/>
+    <property key="labeling/xOffset" value="0"/>
+    <property key="labeling/yOffset" value="0"/>
+  </customproperties>
+  <blendMode>0</blendMode>
+  <featureBlendMode>0</featureBlendMode>
+  <layerTransparency>0</layerTransparency>
+  <displayfield>Name</displayfield>
+  <label>0</label>
+  <labelattributes>
+    <label fieldname="" text="Label"/>
+    <family fieldname="" name="Lucida Grande"/>
+    <size fieldname="" units="pt" value="12"/>
+    <bold fieldname="" on="0"/>
+    <italic fieldname="" on="0"/>
+    <underline fieldname="" on="0"/>
+    <strikeout fieldname="" on="0"/>
+    <color fieldname="" red="0" blue="0" green="0"/>
+    <x fieldname=""/>
+    <y fieldname=""/>
+    <offset x="0" y="0" units="pt" yfieldname="" xfieldname=""/>
+    <angle fieldname="" value="0" auto="0"/>
+    <alignment fieldname="" value="center"/>
+    <buffercolor fieldname="" red="255" blue="255" green="255"/>
+    <buffersize fieldname="" units="pt" value="1"/>
+    <bufferenabled fieldname="" on=""/>
+    <multilineenabled fieldname="" on=""/>
+    <selectedonly on=""/>
+  </labelattributes>
+  <edittypes>
+    <edittype labelontop="0" editable="1" type="0" name="Name"/>
+    <edittype labelontop="0" editable="1" type="0" name="Value"/>
+  </edittypes>
+  <editform></editform>
+  <editforminit></editforminit>
+  <featformsuppress>0</featformsuppress>
+  <annotationform></annotationform>
+  <editorlayout>generatedlayout</editorlayout>
+  <excludeAttributesWMS/>
+  <excludeAttributesWFS/>
+  <attributeactions/>
+</qgis>

tests/testdata/inverted_polys_single.qml

@@ -0,0 +1,201 @@
+<!DOCTYPE qgis PUBLIC 'http://mrcc.com/qgis.dtd' 'SYSTEM'>
+<qgis version="2.3.0-Master" minimumScale="1" maximumScale="1e+08" simplifyDrawingHints="1" minLabelScale="1" maxLabelScale="1e+08" simplifyDrawingTol="1" simplifyMaxScale="1" hasScaleBasedVisibilityFlag="0" simplifyLocal="1" scaleBasedLabelVisibilityFlag="0">
+  <renderer-v2 type="invertedPolygonRenderer">
+    <renderer-v2 symbollevels="0" type="singleSymbol">
+      <symbols>
+        <symbol alpha="1" type="fill" name="0">
+          <layer pass="0" class="SimpleFill" locked="0">
+            <prop k="border_width_map_unit_scale" v="0,0"/>
+            <prop k="border_width_unit" v="MM"/>
+            <prop k="color" v="76,143,160,255"/>
+            <prop k="color_border" v="0,0,0,255"/>
+            <prop k="joinstyle" v="bevel"/>
+            <prop k="offset" v="0,0"/>
+            <prop k="offset_map_unit_scale" v="0,0"/>
+            <prop k="offset_unit" v="MM"/>
+            <prop k="style" v="solid"/>
+            <prop k="style_border" v="solid"/>
+            <prop k="width_border" v="0.26"/>
+          </layer>
+        </symbol>
+      </symbols>
+      <rotation/>
+      <sizescale scalemethod="area"/>
+    </renderer-v2>
+  </renderer-v2>
+  <customproperties>
+    <property key="labeling" value="pal"/>
+    <property key="labeling/addDirectionSymbol" value="false"/>
+    <property key="labeling/angleOffset" value="0"/>
+    <property key="labeling/blendMode" value="0"/>
+    <property key="labeling/bufferBlendMode" value="0"/>
+    <property key="labeling/bufferColorA" value="255"/>
+    <property key="labeling/bufferColorB" value="255"/>
+    <property key="labeling/bufferColorG" value="255"/>
+    <property key="labeling/bufferColorR" value="255"/>
+    <property key="labeling/bufferDraw" value="false"/>
+    <property key="labeling/bufferJoinStyle" value="64"/>
+    <property key="labeling/bufferNoFill" value="false"/>
+    <property key="labeling/bufferSize" value="1"/>
+    <property key="labeling/bufferSizeInMapUnits" value="false"/>
+    <property key="labeling/bufferSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/bufferSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/bufferTransp" value="0"/>
+    <property key="labeling/centroidWhole" value="false"/>
+    <property key="labeling/decimals" value="3"/>
+    <property key="labeling/displayAll" value="false"/>
+    <property key="labeling/dist" value="0"/>
+    <property key="labeling/distInMapUnits" value="false"/>
