Refactor curved text placement generation to use a flag approach

qgis · Mar 31, 2023 · c8db000 · c8db000
1 parent cd3a1bf
commit c8db000
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Showing 6 changed files with 51 additions and 21 deletions.
diff --git a/src/core/pal/feature.cpp b/src/core/pal/feature.cpp
@@ -1309,7 +1309,7 @@ std::size_t FeaturePart::createCandidatesAlongLineNearMidpoint( std::vector< std
   return lPos.size();
 }
 
-std::unique_ptr< LabelPosition > FeaturePart::curvedPlacementAtOffset( PointSet *mapShape, const std::vector< double> &pathDistances, QgsTextRendererUtils::LabelLineDirection direction, const double offsetAlongLine, bool &labeledLineSegmentIsRightToLeft, bool applyAngleConstraints, bool uprightOnly )
+std::unique_ptr< LabelPosition > FeaturePart::curvedPlacementAtOffset( PointSet *mapShape, const std::vector< double> &pathDistances, QgsTextRendererUtils::LabelLineDirection direction, const double offsetAlongLine, bool &labeledLineSegmentIsRightToLeft, bool applyAngleConstraints, QgsTextRendererUtils::CurvedTextFlags flags )
 {
   const QgsPrecalculatedTextMetrics *metrics = qgis::down_cast< QgsTextLabelFeature * >( mLF )->textMetrics();
   Q_ASSERT( metrics );
@@ -1318,10 +1318,10 @@ std::unique_ptr< LabelPosition > FeaturePart::curvedPlacementAtOffset( PointSet
   const double maximumCharacterAngleOutside = applyAngleConstraints ? std::fabs( qgis::down_cast< QgsTextLabelFeature *>( mLF )->maximumCharacterAngleOutside() ) : -1;
 
   std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > placement(
-    QgsTextRendererUtils::generateCurvedTextPlacement( *metrics, mapShape->x.data(), mapShape->y.data(), mapShape->nbPoints, pathDistances, offsetAlongLine, direction, maximumCharacterAngleInside, maximumCharacterAngleOutside, uprightOnly )
+    QgsTextRendererUtils::generateCurvedTextPlacement( *metrics, mapShape->x.data(), mapShape->y.data(), mapShape->nbPoints, pathDistances, offsetAlongLine, direction, maximumCharacterAngleInside, maximumCharacterAngleOutside, flags )
   );
 
-  labeledLineSegmentIsRightToLeft = !uprightOnly ? placement->labeledLineSegmentIsRightToLeft : placement->flippedCharacterPlacementToGetUprightLabels;
+  labeledLineSegmentIsRightToLeft = !( flags & QgsTextRendererUtils::CurvedTextFlag::UprightCharactersOnly ) ? placement->labeledLineSegmentIsRightToLeft : placement->flippedCharacterPlacementToGetUprightLabels;
 
   if ( placement->graphemePlacement.empty() )
     return nullptr;
@@ -1548,9 +1548,11 @@ std::size_t FeaturePart::createCurvedCandidatesAlongLine( std::vector< std::uniq
       // placements may need to be reversed if using map orientation and the line has right-to-left direction
       bool labeledLineSegmentIsRightToLeft = false;
       const QgsTextRendererUtils::LabelLineDirection direction = ( flags & QgsLabeling::LinePlacementFlag::MapOrientation ) ? QgsTextRendererUtils::RespectPainterOrientation : QgsTextRendererUtils::FollowLineDirection;
-      std::unique_ptr< LabelPosition > labelPosition = curvedPlacementAtOffset( currentMapShape, pathDistances, direction, distanceAlongLineToStartCandidate, labeledLineSegmentIsRightToLeft, !singleCandidateOnly,
-          onlyShowUprightLabels() && ( !singleCandidateOnly || !( flags & QgsLabeling::LinePlacementFlag::MapOrientation ) ) );
+      QgsTextRendererUtils::CurvedTextFlags curvedTextFlags;
+      if ( onlyShowUprightLabels() && ( !singleCandidateOnly || !( flags & QgsLabeling::LinePlacementFlag::MapOrientation ) ) )
+        curvedTextFlags |= QgsTextRendererUtils::CurvedTextFlag::UprightCharactersOnly;
 
