[FEATURE][diagrams] New diagram type "stacked bars"

Stacks bars of varying colors for each attribute on top of each other
vertically or horizontally.

Sponsored by SLYR

images/images.qrc

@@ -797,6 +797,7 @@
         <file>themes/default/mActionShowUnplacedLabel.svg</file>
         <file>themes/default/mActionHandleStoreFilterExpressionChecked.svg</file>
         <file>themes/default/mActionHandleStoreFilterExpressionUnchecked.svg</file>
+        <file>themes/default/stacked-bar.svg</file>
     </qresource>
     <qresource prefix="/images/tips">
         <file alias="symbol_levels.png">qgis_tips/symbol_levels.png</file>

images/themes/default/stacked-bar.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" height="16" width="16"><path fill="#fce94f" stroke="#c4a000" stroke-linecap="round" d="M4.5 15.5v-7h7v7z"/><path fill="#8ae234" stroke="#4e9a06" stroke-linecap="round" d="M4.5 7.5v-2h7v2z"/><path fill="#ef2929" stroke="#a40000" stroke-linecap="round" d="M4.5 4.5v-4h7v4z"/></svg>

python/core/auto_generated/diagram/qgsdiagram.sip.in

@@ -20,6 +20,19 @@ Base class for all diagram types*
 %End
   public:
 
+%ConvertToSubClassCode
+    if ( sipCpp->diagramName() == QStringLiteral( "Pie" ) )
+      sipType = sipType_QgsPieDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Histogram" ) )
+      sipType = sipType_QgsHistogramDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Text" ) )
+      sipType = sipType_QgsTextDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Stacked" ) )
+      sipType = sipType_QgsStackedBarDiagram;
+    else
+      sipType = NULL;
+%End
+
     virtual ~QgsDiagram();
 
     virtual QgsDiagram *clone() const = 0 /Factory/;

python/core/auto_generated/diagram/qgsstackedbardiagram.sip.in

@@ -0,0 +1,53 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/diagram/qgsstackedbardiagram.h                              *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+
+class QgsStackedBarDiagram: QgsDiagram
+{
+%Docstring
+
+A stacked bar chart diagram.
+
+.. versionadded:: 3.12
+%End
+
+%TypeHeaderCode
+#include "qgsstackedbardiagram.h"
+%End
+  public:
+    QgsStackedBarDiagram();
+
+    virtual QgsStackedBarDiagram *clone() const /Factory/;
+
+
+    virtual void renderDiagram( const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position );
+
+
+    virtual QSizeF diagramSize( const QgsAttributes &attributes, const QgsRenderContext &c, const QgsDiagramSettings &s );
+
+    virtual QSizeF diagramSize( const QgsFeature &feature, const QgsRenderContext &c, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is );
+
+    virtual double legendSize( double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is ) const;
+
+    virtual QString diagramName() const;
+
+
+};
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/diagram/qgsstackedbardiagram.h                              *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/core/core_auto.sip

@@ -252,6 +252,7 @@
 %Include auto_generated/diagram/qgsdiagram.sip
 %Include auto_generated/diagram/qgshistogramdiagram.sip
 %Include auto_generated/diagram/qgspiediagram.sip
+%Include auto_generated/diagram/qgsstackedbardiagram.sip
 %Include auto_generated/diagram/qgstextdiagram.sip
 %Include auto_generated/dxf/qgsdxfexport.sip
 %Include auto_generated/effects/qgsblureffect.sip

src/app/qgsdiagramproperties.cpp

@@ -18,6 +18,7 @@
 #include "diagram/qgshistogramdiagram.h"
 #include "diagram/qgspiediagram.h"
 #include "diagram/qgstextdiagram.h"
+#include "diagram/qgsstackedbardiagram.h"
 
