qgslayoutitemelevationprofile.cpp

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/***************************************************************************
                             qgslayoutitemelevationprofile.cpp
                             ---------------------------------
    begin                : January 2023
    copyright            : (C) 2023 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 "qgslayoutitemelevationprofile.h"
 
#include <memory>
 
#include "qgscurve.h"
#include "qgslayout.h"
#include "qgslayoutitemregistry.h"
#include "qgslayoutrendercontext.h"
#include "qgslayoutreportcontext.h"
#include "qgslayoututils.h"
#include "qgslinesymbol.h"
#include "qgsmaplayerlistutils_p.h"
#include "qgsmessagelog.h"
#include "qgspainting.h"
#include "qgsplot.h"
#include "qgsprofilerenderer.h"
#include "qgsprofilerequest.h"
#include "qgsprofilesourceregistry.h"
#include "qgsprojectelevationproperties.h"
#include "qgssymbollayerutils.h"
#include "qgsterrainprovider.h"
#include "qgsvectorlayer.h"
 
#include <QString>
#include <QTimer>
 
#include "moc_qgslayoutitemelevationprofile.cpp"
 
using namespace Qt::StringLiterals;
 
#define CACHE_SIZE_LIMIT 5000

class QgsLayoutItemElevationProfilePlot : public Qgs2DXyPlot
{
  public:
    QgsLayoutItemElevationProfilePlot() {}
 
    void setRenderer( QgsProfilePlotRenderer *renderer )
    {
      // cppcheck-suppress danglingLifetime
      mRenderer = renderer;
    }
 
    void renderContent( QgsRenderContext &rc, QgsPlotRenderContext &, const QRectF &plotArea, const QgsPlotData & ) override
    {
      if ( mRenderer )
      {
        const double distanceMin = xMinimum() * xScale;
        const double distanceMax = xMaximum() * xScale;
        rc.painter()->translate( plotArea.left(), plotArea.top() );
        mRenderer->render( rc, plotArea.width(), plotArea.height(), distanceMin, distanceMax, yMinimum(), yMaximum() );
        rc.painter()->translate( -plotArea.left(), -plotArea.top() );
        mRenderer->renderSubsectionsIndicator( rc, plotArea, distanceMin, distanceMax, yMinimum(), yMaximum() );
      }
    }
 
    double xScale = 1;
 
  private:
    QgsProfilePlotRenderer *mRenderer = nullptr;
};
 
QgsLayoutItemElevationProfile::QgsLayoutItemElevationProfile( QgsLayout *layout )
  : QgsLayoutItem( layout )
  , mPlot( std::make_unique< QgsLayoutItemElevationProfilePlot >() )
{
  mBackgroundUpdateTimer = new QTimer( this );
  mBackgroundUpdateTimer->setSingleShot( true );
  connect( mBackgroundUpdateTimer, &QTimer::timeout, this, &QgsLayoutItemElevationProfile::recreateCachedImageInBackground );
 
  setCacheMode( QGraphicsItem::NoCache );
 
  if ( mLayout )
  {
    connect( mLayout, &QgsLayout::refreshed, this, &QgsLayoutItemElevationProfile::invalidateCache );
  }
 
  connect( this, &QgsLayoutItem::sizePositionChanged, this, [this] { invalidateCache(); } );
 
  //default to no background
  setBackgroundEnabled( false );
 
  connect( QgsApplication::profileSourceRegistry(), &QgsProfileSourceRegistry::profileSourceRegistered, this, &QgsLayoutItemElevationProfile::setSourcesPrivate );
  connect( QgsApplication::profileSourceRegistry(), &QgsProfileSourceRegistry::profileSourceUnregistered, this, &QgsLayoutItemElevationProfile::setSourcesPrivate );
 
  setSourcesPrivate(); // Initialize with registered sources
}
 
QgsLayoutItemElevationProfile::~QgsLayoutItemElevationProfile()
{
  if ( mRenderJob )
  {
    disconnect( mRenderJob.get(), &QgsProfilePlotRenderer::generationFinished, this, &QgsLayoutItemElevationProfile::profileGenerationFinished );
    emit backgroundTaskCountChanged( 0 );
    mRenderJob->cancelGeneration(); // blocks
    mPainter->end();
  }
}
 
QgsLayoutItemElevationProfile *QgsLayoutItemElevationProfile::create( QgsLayout *layout )
{
  return new QgsLayoutItemElevationProfile( layout );
}
 
int QgsLayoutItemElevationProfile::type() const
{
  return QgsLayoutItemRegistry::LayoutElevationProfile;
}
 
QIcon QgsLayoutItemElevationProfile::icon() const
{
  return QgsApplication::getThemeIcon( u"mLayoutItemElevationProfile.svg"_s );
}
 
void QgsLayoutItemElevationProfile::refreshDataDefinedProperty( DataDefinedProperty property )
{
  const QgsExpressionContext context = createExpressionContext();
 
