[api] Add labeling flag to collect unplaced labels without rendering …

…them
qgis · Jun 9, 2021 · c95fed5 · c95fed5
1 parent 8e2fb49
commit c95fed5
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Showing 5 changed files with 60 additions and 16 deletions.
diff --git a/python/core/auto_generated/labeling/qgslabelingenginesettings.sip.in b/python/core/auto_generated/labeling/qgslabelingenginesettings.sip.in
@@ -29,6 +29,7 @@ Stores global configuration for labeling engine
       DrawLabelRectOnly,
       DrawCandidates,
       DrawUnplacedLabels,
+      CollectUnplacedLabels,
     };
     typedef QFlags<QgsLabelingEngineSettings::Flag> Flags;
 

diff --git a/src/core/labeling/qgslabelingengine.cpp b/src/core/labeling/qgslabelingengine.cpp
@@ -392,7 +392,9 @@ void QgsLabelingEngine::solve( QgsRenderContext &context )
   }
 
   // find the solution
-  mLabels = mPal->solveProblem( mProblem.get(), settings.testFlag( QgsLabelingEngineSettings::UseAllLabels ), settings.testFlag( QgsLabelingEngineSettings::DrawUnplacedLabels ) ? &mUnlabeled : nullptr );
+  mLabels = mPal->solveProblem( mProblem.get(),
+                                settings.testFlag( QgsLabelingEngineSettings::UseAllLabels ),
+                                settings.testFlag( QgsLabelingEngineSettings::DrawUnplacedLabels ) || settings.testFlag( QgsLabelingEngineSettings::CollectUnplacedLabels ) ? &mUnlabeled : nullptr );
 
   // sort labels
   std::sort( mLabels.begin(), mLabels.end(), QgsLabelSorter( mMapSettings ) );
@@ -476,7 +478,7 @@ void QgsLabelingEngine::drawLabels( QgsRenderContext &context, const QString &la
   }
 
   // draw unplaced labels. These are always rendered on top
-  if ( settings.testFlag( QgsLabelingEngineSettings::DrawUnplacedLabels ) )
+  if ( settings.testFlag( QgsLabelingEngineSettings::DrawUnplacedLabels ) || settings.testFlag( QgsLabelingEngineSettings::CollectUnplacedLabels ) )
   {
     for ( pal::LabelPosition *label : std::as_const( mUnlabeled ) )
     {

diff --git a/src/core/labeling/qgslabelingenginesettings.h b/src/core/labeling/qgslabelingenginesettings.h
@@ -40,6 +40,7 @@ class CORE_EXPORT QgsLabelingEngineSettings
       DrawLabelRectOnly     = 1 << 4,  //!< Whether to only draw the label rect and not the actual label text (used for unit tests)
       DrawCandidates        = 1 << 5,  //!< Whether to draw rectangles of generated candidates (good for debugging)
       DrawUnplacedLabels    = 1 << 6,  //!< Whether to render unplaced labels as an indicator/warning for users
+      CollectUnplacedLabels = 1 << 7,  //!< Whether unplaced labels should be collected in the labeling results (regardless of whether they are being rendered). Since QGIS 3.20
     };
     Q_DECLARE_FLAGS( Flags, Flag )
 

diff --git a/src/core/labeling/qgsvectorlayerlabelprovider.cpp b/src/core/labeling/qgsvectorlayerlabelprovider.cpp
@@ -466,20 +466,23 @@ void QgsVectorLayerLabelProvider::drawLabel( QgsRenderContext &context, pal::Lab
 
 void QgsVectorLayerLabelProvider::drawUnplacedLabel( QgsRenderContext &context, LabelPosition *label ) const
 {
-  if ( !mSettings.drawLabels || mSettings.unplacedVisibility() == Qgis::UnplacedLabelVisibility::NeverShow )
-    return;
-
   QgsTextLabelFeature *lf = dynamic_cast<QgsTextLabelFeature *>( label->getFeaturePart()->feature() );
 
-  QgsPalLayerSettings tmpLyr( mSettings );
-  QgsTextFormat format = tmpLyr.format();
-  format.setColor( mEngine->engineSettings().unplacedLabelColor() );
-  tmpLyr.setFormat( format );
-  drawLabelPrivate( label, context, tmpLyr, QgsTextRenderer::Text );
+  QgsTextFormat format = mSettings.format();
+  if ( mSettings.drawLabels
+       && mSettings.unplacedVisibility() != Qgis::UnplacedLabelVisibility::NeverShow
+       && mEngine->engineSettings().flags() & QgsLabelingEngineSettings::DrawUnplacedLabels )
+  {
+    QgsPalLayerSettings tmpLyr( mSettings );
+    format = tmpLyr.format();
+    format.setColor( mEngine->engineSettings().unplacedLabelColor() );
+    tmpLyr.setFormat( format );
+    drawLabelPrivate( label, context, tmpLyr, QgsTextRenderer::Text );
+  }
 
