qgsscalebarrenderer.cpp

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/***************************************************************************
                            qgsscalebarrenderer.cpp
                            -----------------------
    begin                : June 2008
    copyright            : (C) 2008 by Marco Hugentobler
    email                : [email protected]
 ***************************************************************************/
/***************************************************************************
 *                                                                         *
 *   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 "qgsscalebarrenderer.h"
 
#include "qgsexpressioncontextutils.h"
#include "qgslayoututils.h"
#include "qgslinesymbol.h"
#include "qgsnumericformat.h"
#include "qgsscalebarsettings.h"
#include "qgssymbol.h"
#include "qgssymbollayerutils.h"
#include "qgstextrenderer.h"
 
#include <QFontMetricsF>
#include <QPainter>
#include <QString>
 
using namespace Qt::StringLiterals;
 
void QgsScaleBarRenderer::drawDefaultLabels( QgsRenderContext &context, const QgsScaleBarSettings &settings, const ScaleBarContext &scaleContext ) const
{
  if ( !context.painter() )
  {
    return;
  }
 
  QPainter *painter = context.painter();
 
  painter->save();
 
  const QgsTextFormat format = settings.textFormat();
 
  QgsExpressionContextScope *scaleScope = new QgsExpressionContextScope( u"scalebar_text"_s );
  const QgsExpressionContextScopePopper scopePopper( context.expressionContext(), scaleScope );
 
  const QString firstLabel = firstLabelString( settings );
  const QFontMetricsF fontMetrics = QgsTextRenderer::fontMetrics( context, format );
  const double xOffset = fontMetrics.horizontalAdvance( firstLabel ) / 2.0;
 
  const double scaledBoxContentSpace = context.convertToPainterUnits( settings.boxContentSpace(), Qgis::RenderUnit::Millimeters );
  const double scaledLabelBarSpace = context.convertToPainterUnits( settings.labelBarSpace(), Qgis::RenderUnit::Millimeters );
  double scaledHeight;
  if ( ( scaleContext.flags & Flag::FlagUsesSubdivisionsHeight ) && ( settings.numberOfSubdivisions() > 1 ) && ( settings.subdivisionsHeight() > settings.height() ) )
  {
    scaledHeight = context.convertToPainterUnits( settings.subdivisionsHeight(), Qgis::RenderUnit::Millimeters );
  }
  else
  {
    scaledHeight = context.convertToPainterUnits( settings.height(), Qgis::RenderUnit::Millimeters );
  }
 
  double currentLabelNumber = 0.0;
 
  const int nSegmentsLeft = settings.numberOfSegmentsLeft();
  int segmentCounter = 0;
 
  QString currentNumericLabel;
  const QList<double> positions = segmentPositions( context, scaleContext, settings );
 
  bool drawZero = true;
  switch ( settings.labelHorizontalPlacement() )
  {
    case Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment:
      drawZero = false;
      break;
    case Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredEdge:
      drawZero = true;
      break;
  }
 
  const QgsNumericFormatContext numericContext;
 
  for ( int i = 0; i < positions.size(); ++i )
  {
    if ( segmentCounter == 0 && nSegmentsLeft > 0 )
    {
      //label first left segment
      currentNumericLabel = firstLabel;
    }
    else if ( segmentCounter != 0 && segmentCounter == nSegmentsLeft ) //reset label number to 0 if there are left segments
    {
      currentLabelNumber = 0.0;
    }
 
    if ( segmentCounter >= nSegmentsLeft )
    {
      currentNumericLabel = settings.numericFormat()->formatDouble( currentLabelNumber / settings.mapUnitsPerScaleBarUnit(), numericContext );
    }
 
    //don't draw label for intermediate left segments or the zero label when it needs to be skipped
    if ( ( segmentCounter == 0 || segmentCounter >= nSegmentsLeft ) && ( currentNumericLabel != "0"_L1 || drawZero ) )
    {
      scaleScope->addVariable( QgsExpressionContextScope::StaticVariable( u"scale_value"_s, currentNumericLabel, true, false ) );
      QPointF pos;
      if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment )
      {
        if ( segmentCounter == 0 )
        {
          // if the segment counter is zero with a non zero label, this is the left-of-zero label
          pos.setX( context.convertToPainterUnits( positions.at( i ) + ( scaleContext.segmentWidth / 2 ), Qgis::RenderUnit::Millimeters ) );
        }
        else
        {
          pos.setX( context.convertToPainterUnits( positions.at( i ) - ( scaleContext.segmentWidth / 2 ), Qgis::RenderUnit::Millimeters ) );
        }
      }
      else
      {
        pos.setX( context.convertToPainterUnits( positions.at( i ), Qgis::RenderUnit::Millimeters ) + xOffset );
      }
      pos.setY(
        fontMetrics.ascent() + scaledBoxContentSpace + ( settings.labelVerticalPlacement() == Qgis::ScaleBarDistanceLabelVerticalPlacement::BelowSegment ? scaledHeight + scaledLabelBarSpace : 0 )
      );
      QgsTextRenderer::drawText( pos, 0, Qgis::TextHorizontalAlignment::Center, QStringList() << currentNumericLabel, context, format );
    }
 
    if ( segmentCounter >= nSegmentsLeft )
    {
      currentLabelNumber += settings.unitsPerSegment();
    }
    ++segmentCounter;
  }
 