  bool forceUpdate = false;
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileTolerance || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileTolerance ) ) )
  {
    double value = mTolerance;
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileTolerance, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile tolerance expression eval error" ) );
    }
    else
    {
      mTolerance = value;
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumDistance || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumDistance ) ) )
  {
    double value = mPlot->xMinimum();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumDistance, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile minimum distance expression eval error" ) );
    }
    else
    {
      mPlot->setXMinimum( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumDistance || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumDistance ) ) )
  {
    double value = mPlot->xMaximum();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumDistance, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile maximum distance expression eval error" ) );
    }
    else
    {
      mPlot->setXMaximum( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumElevation || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumElevation ) ) )
  {
    double value = mPlot->yMinimum();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileMinimumElevation, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile minimum elevation expression eval error" ) );
    }
    else
    {
      mPlot->setYMinimum( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumElevation || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumElevation ) ) )
  {
    double value = mPlot->yMaximum();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileMaximumElevation, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile maximum elevation expression eval error" ) );
    }
    else
    {
      mPlot->setYMaximum( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMajorInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMajorInterval ) ) )
  {
    double value = mPlot->xAxis().gridIntervalMajor();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMajorInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile distance axis major interval expression eval error" ) );
    }
    else
    {
      mPlot->xAxis().setGridIntervalMajor( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMinorInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMinorInterval ) ) )
  {
    double value = mPlot->xAxis().gridIntervalMinor();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceMinorInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile distance axis minor interval expression eval error" ) );
    }
    else
    {
      mPlot->xAxis().setGridIntervalMinor( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceLabelInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceLabelInterval ) ) )
  {
    double value = mPlot->xAxis().labelInterval();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileDistanceLabelInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile distance axis label interval expression eval error" ) );
    }
    else
    {
      mPlot->xAxis().setLabelInterval( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMajorInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMajorInterval ) ) )
  {
    double value = mPlot->yAxis().gridIntervalMajor();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMajorInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile elevation axis major interval expression eval error" ) );
    }
    else
    {
      mPlot->yAxis().setGridIntervalMajor( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMinorInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMinorInterval ) ) )
  {
    double value = mPlot->yAxis().gridIntervalMinor();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationMinorInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile elevation axis minor interval expression eval error" ) );
    }
    else
    {
      mPlot->yAxis().setGridIntervalMinor( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationLabelInterval || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationLabelInterval ) ) )
  {
    double value = mPlot->yAxis().labelInterval();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::ElevationProfileElevationLabelInterval, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile elevation axis label interval expression eval error" ) );
    }
    else
    {
      mPlot->yAxis().setLabelInterval( value );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::MarginLeft || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::MarginLeft ) ) )
  {
    double value = mPlot->margins().left();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::MarginLeft, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile left margin expression eval error" ) );
    }
    else
    {
      QgsMargins margins = mPlot->margins();
      margins.setLeft( value );
      mPlot->setMargins( margins );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::MarginRight || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::MarginRight ) ) )
  {
    double value = mPlot->margins().right();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::MarginRight, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile right margin expression eval error" ) );
    }
    else
    {
      QgsMargins margins = mPlot->margins();
      margins.setRight( value );
      mPlot->setMargins( margins );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::MarginTop || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::MarginTop ) ) )
  {
    double value = mPlot->margins().top();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::MarginTop, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile top margin expression eval error" ) );
    }
    else
    {
      QgsMargins margins = mPlot->margins();
      margins.setTop( value );
      mPlot->setMargins( margins );
    }
 
    forceUpdate = true;
  }
 
  if ( ( property == QgsLayoutObject::DataDefinedProperty::MarginBottom || property == QgsLayoutObject::DataDefinedProperty::AllProperties )
       && ( mDataDefinedProperties.isActive( QgsLayoutObject::DataDefinedProperty::MarginBottom ) ) )
  {
    double value = mPlot->margins().bottom();
 
    bool ok = false;
    value = mDataDefinedProperties.valueAsDouble( QgsLayoutObject::DataDefinedProperty::MarginBottom, context, value, &ok );
 
    if ( !ok )
    {
      QgsMessageLog::logMessage( tr( "Elevation profile bottom margin expression eval error" ) );
    }
    else
    {
      QgsMargins margins = mPlot->margins();
      margins.setBottom( value );
      mPlot->setMargins( margins );
    }
 
    forceUpdate = true;
  }
 
  if ( forceUpdate )
  {
    mCacheInvalidated = true;
 
    refreshItemSize();
    update();
  }
 
  QgsLayoutItem::refreshDataDefinedProperty( property );
}
 
QgsLayoutItem::Flags QgsLayoutItemElevationProfile::itemFlags() const
{
  return QgsLayoutItem::FlagOverridesPaint | QgsLayoutItem::FlagDisableSceneCaching;
}
 
bool QgsLayoutItemElevationProfile::requiresRasterization() const
{
  return blendMode() != QPainter::CompositionMode_SourceOver;
}
 
bool QgsLayoutItemElevationProfile::containsAdvancedEffects() const
{
  return mEvaluatedOpacity < 1.0;
}
 
Qgs2DXyPlot *QgsLayoutItemElevationProfile::plot()
{
  return mPlot.get();
}
 
const Qgs2DXyPlot *QgsLayoutItemElevationProfile::plot() const
{
  return mPlot.get();
}
 
QList<QgsMapLayer *> QgsLayoutItemElevationProfile::layers() const
{
  return _qgis_listRefToRaw( mLayers );
}
 
void QgsLayoutItemElevationProfile::setLayers( const QList<QgsMapLayer *> &layers )
{
  if ( layers == _qgis_listRefToRaw( mLayers ) )
    return;
 
  mLayers = _qgis_listRawToRef( layers );
  invalidateCache();
}
 
QList<QgsAbstractProfileSource *> QgsLayoutItemElevationProfile::sources() const
{
  if ( mSources.isEmpty() && !mLayers.isEmpty() )
  {
    // Legacy: If we have layers, extract their sources and return them.
    // We don't set mSources here, because we want the previous check to
    // continue failing if only layers are set.
    // TODO: Remove this if block in QGIS 5.0 along with setLayers/layers methods.
    QList< QgsAbstractProfileSource * > sources;
    const QList<QgsMapLayer *> layersToGenerate = layers();
    sources.reserve( layersToGenerate.size() );
 
    for ( QgsMapLayer *layer : layersToGenerate )
    {
      if ( QgsAbstractProfileSource *source = layer->profileSource() )
        sources << source;
    }
 
