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       1                 :            : /***************************************************************************
       2                 :            :                          qgscoordinatetransformcontext.h
       3                 :            :                          -------------------------------
       4                 :            :     begin                : November 2017
       5                 :            :     copyright            : (C) 2017 by Nyall Dawson
       6                 :            :     email                : nyall dot dawson at gmail dot com
       7                 :            :  ***************************************************************************/
       8                 :            : 
       9                 :            : /***************************************************************************
      10                 :            :  *                                                                         *
      11                 :            :  *   This program is free software; you can redistribute it and/or modify  *
      12                 :            :  *   it under the terms of the GNU General Public License as published by  *
      13                 :            :  *   the Free Software Foundation; either version 2 of the License, or     *
      14                 :            :  *   (at your option) any later version.                                   *
      15                 :            :  *                                                                         *
      16                 :            :  ***************************************************************************/
      17                 :            : 
      18                 :            : #ifndef QGSCOORDINATETRANSFORMCONTEXT_H
      19                 :            : #define QGSCOORDINATETRANSFORMCONTEXT_H
      20                 :            : 
      21                 :            : #include "qgis_core.h"
      22                 :            : #include "qgis_sip.h"
      23                 :            : #include "qgsdatumtransform.h"
      24                 :            : 
      25                 :            : #include <QMetaType>
      26                 :            : #include <QExplicitlySharedDataPointer>
      27                 :            : class QgsCoordinateReferenceSystem;
      28                 :            : class QgsReadWriteContext;
      29                 :            : class QgsCoordinateTransformContextPrivate;
      30                 :            : class QDomElement;
      31                 :            : 
      32                 :            : /***************************************************************************
      33                 :            :  * This class is considered CRITICAL and any change MUST be accompanied with
      34                 :            :  * full unit tests in testqgsfeature.cpp.
      35                 :            :  * See details in QEP #17
      36                 :            :  ****************************************************************************/
      37                 :            : 
      38                 :            : /**
      39                 :            :  * \class QgsCoordinateTransformContext
      40                 :            :  * \ingroup core
      41                 :            :  * \brief Contains information about the context in which a coordinate transform is executed.
      42                 :            :  *
      43                 :            :  * The context stores various information regarding which coordinate operations should
      44                 :            :  * be used when transforming points from a source to destination coordinate reference
      45                 :            :  * system.
      46                 :            :  *
      47                 :            :  * \note QgsCoordinateTransformContext objects are thread safe for read and write.
      48                 :            :  *
      49                 :            :  * \note QgsCoordinateTransformContext objects are implicitly shared.
      50                 :            :  *
      51                 :            :  * \see QgsDatumTransform
      52                 :            :  * \see QgsCoordinateTransform
      53                 :            :  *
      54                 :            :  * \since QGIS 3.0
      55                 :            : */
      56                 :            : 
      57                 :            : class CORE_EXPORT QgsCoordinateTransformContext
      58                 :            : {
      59                 :            :   public:
      60                 :            : 
      61                 :            :     /**
      62                 :            :      * Constructor for QgsCoordinateTransformContext.
      63                 :            :      */
      64                 :            :     QgsCoordinateTransformContext();
      65                 :            : 
      66                 :            :     ~QgsCoordinateTransformContext() ;
      67                 :            : 
      68                 :            :     /**
      69                 :            :      * Copy constructor
      70                 :            :      */
      71                 :            :     QgsCoordinateTransformContext( const QgsCoordinateTransformContext &rhs );
      72                 :            : 
      73                 :            :     /**
      74                 :            :      * Assignment operator
      75                 :            :      */
      76                 :            :     QgsCoordinateTransformContext &operator=( const QgsCoordinateTransformContext &rhs ) SIP_SKIP;
      77                 :            : 
      78                 :            :     bool operator==( const QgsCoordinateTransformContext &rhs ) const ;
      79                 :            : 
      80                 :            :     /**
      81                 :            :      * Clears all stored transform information from the context.