  //also draw the last label
  if ( !positions.isEmpty() )
  {
    // note: this label is NOT centered over the end of the bar - rather the numeric portion
    // of it is, without considering the unit label suffix. That's drawn at the end after
    // horizontally centering just the numeric portion.
    currentNumericLabel = settings.numericFormat()->formatDouble( currentLabelNumber / settings.mapUnitsPerScaleBarUnit(), numericContext );
    scaleScope->addVariable( QgsExpressionContextScope::StaticVariable( u"scale_value"_s, currentNumericLabel, true, false ) );
    QPointF pos;
    pos.setY( fontMetrics.ascent() + scaledBoxContentSpace + ( settings.labelVerticalPlacement() == Qgis::ScaleBarDistanceLabelVerticalPlacement::BelowSegment ? scaledHeight + scaledLabelBarSpace : 0 ) );
    if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment )
    {
      pos.setX( context.convertToPainterUnits( positions.at( positions.size() - 1 ) + ( scaleContext.segmentWidth / 2 ), Qgis::RenderUnit::Millimeters ) + xOffset );
      QgsTextRenderer::drawText( pos, 0, Qgis::TextHorizontalAlignment::Center, QStringList() << ( currentNumericLabel + ' ' + settings.unitLabel() ), context, format );
    }
    else
    {
      pos.setX(
        context.convertToPainterUnits( positions.at( positions.size() - 1 ) + scaleContext.segmentWidth, Qgis::RenderUnit::Millimeters ) + xOffset - fontMetrics.horizontalAdvance( currentNumericLabel ) / 2.0
      );
      QgsTextRenderer::drawText( pos, 0, Qgis::TextHorizontalAlignment::Left, QStringList() << ( currentNumericLabel + ' ' + settings.unitLabel() ), context, format );
    }
  }
 
  painter->restore();
}
 
QgsScaleBarRenderer::Flags QgsScaleBarRenderer::flags() const
{
  return QgsScaleBarRenderer::Flags();
}
 
int QgsScaleBarRenderer::sortKey() const
{
  return 100;
}
 
QSizeF QgsScaleBarRenderer::calculateBoxSize( const QgsScaleBarSettings &settings, const QgsScaleBarRenderer::ScaleBarContext &scaleContext ) const
{
  const QFont font = settings.textFormat().toQFont();
 
  //consider centered first label
  double firstLabelWidth = QgsLayoutUtils::textWidthMM( font, firstLabelString( settings ) );
  if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment )
  {
    if ( firstLabelWidth > scaleContext.segmentWidth )
    {
      firstLabelWidth = ( firstLabelWidth - scaleContext.segmentWidth ) / 2;
    }
    else
    {
      firstLabelWidth = 0.0;
    }
  }
  else
  {
    firstLabelWidth = firstLabelWidth / 2;
  }
 
  //consider last number and label
  const double largestLabelNumber = settings.numberOfSegments() * settings.unitsPerSegment() / settings.mapUnitsPerScaleBarUnit();
  const QString largestNumberLabel = settings.numericFormat()->formatDouble( largestLabelNumber, QgsNumericFormatContext() );
  const QString largestLabel = largestNumberLabel + ' ' + settings.unitLabel();
  double largestLabelWidth;
  if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment )
  {
    largestLabelWidth = QgsLayoutUtils::textWidthMM( font, largestLabel );
    if ( largestLabelWidth > scaleContext.segmentWidth )
    {
      largestLabelWidth = ( largestLabelWidth - scaleContext.segmentWidth ) / 2;
    }
    else
    {
      largestLabelWidth = 0.0;
    }
  }
  else
  {
    largestLabelWidth = QgsLayoutUtils::textWidthMM( font, largestLabel ) - QgsLayoutUtils::textWidthMM( font, largestNumberLabel ) / 2;
  }
 
  const double totalBarLength = scaleContext.segmentWidth * ( settings.numberOfSegments() + ( settings.numberOfSegmentsLeft() > 0 ? 1 : 0 ) );
 