    // More legacy: elevation profile layers are in opposite direction
    // to what the layer tree requires, and are in the same direction as
    // the renderer expects, but since we reverse sources() (i.e., layers)
    // before passing them to the renderer, then we need to reverse here first.
    std::reverse( sources.begin(), sources.end() );
 
    return sources;
  }
 
  QList< QgsAbstractProfileSource * > sources;
  sources.reserve( mSources.count() );
  for ( const auto &source : mSources )
  {
    if ( const QgsMapLayerRef *layerRef = std::get_if< QgsMapLayerRef >( &source ) )
    {
      if ( QgsMapLayer *layer = layerRef->get() )
      {
        sources << layer->profileSource();
      }
    }
    else if ( auto profileSource = std::get_if< QgsAbstractProfileSource * >( &source ) )
    {
      if ( QgsApplication::profileSourceRegistry()->findSourceById( ( *profileSource )->profileSourceId() ) )
      {
        sources << *profileSource;
      }
    }
  }
 
  return sources;
}
 
void QgsLayoutItemElevationProfile::setSources( const QList<QgsAbstractProfileSource *> &sources )
{
  mSources.clear();
  mSources.reserve( sources.count() );
  for ( QgsAbstractProfileSource *profileSource : sources )
  {
    if ( auto layer = dynamic_cast<QgsMapLayer *>( profileSource ) )
    {
      mSources << QgsMapLayerRef( layer );
    }
    else if ( QgsApplication::profileSourceRegistry()->findSourceById( profileSource->profileSourceId() ) )
    {
      mSources << profileSource;
    }
  }
 
  invalidateCache();
}
 
void QgsLayoutItemElevationProfile::setProfileCurve( QgsCurve *curve )
{
  mCurve.reset( curve );
  invalidateCache();
}
 
QgsCurve *QgsLayoutItemElevationProfile::profileCurve() const
{
  return mCurve.get();
}
 
void QgsLayoutItemElevationProfile::setCrs( const QgsCoordinateReferenceSystem &crs )
{
  if ( mCrs == crs )
    return;
 
  mCrs = crs;
  invalidateCache();
}
 
QgsCoordinateReferenceSystem QgsLayoutItemElevationProfile::crs() const
{
  return mCrs;
}
 
void QgsLayoutItemElevationProfile::setTolerance( double tolerance )
{
  if ( mTolerance == tolerance )
    return;
 
  mTolerance = tolerance;
  invalidateCache();
}
 
double QgsLayoutItemElevationProfile::tolerance() const
{
  return mTolerance;
}
 
void QgsLayoutItemElevationProfile::setAtlasDriven( bool enabled )
{
  mAtlasDriven = enabled;
}
 
QgsProfileRequest QgsLayoutItemElevationProfile::profileRequest() const
{
  QgsProfileRequest req( mCurve ? mCurve.get()->clone() : nullptr );
 
  req.setCrs( mCrs );
  req.setTolerance( mTolerance );
  req.setExpressionContext( createExpressionContext() );
  if ( mLayout )
  {
    if ( QgsProject *project = mLayout->project() )
    {
      req.setTransformContext( project->transformContext() );
      if ( QgsAbstractTerrainProvider *provider = project->elevationProperties()->terrainProvider() )
      {
        req.setTerrainProvider( provider->clone() );
      }
    }
  }
  return req;
}
 
void QgsLayoutItemElevationProfile::paint( QPainter *painter, const QStyleOptionGraphicsItem *itemStyle, QWidget * )
{
  if ( !mLayout || !painter || !painter->device() || !mUpdatesEnabled )
  {
    return;
  }
  if ( !shouldDrawItem() )
  {
    return;
  }
 
  QRectF thisPaintRect = rect();
  if ( qgsDoubleNear( thisPaintRect.width(), 0.0 ) || qgsDoubleNear( thisPaintRect.height(), 0 ) )
    return;
 
  QgsRenderContext rc = QgsLayoutUtils::createRenderContextForLayout( mLayout, painter );
  calculateAxisRanges( rc );
 
  if ( mLayout->renderContext().isPreviewRender() )
  {
    rc.setExpressionContext( createExpressionContext() );
 
    QgsScopedQPainterState painterState( painter );
    painter->setClipRect( thisPaintRect );
    if ( !mCacheFinalImage || mCacheFinalImage->isNull() )
    {
      // No initial render available - so draw some preview text alerting user
      painter->setBrush( QBrush( QColor( 125, 125, 125, 125 ) ) );
      painter->drawRect( thisPaintRect );
      painter->setBrush( Qt::NoBrush );
      QFont messageFont;
      messageFont.setPointSize( 12 );
      painter->setFont( messageFont );
      painter->setPen( QColor( 255, 255, 255, 255 ) );
      painter->drawText( thisPaintRect, Qt::AlignCenter | Qt::AlignHCenter, tr( "Rendering profile" ) );
 
      if (
        ( mRenderJob && mCacheInvalidated && !mDrawingPreview ) // current job was invalidated - start a new one
        || ( !mRenderJob && !mDrawingPreview )                  // this is the profiles's very first paint - trigger a cache update
      )
      {
        mPreviewScaleFactor = QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle, painter );
        mBackgroundUpdateTimer->start( 1 );
      }
    }
    else
    {
      if ( mCacheInvalidated && !mDrawingPreview )
      {
        // cache was invalidated - trigger a background update
        mPreviewScaleFactor = QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle, painter );
        mBackgroundUpdateTimer->start( 1 );
      }
 
      //Background color is already included in cached image, so no need to draw
 
      double imagePixelWidth = mCacheFinalImage->width(); //how many pixels of the image are for the map extent?
      double scale = rect().width() / imagePixelWidth;
 