+      std::unique_ptr< LabelPosition > labelPosition = curvedPlacementAtOffset( currentMapShape, pathDistances, direction, distanceAlongLineToStartCandidate, labeledLineSegmentIsRightToLeft, !singleCandidateOnly, curvedTextFlags );
       if ( !labelPosition )
       {
         continue;

diff --git a/src/core/pal/feature.h b/src/core/pal/feature.h
@@ -224,7 +224,8 @@ namespace pal
        * \returns calculated label position
        */
       std::unique_ptr< LabelPosition > curvedPlacementAtOffset( PointSet *mapShape, const std::vector<double> &pathDistances,
-          QgsTextRendererUtils::LabelLineDirection direction, double distance, bool &labeledLineSegmentIsRightToLeft, bool applyAngleConstraints, bool uprightOnly );
+          QgsTextRendererUtils::LabelLineDirection direction, double distance, bool &labeledLineSegmentIsRightToLeft, bool applyAngleConstraints,
+          QgsTextRendererUtils::CurvedTextFlags flags );
 
       /**
        * Generate curved candidates for line features.

diff --git a/src/core/textrenderer/qgstextrenderer.cpp b/src/core/textrenderer/qgstextrenderer.cpp
@@ -290,7 +290,13 @@ void QgsTextRenderer::drawDocumentOnLine( const QPolygonF &line, const QgsTextFo
   QgsPrecalculatedTextMetrics metrics( graphemes, std::move( characterWidths ), std::move( characterHeights ), std::move( characterDescents ) );
   metrics.setGraphemeFormats( graphemeFormats );
 
-  std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > placement = QgsTextRendererUtils::generateCurvedTextPlacement( metrics, labelBaselineCurve, offsetAlongLine );
+  std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > placement = QgsTextRendererUtils::generateCurvedTextPlacement(
+        metrics, labelBaselineCurve, offsetAlongLine,
+        QgsTextRendererUtils::RespectPainterOrientation,
+        -1, -1,
+        QgsTextRendererUtils::CurvedTextFlag::UseBaselinePlacement
+        | QgsTextRendererUtils::CurvedTextFlag::UprightCharactersOnly );
+
   if ( placement->graphemePlacement.empty() )
     return;
 

diff --git a/src/core/textrenderer/qgstextrendererutils.cpp b/src/core/textrenderer/qgstextrendererutils.cpp
@@ -151,7 +151,7 @@ QColor QgsTextRendererUtils::readColor( QgsVectorLayer *layer, const QString &pr
   return QColor( r, g, b, a );
 }
 
-std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const QPolygonF &line, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle, double maxConvexAngle, bool uprightOnly )
+std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const QPolygonF &line, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle, double maxConvexAngle, CurvedTextFlags flags )
 {
   const int numPoints = line.size();
   std::vector<double> pathDistances( numPoints );
@@ -182,15 +182,15 @@ std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendere
     y[i] = prevY;
   }
 
-  return generateCurvedTextPlacementPrivate( metrics, x.data(), y.data(), numPoints, pathDistances, offsetAlongLine, direction, maxConcaveAngle, maxConvexAngle, uprightOnly, false, true );
+  return generateCurvedTextPlacementPrivate( metrics, x.data(), y.data(), numPoints, pathDistances, offsetAlongLine, direction, flags, maxConcaveAngle, maxConvexAngle, false );
 }
 