 #include "qgsproject.h"
 #include "qgsapplication.h"
@@ -92,13 +93,15 @@ QgsDiagramProperties::QgsDiagramProperties( QgsVectorLayer *layer, QWidget *pare
 
   mDiagramTypeComboBox->blockSignals( true );
   QPixmap pix = QgsApplication::getThemePixmap( QStringLiteral( "diagramNone" ) );
-  mDiagramTypeComboBox->addItem( pix, tr( "No diagrams" ), "None" );
+  mDiagramTypeComboBox->addItem( pix, tr( "No Diagrams" ), "None" );
   pix = QgsApplication::getThemePixmap( QStringLiteral( "pie-chart" ) );
-  mDiagramTypeComboBox->addItem( pix, tr( "Pie chart" ), DIAGRAM_NAME_PIE );
+  mDiagramTypeComboBox->addItem( pix, tr( "Pie Chart" ), DIAGRAM_NAME_PIE );
   pix = QgsApplication::getThemePixmap( QStringLiteral( "text" ) );
-  mDiagramTypeComboBox->addItem( pix, tr( "Text diagram" ), DIAGRAM_NAME_TEXT );
+  mDiagramTypeComboBox->addItem( pix, tr( "Text Diagram" ), DIAGRAM_NAME_TEXT );
   pix = QgsApplication::getThemePixmap( QStringLiteral( "histogram" ) );
   mDiagramTypeComboBox->addItem( pix, tr( "Histogram" ), DIAGRAM_NAME_HISTOGRAM );
+  pix = QgsApplication::getThemePixmap( QStringLiteral( "stacked-bar" ) );
+  mDiagramTypeComboBox->addItem( pix, tr( "Stacked Bars" ), DIAGRAM_NAME_STACKED );
   mDiagramTypeComboBox->blockSignals( false );
 
   mAxisLineStyleButton->setSymbolType( QgsSymbol::Line );
@@ -549,7 +552,7 @@ void QgsDiagramProperties::mDiagramTypeComboBox_currentIndexChanged( int index )
       mDiagramFontButton->hide();
     }
 
-    if ( DIAGRAM_NAME_HISTOGRAM == mDiagramType )
+    if ( DIAGRAM_NAME_HISTOGRAM == mDiagramType || DIAGRAM_NAME_STACKED == mDiagramType )
     {
       mBarWidthLabel->show();
       mBarWidthSpinBox->show();
@@ -558,9 +561,10 @@ void QgsDiagramProperties::mDiagramTypeComboBox_currentIndexChanged( int index )
       mBarSpacingUnitComboBox->show();
       mBarOptionsFrame->show();
       mShowAxisGroupBox->show();
+      if ( DIAGRAM_NAME_HISTOGRAM == mDiagramType )
         mAttributeBasedScalingRadio->setChecked( true );
-      mFixedSizeRadio->setEnabled( false );
-      mDiagramSizeSpinBox->setEnabled( false );
+      mFixedSizeRadio->setEnabled( DIAGRAM_NAME_STACKED == mDiagramType );
+      mDiagramSizeSpinBox->setEnabled( DIAGRAM_NAME_STACKED == mDiagramType );
       mLinearlyScalingLabel->setText( tr( "Bar length: Scale linearly, so that the following value matches the specified bar length:" ) );
       mSizeLabel->setText( tr( "Bar length" ) );
       mFrameIncreaseSize->setVisible( false );
@@ -748,7 +752,7 @@ void QgsDiagramProperties::apply()
   int index = mDiagramTypeComboBox->currentIndex();
   bool diagramsEnabled = ( index != 0 );
 
-  QgsDiagram *diagram = nullptr;
+  std::unique_ptr< QgsDiagram > diagram;
 
   if ( diagramsEnabled && 0 == mDiagramAttributesTreeWidget->topLevelItemCount() )
   {
@@ -760,15 +764,19 @@ void QgsDiagramProperties::apply()
 
   if ( mDiagramType == DIAGRAM_NAME_TEXT )
   {
-    diagram = new QgsTextDiagram();
+    diagram = qgis::make_unique< QgsTextDiagram >();
   }
   else if ( mDiagramType == DIAGRAM_NAME_PIE )
   {
-    diagram = new QgsPieDiagram();
+    diagram = qgis::make_unique< QgsPieDiagram >();
+  }
+  else if ( mDiagramType == DIAGRAM_NAME_STACKED )
+  {
+    diagram = qgis::make_unique< QgsStackedBarDiagram >();
   }
   else // if ( diagramType == DIAGRAM_NAME_HISTOGRAM )
   {
-    diagram = new QgsHistogramDiagram();
+    diagram = qgis::make_unique< QgsHistogramDiagram >();
   }
 
