[composer] Remove more use of composition map settings

Use relevant composer map item CRS instead of composition mapsetting's
CRS. For items directly linked to a map (eg scalebar, legend) we
use that map's CRS, for others (eg labels, html items) we use the
composition's reference map CRS.

(Note that the CRS cannot be set for a map, and is still currently
linked to the canvas CRS. Fixing that is a future TODO.)

python/core/composer/qgscomposermap.sip

@@ -127,6 +127,8 @@ class QgsComposerMap : QgsComposerItem
     //! @note not available in python bindings
     // QgsRectangle* currentMapExtent();
 
+    QgsCoordinateReferenceSystem crs() const;
+
     PreviewMode previewMode() const;
     void setPreviewMode( PreviewMode m );
 

src/app/composer/qgscomposermapgridwidget.cpp

@@ -1035,7 +1035,7 @@ void QgsComposerMapGridWidget::on_mMapGridCRSButton_clicked()
 
   QgsGenericProjectionSelector crsDialog( this );
   QgsCoordinateReferenceSystem crs = mComposerMapGrid->crs();
-  QString currentAuthId = crs.isValid() ? crs.authid() : mComposerMap->composition()->mapSettings().destinationCrs().authid();
+  QString currentAuthId = crs.isValid() ? crs.authid() : mComposerMap->crs().authid();
   crsDialog.setSelectedAuthId( currentAuthId );
 
   if ( crsDialog.exec() == QDialog::Accepted )

src/core/composer/qgsatlascomposition.cpp

@@ -439,7 +439,7 @@ void QgsAtlasComposition::computeExtent( QgsComposerMap* map )
   // QgsGeometry::boundingBox is expressed in the geometry"s native CRS
   // We have to transform the grometry to the destination CRS and ask for the bounding box
   // Note: we cannot directly take the transformation of the bounding box, since transformations are not linear
-  mTransformedFeatureBounds = currentGeometry( map->composition()->mapSettings().destinationCrs() ).boundingBox();
+  mTransformedFeatureBounds = currentGeometry( map->crs() ).boundingBox();
 }
 
 void QgsAtlasComposition::prepareMap( QgsComposerMap* map )
@@ -481,7 +481,7 @@ void QgsAtlasComposition::prepareMap( QgsComposerMap* map )
   if ( map->atlasScalingMode() == QgsComposerMap::Fixed || map->atlasScalingMode() == QgsComposerMap::Predefined || isPointLayer )
   {
     QgsScaleCalculator calc;
-    calc.setMapUnits( composition()->mapSettings().mapUnits() );
+    calc.setMapUnits( map->crs().mapUnits() );
     calc.setDpi( 25.4 );
     double originalScale = calc.calculate( mOrigExtent, map->rect().width() );
     double geomCenterX = ( xa1 + xa2 ) / 2.0;

src/core/composer/qgscomposerattributetablev2.cpp

@@ -422,7 +422,7 @@ bool QgsComposerAttributeTableV2::getTableContents( QgsComposerTableContents &co
     if ( layer )
     {
       //transform back to layer CRS
-      QgsCoordinateTransform coordTransform( layer->crs(), mComposition->mapSettings().destinationCrs() );
+      QgsCoordinateTransform coordTransform( layer->crs(), mComposerMap->crs() );
       try
       {
         selectionRect = coordTransform.transformBoundingBox( selectionRect, QgsCoordinateTransform::ReverseTransform );

src/core/composer/qgscomposerhtml.cpp

@@ -27,6 +27,7 @@
 #include "qgsdistancearea.h"
 #include "qgsjsonutils.h"
 #include "qgsmapsettings.h"
+#include "qgscomposermap.h"
 
 #include "qgswebpage.h"
 #include "qgswebframe.h"
@@ -542,7 +543,9 @@ void QgsComposerHtml::setExpressionContext( const QgsFeature &feature, QgsVector
   else if ( mComposition )
   {
     //set to composition's mapsettings' crs
-    mDistanceArea->setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
+    QgsComposerMap* referenceMap = mComposition->referenceMap();
+    if ( referenceMap )
+      mDistanceArea->setSourceCrs( referenceMap->crs().srsid() );
   }
   if ( mComposition )
   {

src/core/composer/qgscomposerlabel.cpp

@@ -27,6 +27,7 @@
 #include "qgsfontutils.h"
 #include "qgsexpressioncontext.h"
 #include "qgsmapsettings.h"
+#include "qgscomposermap.h"
 