      QgsScopedQPainterState rotatedPainterState( painter );
 
      painter->scale( scale, scale );
      painter->setCompositionMode( blendModeForRender() );
      painter->drawImage( 0, 0, *mCacheFinalImage );
    }
 
    painter->setClipRect( thisPaintRect, Qt::NoClip );
 
    if ( frameEnabled() )
    {
      QgsLayoutItem::drawFrame( rc );
    }
  }
  else
  {
    if ( mDrawing )
      return;
 
    mDrawing = true;
    QPaintDevice *paintDevice = painter->device();
    if ( !paintDevice )
      return;
 
    QSizeF layoutSize = mLayout->convertToLayoutUnits( sizeWithUnits() );
 
    if ( mLayout->renderContext().flags() & Qgis::LayoutRenderFlag::LosslessImageRendering )
      painter->setRenderHint( QPainter::LosslessImageRendering, true );
 
    mPlot->xScale = QgsUnitTypes::fromUnitToUnitFactor( mDistanceUnit, mCrs.mapUnits() );
 
    if ( !qgsDoubleNear( layoutSize.width(), 0.0 ) && !qgsDoubleNear( layoutSize.height(), 0.0 ) )
    {
      const bool forceVector = mLayout && mLayout->renderContext().rasterizedRenderingPolicy() == Qgis::RasterizedRenderingPolicy::ForceVector;
      if ( ( containsAdvancedEffects() || ( blendModeForRender() != QPainter::CompositionMode_SourceOver ) ) && !forceVector )
      {
        // rasterize
        double destinationDpi = QgsLayoutUtils::scaleFactorFromItemStyle( itemStyle, painter ) * 25.4;
        double layoutUnitsInInches = mLayout ? mLayout->convertFromLayoutUnits( 1, Qgis::LayoutUnit::Inches ).length() : 1;
        int widthInPixels = static_cast< int >( std::round( boundingRect().width() * layoutUnitsInInches * destinationDpi ) );
        int heightInPixels = static_cast< int >( std::round( boundingRect().height() * layoutUnitsInInches * destinationDpi ) );
        QImage image = QImage( widthInPixels, heightInPixels, QImage::Format_ARGB32 );
 
        image.fill( Qt::transparent );
        image.setDotsPerMeterX( static_cast< int >( std::round( 1000 * destinationDpi / 25.4 ) ) );
        image.setDotsPerMeterY( static_cast< int >( std::round( 1000 * destinationDpi / 25.4 ) ) );
        double dotsPerMM = destinationDpi / 25.4;
        layoutSize *= dotsPerMM; // output size will be in dots (pixels)
        QPainter p( &image );
        preparePainter( &p );
 
        QgsRenderContext rc = QgsLayoutUtils::createRenderContextForLayout( mLayout, &p );
        rc.setExpressionContext( createExpressionContext() );
 
        p.scale( dotsPerMM, dotsPerMM );
        if ( hasBackground() )
        {
          QgsLayoutItem::drawBackground( rc );
        }
 
        p.scale( 1.0 / dotsPerMM, 1.0 / dotsPerMM );
 
        const double mapUnitsPerPixel = static_cast<double>( mPlot->xMaximum() - mPlot->xMinimum() ) * mPlot->xScale / layoutSize.width();
        rc.setMapToPixel( QgsMapToPixel( mapUnitsPerPixel ) );
 
        QList< QgsAbstractProfileSource *> sourcesToRender = sources();
        std::reverse( sourcesToRender.begin(), sourcesToRender.end() ); // sources are rendered from bottom to top
 
        QgsProfilePlotRenderer renderer( sourcesToRender, profileRequest() );
        std::unique_ptr<QgsLineSymbol> rendererSubSectionsSymbol( subsectionsSymbol() ? subsectionsSymbol()->clone() : nullptr );
        renderer.setSubsectionsSymbol( rendererSubSectionsSymbol.release() );
 
        renderer.generateSynchronously();
        mPlot->setRenderer( &renderer );
 
        // size must be in pixels, not layout units
        mPlot->setSize( layoutSize );
 
        QgsPlotRenderContext plotContext;
        mPlot->render( rc, plotContext );
 
        mPlot->setRenderer( nullptr );
 
        p.scale( dotsPerMM, dotsPerMM );
 
        if ( frameEnabled() )
        {
          QgsLayoutItem::drawFrame( rc );
        }
 
        QgsScopedQPainterState painterState( painter );
        painter->setCompositionMode( blendModeForRender() );
        painter->scale( 1 / dotsPerMM, 1 / dotsPerMM ); // scale painter from mm to dots
        painter->drawImage( 0, 0, image );
        painter->scale( dotsPerMM, dotsPerMM );
      }
      else
      {
        QgsRenderContext rc = QgsLayoutUtils::createRenderContextForLayout( mLayout, painter );
        rc.setExpressionContext( createExpressionContext() );
 
        // Fill with background color
        if ( hasBackground() )
        {
          QgsLayoutItem::drawBackground( rc );
        }
 
        QgsScopedQPainterState painterState( painter );
        QgsScopedQPainterState stagedPainterState( painter );
        double dotsPerMM = paintDevice->logicalDpiX() / 25.4;
        layoutSize *= dotsPerMM;                        // output size will be in dots (pixels)
        painter->scale( 1 / dotsPerMM, 1 / dotsPerMM ); // scale painter from mm to dots
 
        const double mapUnitsPerPixel = static_cast<double>( mPlot->xMaximum() - mPlot->xMinimum() ) * mPlot->xScale / layoutSize.width();
        rc.setMapToPixel( QgsMapToPixel( mapUnitsPerPixel ) );
 
        QList< QgsAbstractProfileSource *> sourcesToRender = sources();
        std::reverse( sourcesToRender.begin(), sourcesToRender.end() ); // sources are rendered from bottom to top
 