   QgsDiagramSettings ds;
@@ -799,7 +807,7 @@ void QgsDiagramProperties::apply()
   ds.lineSizeUnit = mDiagramLineUnitComboBox->unit();
   ds.lineSizeScale = mDiagramLineUnitComboBox->getMapUnitScale();
   ds.labelPlacementMethod = static_cast<QgsDiagramSettings::LabelPlacementMethod>( mLabelPlacementComboBox->currentData().toInt() );
-  ds.scaleByArea = mScaleDependencyComboBox->currentData().toBool();
+  ds.scaleByArea = ( mDiagramType == DIAGRAM_NAME_STACKED ) ? false : mScaleDependencyComboBox->currentData().toBool();
 
   if ( mIncreaseSmallDiagramsCheck->isChecked() )
   {
@@ -865,7 +873,7 @@ void QgsDiagramProperties::apply()
 
     renderer = dr;
   }
-  renderer->setDiagram( diagram );
+  renderer->setDiagram( diagram.release() );
   renderer->setAttributeLegend( mCheckBoxAttributeLegend->isChecked() );
   mLayer->setDiagramRenderer( renderer );
 

src/core/CMakeLists.txt

@@ -76,6 +76,7 @@ SET(QGIS_CORE_SRCS
   diagram/qgsdiagram.cpp
   diagram/qgshistogramdiagram.cpp
   diagram/qgspiediagram.cpp
+  diagram/qgsstackedbardiagram.cpp
   diagram/qgstextdiagram.cpp
 
   effects/qgsblureffect.cpp
@@ -944,6 +945,7 @@ SET(QGIS_CORE_HDRS
   diagram/qgsdiagram.h
   diagram/qgshistogramdiagram.h
   diagram/qgspiediagram.h
+  diagram/qgsstackedbardiagram.h
   diagram/qgstextdiagram.h
 
   dxf/qgsdxfexport.h

src/core/diagram/qgsdiagram.h

@@ -39,6 +39,21 @@ class CORE_EXPORT QgsDiagram
 {
   public:
 
+#ifdef SIP_RUN
+    SIP_CONVERT_TO_SUBCLASS_CODE
+    if ( sipCpp->diagramName() == QStringLiteral( "Pie" ) )
+      sipType = sipType_QgsPieDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Histogram" ) )
+      sipType = sipType_QgsHistogramDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Text" ) )
+      sipType = sipType_QgsTextDiagram;
+    else if ( sipCpp->diagramName() == QStringLiteral( "Stacked" ) )
+      sipType = sipType_QgsStackedBarDiagram;
+    else
+      sipType = NULL;
+    SIP_END
+#endif
+
     virtual ~QgsDiagram() { clearCache(); }
 
