[FEATURE] Save map/canvas as PDF (#4516)

python/core/qgsmapsettingsutils.sip

@@ -22,6 +22,13 @@ class QgsMapSettingsUtils
 %End
   public:
 
+    static bool containsAdvancedEffects( const QgsMapSettings &mapSettings );
+%Docstring
+ Checks whether any of the layers attached to a map settings object contain advanced effects
+ \param mapSettings map settings
+ :rtype: bool
+%End
+
     static QString worldFileContent( const QgsMapSettings &mapSettings );
 %Docstring
  Creates the content of a world file.

src/app/qgisapp.cpp

@@ -1706,6 +1706,7 @@ void QgisApp::createActions()
   connect( mActionSaveProject, &QAction::triggered, this, &QgisApp::fileSave );
   connect( mActionSaveProjectAs, &QAction::triggered, this, &QgisApp::fileSaveAs );
   connect( mActionSaveMapAsImage, &QAction::triggered, this, [ = ] { saveMapAsImage(); } );
+  connect( mActionSaveMapAsPdf, &QAction::triggered, this, [ = ] { saveMapAsPdf(); } );
   connect( mActionNewMapCanvas, &QAction::triggered, this, &QgisApp::newMapCanvas );
   connect( mActionNewPrintComposer, &QAction::triggered, this, &QgisApp::newPrintComposer );
   connect( mActionShowComposerManager, &QAction::triggered, this, &QgisApp::showComposerManager );
@@ -2703,6 +2704,7 @@ void QgisApp::setTheme( const QString &themeName )
   mActionNewPrintComposer->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionNewComposer.svg" ) ) );
   mActionShowComposerManager->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionComposerManager.svg" ) ) );
   mActionSaveMapAsImage->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionSaveMapAsImage.svg" ) ) );
+  mActionSaveMapAsPdf->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionSaveAsPDF.svg" ) ) );
   mActionExit->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionFileExit.png" ) ) );
   mActionAddOgrLayer->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionAddOgrLayer.svg" ) ) );
   mActionAddRasterLayer->setIcon( QgsApplication::getThemeIcon( QStringLiteral( "/mActionAddRasterLayer.svg" ) ) );
@@ -5801,8 +5803,8 @@ void QgisApp::saveMapAsImage()
   if ( !dlg.exec() )
     return;
 
-  QPair< QString, QString> myFileNameAndFilter = QgisGui::getSaveAsImageName( this, tr( "Choose a file name to save the map image as" ) );
-  if ( myFileNameAndFilter.first != QLatin1String( "" ) )
+  QPair< QString, QString> fileNameAndFilter = QgisGui::getSaveAsImageName( this, tr( "Choose a file name to save the map image as" ) );
+  if ( fileNameAndFilter.first != QLatin1String( "" ) )
   {
     QgsMapSettings ms = QgsMapSettings();
     ms.setDestinationCrs( QgsProject::instance()->crs() );
@@ -5813,7 +5815,7 @@ void QgisApp::saveMapAsImage()
     ms.setRotation( mMapCanvas->rotation() );
     ms.setLayers( mMapCanvas->layers() );
 
-    QgsMapRendererTask *mapRendererTask = new QgsMapRendererTask( ms, myFileNameAndFilter.first, myFileNameAndFilter.second );
+    QgsMapRendererTask *mapRendererTask = new QgsMapRendererTask( ms, fileNameAndFilter.first, fileNameAndFilter.second );
 
     if ( dlg.drawAnnotations() )
     {
@@ -5853,6 +5855,117 @@ void QgisApp::saveMapAsImage()
 