-std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector<double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle, double maxConvexAngle, bool uprightOnly )
+std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector<double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle, double maxConvexAngle, bool uprightOnly, CurvedTextFlags flags )
 {
-  return generateCurvedTextPlacementPrivate( metrics, x, y, numPoints, pathDistances, offsetAlongLine, direction, maxConcaveAngle, maxConvexAngle, uprightOnly );
+  return generateCurvedTextPlacementPrivate( metrics, x, y, numPoints, pathDistances, offsetAlongLine, direction, flags, maxConcaveAngle, maxConvexAngle, uprightOnly );
 }
 
-std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacementPrivate( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector<double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle, double maxConvexAngle, bool uprightOnly, bool isSecondAttempt, bool calculateBaselinePlacement )
+std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendererUtils::generateCurvedTextPlacementPrivate( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector<double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, CurvedTextFlags flags, double maxConcaveAngle, double maxConvexAngle, bool isSecondAttempt )
 {
   std::unique_ptr< CurvePlacementProperties > output = std::make_unique< CurvePlacementProperties >();
   output->graphemePlacement.reserve( metrics.count() );
@@ -314,7 +314,7 @@ std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendere
       }
     }
 
-    if ( !calculateBaselinePlacement )
+    if ( !( flags & CurvedTextFlag::UseBaselinePlacement ) )
     {
       // Shift the character downwards since the draw position is specified at the baseline
       // and we're calculating the mean line here
@@ -354,11 +354,11 @@ std::unique_ptr< QgsTextRendererUtils::CurvePlacementProperties > QgsTextRendere
       output->upsideDownCharCount++;
   }
 
-  if ( !isSecondAttempt && uprightOnly && output->upsideDownCharCount >= characterCount / 2.0 )
+  if ( !isSecondAttempt && ( flags & QgsTextRendererUtils::CurvedTextFlag::UprightCharactersOnly ) && output->upsideDownCharCount >= characterCount / 2.0 )
   {
     // more of text is upside down then right side up...
     // if text should be shown upright then retry with the opposite orientation
-    return generateCurvedTextPlacementPrivate( metrics, x, y, numPoints, pathDistances, offsetAlongLine, direction, maxConcaveAngle, maxConvexAngle, uprightOnly, true );
+    return generateCurvedTextPlacementPrivate( metrics, x, y, numPoints, pathDistances, offsetAlongLine, direction, flags, maxConcaveAngle, maxConvexAngle, true );
   }
 
   return output;

diff --git a/src/core/textrenderer/qgstextrendererutils.h b/src/core/textrenderer/qgstextrendererutils.h
@@ -141,6 +141,24 @@ class CORE_EXPORT QgsTextRendererUtils
       FollowLineDirection //!< Curved text placement will respect the line direction and ignore painter orientation
     };
 
+    /**
+     * Flags controlling behavior of curved text generation.
+     *
+     * \since QGIS 3.2
+     */
+    enum class CurvedTextFlag : int
+    {
+      UseBaselinePlacement = 1 << 1, //!< Generate placement based on the character baselines instead of centers
+      UprightCharactersOnly = 1 << 2, //!< Permit upright characters only. If not present then upside down text placement is permitted.
+    };
+
+    /**
+     * Flags controlling behavior of curved text generation.
+     *
+     * \since QGIS 3.2
+     */
+    Q_DECLARE_FLAGS( CurvedTextFlags, CurvedTextFlag )
+
     /**
      * Calculates curved text placement properties.
      *
@@ -150,12 +168,12 @@ class CORE_EXPORT QgsTextRendererUtils
      * \param direction controls placement of text with respect to painter orientation or line direction
      * \param maxConcaveAngle maximum angle between characters for concave text, or -1 if not set
      * \param maxConvexAngle maximum angle between characters for convex text, or -1 if not set
-     * \param uprightOnly set to TRUE if text should be placed in an upright orientation only, or FALSE to allow upside down text placement
+     * \param flags flags controlling behavior of curved text generation
      *
      * \returns calculated placement properties, or NULLPTR if placement could not be calculated. Caller takes ownership of the returned placement.
      * \since QGIS 3.20
      */
-    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const QPolygonF &line, double offsetAlongLine, LabelLineDirection direction = RespectPainterOrientation, double maxConcaveAngle = -1, double maxConvexAngle = -1, bool uprightOnly = true ) SIP_SKIP;
+    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const QPolygonF &line, double offsetAlongLine, LabelLineDirection direction = RespectPainterOrientation, double maxConcaveAngle = -1, double maxConvexAngle = -1, CurvedTextFlags flags = CurvedTextFlags() ) SIP_SKIP;
 