     /**

src/core/diagram/qgsstackedbardiagram.cpp

@@ -0,0 +1,238 @@
+/***************************************************************************
+    qgsstackedbardiagram.cpp
+    ---------------------
+    begin                : November 2019
+    copyright            : (C) 2019 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsstackedbardiagram.h"
+#include "qgsdiagramrenderer.h"
+#include "qgsrendercontext.h"
+#include "qgsexpression.h"
+
+#include <QPainter>
+
+QgsStackedBarDiagram::QgsStackedBarDiagram()
+{
+  mCategoryBrush.setStyle( Qt::SolidPattern );
+  mPen.setStyle( Qt::SolidLine );
+}
+
+QgsStackedBarDiagram *QgsStackedBarDiagram::clone() const
+{
+  return new QgsStackedBarDiagram( *this );
+}
+
+QSizeF QgsStackedBarDiagram::diagramSize( const QgsFeature &feature, const QgsRenderContext &c, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is )
+{
+  if ( qgsDoubleNear( is.upperValue, is.lowerValue ) )
+    return QSizeF(); // invalid value range => zero size
+
+  QVariant attrVal;
+  if ( is.classificationAttributeIsExpression )
+  {
+    QgsExpressionContext expressionContext = c.expressionContext();
+    if ( !feature.fields().isEmpty() )
+      expressionContext.setFields( feature.fields() );
+    expressionContext.setFeature( feature );
+
+    QgsExpression *expression = getExpression( is.classificationAttributeExpression, expressionContext );
+    attrVal = expression->evaluate( &expressionContext );
+  }
+  else
+  {
+    attrVal = feature.attribute( is.classificationField );
+  }
+
+  bool ok = false;
+  double value = attrVal.toDouble( &ok );
+  if ( !ok )
+  {
+    return QSizeF(); //zero size if attribute is missing
+  }
+
+  QSizeF size = sizeForValue( value, s, is );
+
+  // eh - this method returns size in unknown units ...! We'll have to fake it and use a rough estimation of
+  // a conversion factor to painter units...
+  // TODO QGIS 4.0 -- these methods should all use painter units, dependent on the render context scaling...
+  double painterUnitConversionScale = c.convertToPainterUnits( 1, s.sizeType );
+
+  const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() ) / painterUnitConversionScale;
+  mApplySpacingAdjust = true;
+
+  switch ( s.diagramOrientation )
+  {
+    case QgsDiagramSettings::Up:
+    case QgsDiagramSettings::Down:
+    {
+      const double totalBarLength = size.height() + spacing * std::max( 0, s.categoryAttributes.size() - 1 );
+      size = QSizeF( s.barWidth, totalBarLength );
+      break;
+    }
+
+    case QgsDiagramSettings::Right:
+    case QgsDiagramSettings::Left:
+    {
+      const double totalBarLength = size.width() + spacing * std::max( 0, s.categoryAttributes.size() - 1 );
+      size = QSizeF( totalBarLength, s.barWidth );
+      break;
+    }
+  }
+
+  return size;
+}
+
+double QgsStackedBarDiagram::legendSize( double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is ) const
+{
+  if ( qgsDoubleNear( is.upperValue, is.lowerValue ) )
+    return s.minimumSize; // invalid value range => zero size
+
+  // Scale, if extension is smaller than the specified minimum
+  if ( value < s.minimumSize )
+  {
+    value = s.minimumSize;
+  }
+
+  double scaleFactor = ( ( is.upperSize.width() - is.lowerSize.width() ) / ( is.upperValue - is.lowerValue ) );
+  return value * scaleFactor;
+}
+
+QString QgsStackedBarDiagram::diagramName() const
+{
+  return DIAGRAM_NAME_STACKED;
+}
+
+QSizeF QgsStackedBarDiagram::diagramSize( const QgsAttributes &attributes, const QgsRenderContext &c, const QgsDiagramSettings &s )
+{
+  Q_UNUSED( c )
+  QSizeF size;
+
+  if ( attributes.isEmpty() )
+  {
+    return QSizeF(); //zero size if no attributes
+  }
+
+  double totalSum = 0;
+  for ( int i = 0; i < attributes.count(); ++i )
+  {
+    totalSum += attributes.at( i ).toDouble();
+  }
+
+  // eh - this method returns size in unknown units ...! We'll have to fake it and use a rough estimation of
+  // a conversion factor to painter units...
+  // TODO QGIS 4.0 -- these methods should all use painter units, dependent on the render context scaling...
+  double painterUnitConversionScale = c.convertToPainterUnits( 1, s.sizeType );
+
+  const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() ) / painterUnitConversionScale;
+
+  switch ( s.diagramOrientation )
+  {
+    case QgsDiagramSettings::Up:
+    case QgsDiagramSettings::Down:
+      size.scale( s.barWidth, s.size.height() + spacing * std::max( 0, s.categoryAttributes.size() - 1 ), Qt::IgnoreAspectRatio );
+      break;
+
+    case QgsDiagramSettings::Right:
+    case QgsDiagramSettings::Left:
+      size.scale( s.size.width() + spacing * std::max( 0, s.categoryAttributes.size() - 1 ), s.barWidth, Qt::IgnoreAspectRatio );
+      break;
+  }
+
+  return size;
+}
+
+void QgsStackedBarDiagram::renderDiagram( const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position )
+{
+  QPainter *p = c.painter();
+  if ( !p )
+  {
+    return;
+  }
+
+  QList<double> values;
+
+  QgsExpressionContext expressionContext = c.expressionContext();
+  expressionContext.setFeature( feature );
+  if ( !feature.fields().isEmpty() )
+    expressionContext.setFields( feature.fields() );
+
+  values.reserve( s.categoryAttributes.size() );
+  double total = 0;
+  for ( const QString &cat : qgis::as_const( s.categoryAttributes ) )
+  {
+    QgsExpression *expression = getExpression( cat, expressionContext );
+    double currentVal = expression->evaluate( &expressionContext ).toDouble();
+    values.push_back( currentVal );
+    total += currentVal;
+  }
+
+  const double spacing = c.convertToPainterUnits( s.spacing(), s.spacingUnit(), s.spacingMapUnitScale() );
+  const double totalSpacing = std::max( 0, s.categoryAttributes.size() - 1 ) * spacing;
+
+  double scaledMaxVal = 0;
+  switch ( s.diagramOrientation )
+  {
+    case QgsDiagramSettings::Up:
+    case QgsDiagramSettings::Down:
+      scaledMaxVal = sizePainterUnits( s.size.height(), s, c );
+      break;
+
+    case QgsDiagramSettings::Right:
+    case QgsDiagramSettings::Left:
+      scaledMaxVal = sizePainterUnits( s.size.width(), s, c );
+      break;
+  }
+  if ( mApplySpacingAdjust )
+    scaledMaxVal -= totalSpacing;
+
+  double currentOffset = 0;
+  double scaledWidth = sizePainterUnits( s.barWidth, s, c );
+
+
+  double baseX = position.x();
+  double baseY = position.y();
+
+  mPen.setColor( s.penColor );
+  setPenWidth( mPen, s, c );
+  p->setPen( mPen );
+
+  QList<double>::const_iterator valIt = values.constBegin();
+  QList< QColor >::const_iterator colIt = s.categoryColors.constBegin();
+  for ( ; valIt != values.constEnd(); ++valIt, ++colIt )
+  {
+    double length = *valIt / total * scaledMaxVal;
+
+    mCategoryBrush.setColor( *colIt );
+    p->setBrush( mCategoryBrush );
+
+    switch ( s.diagramOrientation )
+    {
+      case QgsDiagramSettings::Up:
+        p->drawRect( QRectF( baseX, baseY - currentOffset, scaledWidth, length * -1 ) );
+        break;
+
+      case QgsDiagramSettings::Down:
+        p->drawRect( QRectF( baseX, baseY + currentOffset - scaledMaxVal - spacing * std::max( 0, values.size() - 1 ), scaledWidth, length ) );
+        break;
+
+      case QgsDiagramSettings::Right:
+        p->drawRect( QRectF( baseX + currentOffset, baseY - scaledWidth, length, scaledWidth ) );
+        break;
+
+      case QgsDiagramSettings::Left:
+        p->drawRect( QRectF( baseX + scaledMaxVal - currentOffset + spacing * std::max( 0, values.size() - 1 ), baseY - scaledWidth, 0 - length, scaledWidth ) );
+        break;
+    }
+
+    currentOffset += length + spacing;
+  }
+}