        QgsProfilePlotRenderer renderer( sourcesToRender, profileRequest() );
        std::unique_ptr<QgsLineSymbol> rendererSubSectionsSymbol( subsectionsSymbol() ? subsectionsSymbol()->clone() : nullptr );
        renderer.setSubsectionsSymbol( rendererSubSectionsSymbol.release() );
 
        // TODO
        // we should be able to call renderer.start()/renderer.waitForFinished() here and
        // benefit from parallel source generation. BUT
        // for some reason the QtConcurrent::map call in start() never triggers
        // the actual background thread execution.
        // So for now just generate the results one by one
        renderer.generateSynchronously();
        mPlot->setRenderer( &renderer );
 
        // size must be in pixels, not layout units
        mPlot->setSize( layoutSize );
 
        QgsPlotRenderContext plotContext;
        mPlot->render( rc, plotContext );
 
        mPlot->setRenderer( nullptr );
 
        painter->setClipRect( thisPaintRect, Qt::NoClip );
 
        if ( frameEnabled() )
        {
          QgsLayoutItem::drawFrame( rc );
        }
      }
    }
 
    mDrawing = false;
  }
}
 
void QgsLayoutItemElevationProfile::refresh()
{
  if ( mAtlasDriven && mLayout && mLayout->reportContext().layer() )
  {
    if ( QgsVectorLayer *layer = mLayout->reportContext().layer() )
    {
      mCrs = layer->crs();
    }
    const QgsGeometry curveGeom( mLayout->reportContext().currentGeometry( mCrs ) );
    if ( const QgsAbstractGeometry *geom = curveGeom.constGet() )
    {
      if ( const QgsCurve *curve = qgsgeometry_cast< const QgsCurve * >( geom->simplifiedTypeRef() ) )
      {
        mCurve.reset( curve->clone() );
      }
    }
  }
 
  QgsLayoutItem::refresh();
  invalidateCache();
}
 
void QgsLayoutItemElevationProfile::invalidateCache()
{
  if ( mDrawing )
    return;
 
  mCacheInvalidated = true;
  update();
}
 
void QgsLayoutItemElevationProfile::draw( QgsLayoutItemRenderContext & )
{}
 
bool QgsLayoutItemElevationProfile::writePropertiesToElement( QDomElement &layoutProfileElem, QDomDocument &doc, const QgsReadWriteContext &rwContext ) const
{
  {
    QDomElement plotElement = doc.createElement( u"plot"_s );
    mPlot->writeXml( plotElement, doc, rwContext );
    layoutProfileElem.appendChild( plotElement );
  }
 
  if ( mRangeMethod != Qgis::ElevationProfileRangeMethod::ManualRange )
  {
    layoutProfileElem.setAttribute( u"rangeMethod"_s, qgsEnumValueToKey( mRangeMethod ) );
  }
  if ( !qgsDoubleNear( mDistanceScale, 1000 ) )
  {
    layoutProfileElem.setAttribute( u"distanceScale"_s, qgsDoubleToString( mDistanceScale ) );
  }
  if ( !qgsDoubleNear( mElevationScale, 10 ) )
  {
    layoutProfileElem.setAttribute( u"elevationScale"_s, qgsDoubleToString( mElevationScale ) );
  }
 
  layoutProfileElem.setAttribute( u"distanceUnit"_s, qgsEnumValueToKey( mDistanceUnit ) );
 
  layoutProfileElem.setAttribute( u"tolerance"_s, mTolerance );
  layoutProfileElem.setAttribute( u"atlasDriven"_s, mAtlasDriven ? u"1"_s : u"0"_s );
  if ( mCrs.isValid() )
  {
    QDomElement crsElem = doc.createElement( u"crs"_s );
    mCrs.writeXml( crsElem, doc );
    layoutProfileElem.appendChild( crsElem );
  }
  if ( mCurve )
  {
    QDomElement curveElem = doc.createElement( u"curve"_s );
    curveElem.appendChild( doc.createTextNode( mCurve->asWkt() ) );
    layoutProfileElem.appendChild( curveElem );
  }
 
  {
    QDomElement layersElement = doc.createElement( u"layers"_s );
    for ( const QgsMapLayerRef &layer : mLayers )
    {
      QDomElement layerElement = doc.createElement( u"layer"_s );
      layer.writeXml( layerElement, rwContext );
      layersElement.appendChild( layerElement );
    }
    layoutProfileElem.appendChild( layersElement );
  }
 
  {
    QDomElement sourcesElement = doc.createElement( u"profileSources"_s );
    for ( const auto &source : mSources )
    {
      if ( const QgsMapLayerRef *layerRef = std::get_if< QgsMapLayerRef >( &source ) )
      {
        if ( layerRef->get() )
        {
          QDomElement sourceElement = doc.createElement( u"profileLayerSource"_s );
          layerRef->writeXml( sourceElement, rwContext );
          sourcesElement.appendChild( sourceElement );
        }
      }
      else if ( auto profileSource = std::get_if< QgsAbstractProfileSource * >( &source ) )
      {
        if ( QgsApplication::profileSourceRegistry()->findSourceById( ( *profileSource )->profileSourceId() ) )
        {
          QDomElement sourceElement = doc.createElement( u"profileCustomSource"_s );
          sourceElement.setAttribute( u"id"_s, ( *profileSource )->profileSourceId() );
          sourcesElement.appendChild( sourceElement );
        }
      }
    }
 
    layoutProfileElem.appendChild( sourcesElement );
  }
 
  if ( mSubsectionsSymbol )
  {
    QDomElement subsectionsElement = doc.createElement( u"subsections"_s );
    const QDomElement symbolElement = QgsSymbolLayerUtils::saveSymbol( u"subsections"_s, mSubsectionsSymbol.get(), doc, rwContext );
    subsectionsElement.appendChild( symbolElement );
    layoutProfileElem.appendChild( subsectionsElement );
  }
 
