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       1                 :            : /***************************************************************************
       2                 :            :   qgsvectortilelayer.h
       3                 :            :   --------------------------------------
       4                 :            :   Date                 : March 2020
       5                 :            :   Copyright            : (C) 2020 by Martin Dobias
       6                 :            :   Email                : wonder dot sk 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                 :            : #ifndef QGSVECTORTILELAYER_H
      17                 :            : #define QGSVECTORTILELAYER_H
      18                 :            : 
      19                 :            : #include "qgis_core.h"
      20                 :            : #include "qgis_sip.h"
      21                 :            : 
      22                 :            : #include "qgsmaplayer.h"
      23                 :            : 
      24                 :            : class QgsVectorTileLabeling;
      25                 :            : class QgsVectorTileRenderer;
      26                 :            : 
      27                 :            : class QgsTileXYZ;
      28                 :            : 
      29                 :            : /**
      30                 :            :  * \ingroup core
      31                 :            :  * \brief Implements a map layer that is dedicated to rendering of vector tiles.
      32                 :            :  * Vector tiles compared to "ordinary" vector layers are pre-processed data
      33                 :            :  * optimized for fast rendering. A dataset is provided with a series of zoom levels
      34                 :            :  * for different map scales. Each zoom level has a matrix of tiles that contain
      35                 :            :  * actual data. A single vector tile may be a a file stored on a local drive,
      36                 :            :  * requested over HTTP request or retrieved from a database.
      37                 :            :  *
      38                 :            :  * Content of a vector tile is divided into one or more named sub-layers. Each such
      39                 :            :  * sub-layer may contain many features which consist of geometry and attributes.
      40                 :            :  * Contrary to traditional vector layers, these sub-layers do not need to have a rigid
      41                 :            :  * schema where geometry type and attributes are the same for all features. A single
      42                 :            :  * sub-layer may have multiple geometry types in a single tile or have some attributes
      43                 :            :  * defined only at particular zoom levels.
      44                 :            :  *
      45                 :            :  * Vector tile layer currently does not use the concept of data providers that other
      46                 :            :  * layer types use. The process of rendering of vector tiles looks like this:
      47                 :            :  *
      48                 :            :  * +--------+                +------+                 +---------+
      49                 :            :  * |  DATA  |                |  RAW |                 | DECODED |
      50                 :            :  * |        | --> LOADER --> |      | --> DECODER --> |         | --> RENDERER
      51                 :            :  * | SOURCE |                | TILE |                 |  TILE   |
      52                 :            :  * +--------+                +------+                 +---------+
      53                 :            :  *
      54                 :            :  * Data source is a place from where tiles are fetched from (URL for HTTP access, local
      55                 :            :  * files, MBTiles file, GeoPackage file or others. Loader (QgsVectorTileLoader) class
      56                 :            :  * takes care of loading data from the data source. The "raw tile" data is just a blob
      57                 :            :  * (QByteArray) that is encoded in some way. There are multiple ways how vector tiles
      58                 :            :  * are encoded just like there are different formats how to store images. For example,
      59                 :            :  * tiles can be encoded using Mapbox Vector Tiles (MVT) format or in GeoJSON. Decoder
      60                 :            :  * (QgsVectorTileDecoder) takes care of decoding raw tile data into QgsFeature objects.
      61                 :            :  * A decoded tile is essentially an array of vector features for each sub-layer found
      62                 :            :  * in the tile - this is what vector tile renderer (QgsVectorTileRenderer) expects
      63                 :            :  * and does the map rendering.