src/core/diagram/qgsstackedbardiagram.h

@@ -0,0 +1,64 @@
+/***************************************************************************
+    qgsstackedbardiagram.h
+    ---------------------
+    begin                : November 2019
+    copyright            : (C) 2019 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSSTACKEDBARDIAGRAM_H
+#define QGSSTACKEDBARDIAGRAM_H
+
+#define DIAGRAM_NAME_STACKED "Stacked"
+
+#include "qgis_core.h"
+#include "qgis.h"
+#include "qgsdiagram.h"
+#include <QPen>
+#include <QBrush>
+
+class QgsFeature;
+class QPainter;
+class QPointF;
+class QgsDiagramSettings;
+class QgsDiagramInterpolationSettings;
+
+class QgsRenderContext;
+
+/**
+ * \ingroup core
+ * \class QgsStackedBarDiagram
+ *
+ * A stacked bar chart diagram.
+ *
+ * \since QGIS 3.12
+ */
+class CORE_EXPORT QgsStackedBarDiagram: public QgsDiagram
+{
+  public:
+    QgsStackedBarDiagram();
+
+    QgsStackedBarDiagram *clone() const override SIP_FACTORY;
+
+    void renderDiagram( const QgsFeature &feature, QgsRenderContext &c, const QgsDiagramSettings &s, QPointF position ) override;
+
+    QSizeF diagramSize( const QgsAttributes &attributes, const QgsRenderContext &c, const QgsDiagramSettings &s ) override;
+    QSizeF diagramSize( const QgsFeature &feature, const QgsRenderContext &c, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is ) override;
+    double legendSize( double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is ) const override;
+    QString diagramName() const override;
+
+  private:
+    QBrush mCategoryBrush;
+    QPen   mPen;
+    bool mApplySpacingAdjust = false;
+};
+
+
+#endif // QGSSTACKEDBARDIAGRAM_H

