[api] Add method to retrieve labeling results for layout maps

qgis · Jun 9, 2021 · 643e468 · 643e468
1 parent c95fed5
commit 643e468
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diff --git a/python/core/auto_generated/layout/qgslayoutitemmap.sip.in b/python/core/auto_generated/layout/qgslayoutitemmap.sip.in
@@ -870,6 +870,15 @@ in the area of the map item covered by the item.
 Returns map rendering errors
 
 :return: list of errors
+%End
+
+    QgsLabelingResults *previewLabelingResults() const;
+%Docstring
+Returns the labeling results of the most recent preview map render. May be ``None`` if no map preview has been rendered in the item.
+
+The map item retains ownership of the returned results.
+
+.. versionadded:: 3.20
 %End
 
     virtual bool accept( QgsStyleEntityVisitorInterface *visitor ) const;

diff --git a/src/core/layout/qgslayoutitemmap.cpp b/src/core/layout/qgslayoutitemmap.cpp
@@ -36,6 +36,7 @@
 #include "qgsannotationlayer.h"
 #include "qgscoordinatereferencesystemregistry.h"
 #include "qgsprojoperation.h"
+#include "qgslabelingresults.h"
 
 #include <QPainter>
 #include <QStyleOptionGraphicsItem>
@@ -1138,7 +1139,10 @@ bool QgsLayoutItemMap::nextExportPart()
         if ( mStagedRendererJob->nextPart() )
           return true;
         else
+        {
+          mExportLabelingResults.reset( mStagedRendererJob->takeLabelingResults() );
           mStagedRendererJob.reset(); // no more map layer parts
+        }
       }
 
       if ( mExportThemeIt != mExportThemes.end() && ++mExportThemeIt != mExportThemes.end() )
@@ -1358,6 +1362,8 @@ void QgsLayoutItemMap::drawMap( QPainter *painter, const QgsRectangle &extent, Q
   // Raster images were not displayed - see #10599
   job.renderSynchronously();
 
+  mExportLabelingResults.reset( job.takeLabelingResults() );
+
   mRenderingErrors = job.errors();
 }
 
@@ -1754,6 +1760,11 @@ bool QgsLayoutItemMap::isLabelBlockingItem( QgsLayoutItem *item ) const
   return mBlockingLabelItems.contains( item );
 }
 
+QgsLabelingResults *QgsLayoutItemMap::previewLabelingResults() const
+{
+  return mPreviewLabelingResults.get();
+}
+
 bool QgsLayoutItemMap::accept( QgsStyleEntityVisitorInterface *visitor ) const
 {
   // NOTE: if visitEnter returns false it means "don't visit the item", not "abort all further visitations"
@@ -1951,6 +1962,7 @@ void QgsLayoutItemMap::layersAboutToBeRemoved( const QList<QgsMapLayer *> &layer
 void QgsLayoutItemMap::painterJobFinished()
 {
   mPainter->end();
+  mPreviewLabelingResults.reset( mPainterJob->takeLabelingResults() );
   mPainterJob.reset( nullptr );
   mPainter.reset( nullptr );
   mCacheFinalImage = std::move( mCacheRenderingImage );

diff --git a/src/core/layout/qgslayoutitemmap.h b/src/core/layout/qgslayoutitemmap.h
@@ -811,6 +811,15 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem, public QgsTemporalRan
      */
     QgsMapRendererJob::Errors renderingErrors() const { return mRenderingErrors; }
 
+    /**
+     * Returns the labeling results of the most recent preview map render. May be NULLPTR if no map preview has been rendered in the item.
+     *
+     * The map item retains ownership of the returned results.
+     *
+     * \since QGIS 3.20
+     */
+    QgsLabelingResults *previewLabelingResults() const;
+
     bool accept( QgsStyleEntityVisitorInterface *visitor ) const override;
 
     /**
@@ -1099,6 +1108,9 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem, public QgsTemporalRan
 
     std::unique_ptr< QgsMapRendererStagedRenderJob > mStagedRendererJob;
 
+    std::unique_ptr< QgsLabelingResults > mPreviewLabelingResults;
+    std::unique_ptr< QgsLabelingResults > mExportLabelingResults;
+
     void init();
 
     //! Resets the item tooltip to reflect current map id
@@ -1172,6 +1184,7 @@ class CORE_EXPORT QgsLayoutItemMap : public QgsLayoutItem, public QgsTemporalRan
     friend class TestQgsLayoutMap;
     friend class QgsCompositionConverter;
     friend class QgsGeoPdfRenderedFeatureHandler;
+    friend class QgsLayoutExporter;
 