      82                 :            :      */
      83                 :            :     void clear();
      84                 :            : 
      85                 :            :     /**
      86                 :            :      * Returns the stored mapping for source to destination CRS pairs to associated datum transforms to use.
      87                 :            :      * The map keys will be QgsCoordinateReferenceSystems::authid()s.
      88                 :            :      *
      89                 :            :      * If either the source transform ID or destination transform ID is -1, then no datum transform is
      90                 :            :      * required for transformations for that source or destination.
      91                 :            :      *
      92                 :            :      * \warning This method should not be used to calculate the corresponding datum transforms
      93                 :            :      * to use for a coordinate transform. Instead, always use calculateDatumTransforms()
      94                 :            :      * to determine this.
      95                 :            :      *
      96                 :            :      * \see addSourceDestinationDatumTransform()
      97                 :            :      *
      98                 :            :      * \deprecated Has no effect on builds based on Proj 6.0 or later, use coordinateOperations() instead.
      99                 :            :      */
     100                 :            :     Q_DECL_DEPRECATED QMap< QPair< QString, QString>, QgsDatumTransform::TransformPair > sourceDestinationDatumTransforms() const SIP_DEPRECATED;
     101                 :            : 
     102                 :            :     /**
     103                 :            :      * Returns the stored mapping for source to destination CRS pairs to associated coordinate operation to use
     104                 :            :      * (as a proj string). The map keys will be QgsCoordinateReferenceSystems::authid()s.
     105                 :            :      *
     106                 :            :      * \warning This method should not be used to calculate the corresponding coordinate operation
     107                 :            :      * to use for a coordinate transform. Instead, always use calculateCoordinateOperation()
     108                 :            :      * to determine this.
     109                 :            :      *
     110                 :            :      * \see addCoordinateOperation()
     111                 :            :      *
     112                 :            :      * \note Requires Proj 6.0 or later. Builds based on earlier Proj versions will always return an empty list,
     113                 :            :      * and the deprecated sourceDestinationDatumTransforms() method must be used instead.
     114                 :            :      *
     115                 :            :      * \since QGIS 3.8
     116                 :            :      */
     117                 :            :     QMap< QPair< QString, QString>, QString > coordinateOperations() const;
     118                 :            : 
     119                 :            :     /**
     120                 :            :      * Adds a new \a sourceTransform and \a destinationTransform to use when projecting coordinates
     121                 :            :      * from the specified \a sourceCrs to the specified \a destinationCrs.
     122                 :            :      *
     123                 :            :      * If either \a sourceTransformId or \a destinationTransformId is -1, then no datum transform is
     124                 :            :      * required for transformations for that source or destination.
     125                 :            :      *
     126                 :            :      * Returns TRUE if the new transform pair was added successfully.
     127                 :            :      *
     128                 :            :      * \see sourceDestinationDatumTransforms()
     129                 :            :      * \see removeSourceDestinationDatumTransform()
     130                 :            :      *
     131                 :            :      * \deprecated Has no effect on builds based on Proj 6.0 or later, use addCoordinateOperation() instead.
     132                 :            :      */
     133                 :            :     Q_DECL_DEPRECATED bool addSourceDestinationDatumTransform( const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, int sourceTransformId, int destinationTransformId ) SIP_DEPRECATED;
     134                 :            : 
     135                 :            :     /**
     136                 :            :      * Adds a new \a coordinateOperationProjString to use when projecting coordinates
     137                 :            :      * from the specified \a sourceCrs to the specified \a destinationCrs.
     138                 :            :      *
     139                 :            :      * \a coordinateOperationProjString should be set to a valid Proj coordinate operation
     140                 :            :      * string. If \a coordinateOperationProjString is empty, then the default Proj operation
     141                 :            :      * will be used when transforming between the coordinate reference systems.