 } // saveMapAsImage
 
+void QgisApp::saveMapAsPdf()
+{
+  QList< QgsMapDecoration * > decorations;
+  QString activeDecorations;
+  Q_FOREACH ( QgsDecorationItem *decoration, mDecorationItems )
+  {
+    if ( decoration->enabled() )
+    {
+      decorations << decoration;
+      if ( activeDecorations.isEmpty() )
+        activeDecorations = decoration->name().toLower();
+      else
+        activeDecorations += QString( ", %1" ).arg( decoration->name().toLower() );
+    }
+  }
+
+  QgsMapSaveDialog dlg( this, mMapCanvas, activeDecorations, QgsMapSaveDialog::Pdf );
+  if ( !dlg.exec() )
+    return;
+
+  QgsSettings settings;
+  QString lastUsedDir = settings.value( QStringLiteral( "UI/lastSaveAsImageDir" ), QDir::homePath() ).toString();
+  QString fileName = QFileDialog::getSaveFileName( this, tr( "Save map as" ), lastUsedDir, tr( "PDF Format" ) + " (*.pdf *.PDF)" );
+  if ( !fileName.isEmpty() )
+  {
+    QgsMapSettings ms = QgsMapSettings();
+    ms.setDestinationCrs( QgsProject::instance()->crs() );
+    ms.setExtent( dlg.extent() );
+    ms.setOutputSize( dlg.size() );
+    ms.setOutputDpi( dlg.dpi() );
+    ms.setBackgroundColor( mMapCanvas->canvasColor() );
+    ms.setRotation( mMapCanvas->rotation() );
+    ms.setLayers( mMapCanvas->layers() );
+
+    QPrinter *printer = new QPrinter();
+    printer->setOutputFileName( fileName );
+    printer->setOutputFormat( QPrinter::PdfFormat );
+    printer->setOrientation( QPrinter::Portrait );
+    printer->setPaperSize( dlg.size(), QPrinter::DevicePixel );
+    printer->setPageMargins( 0, 0, 0, 0, QPrinter::DevicePixel );
+
+    QPainter *p = new QPainter();
+    QImage *image = nullptr;
+    if ( dlg.saveAsRaster() )
+    {
+      image = new QImage( dlg.size(), QImage::Format_ARGB32 );
+      p->begin( image );
+    }
+    else
+    {
+      p->begin( printer );
+    }
+
+    QgsMapRendererTask *mapRendererTask = new QgsMapRendererTask( ms, p );
+
+    if ( dlg.drawAnnotations() )
+    {
+      mapRendererTask->addAnnotations( QgsProject::instance()->annotationManager()->annotations() );
+    }
+
+    if ( dlg.drawDecorations() )
+    {
+      mapRendererTask->addDecorations( decorations );
+    }
+
+    mapRendererTask->setSaveWorldFile( dlg.saveWorldFile() );
+
+    connect( mapRendererTask, &QgsMapRendererTask::renderingComplete, this, [ this, p, image, printer ]
+    {
+      messageBar()->pushSuccess( tr( "Save as image" ), tr( "Successfully saved map to image" ) );
+      p->end();
+
+      if ( image )
+      {
+        QPainter pp;
+        pp.begin( printer );
+        QRectF rect( 0, 0, image->width(), image->height() );
+        pp.drawImage( rect, *image, rect );
+        pp.end();
+      }
+
+      delete p;
+      delete image;
+      delete printer;
+    } );
+    connect( mapRendererTask, &QgsMapRendererTask::errorOccurred, this, [ this, p, image, printer ]( int error )
+    {
+      switch ( error )
+      {
+        case QgsMapRendererTask::ImageAllocationFail:
+        {
+          messageBar()->pushWarning( tr( "Save as image" ), tr( "Could not allocate required memory for image" ) );
+          break;
+        }
+        case QgsMapRendererTask::ImageSaveFail:
+        {
+          messageBar()->pushWarning( tr( "Save as image" ), tr( "Could not save the image to file" ) );
+          break;
+        }
+      }
+
+      delete p;
+      delete image;
+      delete printer;
+    } );
+
+    QgsApplication::taskManager()->addTask( mapRendererTask );
+  }
+
+} // saveMapAsPdf
+
 //overloaded version of the above function
 void QgisApp::saveMapAsImage( const QString &imageFileNameQString, QPixmap *theQPixmap )
 {

src/app/qgisapp.h

@@ -391,6 +391,7 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
     QAction *actionSaveProject() { return mActionSaveProject; }
     QAction *actionSaveProjectAs() { return mActionSaveProjectAs; }
     QAction *actionSaveMapAsImage() { return mActionSaveMapAsImage; }
+    QAction *actionSaveMapAsPdf() { return mActionSaveMapAsPdf; }
     QAction *actionProjectProperties() { return mActionProjectProperties; }
     QAction *actionShowComposerManager() { return mActionShowComposerManager; }
     QAction *actionNewPrintComposer() { return mActionNewPrintComposer; }
@@ -1080,6 +1081,8 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
     void runScript( const QString &filePath );
     //! Save the map view as an image - user is prompted for image name using a dialog
     void saveMapAsImage();
+    //! Save the map view as a pdf - user is prompted for image name using a dialog
+    void saveMapAsPdf();
     //! Open a project
     void fileOpen();
     //! Create a new project

src/app/qgsmapsavedialog.cpp

@@ -22,6 +22,7 @@
 #include "qgsdecorationitem.h"
 #include "qgsextentgroupbox.h"
 #include "qgsmapsettings.h"
+#include "qgsmapsettingsutils.h"
 