     /**
      * Calculates curved text placement properties.
@@ -169,17 +187,17 @@ class CORE_EXPORT QgsTextRendererUtils
      * \param direction controls placement of text with respect to painter orientation or line direction
      * \param maxConcaveAngle maximum angle between characters for concave text, or -1 if not set
      * \param maxConvexAngle maximum angle between characters for convex text, or -1 if not set
-     * \param uprightOnly set to TRUE if text should be placed in an upright orientation only, or FALSE to allow upside down text placement
+     * \param flags flags controlling behavior of curved text generation
      *
      * \returns calculated placement properties, or NULLPTR if placement could not be calculated. Caller takes ownership of the returned placement.
      * \since QGIS 3.20
      */
-    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector< double> &pathDistances, double offsetAlongLine, LabelLineDirection direction = RespectPainterOrientation, double maxConcaveAngle = -1, double maxConvexAngle = -1, bool uprightOnly = true ) SIP_SKIP;
+    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacement( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector< double> &pathDistances, double offsetAlongLine, LabelLineDirection direction = RespectPainterOrientation, double maxConcaveAngle = -1, double maxConvexAngle = -1, bool uprightOnly = true, CurvedTextFlags flags = CurvedTextFlags() ) SIP_SKIP;
 #endif
 
   private:
 
-    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacementPrivate( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector< double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, double maxConcaveAngle = -1, double maxConvexAngle = -1, bool uprightOnly = true, bool isSecondAttempt = false, bool calculateBaselinePlacement = false ) SIP_SKIP;
+    static std::unique_ptr< CurvePlacementProperties > generateCurvedTextPlacementPrivate( const QgsPrecalculatedTextMetrics &metrics, const double *x, const double *y, int numPoints, const std::vector< double> &pathDistances, double offsetAlongLine, LabelLineDirection direction, CurvedTextFlags flags, double maxConcaveAngle = -1, double maxConvexAngle = -1, bool isSecondAttempt = false ) SIP_SKIP;
 
     //! Returns TRUE if the next char position is found. The referenced parameters are updated.
     static bool nextCharPosition( double charWidth, double segmentLength, const double *x, const double *y, int numPoints, int &index, double &currentDistanceAlongSegment,
@@ -189,6 +207,9 @@ class CORE_EXPORT QgsTextRendererUtils
                                             double x1, double y1, double x2, double y2,
                                             double &xRes, double &yRes );
 };
+#ifndef SIP_RUN
+Q_DECLARE_OPERATORS_FOR_FLAGS( QgsTextRendererUtils::CurvedTextFlags );
+#endif
 
 
 #endif // QGSTEXTRENDERERUTILS_H
diff --git a/tests/src/python/test_qgsannotationlinetextitem.py b/tests/src/python/test_qgsannotationlinetextitem.py
@@ -272,7 +272,7 @@ def testRenderWithTransform(self):
     def imageCheck(self, name, reference_image, image):
         TestQgsAnnotationLineTextItem.report += f"<h2>Render {name}</h2>\n"
         temp_dir = QDir.tempPath() + '/'
-        file_name = temp_dir + 'patch_' + name + ".png"
+        file_name = temp_dir + 'annotation_' + name + ".png"
         image.save(file_name, "PNG")
         checker = QgsRenderChecker()
         checker.setControlPathPrefix("annotation_layer")