  return true;
}
 
bool QgsLayoutItemElevationProfile::readPropertiesFromElement( const QDomElement &itemElem, const QDomDocument &, const QgsReadWriteContext &context )
{
  const QDomElement plotElement = itemElem.firstChildElement( u"plot"_s );
  if ( !plotElement.isNull() )
  {
    mPlot->readXml( plotElement, context );
  }
 
  const QDomNodeList crsNodeList = itemElem.elementsByTagName( u"crs"_s );
  QgsCoordinateReferenceSystem crs;
  if ( !crsNodeList.isEmpty() )
  {
    const QDomElement crsElem = crsNodeList.at( 0 ).toElement();
    crs.readXml( crsElem );
  }
  mCrs = crs;
 
  mRangeMethod = qgsEnumKeyToValue( itemElem.attribute( u"rangeMethod"_s ), Qgis::ElevationProfileRangeMethod::ManualRange );
  mDistanceScale = itemElem.attribute( u"distanceScale"_s ).toDouble();
  mElevationScale = itemElem.attribute( u"elevationScale"_s ).toDouble();
 
  setDistanceUnit( qgsEnumKeyToValue( itemElem.attribute( u"distanceUnit"_s ), mCrs.mapUnits() ) );
 
  const QDomNodeList curveNodeList = itemElem.elementsByTagName( u"curve"_s );
  if ( !curveNodeList.isEmpty() )
  {
    const QDomElement curveElem = curveNodeList.at( 0 ).toElement();
    const QgsGeometry curve = QgsGeometry::fromWkt( curveElem.text() );
    if ( const QgsCurve *curveGeom = qgsgeometry_cast< const QgsCurve * >( curve.constGet() ) )
    {
      mCurve.reset( curveGeom->clone() );
    }
    else
    {
      mCurve.reset();
    }
  }
 
  mTolerance = itemElem.attribute( u"tolerance"_s ).toDouble();
  mAtlasDriven = static_cast< bool >( itemElem.attribute( u"atlasDriven"_s, u"0"_s ).toInt() );
 
  {
    mLayers.clear();
    const QDomElement layersElement = itemElem.firstChildElement( u"layers"_s );
    QDomElement layerElement = layersElement.firstChildElement( u"layer"_s );
    while ( !layerElement.isNull() )
    {
      QgsMapLayerRef ref;
      ref.readXml( layerElement, context );
      ref.resolveWeakly( mLayout->project() );
      mLayers.append( ref );
 
      layerElement = layerElement.nextSiblingElement( u"layer"_s );
    }
  }
 
  {
    mSources.clear();
    mSources.reserve( itemElem.elementsByTagName( u"profileSources"_s ).count() );
    const QDomElement sourcesElement = itemElem.firstChildElement( u"profileSources"_s );
    QDomElement sourceElement = sourcesElement.firstChildElement();
    while ( !sourceElement.isNull() )
    {
      if ( sourceElement.tagName() == "profileCustomSource"_L1 )
      {
        const QString sourceId = sourceElement.attribute( u"id"_s );
        if ( QgsAbstractProfileSource *profileSource = QgsApplication::profileSourceRegistry()->findSourceById( sourceId ) )
        {
          mSources << profileSource;
        }
      }
      else if ( sourceElement.tagName() == "profileLayerSource"_L1 )
      {
        QgsMapLayerRef ref;
        ref.readXml( sourceElement, context );
        ref.resolveWeakly( mLayout->project() );
        if ( ref.get() )
        {
          mSources << ref;
        }
      }
 
      sourceElement = sourceElement.nextSiblingElement();
    }
  }
 
  const QDomElement subsectionsElement = itemElem.firstChildElement( u"subsections"_s );
  const QDomElement symbolsElement = subsectionsElement.firstChildElement( u"symbol"_s );
  if ( !symbolsElement.isNull() )
  {
    std::unique_ptr< QgsLineSymbol > subSectionsSymbol = QgsSymbolLayerUtils::loadSymbol<QgsLineSymbol >( symbolsElement, context );
    if ( subSectionsSymbol )
    {
      setSubsectionsSymbol( subSectionsSymbol.release() );
    }
  }
 
  return true;
}
 
void QgsLayoutItemElevationProfile::recreateCachedImageInBackground()
{
  if ( mRenderJob )
  {
    disconnect( mRenderJob.get(), &QgsProfilePlotRenderer::generationFinished, this, &QgsLayoutItemElevationProfile::profileGenerationFinished );
    QgsProfilePlotRenderer *oldJob = mRenderJob.release();
    QPainter *oldPainter = mPainter.release();
    QImage *oldImage = mCacheRenderingImage.release();
    connect( oldJob, &QgsProfilePlotRenderer::generationFinished, this, [oldPainter, oldJob, oldImage] {
      oldJob->deleteLater();
      delete oldPainter;
      delete oldImage;
    } );
    oldJob->cancelGenerationWithoutBlocking();
  }
  else
  {
    mCacheRenderingImage.reset( nullptr );
    emit backgroundTaskCountChanged( 1 );
  }
 
  Q_ASSERT( !mRenderJob );
  Q_ASSERT( !mPainter );
  Q_ASSERT( !mCacheRenderingImage );
 
  const QSizeF layoutSize = mLayout->convertToLayoutUnits( sizeWithUnits() );
  double widthLayoutUnits = layoutSize.width();
  double heightLayoutUnits = layoutSize.height();
 
  int w = static_cast< int >( std::round( widthLayoutUnits * mPreviewScaleFactor ) );
  int h = static_cast< int >( std::round( heightLayoutUnits * mPreviewScaleFactor ) );
 