      64                 :            :  *
      65                 :            :  * To construct a vector tile layer, it is best to use QgsDataSourceUri class and set
      66                 :            :  * the following parameters to get a valid encoded URI:
      67                 :            :  *
      68                 :            :  * - "type" - what kind of data source will be used
      69                 :            :  * - "url" - URL or path of the data source (specific to each data source type, see below)
      70                 :            :  *
      71                 :            :  * Currently supported data source types:
      72                 :            :  *
      73                 :            :  * - "xyz" - the "url" should be a template like http://example.com/{z}/{x}/{y}.pbf where
      74                 :            :  *   {x},{y},{z} will be replaced by tile coordinates
      75                 :            :  * - "mbtiles" - tiles read from a MBTiles file (a SQLite database)
      76                 :            :  *
      77                 :            :  * Currently supported decoders:
      78                 :            :  *
      79                 :            :  * - MVT - following Mapbox Vector Tiles specification
      80                 :            :  *
      81                 :            :  * \since QGIS 3.14
      82                 :            :  */
      83                 :            : class CORE_EXPORT QgsVectorTileLayer : public QgsMapLayer
      84                 :            : {
      85                 :          0 :     Q_OBJECT
      86                 :            : 
      87                 :            :   public:
      88                 :            :     //! Constructs a new vector tile layer
      89                 :            :     explicit QgsVectorTileLayer( const QString &path = QString(), const QString &baseName = QString() );
      90                 :            :     ~QgsVectorTileLayer() override;
      91                 :            : 
      92                 :            : #ifdef SIP_RUN
      93                 :            :     SIP_PYOBJECT __repr__();
      94                 :            :     % MethodCode
      95                 :            :     QString str = QStringLiteral( "<QgsVectorTileLayer: '%1'>" ).arg( sipCpp->name() );
      96                 :            :     sipRes = PyUnicode_FromString( str.toUtf8().constData() );
      97                 :            :     % End
      98                 :            : #endif
      99                 :            : 
     100                 :            :     // implementation of virtual functions from QgsMapLayer
     101                 :            : 
     102                 :            :     QgsVectorTileLayer *clone() const override SIP_FACTORY;
     103                 :            : 
     104                 :            :     QgsMapLayerRenderer *createMapRenderer( QgsRenderContext &rendererContext ) override SIP_FACTORY;
     105                 :            : 
     106                 :            :     bool readXml( const QDomNode &layerNode, QgsReadWriteContext &context ) override;
     107                 :            : 
     108                 :            :     bool writeXml( QDomNode &layerNode, QDomDocument &doc, const QgsReadWriteContext &context ) const override;
     109                 :            : 
     110                 :            :     bool readSymbology( const QDomNode &node, QString &errorMessage,
     111                 :            :                         QgsReadWriteContext &context, StyleCategories categories = AllStyleCategories ) override;
     112                 :            : 
     113                 :            :     bool writeSymbology( QDomNode &node, QDomDocument &doc, QString &errorMessage, const QgsReadWriteContext &context,
     114                 :            :                          StyleCategories categories = AllStyleCategories ) const override;
     115                 :            : 
     116                 :            :     void setTransformContext( const QgsCoordinateTransformContext &transformContext ) override;
     117                 :            :     QString loadDefaultStyle( bool &resultFlag SIP_OUT ) override;
     118                 :            : 
     119                 :            :     /**
     120                 :            :      * Loads the default style for the layer, and returns TRUE if the style was
     121                 :            :      * successfully loaded.
     122                 :            :      *
     123                 :            :      * The \a error string will be filled with a translated error message if an error
     124                 :            :      * occurs during the style load. The \a warnings list will be populated with any
     125                 :            :      * warning messages generated during the style load (e.g. default style properties
     126                 :            :      * which could not be converted).
