qgspointcloudrendererregistry.cpp

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/***************************************************************************
    qgspointcloudrendererregistry.cpp
    ---------------------
    begin                : November 2020
    copyright            : (C) 2020 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 "qgspointcloudrendererregistry.h"
#include "qgspointcloudrenderer.h"
 
// default renderers
#include "qgspointcloudattributebyramprenderer.h"
#include "qgspointcloudrgbrenderer.h"
#include "qgspointcloudclassifiedrenderer.h"
#include "qgspointcloudlayer.h"
#include "qgspointcloudextentrenderer.h"
 
QgsPointCloudRendererRegistry::QgsPointCloudRendererRegistry()
{
  // add default renderers
  addRenderer( new QgsPointCloudRendererMetadata( QStringLiteral( "extent" ),
               QObject::tr( "Extent Only" ),
               QgsPointCloudExtentRenderer::create ) );
  addRenderer( new QgsPointCloudRendererMetadata( QStringLiteral( "ramp" ),
               QObject::tr( "Attribute by Ramp" ),
               QgsPointCloudAttributeByRampRenderer::create ) );
  addRenderer( new QgsPointCloudRendererMetadata( QStringLiteral( "rgb" ),
               QObject::tr( "RGB" ),
               QgsPointCloudRgbRenderer::create ) );
  addRenderer( new QgsPointCloudRendererMetadata( QStringLiteral( "classified" ),
               QObject::tr( "Classification" ),
               QgsPointCloudClassifiedRenderer::create ) );
}
 
QgsPointCloudRendererRegistry::~QgsPointCloudRendererRegistry()
{
  qDeleteAll( mRenderers );
}
 
bool QgsPointCloudRendererRegistry::addRenderer( QgsPointCloudRendererAbstractMetadata *metadata )
{
  if ( !metadata || mRenderers.contains( metadata->name() ) )
    return false;
 
  mRenderers[metadata->name()] = metadata;
  mRenderersOrder << metadata->name();
  return true;
}
 
bool QgsPointCloudRendererRegistry::removeRenderer( const QString &rendererName )
{
  if ( !mRenderers.contains( rendererName ) )
    return false;
 
  delete mRenderers[rendererName];
  mRenderers.remove( rendererName );
  mRenderersOrder.removeAll( rendererName );
  return true;
}
 
QgsPointCloudRendererAbstractMetadata *QgsPointCloudRendererRegistry::rendererMetadata( const QString &rendererName )
{
  return mRenderers.value( rendererName );
}
 
QStringList QgsPointCloudRendererRegistry::renderersList() const
{
  QStringList renderers;
  for ( const QString &renderer : mRenderersOrder )
  {
    QgsPointCloudRendererAbstractMetadata *r = mRenderers.value( renderer );
    if ( r )
      renderers << renderer;
  }
  return renderers;
}
 
QgsPointCloudRenderer *QgsPointCloudRendererRegistry::defaultRenderer( const QgsPointCloudDataProvider *provider )
{
  if ( !provider )
    return new QgsPointCloudAttributeByRampRenderer();
 
  if ( ( provider->name() == QLatin1String( "pdal" ) ) && ( !provider->hasValidIndex() ) )
  {
    // for now, default to extent renderer only for las/laz files
    return new QgsPointCloudExtentRenderer();
  }
 
  const QgsPointCloudAttributeCollection attributes = provider->attributes();
 
  //if red/green/blue attributes are present, then default to a RGB renderer
  if ( attributes.indexOf( QLatin1String( "Red" ) ) >= 0 && attributes.indexOf( QLatin1String( "Green" ) ) >= 0 && attributes.indexOf( QLatin1String( "Blue" ) ) >= 0 )
  {
    std::unique_ptr< QgsPointCloudRgbRenderer > renderer = qgis::make_unique< QgsPointCloudRgbRenderer >();
 
    // set initial guess for rgb ranges
    const QVariant redMax = provider->metadataStatistic( QStringLiteral( "Red" ), QgsStatisticalSummary::Max );
    const QVariant greenMax = provider->metadataStatistic( QStringLiteral( "Red" ), QgsStatisticalSummary::Max );
    const QVariant blueMax = provider->metadataStatistic( QStringLiteral( "Red" ), QgsStatisticalSummary::Max );
    if ( redMax.isValid() && greenMax.isValid() && blueMax.isValid() )
    {
      const int maxValue = std::max( blueMax.toInt(), std::max( redMax.toInt(), greenMax.toInt() ) );
 
      if ( maxValue == 0 )
      {
        // r/g/b max value is 0 -- likely these attributes have been created by some process, but are empty.
        // in any case they won't result in a useful render, so don't use RGB renderer for this dataset.
        renderer.reset();
      }
      else
      {
        // try and guess suitable range from input max values -- we don't just take the provider max value directly here, but rather see if it's
        // likely to be 8 bit or 16 bit color values
        const int rangeGuess = maxValue > 255 ? 65535 : 255;
 
        if ( rangeGuess > 255 )
        {
          // looks like 16 bit colors, so default to a stretch contrast enhancement
          QgsContrastEnhancement contrast( Qgis::UnknownDataType );
          contrast.setMinimumValue( 0 );
          contrast.setMaximumValue( rangeGuess );
          contrast.setContrastEnhancementAlgorithm( QgsContrastEnhancement::StretchToMinimumMaximum );
          renderer->setRedContrastEnhancement( new QgsContrastEnhancement( contrast ) );
          renderer->setGreenContrastEnhancement( new QgsContrastEnhancement( contrast ) );
          renderer->setBlueContrastEnhancement( new QgsContrastEnhancement( contrast ) );
        }
      }
    }
 
    if ( renderer )
      return renderer.release();
  }
 
  // otherwise try a classified renderer...
  if ( attributes.indexOf( QLatin1String( "Classification" ) ) >= 0 )
  {
    // are any classifications present?
    QVariantList classes = provider->metadataClasses( QStringLiteral( "Classification" ) );
    // ignore "not classified" classes, and see if any are left...
    classes.removeAll( 0 );
    classes.removeAll( 1 );
    if ( !classes.empty() )
    {
      std::unique_ptr< QgsPointCloudClassifiedRenderer > renderer = qgis::make_unique< QgsPointCloudClassifiedRenderer >();
      renderer->setAttribute( QStringLiteral( "Classification" ) );
      return renderer.release();
    }
  }
 
  // fallback to shading by Z
  std::unique_ptr< QgsPointCloudAttributeByRampRenderer > renderer = qgis::make_unique< QgsPointCloudAttributeByRampRenderer >();
  renderer->setAttribute( QStringLiteral( "Z" ) );
 
  // set initial range for z values if possible
  const QVariant zMin = provider->metadataStatistic( QStringLiteral( "Z" ), QgsStatisticalSummary::Min );
  const QVariant zMax = provider->metadataStatistic( QStringLiteral( "Z" ), QgsStatisticalSummary::Max );
  if ( zMin.isValid() && zMax.isValid() )
  {
    renderer->setMinimum( zMin.toDouble() );
    renderer->setMaximum( zMax.toDouble() );
 
    QgsColorRampShader shader = renderer->colorRampShader();
    shader.setMinimumValue( zMin.toDouble() );
    shader.setMaximumValue( zMax.toDouble() );
    shader.classifyColorRamp( 5, -1, QgsRectangle(), nullptr );
    renderer->setColorRampShader( shader );
  }
  return renderer.release();
}