  // this whole method is deprecated, so we can still call the deprecated settings.pen() getter
  Q_NOWARN_DEPRECATED_PUSH
  const double width = firstLabelWidth + totalBarLength + 2 * settings.pen().widthF() + largestLabelWidth + 2 * settings.boxContentSpace();
  Q_NOWARN_DEPRECATED_POP
 
  const double height = settings.height() + settings.labelBarSpace() + 2 * settings.boxContentSpace() + QgsLayoutUtils::fontAscentMM( font );
 
  return QSizeF( width, height );
}
 
QSizeF QgsScaleBarRenderer::calculateBoxSize( QgsRenderContext &context, const QgsScaleBarSettings &settings, const QgsScaleBarRenderer::ScaleBarContext &scaleContext ) const
{
  const double painterToMm = 1.0 / context.convertToPainterUnits( 1, Qgis::RenderUnit::Millimeters );
  //consider centered first label
  double firstLabelWidth = QgsTextRenderer::textWidth( context, settings.textFormat(), QStringList() << firstLabelString( settings ) ) * painterToMm;
 
  if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment && !std::isnan( scaleContext.segmentWidth ) )
  {
    if ( firstLabelWidth > scaleContext.segmentWidth )
    {
      firstLabelWidth = ( firstLabelWidth - scaleContext.segmentWidth ) / 2;
    }
    else
    {
      firstLabelWidth = 0.0;
    }
  }
  else
  {
    firstLabelWidth = firstLabelWidth / 2;
  }
 
  //consider last number and label
  const double largestLabelNumber = settings.numberOfSegments() * settings.unitsPerSegment() / settings.mapUnitsPerScaleBarUnit();
  const QString largestNumberLabel = std::isnan( largestLabelNumber ) ? QString() : settings.numericFormat()->formatDouble( largestLabelNumber, QgsNumericFormatContext() );
  const QString largestLabel = largestNumberLabel + ' ' + settings.unitLabel();
  double largestLabelWidth;
  if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment && !std::isnan( scaleContext.segmentWidth ) )
  {
    largestLabelWidth = QgsTextRenderer::textWidth( context, settings.textFormat(), QStringList() << largestLabel ) * painterToMm;
 
    if ( largestLabelWidth > scaleContext.segmentWidth )
    {
      largestLabelWidth = ( largestLabelWidth - scaleContext.segmentWidth ) / 2;
    }
    else
    {
      largestLabelWidth = 0.0;
    }
  }
  else
  {
    largestLabelWidth = QgsTextRenderer::textWidth( context, settings.textFormat(), QStringList() << largestLabel ) * painterToMm
                        - QgsTextRenderer::textWidth( context, settings.textFormat(), QStringList() << largestNumberLabel ) * painterToMm / 2;
  }
 
  // segmentWidth can be NaN in extreme cases, eg trying to make a scalebar for a global map with a very small segment size (eg meters)
  const double totalBarLength = std::isnan( scaleContext.segmentWidth ) ? 0 : scaleContext.segmentWidth * ( settings.numberOfSegments() + ( settings.numberOfSegmentsLeft() > 0 ? 1 : 0 ) );
 
  double lineWidth = QgsSymbolLayerUtils::estimateMaxSymbolBleed( settings.lineSymbol(), context ) * 2;
  // need to convert to mm
  lineWidth /= context.convertToPainterUnits( 1, Qgis::RenderUnit::Millimeters );
 
  const double width = firstLabelWidth + totalBarLength + 2 * lineWidth + largestLabelWidth + 2 * settings.boxContentSpace();
  double height;
  if ( ( scaleContext.flags & Flag::FlagUsesSubdivisionsHeight ) && ( settings.numberOfSubdivisions() > 1 ) && ( settings.subdivisionsHeight() > settings.height() ) )
  {
    height = settings.subdivisionsHeight();
  }
  else
  {
    height = settings.height();
  }
 
  // TODO -- we technically should check the height of ALL labels here and take the maximum
  height += settings.labelBarSpace() + 2 * settings.boxContentSpace() + QgsTextRenderer::textHeight( context, settings.textFormat(), QStringList() << largestLabel ) * painterToMm;
 
  return QSizeF( width, height );
}
 
bool QgsScaleBarRenderer::applyDefaultSettings( QgsScaleBarSettings & ) const
{
  return false;
}
 