 #include <QCheckBox>
 #include <QSpinBox>
@@ -29,7 +30,7 @@
 
 Q_GUI_EXPORT extern int qt_defaultDpiX();
 
-QgsMapSaveDialog::QgsMapSaveDialog( QWidget *parent, QgsMapCanvas *mapCanvas, const QString &activeDecorations )
+QgsMapSaveDialog::QgsMapSaveDialog( QWidget *parent, QgsMapCanvas *mapCanvas, const QString &activeDecorations, DialogType type )
   : QDialog( parent )
 {
   setupUi( this );
@@ -60,6 +61,16 @@ QgsMapSaveDialog::QgsMapSaveDialog( QWidget *parent, QgsMapCanvas *mapCanvas, co
   connect( mScaleWidget, &QgsScaleWidget::scaleChanged, this, &QgsMapSaveDialog::updateScale );
 
   updateOutputSize();
+
+  if ( type == QgsMapSaveDialog::Pdf )
+  {
+    mSaveWorldFile->setVisible( false );
+
+    mSaveAsRaster->setChecked( QgsMapSettingsUtils::containsAdvancedEffects( mapCanvas->mapSettings() ) );
+    mSaveAsRaster->setVisible( true );
+
+    this->setWindowTitle( tr( "Save map as PDF" ) );
+  }
 }
 
 void QgsMapSaveDialog::updateDpi( int dpi )
@@ -152,3 +163,8 @@ bool QgsMapSaveDialog::saveWorldFile() const
 {
   return mSaveWorldFile->isChecked();
 }
+
+bool QgsMapSaveDialog::saveAsRaster() const
+{
+  return mSaveAsRaster->isChecked();
+}

src/app/qgsmapsavedialog.h

@@ -37,9 +37,15 @@ class APP_EXPORT QgsMapSaveDialog: public QDialog, private Ui::QgsMapSaveDialog
 
   public:
 
+    enum DialogType
+    {
+      Image = 1, // Image-specific dialog
+      Pdf        // PDF-specific dialog
+    };
+
     /** Constructor for QgsMapSaveDialog
      */
-    QgsMapSaveDialog( QWidget *parent = nullptr, QgsMapCanvas *mapCanvas = nullptr, const QString &activeDecorations = QString() );
+    QgsMapSaveDialog( QWidget *parent = nullptr, QgsMapCanvas *mapCanvas = nullptr, const QString &activeDecorations = QString(), DialogType type = Image );
 
     //! returns extent rectangle
     QgsRectangle extent() const;
@@ -59,6 +65,9 @@ class APP_EXPORT QgsMapSaveDialog: public QDialog, private Ui::QgsMapSaveDialog
     //! returns whether a world file will be created
     bool saveWorldFile() const;
 
+    //! returns whether the map will be rasterized
+    bool saveAsRaster() const;
+
   private:
 
     void updateDpi( int dpi );

src/core/composer/qgscomposermap.cpp

@@ -25,6 +25,7 @@
 #include "qgsmaplayerlistutils.h"
 #include "qgsmaplayerstylemanager.h"
 #include "qgsmaptopixel.h"
+#include "qgsmapsettingsutils.h"
 #include "qgspainting.h"
 #include "qgsproject.h"
 #include "qgsrasterdataprovider.h"
@@ -1071,43 +1072,10 @@ bool QgsComposerMap::containsAdvancedEffects() const
     return true;
   }
 
-  // check if map contains advanced effects like blend modes, or flattened layers for transparency
 
-  QgsTextFormat layerFormat;
-  Q_FOREACH ( QgsMapLayer *layer, layersToRender() )
-  {
-    if ( layer )
-    {
-      if ( layer->blendMode() != QPainter::CompositionMode_SourceOver )
-      {
-        return true;
-      }
-      // if vector layer, check labels and feature blend mode
-      QgsVectorLayer *currentVectorLayer = qobject_cast<QgsVectorLayer *>( layer );
-      if ( currentVectorLayer )
-      {
-        if ( currentVectorLayer->layerTransparency() != 0 )
-        {
-          return true;
-        }
-        if ( currentVectorLayer->featureBlendMode() != QPainter::CompositionMode_SourceOver )
-        {
-          return true;
-        }
-        // check label blend modes
-        if ( QgsPalLabeling::staticWillUseLayer( currentVectorLayer ) )
-        {
-          // Check all label blending properties
-
-          layerFormat.readFromLayer( currentVectorLayer );
-          if ( layerFormat.containsAdvancedEffects() )
-            return true;
-        }
-      }
-    }
-  }
-
-  return false;
+  QgsMapSettings ms;
+  ms.setLayers( layersToRender() );
+  return QgsMapSettingsUtils::containsAdvancedEffects( ms );
 }
 
 void QgsComposerMap::connectUpdateSlot()

src/core/qgsmapsettingsutils.cpp

@@ -17,9 +17,49 @@
 
 #include "qgsmapsettings.h"
 #include "qgsmapsettingsutils.h"
+#include "qgspallabeling.h"
+#include "qgstextrenderer.h"
+#include "qgsvectorlayer.h"
 