     142                 :            :      *
     143                 :            :      * If \a allowFallback is TRUE (since QGIS 3.12), then "ballpark" fallback transformations
     144                 :            :      * will be used in the case that the specified coordinate operation fails (such as when
     145                 :            :      * coordinates from outside a required grid shift file are transformed). See
     146                 :            :      * QgsCoordinateTransform::fallbackOperationOccurred() for further details. Note that if an
     147                 :            :      * existing \a sourceCrs and \a destinationCrs pair are added with a different \a allowFallback
     148                 :            :      * value, that value will replace the existing one (i.e. each combination of \a sourceCrs and
     149                 :            :      * \a destinationCrs must be unique).
     150                 :            :      *
     151                 :            :      * \warning coordinateOperationProjString MUST be a proj string which has been normalized for
     152                 :            :      * visualization, and must be constructed so that coordinates are always input and output
     153                 :            :      * with x/y coordinate ordering. (Proj strings output by utilities such as projinfo will NOT
     154                 :            :      * automatically normalize the axis order!).
     155                 :            :      *
     156                 :            :      * Returns TRUE if the new coordinate operation was added successfully.
     157                 :            :      *
     158                 :            :      * \see coordinateOperations()
     159                 :            :      * \see removeCoordinateOperation()
     160                 :            :      *
     161                 :            :      * \note Requires Proj 6.0 or later. Builds based on earlier Proj versions will ignore this setting,
     162                 :            :      * and the deprecated addSourceDestinationDatumTransform() method must be used instead.
     163                 :            :      *
     164                 :            :      * \since QGIS 3.8
     165                 :            :      */
     166                 :            :     bool addCoordinateOperation( const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs, const QString &coordinateOperationProjString, bool allowFallback = true );
     167                 :            : 
     168                 :            :     /**
     169                 :            :      * Removes the source to destination datum transform pair for the specified \a sourceCrs and
     170                 :            :      * \a destinationCrs.
     171                 :            :      * \see addSourceDestinationDatumTransform()
     172                 :            :      *
     173                 :            :      * \deprecated Use removeCoordinateOperation() instead
     174                 :            :      */
     175                 :            :     Q_DECL_DEPRECATED void removeSourceDestinationDatumTransform( const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs ) SIP_DEPRECATED ;
     176                 :            : 
     177                 :            :     /**
     178                 :            :      * Removes the coordinate operation for the specified \a sourceCrs and \a destinationCrs.
     179                 :            :      *
     180                 :            :      * \since QGIS 3.8
     181                 :            :      */
     182                 :            :     void removeCoordinateOperation( const QgsCoordinateReferenceSystem &sourceCrs, const QgsCoordinateReferenceSystem &destinationCrs );
     183                 :            : 
     184                 :            :     /**
     185                 :            :      * Returns TRUE if the context has a valid coordinate operation to use
     186                 :            :      * when transforming from the specified \a source CRS to \a destination CRS.
     187                 :            :      * \note source and destination are reversible.
     188                 :            :      */
     189                 :            :     bool hasTransform( const QgsCoordinateReferenceSystem &source,
     190                 :            :                        const QgsCoordinateReferenceSystem &destination ) const;
     191                 :            : 
     192                 :            :     /**
     193                 :            :      * Returns the pair of source and destination datum transforms to use
     194                 :            :      * for a transform from the specified \a source CRS to \a destination CRS.
     195                 :            :      *
     196                 :            :      * Returns an ID of -1 if a datum transform should not be used for the source or
     197                 :            :      * destination.
     198                 :            :      *
     199                 :            :      * \note source and destination are reversible.
     200                 :            :      * \deprecated Has no effect on builds based on Proj 6.0 or later. Use calculateCoordinateOperation() instead.
     201                 :            :      */
     202                 :            :     Q_DECL_DEPRECATED QgsDatumTransform::TransformPair calculateDatumTransforms( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination ) const SIP_DEPRECATED;
     203                 :            : 
     204                 :            :     /**
     205                 :            :      * Returns the Proj coordinate operation string to use when transforming
     206                 :            :      * from the specified \a source CRS to \a destination CRS.
     207                 :            :      *
     208                 :            :      * Returns an empty string if no specific coordinate operation is set for the source to
     209                 :            :      * destination pair, in which case the default Proj coordinate operation should
     210                 :            :      * be used.