  // limit size of image for better performance
  if ( w > 5000 || h > 5000 )
  {
    if ( w > h )
    {
      w = 5000;
      h = static_cast< int>( std::round( w * heightLayoutUnits / widthLayoutUnits ) );
    }
    else
    {
      h = 5000;
      w = static_cast< int >( std::round( h * widthLayoutUnits / heightLayoutUnits ) );
    }
  }
 
  if ( w <= 0 || h <= 0 )
    return;
 
  mCacheRenderingImage = std::make_unique<QImage>( w, h, QImage::Format_ARGB32 );
 
  // set DPI of the image
  mCacheRenderingImage->setDotsPerMeterX( static_cast< int >( std::round( 1000 * w / widthLayoutUnits ) ) );
  mCacheRenderingImage->setDotsPerMeterY( static_cast< int >( std::round( 1000 * h / heightLayoutUnits ) ) );
 
  //start with empty fill to avoid artifacts
  mCacheRenderingImage->fill( Qt::transparent );
  if ( hasBackground() )
  {
    //Initially fill image with specified background color
    mCacheRenderingImage->fill( backgroundColor().rgba() );
  }
 
  mCacheInvalidated = false;
  mPainter = std::make_unique<QPainter>( mCacheRenderingImage.get() );
 
  QList< QgsAbstractProfileSource *> sourcesToRender = sources();
  std::reverse( sourcesToRender.begin(), sourcesToRender.end() ); // sources are rendered from bottom to top
 
  mRenderJob = std::make_unique< QgsProfilePlotRenderer >( sourcesToRender, profileRequest() );
  std::unique_ptr<QgsLineSymbol> rendererSubSectionsSymbol( subsectionsSymbol() ? subsectionsSymbol()->clone() : nullptr );
  mRenderJob->setSubsectionsSymbol( rendererSubSectionsSymbol.release() );
  connect( mRenderJob.get(), &QgsProfilePlotRenderer::generationFinished, this, &QgsLayoutItemElevationProfile::profileGenerationFinished );
  mRenderJob->startGeneration();
 
  mDrawingPreview = false;
}
 
void QgsLayoutItemElevationProfile::profileGenerationFinished()
{
  mPlot->setRenderer( mRenderJob.get() );
 
  QgsRenderContext rc = QgsLayoutUtils::createRenderContextForLayout( mLayout, mPainter.get() );
 
  mPlot->xScale = QgsUnitTypes::fromUnitToUnitFactor( mDistanceUnit, mCrs.mapUnits() );
 
  const double mapUnitsPerPixel = static_cast< double >( mPlot->xMaximum() - mPlot->xMinimum() ) * mPlot->xScale / mCacheRenderingImage->size().width();
  rc.setMapToPixel( QgsMapToPixel( mapUnitsPerPixel ) );
 
  // size must be in pixels, not layout units
  mPlot->setSize( mCacheRenderingImage->size() );
 
  QgsPlotRenderContext plotContext;
  mPlot->render( rc, plotContext );
 
  mPlot->setRenderer( nullptr );
 
  mPainter->end();
  mRenderJob.reset( nullptr );
  mPainter.reset( nullptr );
  mCacheFinalImage = std::move( mCacheRenderingImage );
  emit backgroundTaskCountChanged( 0 );
  update();
  emit previewRefreshed();
}
 
Qgis::DistanceUnit QgsLayoutItemElevationProfile::distanceUnit() const
{
  return mDistanceUnit;
}
 
void QgsLayoutItemElevationProfile::setDistanceUnit( Qgis::DistanceUnit unit )
{
  mDistanceUnit = unit;
 
  switch ( mDistanceUnit )
  {
    case Qgis::DistanceUnit::Meters:
    case Qgis::DistanceUnit::Kilometers:
    case Qgis::DistanceUnit::Feet:
    case Qgis::DistanceUnit::NauticalMiles:
    case Qgis::DistanceUnit::Yards:
    case Qgis::DistanceUnit::Miles:
    case Qgis::DistanceUnit::Centimeters:
    case Qgis::DistanceUnit::Millimeters:
    case Qgis::DistanceUnit::Inches:
    case Qgis::DistanceUnit::ChainsInternational:
    case Qgis::DistanceUnit::ChainsBritishBenoit1895A:
    case Qgis::DistanceUnit::ChainsBritishBenoit1895B:
    case Qgis::DistanceUnit::ChainsBritishSears1922Truncated:
    case Qgis::DistanceUnit::ChainsBritishSears1922:
    case Qgis::DistanceUnit::ChainsClarkes:
    case Qgis::DistanceUnit::ChainsUSSurvey:
    case Qgis::DistanceUnit::FeetBritish1865:
    case Qgis::DistanceUnit::FeetBritish1936:
    case Qgis::DistanceUnit::FeetBritishBenoit1895A:
    case Qgis::DistanceUnit::FeetBritishBenoit1895B:
    case Qgis::DistanceUnit::FeetBritishSears1922Truncated:
    case Qgis::DistanceUnit::FeetBritishSears1922:
    case Qgis::DistanceUnit::FeetClarkes:
    case Qgis::DistanceUnit::FeetGoldCoast:
    case Qgis::DistanceUnit::FeetIndian:
    case Qgis::DistanceUnit::FeetIndian1937:
    case Qgis::DistanceUnit::FeetIndian1962:
    case Qgis::DistanceUnit::FeetIndian1975:
    case Qgis::DistanceUnit::FeetUSSurvey:
    case Qgis::DistanceUnit::LinksInternational:
    case Qgis::DistanceUnit::LinksBritishBenoit1895A:
    case Qgis::DistanceUnit::LinksBritishBenoit1895B:
    case Qgis::DistanceUnit::LinksBritishSears1922Truncated:
    case Qgis::DistanceUnit::LinksBritishSears1922:
    case Qgis::DistanceUnit::LinksClarkes:
    case Qgis::DistanceUnit::LinksUSSurvey:
    case Qgis::DistanceUnit::YardsBritishBenoit1895A:
    case Qgis::DistanceUnit::YardsBritishBenoit1895B:
    case Qgis::DistanceUnit::YardsBritishSears1922Truncated:
    case Qgis::DistanceUnit::YardsBritishSears1922:
    case Qgis::DistanceUnit::YardsClarkes:
    case Qgis::DistanceUnit::YardsIndian:
    case Qgis::DistanceUnit::YardsIndian1937:
    case Qgis::DistanceUnit::YardsIndian1962:
    case Qgis::DistanceUnit::YardsIndian1975:
    case Qgis::DistanceUnit::MilesUSSurvey:
    case Qgis::DistanceUnit::Fathoms:
    case Qgis::DistanceUnit::MetersGermanLegal:
      mPlot->xAxis().setLabelSuffix( u" %1"_s.arg( QgsUnitTypes::toAbbreviatedString( mDistanceUnit ) ) );
      break;
 
