qgsmaptoolshowhidelabels.cpp

/***************************************************************************
                          qgsmaptoolshowhidelabels.cpp
                          -----------------------
    begin                : 2012-08-12
    copyright            : (C) 2012 by Larry Shaffer
    email                : larrys at dakotacarto 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 "qgsmaptoolshowhidelabels.h"

#include "qgsapplication.h"
#include "qgsmapcanvas.h"
#include "qgsvectorlayer.h"

#include "qgsmaptoolselectutils.h"
#include "qgsrubberband.h"
#include <qgslogger.h>

#include <QMouseEvent>

QgsMapToolShowHideLabels::QgsMapToolShowHideLabels( QgsMapCanvas* canvas )
    : QgsMapToolLabel( canvas )
    , mDragging( false )
{
  mToolName = tr( "Show/hide labels" );
  mRubberBand = nullptr;
}

QgsMapToolShowHideLabels::~QgsMapToolShowHideLabels()
{
  delete mRubberBand;
}

void QgsMapToolShowHideLabels::canvasPressEvent( QgsMapMouseEvent* e )
{
  Q_UNUSED( e );
  mSelectRect.setRect( 0, 0, 0, 0 );
  mSelectRect.setTopLeft( e->pos() );
  mSelectRect.setBottomRight( e->pos() );
  mRubberBand = new QgsRubberBand( mCanvas, QGis::Polygon );
}

void QgsMapToolShowHideLabels::canvasMoveEvent( QgsMapMouseEvent* e )
{
  if ( e->buttons() != Qt::LeftButton )
    return;

  if ( !mDragging )
  {
    mDragging = true;
    mSelectRect.setTopLeft( e->pos() );
  }
  mSelectRect.setBottomRight( e->pos() );
  QgsMapToolSelectUtils::setRubberBand( mCanvas, mSelectRect, mRubberBand );
}

void QgsMapToolShowHideLabels::canvasReleaseEvent( QgsMapMouseEvent* e )
{
  //if the user simply clicked without dragging a rect
  //we will fabricate a small 1x1 pix rect and then continue
  //as if they had dragged a rect
  if ( !mDragging )
  {
    mSelectRect.setLeft( e->pos().x() - 1 );
    mSelectRect.setRight( e->pos().x() + 1 );
    mSelectRect.setTop( e->pos().y() - 1 );
    mSelectRect.setBottom( e->pos().y() + 1 );
  }
  else
  {
    // Set valid values for rectangle's width and height
    if ( mSelectRect.width() == 1 )
    {
      mSelectRect.setLeft( mSelectRect.left() + 1 );
    }
    if ( mSelectRect.height() == 1 )
    {
      mSelectRect.setBottom( mSelectRect.bottom() + 1 );
    }
  }

  if ( mRubberBand )
  {
    QgsMapToolSelectUtils::setRubberBand( mCanvas, mSelectRect, mRubberBand );

    showHideLabels( e );

    mRubberBand->reset( QGis::Polygon );
    delete mRubberBand;
    mRubberBand = nullptr;
  }

  mDragging = false;
}

void QgsMapToolShowHideLabels::showHideLabels( QMouseEvent * e )
{
  QgsMapLayer* layer = mCanvas->currentLayer();

  QgsVectorLayer* vlayer = dynamic_cast<QgsVectorLayer*>( layer );
  if ( !vlayer )
  {
    QgsDebugMsg( "Failed to cast label layer to vector layer" );
    return;
  }
  if ( !vlayer->isEditable() )
  {
    QgsDebugMsg( "Vector layer not editable, skipping label" );
    return;
  }

  bool doHide = e->modifiers() & Qt::ShiftModifier;
  bool labelChanged = false;
  QString editTxt = doHide ? tr( "Hid labels" ) : tr( "Showed labels" );
  vlayer->beginEditCommand( editTxt );

  if ( !doHide )
  {
    QgsDebugMsg( "Showing labels operation" );

    QgsFeatureIds selectedFeatIds;
    if ( !selectedFeatures( vlayer, selectedFeatIds ) )
    {
      vlayer->destroyEditCommand();
      return;
    }

    QgsDebugMsg( "Number of selected labels or features: " + QString::number( selectedFeatIds.size() ) );

    if ( selectedFeatIds.isEmpty() )
    {
      vlayer->destroyEditCommand();
      return;
    }

    Q_FOREACH ( QgsFeatureId fid, selectedFeatIds )
    {
      mCurrentLabel.pos.featureId = fid;

      mCurrentLabel.pos.isDiagram = false;
      bool labChanged = showHide( vlayer, true );

      mCurrentLabel.pos.isDiagram = true;
      bool diagChanged = showHide( vlayer, true );

      if ( labChanged || diagChanged )
      {
        // TODO: highlight features (maybe with QTimer?)
        labelChanged = labelChanged || true;
      }
    }
  }
  else
  {
    QgsDebugMsg( "Hiding labels operation" );

