Add warning for printing and pdf export with blend modes with option to print as raster

nyalldawson · nyalldawson · commit 2479d83262dc · 2013-05-06T08:39:07.000+10:00
diff --git a/src/app/composer/qgscomposer.cpp b/src/app/composer/qgscomposer.cpp
@@ -631,6 +631,11 @@ void QgsComposer::on_mActionExportAsPDF_triggered()
     showWMSPrintingWarning();
   }
 
+  if ( containsBlendModes() )
+  {
+    showBlendModePrintingWarning();
+  }
+
   bool hasAnAtlas = mComposition->atlasComposition().enabled();
   bool atlasOnASingleFile = hasAnAtlas && mComposition->atlasComposition().singleFile();
   QgsAtlasComposition* atlasMap = &mComposition->atlasComposition();
@@ -805,6 +810,11 @@ void QgsComposer::on_mActionPrint_triggered()
     showWMSPrintingWarning();
   }
 
+  if ( containsBlendModes() )
+  {
+    showBlendModePrintingWarning();
+  }
+
   //orientation and page size are already set to QPrinter in the page setup dialog
   QPrintDialog printDialog( &mPrinter, 0 );
   if ( printDialog.exec() != QDialog::Accepted )
@@ -2010,6 +2020,42 @@ bool QgsComposer::containsWMSLayer() const
   return false;
 }
 
+bool QgsComposer::containsBlendModes() const
+{
+  // Check if composer contains any blend modes
+  QMap<QgsComposerItem*, QWidget*>::const_iterator item_it = mItemWidgetMap.constBegin();
+  QgsComposerItem* currentItem = 0;
+  QgsComposerMap* currentMap = 0;
+
+  for ( ; item_it != mItemWidgetMap.constEnd(); ++item_it )
+  {
+    currentItem = item_it.key();
+    // Check composer item's blend mode
+    if ( currentItem->blendMode() != QPainter::CompositionMode_SourceOver )
+    {
+      return true;
+    }
+    // If item is a composer map, check if it contains any blended layers
+    currentMap = dynamic_cast<QgsComposerMap *>( currentItem );
+    if ( currentMap )
+    {
+      if ( currentMap->containsBlendModes() )
+      {
+        return true;
+      }
+      if ( currentMap->overviewFrameMapId() != -1 )
+      {
+        // map contains an overview, check its blend mode
+        if ( currentMap->overviewBlendMode() != QPainter::CompositionMode_SourceOver )
+        {
+          return true;
+        }
+      }
+    }
+  }
+  return false;
+}
+
 void QgsComposer::showWMSPrintingWarning()
 {
   QString myQSettingsLabel = "/UI/displayComposerWMSWarning";
@@ -2029,6 +2075,31 @@ void QgsComposer::showWMSPrintingWarning()
   }
 }
 
+void QgsComposer::showBlendModePrintingWarning()
+{
+  if ( ! mComposition->printAsRaster() )
+  {
+    QgsMessageViewer* m = new QgsMessageViewer( this );
+    m->setWindowTitle( tr( "Project contains blend modes" ) );
+    m->setMessage( tr( "Blend modes are enabled in this project, which cannot be printed as vectors. Printing as a raster is recommended." ), QgsMessageOutput::MessageText );
+    m->setCheckBoxText( tr( "Print as raster" ) );
+    m->setCheckBoxState( Qt::Checked );
+    m->setCheckBoxVisible( true );
+    m->showMessage( true );
+
+    // TODO - fix this - checkBoxState is never true
+    // also need to make sure composer print as raster checkbox is updated
+    if ( m->checkBoxState() == Qt::Checked )
+    {
+      mComposition->setPrintAsRaster( true );
+    }
+    else
+    {
+      mComposition->setPrintAsRaster( true );
+    }
+  }
+}
+
 void QgsComposer::cleanupAfterTemplateRead()
 {
   QMap<QgsComposerItem*, QWidget*>::const_iterator itemIt = mItemWidgetMap.constBegin();
diff --git a/src/app/composer/qgscomposer.h b/src/app/composer/qgscomposer.h
@@ -309,9 +309,15 @@ class QgsComposer: public QMainWindow, private Ui::QgsComposerBase
     //! True if a composer map contains a WMS layer
     bool containsWMSLayer() const;
 
+    //! True if a composer contains blend modes
+    bool containsBlendModes() const;
+
     //! Displays a warning because of possible min/max size in WMS
     void showWMSPrintingWarning();
 
+    //! Displays a warning because of incompatibility between blend modes and QPrinter
+    void showBlendModePrintingWarning();
+
     //! Changes elements that are not suitable for this project
     void cleanupAfterTemplateRead();
 
diff --git a/src/core/composer/qgscomposermap.cpp b/src/core/composer/qgscomposermap.cpp
@@ -27,6 +27,7 @@
 #include "qgsrendercontext.h"
 #include "qgsscalecalculator.h"
 #include "qgsvectorlayer.h"
+#include "qgspallabeling.h"
 
 #include "qgslabel.h"
 #include "qgslabelattributes.h"
@@ -627,6 +628,53 @@ bool QgsComposerMap::containsWMSLayer() const
   return false;
 }
 
+bool QgsComposerMap::containsBlendModes() const
+{
+  if ( !mMapRenderer )
+  {
+    return false;
+  }
+
+  QStringList layers = mMapRenderer->layerSet();
+
+  //Also need to check PAL labeling for blend modes
+  QgsPalLabeling* lbl = dynamic_cast<QgsPalLabeling*>( mMapRenderer->labelingEngine() );
+
+  QStringList::const_iterator layer_it = layers.constBegin();
+  QgsMapLayer* currentLayer = 0;
+
+  for ( ; layer_it != layers.constEnd(); ++layer_it )
+  {
+    currentLayer = QgsMapLayerRegistry::instance()->mapLayer( *layer_it );
+    if ( currentLayer )
+    {
+      if ( currentLayer->blendMode() != QPainter::CompositionMode_SourceOver )
+      {
+        return true;
+      }
+      // if vector layer and has labels, check label blend modes
+      QgsVectorLayer* currentVectorLayer = qobject_cast<QgsVectorLayer *>( currentLayer );
+      if ( currentVectorLayer )
+      {
+        if ( lbl->willUseLayer( currentVectorLayer ) )
+        {
+          // Check all label blending properties
+          QgsPalLayerSettings& layerSettings = lbl->layer( currentVectorLayer->id() );
+          if (( layerSettings.blendMode != QPainter::CompositionMode_SourceOver ) ||
+              ( layerSettings.bufferSize != 0 && layerSettings.bufferBlendMode != QPainter::CompositionMode_SourceOver ) ||
+              ( layerSettings.shadowDraw && layerSettings.shadowBlendMode != QPainter::CompositionMode_SourceOver ) ||
+              ( layerSettings.shapeDraw && layerSettings.shapeBlendMode != QPainter::CompositionMode_SourceOver ) )
+          {
+            return true;
+          }
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
 void QgsComposerMap::connectUpdateSlot()
 {
   //connect signal from layer registry to update in case of new or deleted layers
diff --git a/src/core/composer/qgscomposermap.h b/src/core/composer/qgscomposermap.h
@@ -183,6 +183,9 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
     /**True if composer map renders a WMS layer*/
     bool containsWMSLayer() const;
 
+    /**True if composer map contains layers with blend modes*/
+    bool containsBlendModes() const;
+
     /** stores state in Dom node
      * @param elem is Dom element corresponding to 'Composer' tag
      * @param doc Dom document
