Branch data     Line data    Source code

       1                 :            : /***************************************************************************
       2                 :            :     qgstolerance.cpp  -  wrapper for tolerance handling
       3                 :            :     ----------------------
       4                 :            :     begin                : March 2009
       5                 :            :     copyright            : (C) 2009 by Richard Kostecky
       6                 :            :     email                : csf.kostej at gmail dot com
       7                 :            :  ***************************************************************************
       8                 :            :  *                                                                         *
       9                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      10                 :            :  *   it under the terms of the GNU General Public License as published by  *
      11                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      12                 :            :  *   (at your option) any later version.                                   *
      13                 :            :  *                                                                         *
      14                 :            :  ***************************************************************************/
      15                 :            : 
      16                 :            : #include "qgstolerance.h"
      17                 :            : #include "qgsmapsettings.h"
      18                 :            : #include "qgssettings.h"
      19                 :            : #include "qgspointxy.h"
      20                 :            : 
      21                 :            : #include <QPoint>
      22                 :            : #include <cmath>
      23                 :            : 
      24                 :            : 
      25                 :            : // return ratio [mu/lu] between map units and layer units
      26                 :            : // this is of course only an approximation
      27                 :          0 : double _ratioMU2LU( const QgsMapSettings &mapSettings, QgsMapLayer *layer )
      28                 :            : {
      29                 :          0 :   double distMU = mapSettings.mapUnitsPerPixel();
      30                 :          0 :   QgsPointXY ptMapCenterMU = mapSettings.visibleExtent().center();
      31                 :          0 :   QgsPointXY ptMapCenterRightMU( ptMapCenterMU.x() + distMU, ptMapCenterMU.y() );
      32                 :          0 :   QgsPointXY ptMapCenterLU = mapSettings.mapToLayerCoordinates( layer, ptMapCenterMU );
      33                 :          0 :   QgsPointXY ptMapCenterRightLU = mapSettings.mapToLayerCoordinates( layer, ptMapCenterRightMU );
      34                 :          0 :   double distLU = std::sqrt( ptMapCenterLU.sqrDist( ptMapCenterRightLU ) );
      35                 :          0 :   double ratio = distMU / distLU;
      36                 :          0 :   return ratio;
      37                 :            : }
      38                 :            : 
      39                 :          0 : double QgsTolerance::toleranceInProjectUnits( double tolerance, QgsMapLayer *layer, const QgsMapSettings &mapSettings, QgsTolerance::UnitType units )
      40                 :            : {
      41                 :            :   // converts to map units
      42                 :          0 :   if ( units == ProjectUnits )
      43                 :          0 :     return tolerance;
      44                 :          0 :   else if ( units == Pixels )
      45                 :          0 :     return tolerance * mapSettings.mapUnitsPerPixel();
      46                 :            :   else // units == LayerUnits
      47                 :            :   {
      48                 :            :     // [mu] = [lu] * [mu/lu]
      49                 :          0 :     return tolerance * _ratioMU2LU( mapSettings, layer );
      50                 :            :   }
      51                 :          0 : }
      52                 :            : 
      53                 :            : 
      54                 :          0 : double QgsTolerance::toleranceInMapUnits( double tolerance, QgsMapLayer *layer, const QgsMapSettings &mapSettings, QgsTolerance::UnitType units )
      55                 :            : {
      56                 :            :   // converts to layer units
      57                 :          0 :   if ( units == LayerUnits )
      58                 :            :   {
      59                 :          0 :     return tolerance;
      60                 :            :   }
      61                 :          0 :   else if ( units == Pixels )
      62                 :            :   {
      63                 :          0 :     double layerUnitsPerPixel = computeMapUnitPerPixel( layer, mapSettings );
      64                 :          0 :     return tolerance * layerUnitsPerPixel;