src/core/qgsdiagramrenderer.cpp

@@ -19,6 +19,7 @@
 #include "diagram/qgstextdiagram.h"
 #include "diagram/qgspiediagram.h"
 #include "diagram/qgshistogramdiagram.h"
+#include "diagram/qgsstackedbardiagram.h"
 #include "qgsrendercontext.h"
 #include "qgslayertreemodellegendnode.h"
 #include "qgsfontutils.h"
@@ -300,7 +301,7 @@ void QgsDiagramSettings::readXml( const QDomElement &elem, const QgsReadWriteCon
       categoryColors.append( newColor );
       categoryAttributes.append( attrElem.attribute( QStringLiteral( "field" ) ) );
       categoryLabels.append( attrElem.attribute( QStringLiteral( "label" ) ) );
-      if ( categoryLabels.back().isEmpty() )
+      if ( categoryLabels.constLast().isEmpty() )
       {
         categoryLabels.back() = categoryAttributes.back();
       }
@@ -556,6 +557,10 @@ void QgsDiagramRenderer::_readXml( const QDomElement &elem, const QgsReadWriteCo
   {
     mDiagram.reset( new QgsHistogramDiagram() );
   }
+  else if ( diagramType == QLatin1String( "Stacked" ) )
+  {
+    mDiagram.reset( new QgsStackedBarDiagram() );
+  }
   else
   {
     // unknown diagram type -- default to histograms

src/core/qgsdiagramrenderer.h

@@ -621,7 +621,7 @@ class CORE_EXPORT QgsDiagramSettings
   private:
 
     double mSpacing = 0;
-    QgsUnitTypes::RenderUnit mSpacingUnit;
+    QgsUnitTypes::RenderUnit mSpacingUnit = QgsUnitTypes::RenderMillimeters;
     QgsMapUnitScale mSpacingMapUnitScale;
     Direction mDirection = Counterclockwise;
 

tests/src/core/testqgsdiagram.cpp

@@ -24,21 +24,22 @@
 
 //qgis includes...
 // #include <qgisapp.h>
-#include <diagram/qgspiediagram.h>
-#include <diagram/qgstextdiagram.h>
-#include <qgsdiagramrenderer.h>
-#include <qgsmaplayer.h>
-#include <qgsvectordataprovider.h>
-#include <qgsvectorlayer.h>
-#include <qgsapplication.h>
-#include <qgsproviderregistry.h>
-#include <qgsrenderer.h>
+#include "diagram/qgspiediagram.h"
+#include "diagram/qgstextdiagram.h"
+#include "diagram/qgsstackedbardiagram.h"
+#include "diagram/qgshistogramdiagram.h"
+#include "qgsdiagramrenderer.h"
+#include "qgsmaplayer.h"
+#include "qgsvectordataprovider.h"
+#include "qgsvectorlayer.h"
+#include "qgsapplication.h"
+#include "qgsproviderregistry.h"
+#include "qgsrenderer.h"
 #include "qgssinglesymbolrenderer.h"
 //qgis test includes
 #include "qgsmultirenderchecker.h"
 #include "qgspallabeling.h"
 #include "qgsproject.h"
-#include "diagram/qgshistogramdiagram.h"
 
