qgsdiagram.cpp

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/***************************************************************************
    qgsdiagram.cpp
    ---------------------
    begin                : March 2011
    copyright            : (C) 2011 by Marco Hugentobler
    email                : marco dot hugentobler at sourcepole dot ch
 ***************************************************************************
 *                                                                         *
 *   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 "qgsdiagram.h"
#include "qgsdiagramrenderer.h"

#include <QPainter>

QgsDiagram::QgsDiagram( const QgsDiagram &other )
{
  Q_UNUSED( other );
  // do not copy the cached expression map - the expressions need to be created and prepared with getExpression(...) call
}


void QgsDiagram::clearCache()
{
  QMapIterator<QString, QgsExpression *> i( mExpressions );
  while ( i.hasNext() )
  {
    i.next();
    delete i.value();
  }
  mExpressions.clear();
}

QgsExpression *QgsDiagram::getExpression( const QString &expression, const QgsExpressionContext &context )
{
  if ( !mExpressions.contains( expression ) )
  {
    QgsExpression *expr = new QgsExpression( expression );
    expr->prepare( &context );
    mExpressions[expression] = expr;
  }
  return mExpressions[expression];
}

void QgsDiagram::setPenWidth( QPen &pen, const QgsDiagramSettings &s, const QgsRenderContext &c )
{
  pen.setWidthF( c.convertToPainterUnits( s.penWidth, s.lineSizeUnit, s.lineSizeScale ) );
}


QSizeF QgsDiagram::sizePainterUnits( QSizeF size, const QgsDiagramSettings &s, const QgsRenderContext &c )
{
  return QSizeF( c.convertToPainterUnits( size.width(), s.sizeType, s.sizeScale ), c.convertToPainterUnits( size.height(), s.sizeType, s.sizeScale ) );
}

double QgsDiagram::sizePainterUnits( double l, const QgsDiagramSettings &s, const QgsRenderContext &c )
{
  return c.convertToPainterUnits( l, s.sizeType, s.sizeScale );
}

QFont QgsDiagram::scaledFont( const QgsDiagramSettings &s, const QgsRenderContext &c )
{
  QFont f = s.font;
  if ( s.sizeType == QgsUnitTypes::RenderMapUnits )
  {
    int pixelsize = s.font.pointSizeF() / c.mapToPixel().mapUnitsPerPixel();
    f.setPixelSize( pixelsize > 0 ? pixelsize : 1 );
  }
  else
  {
    f.setPixelSize( s.font.pointSizeF() * 0.376 * c.scaleFactor() );
  }

  return f;
}

QSizeF QgsDiagram::sizeForValue( double value, const QgsDiagramSettings &s, const QgsDiagramInterpolationSettings &is ) const
{
  double scaledValue = value;
  double scaledLowerValue = is.lowerValue;
  double scaledUpperValue = is.upperValue;

  // interpolate the squared value if scale by area
  if ( s.scaleByArea )
  {
    scaledValue = std::sqrt( scaledValue );
    scaledLowerValue = std::sqrt( scaledLowerValue );
    scaledUpperValue = std::sqrt( scaledUpperValue );
  }

  //interpolate size
  double scaledRatio = ( scaledValue - scaledLowerValue ) / ( scaledUpperValue - scaledLowerValue );

  QSizeF size = QSizeF( is.upperSize.width() * scaledRatio + is.lowerSize.width() * ( 1 - scaledRatio ),
                        is.upperSize.height() * scaledRatio + is.lowerSize.height() * ( 1 - scaledRatio ) );

  // Scale, if extension is smaller than the specified minimum
  if ( size.width() <= s.minimumSize && size.height() <= s.minimumSize )
  {
    bool p = false; // preserve height == width
    if ( qgsDoubleNear( size.width(), size.height() ) )
      p = true;

    size.scale( s.minimumSize, s.minimumSize, Qt::KeepAspectRatio );

    // If height == width, recover here (overwrite floating point errors)
    if ( p )
      size.setWidth( size.height() );
  }

  return size;
}