 };
 

diff --git a/tests/src/core/testqgslayoutmap.cpp b/tests/src/core/testqgslayoutmap.cpp
@@ -37,6 +37,7 @@
 #include "qgsfontutils.h"
 #include "qgsannotationlayer.h"
 #include "qgsannotationmarkeritem.h"
+#include "qgslabelingresults.h"
 
 #include <QObject>
 #include "qgstest.h"
@@ -75,6 +76,7 @@ class TestQgsLayoutMap : public QObject
     void testLayeredExport();
     void testLayeredExportLabelsByLayer();
     void testTemporal();
+    void testLabelResults();
 
   private:
     QgsRasterLayer *mRasterLayer = nullptr;
@@ -1944,5 +1946,70 @@ void TestQgsLayoutMap::testTemporal()
   QCOMPARE( renderContext.temporalRange(), QgsDateTimeRange( begin, end, true, false ) );
 }
 
+void TestQgsLayoutMap::testLabelResults()
+{
+  QgsProject p;
+  QgsLayout l( &p );
+  QgsLayoutItemMap *map = new QgsLayoutItemMap( &l );
+
+  // test retrieval of labeling results
+  QgsPalLayerSettings settings;
+
+  settings.fieldName = QStringLiteral( "\"id\"" );
+  settings.isExpression = true;
+  settings.placement = QgsPalLayerSettings::OverPoint;
+  settings.priority = 10;
+  settings.displayAll = true;
+
+  QgsVectorLayer *vl2 = new QgsVectorLayer( QStringLiteral( "Point?crs=epsg:4326&field=id:integer" ), QStringLiteral( "vl" ), QStringLiteral( "memory" ) );
+
+  QgsFeature f;
+  f.setAttributes( QgsAttributes() << 1 );
+  f.setGeometry( QgsGeometry::fromPointXY( QgsPointXY( -6.250851540391068, 53.335006994584944 ) ) );
+  QVERIFY( vl2->dataProvider()->addFeature( f ) );
+  f.setAttributes( QgsAttributes() << 8888 );
+  f.setGeometry( QgsGeometry::fromPointXY( QgsPointXY( -21.950014487179544, 64.150023619739216 ) ) );
+  QVERIFY( vl2->dataProvider()->addFeature( f ) );
+  f.setAttributes( QgsAttributes() << 33333 );
+  f.setGeometry( QgsGeometry::fromPointXY( QgsPointXY( -0.118667702475932, 51.5019405883275 ) ) );
+  QVERIFY( vl2->dataProvider()->addFeature( f ) );
+  vl2->updateExtents();
+
+  p.addMapLayer( vl2 );
+
+  vl2->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );
+  vl2->setLabelsEnabled( true );
+
+  map->attemptSetSceneRect( QRectF( 20, 20, 200, 100 ) );
+  map->setFrameEnabled( false );
+  map->setBackgroundEnabled( false );
+  map->setCrs( vl2->crs() );
+  map->zoomToExtent( vl2->extent() );
+  map->setLayers( QList<QgsMapLayer *>() << vl2 );
+  l.addLayoutItem( map );
+
+  l.renderContext().mIsPreviewRender = false;
+  QImage im( 600, 600, QImage::Format_ARGB32_Premultiplied );
+  QPainter painter( &im );
+  map->paint( &painter, nullptr, nullptr );
+  painter.end();
+
+  // retrieve label results
+  std::unique_ptr< QgsLabelingResults > results = std::move( map->mExportLabelingResults );
+  QVERIFY( results );
+  QList<QgsLabelPosition> labels = results->allLabels();
+  QCOMPARE( labels.count(), 3 );
+  std::sort( labels.begin(), labels.end(), []( const QgsLabelPosition & a, const QgsLabelPosition & b )
+  {
+    return a.labelText.compare( b.labelText ) < 0;
+  } );
+  QCOMPARE( labels.at( 0 ).labelText, QStringLiteral( "1" ) );
+  QVERIFY( !labels.at( 0 ).isUnplaced );
+  QCOMPARE( labels.at( 1 ).labelText, QStringLiteral( "33333" ) );
+  QVERIFY( !labels.at( 1 ).isUnplaced );
+  QCOMPARE( labels.at( 2 ).labelText, QStringLiteral( "8888" ) );
+  QVERIFY( !labels.at( 2 ).isUnplaced );
+}
+
 QGSTEST_MAIN( TestQgsLayoutMap )
 #include "testqgslayoutmap.moc"