 /**
  * \ingroup UnitTests
@@ -349,6 +350,103 @@ class TestQgsDiagram : public QObject
 
     }
 
+    void testStackedFixSize()
+    {
+      QgsDiagramSettings ds;
+      QColor col1 = Qt::red;
+      QColor col2 = Qt::yellow;
+      col1.setAlphaF( 0.5 );
+      col2.setAlphaF( 0.5 );
+      ds.categoryColors = QList<QColor>() << col1 << col2;
+      ds.categoryAttributes = QList<QString>() << QStringLiteral( "\"Pilots\"" ) << QStringLiteral( "\"Cabin Crew\"" );
+      ds.minimumScale = -1;
+      ds.maximumScale = -1;
+      ds.minimumSize = 0;
+      ds.penColor = Qt::green;
+      ds.penWidth = .5;
+      ds.scaleByArea = true;
+      ds.sizeType = QgsUnitTypes::RenderMillimeters;
+      ds.size = QSizeF( 15, 15 );
+      ds.rotationOffset = 0;
+      ds.diagramOrientation = QgsDiagramSettings::Up;
+      ds.setSpacing( 3 );
+
+      QgsSingleCategoryDiagramRenderer *dr = new QgsSingleCategoryDiagramRenderer();
+      dr->setDiagram( new QgsStackedBarDiagram() );
+      dr->setDiagramSettings( ds );
+      mPointsLayer->setDiagramRenderer( dr );
+
+      QgsDiagramLayerSettings dls = QgsDiagramLayerSettings();
+      dls.setPlacement( QgsDiagramLayerSettings::OverPoint );
+      dls.setShowAllDiagrams( true );
+      mPointsLayer->setDiagramLayerSettings( dls );
+      QVERIFY( imageCheck( "stacked_up" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Right;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_right" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Left;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_left" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Down;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_down" ) );
+
+    }
+
+    void testStackedVaryingFixSize()
+    {
+      QgsDiagramSettings ds;
+      QColor col1 = Qt::red;
+      QColor col2 = Qt::yellow;
+      col1.setAlphaF( 0.5 );
+      col2.setAlphaF( 0.5 );
+      ds.categoryColors = QList<QColor>() << col1 << col2;
+      ds.categoryAttributes = QList<QString>() << QStringLiteral( "\"Pilots\"" ) << QStringLiteral( "\"Cabin Crew\"" );
+      ds.minimumScale = -1;
+      ds.maximumScale = -1;
+      ds.minimumSize = 0;
+      ds.penColor = Qt::green;
+      ds.penWidth = .5;
+      ds.scaleByArea = true;
+      ds.sizeType = QgsUnitTypes::RenderMillimeters;
+      ds.size = QSizeF( 5, 5 );
+      ds.rotationOffset = 0;
+      ds.diagramOrientation = QgsDiagramSettings::Up;
+      ds.setSpacing( 3 );
+
+      QgsLinearlyInterpolatedDiagramRenderer *dr = new QgsLinearlyInterpolatedDiagramRenderer();
+      dr->setLowerValue( 0.0 );
+      dr->setLowerSize( QSizeF( 0.0, 0.0 ) );
+      dr->setUpperValue( 10 );
+      dr->setUpperSize( QSizeF( 40, 40 ) );
+      dr->setClassificationField( QStringLiteral( "Staff" ) );
+      dr->setDiagram( new QgsStackedBarDiagram() );
+      dr->setDiagramSettings( ds );
+      mPointsLayer->setDiagramRenderer( dr );
+
+      QgsDiagramLayerSettings dls = QgsDiagramLayerSettings();
+      dls.setPlacement( QgsDiagramLayerSettings::OverPoint );
+      dls.setShowAllDiagrams( true );
+      mPointsLayer->setDiagramLayerSettings( dls );
+      QVERIFY( imageCheck( "stacked_varying_up" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Right;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_varying_right" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Left;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_varying_left" ) );
+
+      ds.diagramOrientation = QgsDiagramSettings::Down;
+      dr->setDiagramSettings( ds );
+      QVERIFY( imageCheck( "stacked_varying_down" ) );
+
+    }
+
     void testPieDiagramExpression()
     {
       QgsDiagramSettings ds;