 #include "qgswebview.h"
 #include "qgswebframe.h"
@@ -261,8 +262,10 @@ void QgsComposerLabel::refreshExpressionContext()
   }
   else
   {
-    //set to composition's mapsettings' crs
-    mDistanceArea->setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
+    //set to composition's reference map's crs
+    QgsComposerMap* referenceMap = mComposition->referenceMap();
+    if ( referenceMap )
+      mDistanceArea->setSourceCrs( referenceMap->crs().srsid() );
   }
   mDistanceArea->setEllipsoidalMode( true );
   mDistanceArea->setEllipsoid( mComposition->project()->ellipsoid() );

src/core/composer/qgscomposerlegend.cpp

@@ -704,7 +704,7 @@ void QgsComposerLegend::doUpdateFilterByMap()
     QgsGeometry filterPolygon;
     if ( mInAtlas )
     {
-      filterPolygon = composition()->atlasComposition().currentGeometry( composition()->mapSettings().destinationCrs() );
+      filterPolygon = composition()->atlasComposition().currentGeometry( mComposerMap->crs() );
     }
     mLegendModel->setLegendFilter( &ms, /* useExtent */ mInAtlas || mLegendFilterByMap, filterPolygon, /* useExpressions */ true );
   }

src/core/composer/qgscomposermap.cpp

@@ -208,7 +208,7 @@ QgsMapSettings QgsComposerMap::mapSettings( const QgsRectangle& extent, QSizeF s
   jobMapSettings.setExtent( extent );
   jobMapSettings.setOutputSize( size.toSize() );
   jobMapSettings.setOutputDpi( dpi );
-  jobMapSettings.setMapUnits( ms.mapUnits() );
+  jobMapSettings.setMapUnits( crs().mapUnits() );
   jobMapSettings.setBackgroundColor( Qt::transparent );
   jobMapSettings.setOutputImageFormat( ms.outputImageFormat() );
   jobMapSettings.setRotation( mEvaluatedMapRotation );
@@ -233,7 +233,7 @@ QgsMapSettings QgsComposerMap::mapSettings( const QgsRectangle& extent, QSizeF s
   }
   jobMapSettings.setLayers( layers );
   jobMapSettings.setLayerStyleOverrides( layerStyleOverridesToRender( expressionContext ) );
-  jobMapSettings.setDestinationCrs( ms.destinationCrs() );
+  jobMapSettings.setDestinationCrs( crs() );
   jobMapSettings.setCrsTransformEnabled( ms.hasCrsTransformEnabled() );
   jobMapSettings.setFlags( ms.flags() );
   jobMapSettings.setFlag( QgsMapSettings::DrawSelection, false );
@@ -625,7 +625,7 @@ QMap<QString, QString> QgsComposerMap::layerStyleOverridesToRender( const QgsExp
 double QgsComposerMap::scale() const
 {
   QgsScaleCalculator calculator;
-  calculator.setMapUnits( mComposition->mapSettings().mapUnits() );
+  calculator.setMapUnits( crs().mapUnits() );
   calculator.setDpi( 25.4 );  //QGraphicsView units are mm
   return calculator.calculate( *currentMapExtent(), rect().width() );
 }
@@ -717,7 +717,7 @@ void QgsComposerMap::zoomContent( const double factor, const QPointF point, cons
     //and also apply to the map's original extent (see #9602)
     //we can't use the scaleRatio calculated earlier, as the scale can vary depending on extent for geographic coordinate systems
     QgsScaleCalculator calculator;
-    calculator.setMapUnits( mComposition->mapSettings().mapUnits() );
+    calculator.setMapUnits( crs().mapUnits() );
     calculator.setDpi( 25.4 );  //QGraphicsView units are mm
     double scaleRatio = scale() / calculator.calculate( mExtent, rect().width() );
     mExtent.scale( scaleRatio );
@@ -871,6 +871,18 @@ QgsRectangle* QgsComposerMap::currentMapExtent()
   }
 }
 
