Render axis for stacked bar diagram

This adds support for rendering the axis on stacked bar diagrams if an axis has been set. The implementation is based on the axis rendering for the histogram diagram. Fixes #34915
qgis · Jul 14, 2020 · 4235b76 · 4235b76
1 parent 15a4c39
commit 4235b76
Showing 1 changed file with 48 additions and 0 deletions.
diff --git a/src/core/diagram/qgsstackedbardiagram.cpp b/src/core/diagram/qgsstackedbardiagram.cpp
@@ -17,6 +17,7 @@
 #include "qgsdiagramrenderer.h"
 #include "qgsrendercontext.h"
 #include "qgsexpression.h"
+#include "qgssymbollayerutils.h"
 
 #include <QPainter>
 
@@ -88,6 +89,13 @@ QSizeF QgsStackedBarDiagram::diagramSize( const QgsFeature &feature, const QgsRe
     }
   }
 
+  if ( s.showAxis() && s.axisLineSymbol() )
+  {
+    const double maxBleed = QgsSymbolLayerUtils::estimateMaxSymbolBleed( s.axisLineSymbol(), c ) / painterUnitConversionScale;
+    size.setWidth( size.width() + 2 * maxBleed );
+    size.setHeight( size.height() + 2 * maxBleed );
+  }
+
   return size;
 }
 
@@ -201,6 +209,15 @@ void QgsStackedBarDiagram::renderDiagram( const QgsFeature &feature, QgsRenderCo
   double baseX = position.x();
   double baseY = position.y();
 
+  if ( s.showAxis() && s.axisLineSymbol() )
+  {
+    // if showing axis, the diagram position needs shifting from the default base x so that the axis
+    // line stroke sits within the desired label engine rect (otherwise we risk overlaps of the axis line stroke)
+    const double maxBleed = QgsSymbolLayerUtils::estimateMaxSymbolBleed( s.axisLineSymbol(), c );
+    baseX += maxBleed;
+    baseY -= maxBleed;
+  }
+
   mPen.setColor( s.penColor );
   setPenWidth( mPen, s, c );
   p->setPen( mPen );
@@ -235,4 +252,35 @@ void QgsStackedBarDiagram::renderDiagram( const QgsFeature &feature, QgsRenderCo
 
     currentOffset += length + spacing;
   }
+
+  if ( s.showAxis() && s.axisLineSymbol() )
+  {
+    s.axisLineSymbol()->startRender( c );
+    QPolygonF axisPoints;
+    switch ( s.diagramOrientation )
+    {
+      case QgsDiagramSettings::Up:
+        axisPoints << QPointF( baseX, baseY - scaledMaxVal ) << QPointF( baseX, baseY ) << QPointF( baseX + scaledWidth, baseY );
+        break;
+
+      case QgsDiagramSettings::Down:
+        axisPoints << QPointF( baseX, baseY ) << QPointF( baseX, baseY - scaledMaxVal ) << QPointF( baseX + scaledWidth, baseY - scaledMaxVal );
+        break;
+
+      case QgsDiagramSettings::Right:
+        axisPoints << QPointF( baseX + scaledMaxVal, baseY - scaledWidth)
+                   << QPointF( baseX, baseY - scaledWidth )
+                   << QPointF( baseX, baseY );
+        break;
+
+      case QgsDiagramSettings::Left:
+        axisPoints << QPointF( baseX, baseY - scaledWidth )
+                   << QPointF( baseX + scaledMaxVal, baseY - scaledWidth )
+                   << QPointF( baseX + scaledMaxVal, baseY );
+        break;
+    }
+
+    s.axisLineSymbol()->renderPolyline( axisPoints, nullptr, c );
+    s.axisLineSymbol()->stopRender( c );
+  }
 }