     127                 :            :      *
     128                 :            :      * \since QGIS 3.16
     129                 :            :      */
     130                 :            :     bool loadDefaultStyle( QString &error, QStringList &warnings ) SIP_SKIP;
     131                 :            : 
     132                 :            :     QString loadDefaultMetadata( bool &resultFlag SIP_OUT ) override;
     133                 :            : 
     134                 :            :     QString encodedSource( const QString &source, const QgsReadWriteContext &context ) const FINAL;
     135                 :            :     QString decodedSource( const QString &source, const QString &provider, const QgsReadWriteContext &context ) const FINAL;
     136                 :            :     QString htmlMetadata() const override;
     137                 :            : 
     138                 :            :     // new methods
     139                 :            : 
     140                 :            :     //! Returns type of the data source
     141                 :          0 :     QString sourceType() const { return mSourceType; }
     142                 :            :     //! Returns URL/path of the data source (syntax different to each data source type)
     143                 :          0 :     QString sourcePath() const { return mSourcePath; }
     144                 :            : 
     145                 :            :     //! Returns minimum zoom level at which source has any valid tiles (negative = unconstrained)
     146                 :          0 :     int sourceMinZoom() const { return mSourceMinZoom; }
     147                 :            :     //! Returns maximum zoom level at which source has any valid tiles (negative = unconstrained)
     148                 :          0 :     int sourceMaxZoom() const { return mSourceMaxZoom; }
     149                 :            : 
     150                 :            :     /**
     151                 :            :      * Fetches raw tile data for the give tile coordinates. If failed to fetch tile data,
     152                 :            :      * it will return an empty byte array.
     153                 :            :      *
     154                 :            :      * \note This call may issue a network request (depending on the source type) and will block
     155                 :            :      * the caller until the request is finished.
     156                 :            :      */
     157                 :            :     QByteArray getRawTile( QgsTileXYZ tileID ) SIP_SKIP;
     158                 :            : 
     159                 :            :     /**
     160                 :            :      * Sets renderer for the map layer.
     161                 :            :      * \note Takes ownership of the passed renderer
     162                 :            :      */
     163                 :            :     void setRenderer( QgsVectorTileRenderer *r SIP_TRANSFER );
     164                 :            :     //! Returns currently assigned renderer
     165                 :            :     QgsVectorTileRenderer *renderer() const;
     166                 :            : 
     167                 :            :     /**
     168                 :            :      * Sets labeling for the map layer.
     169                 :            :      * \note Takes ownership of the passed labeling
     170                 :            :      */
     171                 :            :     void setLabeling( QgsVectorTileLabeling *labeling SIP_TRANSFER );
     172                 :            :     //! Returns currently assigned labeling
     173                 :            :     QgsVectorTileLabeling *labeling() const;
     174                 :            : 
     175                 :            :     //! Sets whether to render also borders of tiles (useful for debugging)
     176                 :            :     void setTileBorderRenderingEnabled( bool enabled ) { mTileBorderRendering = enabled; }
     177                 :            :     //! Returns whether to render also borders of tiles (useful for debugging)
     178                 :          0 :     bool isTileBorderRenderingEnabled() const { return mTileBorderRendering; }
     179                 :            : 
     180                 :            :   private:
     181                 :            :     bool loadDataSource();
     182                 :            : 
     183                 :            :   private:
     184                 :            :     //! Type of the data source
     185                 :            :     QString mSourceType;
     186                 :            :     //! URL/Path of the data source
     187                 :            :     QString mSourcePath;
     188                 :            :     //! Minimum zoom level at which source has any valid tiles (negative = unconstrained)
     189                 :            :     int mSourceMinZoom = -1;
     190                 :            :     //! Maximum zoom level at which source has any valid tiles (negative = unconstrained)
     191                 :            :     int mSourceMaxZoom = -1;
     192                 :            : 
     193                 :            :     //! Renderer assigned to the layer to draw map
     194                 :            :     std::unique_ptr<QgsVectorTileRenderer> mRenderer;
     195                 :            :     //! Labeling assigned to the layer to produce labels
     196                 :            :     std::unique_ptr<QgsVectorTileLabeling> mLabeling;
     197                 :            :     //! Whether we draw borders of tiles
     198                 :            :     bool mTileBorderRendering = false;
     199                 :            : 
     200                 :            :     QVariantMap mArcgisLayerConfiguration;
     201                 :            : 
     202                 :            :     bool setupArcgisVectorTileServiceConnection( const QString &uri, const QgsDataSourceUri &dataSourceUri );
     203                 :            : };
     204                 :            : 
     205                 :            : 
     206                 :            : #endif // QGSVECTORTILELAYER_H