QString QgsScaleBarRenderer::firstLabelString( const QgsScaleBarSettings &settings ) const
{
  if ( settings.numberOfSegmentsLeft() > 0 )
  {
    return settings.numericFormat()->formatDouble( settings.unitsPerSegment() / settings.mapUnitsPerScaleBarUnit(), QgsNumericFormatContext() );
  }
  else
  {
    return settings.numericFormat()->formatDouble( 0, QgsNumericFormatContext() );
  }
}
 
double QgsScaleBarRenderer::firstLabelXOffset( const QgsScaleBarSettings &settings ) const
{
  const QString firstLabel = firstLabelString( settings );
  Q_NOWARN_DEPRECATED_PUSH
  return QgsLayoutUtils::textWidthMM( settings.font(), firstLabel ) / 2.0;
  Q_NOWARN_DEPRECATED_POP
}
 
double QgsScaleBarRenderer::firstLabelXOffset( const QgsScaleBarSettings &settings, const QgsRenderContext &context, const ScaleBarContext &scaleContext ) const
{
  const QString firstLabel = firstLabelString( settings );
  double firstLabelWidth = QgsTextRenderer::textWidth( context, settings.textFormat(), QStringList() << firstLabel );
  if ( settings.labelHorizontalPlacement() == Qgis::ScaleBarDistanceLabelHorizontalPlacement::CenteredSegment )
  {
    if ( firstLabelWidth > scaleContext.segmentWidth )
    {
      firstLabelWidth = ( firstLabelWidth - scaleContext.segmentWidth ) / 2;
    }
    else
    {
      firstLabelWidth = 0.0;
    }
  }
  else
  {
    firstLabelWidth = firstLabelWidth / 2;
  }
  return firstLabelWidth;
}
 
QList<double> QgsScaleBarRenderer::segmentPositions( const ScaleBarContext &scaleContext, const QgsScaleBarSettings &settings ) const
{
  QList<double> positions;
 
  // this whole method is deprecated, so calling a deprecated function is fine
  Q_NOWARN_DEPRECATED_PUSH
  double currentXCoord = settings.pen().widthF() + settings.boxContentSpace();
  Q_NOWARN_DEPRECATED_POP
 
  //left segments
  const double leftSegmentSize = scaleContext.segmentWidth / settings.numberOfSegmentsLeft();
  positions.reserve( settings.numberOfSegmentsLeft() + settings.numberOfSegments() );
  for ( int i = 0; i < settings.numberOfSegmentsLeft(); ++i )
  {
    positions << currentXCoord;
    currentXCoord += leftSegmentSize;
  }
 
  //right segments
  for ( int i = 0; i < settings.numberOfSegments(); ++i )
  {
    positions << currentXCoord;
    currentXCoord += scaleContext.segmentWidth;
  }
  return positions;
}
 
QList<double> QgsScaleBarRenderer::segmentPositions( QgsRenderContext &context, const QgsScaleBarRenderer::ScaleBarContext &scaleContext, const QgsScaleBarSettings &settings ) const
{
  QList<double> positions;
 
  double lineWidth = QgsSymbolLayerUtils::estimateMaxSymbolBleed( settings.lineSymbol(), context ) * 2.0;
  // need to convert to mm
  lineWidth /= context.convertToPainterUnits( 1, Qgis::RenderUnit::Millimeters );
 
  double currentXCoord = lineWidth + settings.boxContentSpace();
 
  //left segments
  const double leftSegmentSize = scaleContext.segmentWidth / settings.numberOfSegmentsLeft();
  positions.reserve( settings.numberOfSegmentsLeft() + settings.numberOfSegments() );
  for ( int i = 0; i < settings.numberOfSegmentsLeft(); ++i )
  {
    positions << currentXCoord;
    currentXCoord += leftSegmentSize;
  }
 
  //right segments
  for ( int i = 0; i < settings.numberOfSegments(); ++i )
  {
    positions << currentXCoord;
    currentXCoord += scaleContext.segmentWidth;
  }
  return positions;
}
 
QList<double> QgsScaleBarRenderer::segmentWidths( const ScaleBarContext &scaleContext, const QgsScaleBarSettings &settings ) const
{
  QList<double> widths;
  widths.reserve( settings.numberOfSegmentsLeft() + settings.numberOfSegments() );
 
  //left segments
  if ( settings.numberOfSegmentsLeft() > 0 )
  {
    const double leftSegmentSize = scaleContext.segmentWidth / settings.numberOfSegmentsLeft();
    for ( int i = 0; i < settings.numberOfSegmentsLeft(); ++i )
    {
      widths << leftSegmentSize;
    }
  }
 
  //right segments
  for ( int i = 0; i < settings.numberOfSegments(); ++i )
  {
    widths << scaleContext.segmentWidth;
  }
 
  return widths;
}
 
bool QgsScaleBarRenderer::ScaleBarContext::isValid() const
{
  return !std::isnan( segmentWidth );
}