+    <property key="labeling/distMapUnitMaxScale" value="0"/>
+    <property key="labeling/distMapUnitMinScale" value="0"/>
+    <property key="labeling/enabled" value="false"/>
+    <property key="labeling/fieldName" value=""/>
+    <property key="labeling/fontBold" value="true"/>
+    <property key="labeling/fontCapitals" value="0"/>
+    <property key="labeling/fontFamily" value="Ubuntu"/>
+    <property key="labeling/fontItalic" value="true"/>
+    <property key="labeling/fontLetterSpacing" value="0"/>
+    <property key="labeling/fontLimitPixelSize" value="false"/>
+    <property key="labeling/fontMaxPixelSize" value="10000"/>
+    <property key="labeling/fontMinPixelSize" value="3"/>
+    <property key="labeling/fontSize" value="11"/>
+    <property key="labeling/fontSizeInMapUnits" value="false"/>
+    <property key="labeling/fontSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/fontSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/fontStrikeout" value="false"/>
+    <property key="labeling/fontUnderline" value="false"/>
+    <property key="labeling/fontWeight" value="75"/>
+    <property key="labeling/fontWordSpacing" value="0"/>
+    <property key="labeling/formatNumbers" value="false"/>
+    <property key="labeling/isExpression" value="false"/>
+    <property key="labeling/labelOffsetInMapUnits" value="true"/>
+    <property key="labeling/labelOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/labelOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/labelPerPart" value="false"/>
+    <property key="labeling/leftDirectionSymbol" value="&lt;"/>
+    <property key="labeling/limitNumLabels" value="false"/>
+    <property key="labeling/maxCurvedCharAngleIn" value="20"/>
+    <property key="labeling/maxCurvedCharAngleOut" value="-20"/>
+    <property key="labeling/maxNumLabels" value="2000"/>
+    <property key="labeling/mergeLines" value="false"/>
+    <property key="labeling/minFeatureSize" value="0"/>
+    <property key="labeling/multilineAlign" value="0"/>
+    <property key="labeling/multilineHeight" value="1"/>
+    <property key="labeling/namedStyle" value="Bold Italic"/>
+    <property key="labeling/obstacle" value="true"/>
+    <property key="labeling/placeDirectionSymbol" value="0"/>
+    <property key="labeling/placement" value="0"/>
+    <property key="labeling/placementFlags" value="0"/>
+    <property key="labeling/plussign" value="false"/>
+    <property key="labeling/preserveRotation" value="true"/>
+    <property key="labeling/previewBkgrdColor" value="#ffffff"/>
+    <property key="labeling/priority" value="5"/>
+    <property key="labeling/quadOffset" value="4"/>
+    <property key="labeling/reverseDirectionSymbol" value="false"/>
+    <property key="labeling/rightDirectionSymbol" value=">"/>
+    <property key="labeling/scaleMax" value="10000000"/>
+    <property key="labeling/scaleMin" value="1"/>
+    <property key="labeling/scaleVisibility" value="false"/>
+    <property key="labeling/shadowBlendMode" value="6"/>
+    <property key="labeling/shadowColorB" value="0"/>
+    <property key="labeling/shadowColorG" value="0"/>
+    <property key="labeling/shadowColorR" value="0"/>
+    <property key="labeling/shadowDraw" value="false"/>
+    <property key="labeling/shadowOffsetAngle" value="135"/>
+    <property key="labeling/shadowOffsetDist" value="1"/>
+    <property key="labeling/shadowOffsetGlobal" value="true"/>
+    <property key="labeling/shadowOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/shadowOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/shadowOffsetUnits" value="1"/>
+    <property key="labeling/shadowRadius" value="1.5"/>
+    <property key="labeling/shadowRadiusAlphaOnly" value="false"/>
+    <property key="labeling/shadowRadiusMapUnitMaxScale" value="0"/>
+    <property key="labeling/shadowRadiusMapUnitMinScale" value="0"/>
+    <property key="labeling/shadowRadiusUnits" value="1"/>
+    <property key="labeling/shadowScale" value="100"/>
+    <property key="labeling/shadowTransparency" value="30"/>