      65                 :            :   }
      66                 :            :   else // ProjectUnits
      67                 :            :   {
      68                 :            :     // [lu] = [mu] / [mu/lu]
      69                 :          0 :     return tolerance / _ratioMU2LU( mapSettings, layer );
      70                 :            :   }
      71                 :          0 : }
      72                 :            : 
      73                 :          0 : double QgsTolerance::vertexSearchRadius( const QgsMapSettings &mapSettings )
      74                 :            : {
      75                 :          0 :   QgsSettings settings;
      76                 :          0 :   double tolerance = settings.value( QStringLiteral( "qgis/digitizing/search_radius_vertex_edit" ), 10 ).toDouble();
      77                 :          0 :   UnitType units = settings.enumValue( QStringLiteral( "qgis/digitizing/search_radius_vertex_edit_unit" ),  QgsTolerance::Pixels );
      78                 :          0 :   if ( units == LayerUnits )
      79                 :          0 :     units = ProjectUnits;
      80                 :          0 :   return toleranceInProjectUnits( tolerance, nullptr, mapSettings, units );
      81                 :          0 : }
      82                 :            : 
      83                 :          0 : double QgsTolerance::vertexSearchRadius( QgsMapLayer *layer, const QgsMapSettings &mapSettings )
      84                 :            : {
      85                 :          0 :   QgsSettings settings;
      86                 :          0 :   double tolerance = settings.value( QStringLiteral( "qgis/digitizing/search_radius_vertex_edit" ), 10 ).toDouble();
      87                 :          0 :   UnitType units = settings.enumValue( QStringLiteral( "qgis/digitizing/search_radius_vertex_edit_unit" ),  QgsTolerance::Pixels );
      88                 :          0 :   return toleranceInMapUnits( tolerance, layer, mapSettings, units );
      89                 :          0 : }
      90                 :            : 
      91                 :          0 : double QgsTolerance::defaultTolerance( QgsMapLayer *layer, const QgsMapSettings &mapSettings )
      92                 :            : {
      93                 :          0 :   QgsSettings settings;
      94                 :          0 :   double tolerance = settings.value( QStringLiteral( "qgis/digitizing/default_snapping_tolerance" ), Qgis::DEFAULT_SNAP_TOLERANCE ).toDouble();
      95                 :          0 :   UnitType units = settings.enumValue( QStringLiteral( "qgis/digitizing/default_snapping_tolerance_unit" ),  Qgis::DEFAULT_SNAP_UNITS );
      96                 :          0 :   return toleranceInMapUnits( tolerance, layer, mapSettings, units );
      97                 :          0 : }
      98                 :            : 
      99                 :            : 
     100                 :          0 : double QgsTolerance::computeMapUnitPerPixel( QgsMapLayer *layer, const QgsMapSettings &mapSettings )
     101                 :            : {
     102                 :            :   // the layer is projected. Find out how many pixels are in one map unit - either horizontal and vertical direction
     103                 :            :   // this check might not work correctly in some cases
     104                 :            :   // (on a large area the pixels projected around "0,0" can have different properties from the actual point)
     105                 :          0 :   QgsPointXY p1 = toLayerCoordinates( layer, mapSettings, QPoint( 0, 1 ) );
     106                 :          0 :   QgsPointXY p2 = toLayerCoordinates( layer, mapSettings, QPoint( 0, 2 ) );
     107                 :          0 :   QgsPointXY p3 = toLayerCoordinates( layer, mapSettings, QPoint( 1, 0 ) );
     108                 :          0 :   QgsPointXY p4 = toLayerCoordinates( layer, mapSettings, QPoint( 2, 0 ) );
     109                 :          0 :   double x = p1.sqrDist( p2 );
     110                 :          0 :   double y = p3.sqrDist( p4 );
     111                 :          0 :   if ( x > y )
     112                 :            :   {
     113                 :          0 :     return std::sqrt( x );
     114                 :            :   }
     115                 :            :   else
     116                 :            :   {
     117                 :          0 :     return std::sqrt( y );
     118                 :            :   }
     119                 :          0 : }
     120                 :            : 
     121                 :            : 
     122                 :          0 : QgsPointXY QgsTolerance::toLayerCoordinates( QgsMapLayer *layer, const QgsMapSettings &mapSettings, QPoint point )
     123                 :            : {
     124                 :          0 :   QgsPointXY pt = mapSettings.mapToPixel().toMapCoordinates( point );
     125                 :          0 :   return mapSettings.mapToLayerCoordinates( layer, pt );
     126                 :            : }