qgssnapindicator.cpp

Go to the documentation of this file.

/***************************************************************************
  qgssnapindicator.cpp
  --------------------------------------
  Date                 : October 2017
  Copyright            : (C) 2017 by Martin Dobias
  Email                : wonder dot sk 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 "qgssnapindicator.h"
 
#include "qgsguiutils.h"
#include "qgsmapcanvas.h"
#include "qgssettingsregistrycore.h"
#include "qgsvectorlayer.h"
#include "qgsvertexmarker.h"
 
#include <QToolTip>
 
 
QgsSnapIndicator::QgsSnapIndicator( QgsMapCanvas *canvas )
  : mCanvas( canvas )
{
  // We need to make sure that the internal pointers are invalidated if the canvas is deleted before this
  // indicator.
  // The canvas is specified again as the "receiver", just to silence clazy (official clazy recommendation
  // for false positives).
  mCanvasDestroyedConnection = QObject::connect( canvas, &QgsMapCanvas::destroyed, canvas, [ = ]()
  {
    mCanvas = nullptr;
    mSnappingMarker = nullptr;
  } );
}
 
QgsSnapIndicator::~QgsSnapIndicator()
{
  if ( mSnappingMarker && mCanvas )
  {
    mCanvas->scene()->removeItem( mSnappingMarker );
    delete mSnappingMarker;
  }
 
  QObject::disconnect( mCanvasDestroyedConnection );
};
 
void QgsSnapIndicator::setMatch( const QgsPointLocator::Match &match )
{
  mMatch = match;
 
  if ( !mMatch.isValid() )
  {
    if ( mSnappingMarker )
    {
      mCanvas->scene()->removeItem( mSnappingMarker );
      delete mSnappingMarker; // need to delete since QGraphicsSene::removeItem transfers back ownership
    }
    mSnappingMarker = nullptr;
    QToolTip::hideText();
  }
  else
  {
    if ( !mSnappingMarker )
    {
      mSnappingMarker = new QgsVertexMarker( mCanvas ); // ownership of the marker is transferred to QGraphicsScene
      mSnappingMarker->setIconSize( QgsGuiUtils::scaleIconSize( 10 ) );
      mSnappingMarker->setPenWidth( QgsGuiUtils::scaleIconSize( 3 ) );
    }
 
    QColor color = QgsSettingsRegistryCore::settingsDigitizingSnapColor.value();
    mSnappingMarker->setColor( color );
 
    int iconType;
    if ( match.hasLineEndpoint() )
    {
      iconType = QgsVertexMarker::ICON_INVERTED_TRIANGLE; // line endpoint snap
    }
    else if ( match.hasVertex() )
    {
      if ( match.layer() )
        iconType = QgsVertexMarker::ICON_BOX;  // vertex snap
      else
        iconType = QgsVertexMarker::ICON_X;  // intersection snap
    }
    else if ( match.hasMiddleSegment() )
    {
      iconType = QgsVertexMarker::ICON_TRIANGLE; // middle snap
    }
    else if ( match.hasCentroid() )
    {
      iconType = QgsVertexMarker::ICON_CIRCLE; // centroid snap
    }
    else if ( match.hasArea() )
    {
      iconType = QgsVertexMarker::ICON_RHOMBUS; // area snap
    }
    else  // must be segment snap
    {
      iconType = QgsVertexMarker::ICON_DOUBLE_TRIANGLE;
    }
 
    mSnappingMarker->setIconType( iconType );
 
    mSnappingMarker->setCenter( match.point() );
 
    // tooltip
    if ( QgsSettingsRegistryCore::settingsDigitizingSnapTooltip.value() )
    {
      QPoint ptCanvas = mSnappingMarker->toCanvasCoordinates( match.point() ).toPoint();
      QPoint ptGlobal = mCanvas->mapToGlobal( ptCanvas );
      QRect rect( ptCanvas.x(), ptCanvas.y(), 1, 1 );  // area where is the tooltip valid
      QString layerName = match.layer() ? match.layer()->name() : QString();
      QToolTip::showText( ptGlobal, layerName, mCanvas, rect );
    }
  }
}
 
void QgsSnapIndicator::setVisible( bool visible )
{
  if ( mSnappingMarker )
    mSnappingMarker->setVisible( visible );
}
 
bool QgsSnapIndicator::isVisible() const
{
  if ( mSnappingMarker )
    return mSnappingMarker->isVisible();
 
  return false;
}