   // add to the results
   QString labeltext = label->getFeaturePart()->feature()->labelText();
-  mEngine->results()->mLabelSearchTree->insertLabel( label, label->getFeaturePart()->featureId(), mLayerId, labeltext, tmpLyr.format().font(), false, lf->hasFixedPosition(), mProviderId, true );
+  mEngine->results()->mLabelSearchTree->insertLabel( label, label->getFeaturePart()->featureId(), mLayerId, labeltext, format.font(), false, lf->hasFixedPosition(), mProviderId, true );
 }
 
 void QgsVectorLayerLabelProvider::drawLabelPrivate( pal::LabelPosition *label, QgsRenderContext &context, QgsPalLayerSettings &tmpLyr, QgsTextRenderer::TextPart drawType, double dpiRatio ) const

diff --git a/tests/src/core/testqgslabelingengine.cpp b/tests/src/core/testqgslabelingengine.cpp
@@ -1914,7 +1914,7 @@ void TestQgsLabelingEngine::labelingResults()
   settings.fieldName = QStringLiteral( "\"id\"" );
   settings.isExpression = true;
   settings.placement = QgsPalLayerSettings::OverPoint;
-
+  settings.priority = 10;
 
   std::unique_ptr< QgsVectorLayer> vl2( new QgsVectorLayer( QStringLiteral( "Point?crs=epsg:4326&field=id:integer" ), QStringLiteral( "vl" ), QStringLiteral( "memory" ) ) );
   vl2->setRenderer( new QgsNullSymbolRenderer() );
@@ -1931,6 +1931,8 @@ void TestQgsLabelingEngine::labelingResults()
   QVERIFY( vl2->dataProvider()->addFeature( f ) );
   vl2->updateExtents();
 
+  std::unique_ptr< QgsVectorLayer> vl3( vl2->clone() );
+
   vl2->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );  // TODO: this should not be necessary!
   vl2->setLabelsEnabled( true );
 
@@ -1944,7 +1946,7 @@ void TestQgsLabelingEngine::labelingResults()
   mapSettings.setOutputSize( size );
   mapSettings.setExtent( QgsRectangle( -4137976.6, 6557092.6, 1585557.4, 9656515.0 ) );
 // mapSettings.setRotation( 60 );
-  mapSettings.setLayers( QList<QgsMapLayer *>() << vl2.get() );
+  mapSettings.setLayers( QList<QgsMapLayer *>() << vl2.get() << vl3.get() );
   mapSettings.setOutputDpi( 96 );
 
   QgsLabelingEngineSettings engineSettings = mapSettings.labelingEngineSettings();
@@ -1965,11 +1967,11 @@ void TestQgsLabelingEngine::labelingResults()
   QCOMPARE( labels.count(), 3 );
   std::sort( labels.begin(), labels.end(), []( const QgsLabelPosition & a, const QgsLabelPosition & b )
   {
-    return a.labelText.compare( b.labelText );
+    return a.labelText.compare( b.labelText ) < 0;
   } );
   QCOMPARE( labels.at( 0 ).labelText, QStringLiteral( "1" ) );
-  QCOMPARE( labels.at( 1 ).labelText, QStringLiteral( "8888" ) );
-  QCOMPARE( labels.at( 2 ).labelText, QStringLiteral( "33333" ) );
+  QCOMPARE( labels.at( 1 ).labelText, QStringLiteral( "33333" ) );
+  QCOMPARE( labels.at( 2 ).labelText, QStringLiteral( "8888" ) );
 
   labels = results->labelsAtPosition( QgsPointXY( -654732, 7003282 ) );
   QCOMPARE( labels.count(), 1 );
@@ -2015,6 +2017,41 @@ void TestQgsLabelingEngine::labelingResults()
   labels = results->labelsAtPosition( QgsPointXY( -2463392, 6708478 ) );
   QCOMPARE( labels.count(), 0 );
 
+  // with unplaced labels -- all vl3 labels will be unplaced, because they are conflicting with those in vl2
+  settings.priority = 1;
+  vl3->setLabeling( new QgsVectorLayerSimpleLabeling( settings ) );
+  vl3->setLabelsEnabled( true );
+  engineSettings.setFlag( QgsLabelingEngineSettings::CollectUnplacedLabels, true );
+  mapSettings.setLabelingEngineSettings( engineSettings );
+
+  QgsMapRendererSequentialJob jobB( mapSettings );
+  jobB.start();
+  jobB.waitForFinished();
+
+  results.reset( jobB.takeLabelingResults() );
+  QVERIFY( results );
+
+  labels = results->allLabels();
+  QCOMPARE( labels.count(), 6 );
+  std::sort( labels.begin(), labels.end(), []( const QgsLabelPosition & a, const QgsLabelPosition & b )
+  {
+    return a.isUnplaced == b.isUnplaced ? a.labelText.compare( b.labelText ) < 0 : a.isUnplaced < b.isUnplaced;
+  } );
+  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 );
+  QCOMPARE( labels.at( 3 ).labelText, QStringLiteral( "1" ) );
+  QVERIFY( labels.at( 3 ).isUnplaced );
+  QCOMPARE( labels.at( 4 ).labelText, QStringLiteral( "33333" ) );
+  QVERIFY( labels.at( 4 ).isUnplaced );
+  QCOMPARE( labels.at( 5 ).labelText, QStringLiteral( "8888" ) );
+  QVERIFY( labels.at( 5 ).isUnplaced );
+
+  mapSettings.setLayers( {vl2.get() } );
+
   // with rotation
   mapSettings.setRotation( 60 );
   QgsMapRendererSequentialJob job2( mapSettings );