     211                 :            :      *
     212                 :            :      * \note source and destination are reversible.
     213                 :            :      *
     214                 :            :      * \note Requires Proj 6.0 or later. Builds based on earlier Proj versions will always return
     215                 :            :      * an empty string, and the deprecated calculateDatumTransforms() method should be used instead.
     216                 :            :      *
     217                 :            :      * \warning Always check the result of mustReverseCoordinateOperation() in order to determine if the
     218                 :            :      * proj coordinate operation string returned by this method corresponds to the reverse operation, and
     219                 :            :      * must be manually flipped when calculating coordinate transforms.
     220                 :            :      *
     221                 :            :      * \since QGIS 3.8
     222                 :            :      */
     223                 :            :     QString calculateCoordinateOperation( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination ) const;
     224                 :            : 
     225                 :            :     /**
     226                 :            :      * Returns TRUE if approximate "ballpark" transforms may be used when transforming
     227                 :            :      * between a \a source and \a destination CRS pair, in the case that the preferred
     228                 :            :      * coordinate operation fails (such as when
     229                 :            :      * coordinates from outside a required grid shift file are transformed). See
     230                 :            :      * QgsCoordinateTransform::fallbackOperationOccurred() for further details.
     231                 :            :      *
     232                 :            :      * \since QGIS 3.12
     233                 :            :      */
     234                 :            :     bool allowFallbackTransform( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination ) const;
     235                 :            : 
     236                 :            :     /**
     237                 :            :      * Returns TRUE if the coordinate operation returned by calculateCoordinateOperation() for the \a source to \a destination pair
     238                 :            :      * must be inverted.
     239                 :            :      *
     240                 :            :      * \since QGIS 3.10.2
     241                 :            :      */
     242                 :            :     bool mustReverseCoordinateOperation( const QgsCoordinateReferenceSystem &source, const QgsCoordinateReferenceSystem &destination ) const;
     243                 :            : 
     244                 :            :     // TODO QGIS 4.0 - remove missingTransforms, not used for Proj >= 6.0 builds
     245                 :            : 
     246                 :            :     /**
     247                 :            :      * Reads the context's state from a DOM \a element.
     248                 :            :      *
     249                 :            :      * Returns FALSE if transforms stored in the XML are not available. In this case \a missingTransforms will be
     250                 :            :      * filled with missing datum transform strings.
     251                 :            :      *
     252                 :            :      * \see writeXml()
     253                 :            :      */
     254                 :            :     bool readXml( const QDomElement &element, const QgsReadWriteContext &context, QStringList &missingTransforms SIP_OUT );
     255                 :            : 
     256                 :            :     /**
     257                 :            :      * Writes the context's state to a DOM \a element.
     258                 :            :      * \see readXml()
     259                 :            :      */
     260                 :            :     void writeXml( QDomElement &element, const QgsReadWriteContext &context ) const;
     261                 :            : 
     262                 :            : 
     263                 :            :     /**
     264                 :            :      * Reads the context's state from application settings.
     265                 :            :      * \see readSettings()
     266                 :            :      */
     267                 :            :     void readSettings();
     268                 :            : 
     269                 :            :     /**
     270                 :            :      * Write the context's state to application settings.
     271                 :            :      * \see writeSettings()
     272                 :            :      */
     273                 :            :     void writeSettings();
     274                 :            : 
     275                 :            : 
     276                 :            :   private:
     277                 :            : 
     278                 :            :     QExplicitlySharedDataPointer<QgsCoordinateTransformContextPrivate> d;
     279                 :            : 
     280                 :            : };
     281                 :            : 
     282                 :          1 : Q_DECLARE_METATYPE( QgsCoordinateTransformContext )
     283                 :            : 
     284                 :            : #endif // QGSCOORDINATETRANSFORMCONTEXT_H
     285                 :            : 
     286                 :            : 
     287                 :            : 
     288                 :            :