+QgsCoordinateReferenceSystem QgsComposerMap::crs() const
+{
+  if ( mComposition )
+  {
+    return mComposition->mapSettings().destinationCrs();
+  }
+  else
+  {
+    return QgsCoordinateReferenceSystem();
+  }
+}
+
 const QgsRectangle* QgsComposerMap::currentMapExtent() const
 {
   //const version
@@ -905,7 +917,7 @@ void QgsComposerMap::setNewScale( double scaleDenominator, bool forceUpdate )
     //and also apply to the map's original extent (see #9602)
     //we can't use the scaleRatio calculated earlier, as the scale can vary depending on extent for geographic coordinate systems
     QgsScaleCalculator calculator;
-    calculator.setMapUnits( mComposition->mapSettings().mapUnits() );
+    calculator.setMapUnits( crs().mapUnits() );
     calculator.setDpi( 25.4 );  //QGraphicsView units are mm
     scaleRatio = scaleDenominator / calculator.calculate( mExtent, rect().width() );
     mExtent.scale( scaleRatio );
@@ -1826,9 +1838,10 @@ QgsExpressionContext QgsComposerMap::createExpressionContext() const
 
   if ( mComposition )
   {
-    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_crs" ), mComposition->mapSettings().destinationCrs().authid(), true ) );
-    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_crs_definition" ), mComposition->mapSettings().destinationCrs().toProj4(), true ) );
-    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_units" ), QgsUnitTypes::toString( mComposition->mapSettings().mapUnits() ), true ) );
+    QgsCoordinateReferenceSystem mapCrs = crs();
+    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_crs" ), mapCrs.authid(), true ) );
+    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_crs_definition" ), mapCrs.toProj4(), true ) );
+    scope->addVariable( QgsExpressionContextScope::StaticVariable( QStringLiteral( "map_units" ), QgsUnitTypes::toString( mapCrs.mapUnits() ), true ) );
   }
 
   context.appendScope( scope );
@@ -1979,12 +1992,12 @@ QPointF QgsComposerMap::composerMapPosForItem( const QgsAnnotation* annotation )
 
   mapX = annotation->mapPosition().x();
   mapY = annotation->mapPosition().y();
-  QgsCoordinateReferenceSystem crs = annotation->mapPositionCrs();
+  QgsCoordinateReferenceSystem annotationCrs = annotation->mapPositionCrs();
 
-  if ( crs != mComposition->mapSettings().destinationCrs() )
+  if ( annotationCrs != crs() )
   {
     //need to reproject
-    QgsCoordinateTransform t( crs, mComposition->mapSettings().destinationCrs() );
+    QgsCoordinateTransform t( annotationCrs, crs() );
     double z = 0.0;
     t.transformInPlace( mapX, mapY, z );
   }

src/core/composer/qgscomposermap.h

@@ -21,6 +21,7 @@
 #include "qgis_core.h"
 #include "qgscomposeritem.h"
 #include "qgsrectangle.h"
+#include "qgscoordinatereferencesystem.h"
 #include <QFont>
 #include <QGraphicsRectItem>
 
@@ -166,6 +167,12 @@ class CORE_EXPORT QgsComposerMap : public QgsComposerItem
     //! @note not available in python bindings
     QgsRectangle* currentMapExtent();
 
+    /**
+     * Returns the map's coordinate reference system.
+     * @note added in QGIS 3.0
+     */
+    QgsCoordinateReferenceSystem crs() const;
+
     PreviewMode previewMode() const {return mPreviewMode;}
     void setPreviewMode( PreviewMode m );
 

src/core/composer/qgscomposermapgrid.cpp

@@ -651,7 +651,7 @@ void QgsComposerMapGrid::draw( QPainter* p )
   QList< QPair< double, QLineF > > horizontalLines;
 