    QList<QgsLabelPosition> positions;
    if ( selectedLabelFeatures( vlayer, positions ) )
    {
      Q_FOREACH ( QgsLabelPosition pos, positions )
      {
        mCurrentLabel.pos = pos;

        if ( showHide( vlayer, false ) )
          labelChanged = labelChanged || true;
      }
    }
  }

  if ( labelChanged )
  {
    vlayer->endEditCommand();
    mCanvas->refresh();
  }
  else
  {
    vlayer->destroyEditCommand();
  }
}

bool QgsMapToolShowHideLabels::selectedFeatures( QgsVectorLayer* vlayer,
    QgsFeatureIds& selectedFeatIds )
{
  // culled from QgsMapToolSelectUtils::setSelectFeatures()

  QgsGeometry* selectGeometry = mRubberBand->asGeometry();

  // toLayerCoordinates will throw an exception for any 'invalid' points in
  // the rubber band.
  // For example, if you project a world map onto a globe using EPSG 2163
  // and then click somewhere off the globe, an exception will be thrown.
  QgsGeometry selectGeomTrans( *selectGeometry );

  if ( mCanvas->hasCrsTransformEnabled() )
  {
    try
    {
      QgsCoordinateTransform ct( mCanvas->mapSettings().destinationCrs(), vlayer->crs() );
      selectGeomTrans.transform( ct );
    }
    catch ( QgsCsException &cse )
    {
      Q_UNUSED( cse );
      // catch exception for 'invalid' point and leave existing selection unchanged
      QgsLogger::warning( "Caught CRS exception " + QString( __FILE__ ) + ": " + QString::number( __LINE__ ) );
      emit messageEmitted( tr( "CRS Exception: selection extends beyond layer's coordinate system." ), QgsMessageBar::WARNING );
      return false;
    }
  }

  QApplication::setOverrideCursor( Qt::WaitCursor );

  QgsDebugMsg( "Selection layer: " + vlayer->name() );
  QgsDebugMsg( "Selection polygon: " + selectGeomTrans.exportToWkt() );

  QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest()
                           .setFilterRect( selectGeomTrans.boundingBox() )
                           .setFlags( QgsFeatureRequest::NoGeometry | QgsFeatureRequest::ExactIntersect )
                           .setSubsetOfAttributes( QgsAttributeList() ) );

  QgsFeature f;
  while ( fit.nextFeature( f ) )
  {
    selectedFeatIds.insert( f.id() );
  }

  QApplication::restoreOverrideCursor();

  return true;
}

bool QgsMapToolShowHideLabels::selectedLabelFeatures( QgsVectorLayer* vlayer,
    QList<QgsLabelPosition> &listPos )
{
  listPos.clear();

  // get list of all drawn labels from current layer that intersect rubberband
  const QgsLabelingResults* labelingResults = mCanvas->labelingResults();
  if ( !labelingResults )
  {
    QgsDebugMsg( "No labeling engine" );
    return false;
  }

  QApplication::setOverrideCursor( Qt::WaitCursor );

  QgsRectangle ext = mRubberBand->asGeometry()->boundingBox();
  QList<QgsLabelPosition> labelPosList = labelingResults->labelsWithinRect( ext );

  QList<QgsLabelPosition>::const_iterator it;
  for ( it = labelPosList.constBegin() ; it != labelPosList.constEnd(); ++it )
  {
    const QgsLabelPosition& pos = *it;

    if ( pos.layerID != vlayer->id() )
    {
      // only work with labels from the current active and editable layer
      continue;
    }

    listPos.append( pos );
  }

  QApplication::restoreOverrideCursor();

  return true;
}

bool QgsMapToolShowHideLabels::showHide( QgsVectorLayer *vl, const bool show )
{
  // verify attribute table has proper field setup
  bool showSuccess;
  int showCol;
  int showVal;

  if ( !dataDefinedShowHide( vl, mCurrentLabel.pos.featureId, showVal,
                             showSuccess, showCol ) )
  {
    return false;
  }

  // check if attribute value is already the same
  if ( showSuccess && ( showVal != 0 ) == show )
  {
    return false;
  }

  // allow NULL (maybe default) value to stand for show label (i.e. 1)
  // skip NULL attributes if trying to show label
  if ( !showSuccess && show == 1 )
  {
    return false;
  }

  // different attribute value, edit table
  if ( ! vl->changeAttributeValue( mCurrentLabel.pos.featureId, showCol, show ) )
  {
    QgsDebugMsg( "Failed write to attribute table" );
    return false;
  }

  return true;
}