 #include <QString>
 
+bool QgsMapSettingsUtils::containsAdvancedEffects( const QgsMapSettings &mapSettings )
+{
+  QgsTextFormat layerFormat;
+  Q_FOREACH ( QgsMapLayer *layer, mapSettings.layers() )
+  {
+    if ( layer )
+    {
+      if ( layer->blendMode() != QPainter::CompositionMode_SourceOver )
+      {
+        return true;
+      }
+      // if vector layer, check labels and feature blend mode
+      QgsVectorLayer *currentVectorLayer = qobject_cast<QgsVectorLayer *>( layer );
+      if ( currentVectorLayer )
+      {
+        if ( currentVectorLayer->layerTransparency() != 0 )
+        {
+          return true;
+        }
+        if ( currentVectorLayer->featureBlendMode() != QPainter::CompositionMode_SourceOver )
+        {
+          return true;
+        }
+        // check label blend modes
+        if ( QgsPalLabeling::staticWillUseLayer( currentVectorLayer ) )
+        {
+          // Check all label blending properties
+          layerFormat.readFromLayer( currentVectorLayer );
+          if ( layerFormat.containsAdvancedEffects() )
+            return true;
+        }
+      }
+    }
+  }
+  return false;
+}
+
 QString QgsMapSettingsUtils::worldFileContent( const QgsMapSettings &mapSettings )
 {
   QgsMapSettings ms = mapSettings;

src/core/qgsmapsettingsutils.h

@@ -32,6 +32,11 @@ class CORE_EXPORT QgsMapSettingsUtils
 
   public:
 
+    /** Checks whether any of the layers attached to a map settings object contain advanced effects
+     * \param mapSettings map settings
+     */
+    static bool containsAdvancedEffects( const QgsMapSettings &mapSettings );
+
     /** Creates the content of a world file.
      * \param mapSettings map settings
      * \note Uses 17 places of precision for all numbers output

src/ui/qgisapp.ui

@@ -50,6 +50,7 @@
     <addaction name="mActionSaveProject"/>
     <addaction name="mActionSaveProjectAs"/>
     <addaction name="mActionSaveMapAsImage"/>
+    <addaction name="mActionSaveMapAsPdf"/>
     <addaction name="mActionDxfExport"/>
     <addaction name="mActionDwgImport"/>
     <addaction name="separator"/>
@@ -640,7 +641,16 @@
      <normaloff>:/images/themes/default/mActionSaveMapAsImage.svg</normaloff>:/images/themes/default/mActionSaveMapAsImage.svg</iconset>
    </property>
    <property name="text">
-    <string>Save as &amp;Image...</string>
+    <string>Save Map as &amp;Image...</string>
+   </property>
+  </action>
+  <action name="mActionSaveMapAsPdf">
+   <property name="icon">
+    <iconset resource="../../images/images.qrc">
+     <normaloff>:/images/themes/default/mActionSaveAsPDF.svg</normaloff>:/images/themes/default/mActionSaveAsPDF.svg</iconset>
+   </property>
+   <property name="text">
+    <string>Save Map as &amp;PDF...</string>
    </property>
   </action>
   <action name="mActionNewMapCanvas">

src/ui/qgsmapsavedialog.ui

@@ -16,6 +16,23 @@
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <layout class="QGridLayout" name="gridLayout">
+     <item row="8" column="0" colspan="2">
+      <widget class="QCheckBox" name="mSaveAsRaster">
+       <property name="text">
+        <string>Rasterize map</string>
+       </property>
+       <property name="toolTip">
+        <string>Advanced effects such as blend modes or vector layer transparency cannot be exported as vectors.
+Rasterizing the map is recommended when such effects are used.</string>
+       </property>
+       <property name="checked">
+        <bool>false</bool>
+       </property>
+       <property name="visible">
+        <bool>false</bool>
+       </property>
+      </widget>
+     </item>
      <item row="7" column="0" colspan="2">
       <widget class="QCheckBox" name="mSaveWorldFile">
        <property name="text">