   //is grid in a different crs than map?
-  if ( mGridUnit == MapUnit && mCRS.isValid() && mCRS != ms.destinationCrs() )
+  if ( mGridUnit == MapUnit && mCRS.isValid() && mCRS != mComposerMap->crs() )
   {
     drawGridCrsTransform( context, dotsPerMM, horizontalLines, verticalLines );
   }
@@ -1416,7 +1416,7 @@ QString QgsComposerMapGrid::gridAnnotationString( double value, QgsComposerMapGr
   }
   else if ( mComposerMap && mComposerMap->composition() )
   {
-    geographic = mComposerMap->composition()->mapSettings().destinationCrs().isGeographic();
+    geographic = mComposerMap->crs().isGeographic();
   }
 
   if ( geographic && coord == QgsComposerMapGrid::Longitude &&
@@ -2072,7 +2072,7 @@ void QgsComposerMapGrid::calculateMaxExtension( double& top, double& right, doub
   //collect grid lines
   QList< QPair< double, QLineF > > verticalLines;
   QList< QPair< double, QLineF > > horizontalLines;
-  if ( mGridUnit == MapUnit && mCRS.isValid() && mCRS != ms.destinationCrs() )
+  if ( mGridUnit == MapUnit && mCRS.isValid() && mCRS != mComposerMap->crs() )
   {
     drawGridCrsTransform( context, 0, horizontalLines, verticalLines, false );
   }
@@ -2340,7 +2340,7 @@ int QgsComposerMapGrid::crsGridParams( QgsRectangle& crsRect, QgsCoordinateTrans
 
   try
   {
-    QgsCoordinateTransform tr( mComposerMap->composition()->mapSettings().destinationCrs(), mCRS );
+    QgsCoordinateTransform tr( mComposerMap->crs(), mCRS );
     QPolygonF mapPolygon = mComposerMap->transformedMapPolygon();
     QRectF mbr = mapPolygon.boundingRect();
     QgsRectangle mapBoundingRect( mbr.left(), mbr.bottom(), mbr.right(), mbr.top() );
@@ -2372,7 +2372,7 @@ int QgsComposerMapGrid::crsGridParams( QgsRectangle& crsRect, QgsCoordinateTrans
     }
 
     inverseTransform.setSourceCrs( mCRS );
-    inverseTransform.setDestinationCrs( mComposerMap->composition()->mapSettings().destinationCrs() );
+    inverseTransform.setDestinationCrs( mComposerMap->crs() );
   }
   catch ( QgsCsException & cse )
   {

src/core/composer/qgscomposerpicture.cpp

@@ -426,7 +426,7 @@ void QgsComposerPicture::updateMapRotation()
     case TrueNorth:
     {
       QgsPoint center = mRotationMap->currentMapExtent()->center();
-      QgsCoordinateReferenceSystem crs = mComposition->mapSettings().destinationCrs();
+      QgsCoordinateReferenceSystem crs = mRotationMap->crs();
 
       try
       {

src/core/composer/qgscomposerscalebar.cpp

@@ -303,7 +303,7 @@ double QgsComposerScaleBar::mapWidth() const
   {
     QgsDistanceArea da;
     da.setEllipsoidalMode( true );
-    da.setSourceCrs( mComposition->mapSettings().destinationCrs().srsid() );
+    da.setSourceCrs( mComposerMap->crs().srsid() );
     da.setEllipsoid( mComposition->project()->ellipsoid() );
 
     QgsUnitTypes::DistanceUnit units = QgsUnitTypes::DistanceMeters;

src/core/composer/qgscomposition.cpp

@@ -2850,7 +2850,7 @@ void QgsComposition::georeferenceOutput( const QString& file, QgsComposerMap* ma
     //TODO - metadata can be set here, e.g.:
     GDALSetMetadataItem( outputDS, "AUTHOR", "me", nullptr );
 #endif
-    GDALSetProjection( outputDS, mMapSettings.destinationCrs().toWkt().toLocal8Bit().constData() );
+    GDALSetProjection( outputDS, map->crs().toWkt().toLocal8Bit().constData() );
     GDALClose( outputDS );
   }
   CPLSetConfigOption( "GDAL_PDF_DPI", nullptr );