    case Qgis::DistanceUnit::Degrees:
      mPlot->xAxis().setLabelSuffix( QObject::tr( "°" ) );
      break;
 
    case Qgis::DistanceUnit::Unknown:
      mPlot->xAxis().setLabelSuffix( QString() );
      break;
  }
}
 
void QgsLayoutItemElevationProfile::setSubsectionsSymbol( QgsLineSymbol *symbol )
{
  mSubsectionsSymbol.reset( symbol );
}
 
void QgsLayoutItemElevationProfile::setSourcesPrivate()
{
  mSources.clear();
  mSources.reserve( QgsApplication::profileSourceRegistry()->profileSources().count() );
  for ( QgsAbstractProfileSource *source : QgsApplication::profileSourceRegistry()->profileSources() )
    mSources << source;
}
 
void QgsLayoutItemElevationProfile::calculateAxisRanges( QgsRenderContext &context )
{
  if ( !mLayout )
    return;
 
  switch ( mRangeMethod )
  {
    case Qgis::ElevationProfileRangeMethod::ManualRange:
      return; // nothing to do - axis range can't change!
 
    case Qgis::ElevationProfileRangeMethod::FixedScale:
      break;
  }
 
  const double mmToPainterUnits = context.convertToPainterUnits( 1.0, Qgis::RenderUnit::Millimeters );
  if ( qgsDoubleNear( mmToPainterUnits, 0.0 ) )
    return;
 
  const QSizeF layoutSize = mLayout->convertToLayoutUnits( sizeWithUnits() );
  QgsLayoutSize layoutSizeMm = mLayout->convertFromLayoutUnits( layoutSize, Qgis::LayoutUnit::Millimeters );
 
  mPlot->setSize( layoutSizeMm.toQSizeF() * mmToPainterUnits );
 
  QgsPlotRenderContext plotContext;
 
  // We need to do an iterative approach here. First we set a rough range based on the total size of the item.
  // But this is NOT correct, because that total size also includes the area outside of the plot itself (ie axis labels etc).
  // So then we set that range, and grab the interiorPlotArea corresponding to the plot with those initial guess set of axis labels.
  // From there we iterate, using the interiorPlotArea each time until we converge on the desired scale.
 
  // first guess - assuming the whole item is the interior (incorrect!)
  if ( mDistanceScale > 0 )
  {
    const double widthMeters = layoutSizeMm.width() / 1000;
    const double distanceRange = QgsUnitTypes::fromUnitToUnitFactor( Qgis::DistanceUnit::Meters, mDistanceUnit ) * widthMeters * mDistanceScale;
    mPlot->setXMinimum( 0 );
    mPlot->setXMaximum( distanceRange );
  }
  if ( mElevationScale > 0 )
  {
    const double heightMeters = layoutSizeMm.height() / 1000;
    const double elevationRange = heightMeters * mElevationScale;
    mPlot->setYMaximum( mPlot->yMinimum() + elevationRange );
  }
 
  // now we start the iteration
  QRectF previousPlotArea;
  for ( int iteration = 0; iteration < 5; ++iteration )
  {
    const QRectF currentPlotArea = mPlot->interiorPlotArea( context, plotContext );
    if ( qgsDoubleNear( currentPlotArea.width(), previousPlotArea.width(), 1 ) && qgsDoubleNear( currentPlotArea.height(), previousPlotArea.height(), 1 ) )
      break;
 
    previousPlotArea = currentPlotArea;
 
    if ( mDistanceScale > 0 )
    {
      const double widthMm = currentPlotArea.width() / mmToPainterUnits;
      const double widthMeters = widthMm / 1000.0;
      const double distanceRange = QgsUnitTypes::fromUnitToUnitFactor( Qgis::DistanceUnit::Meters, mDistanceUnit ) * widthMeters * mDistanceScale;
      mPlot->setXMaximum( distanceRange );
    }
 
    if ( mElevationScale > 0 )
    {
      const double heightMm = currentPlotArea.height() / mmToPainterUnits;
      const double heightMeters = heightMm / 1000.0;
      const double elevationRange = heightMeters * mElevationScale;
      mPlot->setYMaximum( mPlot->yMinimum() + elevationRange );
    }
  }
}
 
double QgsLayoutItemElevationProfile::elevationScale() const
{
  return mElevationScale;
}
 
void QgsLayoutItemElevationProfile::setElevationScale( double scale )
{
  mElevationScale = scale;
}
 
double QgsLayoutItemElevationProfile::distanceScale() const
{
  return mDistanceScale;
}
 
void QgsLayoutItemElevationProfile::setDistanceScale( double scale )
{
  mDistanceScale = scale;
}
 
Qgis::ElevationProfileRangeMethod QgsLayoutItemElevationProfile::rangeMethod() const
{
  return mRangeMethod;
}
 
void QgsLayoutItemElevationProfile::setRangeMethod( Qgis::ElevationProfileRangeMethod method )
{
  mRangeMethod = method;
}