QGIS API Documentation 3.27.0-Master (f261cc1f8b)
qgstilingscheme.cpp
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1/***************************************************************************
2 qgstilingscheme.cpp
3 --------------------------------------
4 Date : July 2017
5 Copyright : (C) 2017 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#include "qgstilingscheme.h"
17
18#include "qgschunknode_p.h"
19#include "qgsrectangle.h"
20
22 : mCrs( crs )
23{
24 mMapOrigin = QgsPointXY( fullExtent.xMinimum(), fullExtent.yMinimum() );
25 mBaseTileSide = std::max( fullExtent.width(), fullExtent.height() );
26}
27
28QgsPointXY QgsTilingScheme::tileToMap( int x, int y, int z ) const
29{
30 const double tileSide = mBaseTileSide / pow( 2, z );
31 const double mx = mMapOrigin.x() + x * tileSide;
32 const double my = mMapOrigin.y() + y * tileSide;
33 return QgsPointXY( mx, my );
34}
35
36void QgsTilingScheme::mapToTile( const QgsPointXY &pt, int z, float &x, float &y ) const
37{
38 const double tileSide = mBaseTileSide / pow( 2, z );
39 x = ( pt.x() - mMapOrigin.x() ) / tileSide;
40 y = ( pt.y() - mMapOrigin.y() ) / tileSide;
41}
42
43QgsRectangle QgsTilingScheme::tileToExtent( int x, int y, int z ) const
44{
45 const QgsPointXY pt0 = tileToMap( x, y, z );
46 const QgsPointXY pt1 = tileToMap( x + 1, y + 1, z );
47 return QgsRectangle( pt0, pt1 );
48}
49
50QgsRectangle QgsTilingScheme::tileToExtent( const QgsChunkNodeId &nodeId ) const
51{
52 return tileToExtent( nodeId.x, nodeId.y, nodeId.d );
53}
54
55void QgsTilingScheme::extentToTile( const QgsRectangle &extent, int &x, int &y, int &z ) const
56{
57 x = y = z = 0; // start with root tile
58 while ( true )
59 {
60 // try to see if any child tile fully contains our extent - if so, go deeper
61 if ( tileToExtent( x * 2, y * 2, z + 1 ).contains( extent ) )
62 {
63 x = x * 2;
64 y = y * 2;
65 }
66 else if ( tileToExtent( x * 2 + 1, y * 2, z + 1 ).contains( extent ) )
67 {
68 x = x * 2 + 1;
69 y = y * 2;
70 }
71 else if ( tileToExtent( x * 2, y * 2 + 1, z + 1 ).contains( extent ) )
72 {
73 x = x * 2;
74 y = y * 2 + 1;
75 }
76 else if ( tileToExtent( x * 2 + 1, y * 2 + 1, z + 1 ).contains( extent ) )
77 {
78 x = x * 2 + 1;
79 y = y * 2 + 1;
80 }
81 else
82 {
83 return; // cannot go deeper
84 }
85 z++;
86 }
87}
This class represents a coordinate reference system (CRS).
A class to represent a 2D point.
Definition: qgspointxy.h:59
double y
Definition: qgspointxy.h:63
Q_GADGET double x
Definition: qgspointxy.h:62
A rectangle specified with double values.
Definition: qgsrectangle.h:42
double xMinimum() const SIP_HOLDGIL
Returns the x minimum value (left side of rectangle).
Definition: qgsrectangle.h:188
double yMinimum() const SIP_HOLDGIL
Returns the y minimum value (bottom side of rectangle).
Definition: qgsrectangle.h:198
double height() const SIP_HOLDGIL
Returns the height of the rectangle.
Definition: qgsrectangle.h:230
double width() const SIP_HOLDGIL
Returns the width of the rectangle.
Definition: qgsrectangle.h:223
void mapToTile(const QgsPointXY &pt, int z, float &x, float &y) const
Returns tile coordinates for given map coordinates and Z level.
void extentToTile(const QgsRectangle &extent, int &x, int &y, int &z) const
Returns coordinates of a tile that most tightly fits the whole extent.
QgsPointXY tileToMap(int x, int y, int z) const
Returns map coordinates at tile coordinates (for lower-left corner of the tile)
QgsTilingScheme()=default
Creates invalid tiling scheme.
QgsRectangle tileToExtent(int x, int y, int z) const
Returns map coordinates of the extent of a tile.
const QgsCoordinateReferenceSystem & crs