+    <property key="labeling/shadowUnder" value="0"/>
+    <property key="labeling/shapeBlendMode" value="0"/>
+    <property key="labeling/shapeBorderColorA" value="255"/>
+    <property key="labeling/shapeBorderColorB" value="128"/>
+    <property key="labeling/shapeBorderColorG" value="128"/>
+    <property key="labeling/shapeBorderColorR" value="128"/>
+    <property key="labeling/shapeBorderWidth" value="0"/>
+    <property key="labeling/shapeBorderWidthMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeBorderWidthMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeBorderWidthUnits" value="1"/>
+    <property key="labeling/shapeDraw" value="false"/>
+    <property key="labeling/shapeFillColorA" value="255"/>
+    <property key="labeling/shapeFillColorB" value="255"/>
+    <property key="labeling/shapeFillColorG" value="255"/>
+    <property key="labeling/shapeFillColorR" value="255"/>
+    <property key="labeling/shapeJoinStyle" value="64"/>
+    <property key="labeling/shapeOffsetMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeOffsetMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeOffsetUnits" value="1"/>
+    <property key="labeling/shapeOffsetX" value="0"/>
+    <property key="labeling/shapeOffsetY" value="0"/>
+    <property key="labeling/shapeRadiiMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeRadiiMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeRadiiUnits" value="1"/>
+    <property key="labeling/shapeRadiiX" value="0"/>
+    <property key="labeling/shapeRadiiY" value="0"/>
+    <property key="labeling/shapeRotation" value="0"/>
+    <property key="labeling/shapeRotationType" value="0"/>
+    <property key="labeling/shapeSVGFile" value=""/>
+    <property key="labeling/shapeSizeMapUnitMaxScale" value="0"/>
+    <property key="labeling/shapeSizeMapUnitMinScale" value="0"/>
+    <property key="labeling/shapeSizeType" value="0"/>
+    <property key="labeling/shapeSizeUnits" value="1"/>
+    <property key="labeling/shapeSizeX" value="0"/>
+    <property key="labeling/shapeSizeY" value="0"/>
+    <property key="labeling/shapeTransparency" value="0"/>
+    <property key="labeling/shapeType" value="0"/>
+    <property key="labeling/textColorA" value="255"/>
+    <property key="labeling/textColorB" value="0"/>
+    <property key="labeling/textColorG" value="0"/>
+    <property key="labeling/textColorR" value="0"/>
+    <property key="labeling/textTransp" value="0"/>
+    <property key="labeling/upsidedownLabels" value="0"/>
+    <property key="labeling/wrapChar" value=""/>
+    <property key="labeling/xOffset" value="0"/>
+    <property key="labeling/yOffset" value="0"/>
+  </customproperties>
+  <blendMode>0</blendMode>
+  <featureBlendMode>0</featureBlendMode>
+  <layerTransparency>0</layerTransparency>
+  <displayfield>Name</displayfield>
+  <label>0</label>
+  <labelattributes>
+    <label fieldname="" text="Label"/>
+    <family fieldname="" name="Lucida Grande"/>
+    <size fieldname="" units="pt" value="12"/>
+    <bold fieldname="" on="0"/>
+    <italic fieldname="" on="0"/>
+    <underline fieldname="" on="0"/>
+    <strikeout fieldname="" on="0"/>
+    <color fieldname="" red="0" blue="0" green="0"/>
+    <x fieldname=""/>
+    <y fieldname=""/>
+    <offset x="0" y="0" units="pt" yfieldname="" xfieldname=""/>
+    <angle fieldname="" value="0" auto="0"/>
+    <alignment fieldname="" value="center"/>
+    <buffercolor fieldname="" red="255" blue="255" green="255"/>
+    <buffersize fieldname="" units="pt" value="1"/>
+    <bufferenabled fieldname="" on=""/>
+    <multilineenabled fieldname="" on=""/>
+    <selectedonly on=""/>
+  </labelattributes>
+  <edittypes>
+    <edittype labelontop="0" editable="1" type="0" name="Name"/>
+    <edittype labelontop="0" editable="1" type="0" name="Value"/>
+  </edittypes>
+  <editform></editform>
+  <editforminit></editforminit>
+  <featformsuppress>0</featformsuppress>
+  <annotationform></annotationform>
+  <editorlayout>generatedlayout</editorlayout>
+  <excludeAttributesWMS/>
+  <excludeAttributesWFS/>
+  <attributeactions/>
+</qgis>