Marble

StackedTile.h
1// SPDX-License-Identifier: LGPL-2.1-or-later
2//
3// SPDX-FileCopyrightText: 2007-2010 Torsten Rahn <tackat@kde.org>
4// SPDX-FileCopyrightText: 2007 Inge Wallin <ingwa@kde.org>
5// SPDX-FileCopyrightText: 2010 Jens-Michael Hoffmann <jensmh@gmx.de>
6// SPDX-FileCopyrightText: 2010-2013 Bernhard Beschow <bbeschow@cs.tu-berlin.de>
7//
8
9#ifndef MARBLE_STACKEDTILE_H
10#define MARBLE_STACKEDTILE_H
11
12#include <QSharedPointer>
13#include <QVector>
14#include <QImage>
15
16#include "Tile.h"
17
18namespace Marble
19{
20
21class TextureTile;
22
23/*!
24 \class StackedTile
25 \brief A single tile that consists of a stack of Tile layers.
26
27 The StackedTile is a tile container that covers a certain area and is used
28 for a particular zoom level. It consists of a <b>stack of several
29 individual thematic Tiles</b> that cover the very same area and
30 are used for the very same zoom level: This stack of Tiles is
31 built up from the ground: The first Tile at the bottom usually
32 represents the ground surface. Optionally there might be a range of other
33 Tiles stacked on top which cover e.g. relief, streets and clouds.
34
35 For rendering the whole stack of tiles gets merged and blended into a
36 single QImage. This merging/blending operation is usually only performed
37 once the stack of tiles changes visually. As a result access to the visual
38 composition of all TextureTile layers is very fast since it is reduced to
39 a single QImage that also consumes very little memory.
40
41 The whole mechanism is comparable to layers in applications like
42 Gimp or Photoshop (TM) which can be blended on top of each other via
43 so called filters and can be merged into a single layer if required.
44
45 Restrictions: The Tiles that are part of the stack need to be of
46 the same size and need to cover the same area at the same zoom level using
47 the very same projection.
48*/
49
50class StackedTile : public Tile
51{
52 public:
53 explicit StackedTile( TileId const &id, QImage const &resultImage, QVector<QSharedPointer<TextureTile> > const &tiles );
54 ~StackedTile() override;
55
56 void setUsed( bool used );
57 bool used() const;
58
59 int depth() const;
60 int byteCount() const;
61
62/*!
63 \brief Returns the stack of Tiles
64 \return A container of Tile objects.
65*/
67
68/*!
69 \brief Returns the QImage that describes the merged stack of Tiles
70 \return A non-zero pointer to the resulting QImage
71*/
72 QImage const * resultImage() const;
73
74/*!
75 \brief Returns the color value of the result tile at the given integer position.
76 \return The uint that describes the color value of the given pixel
77
78 Note: for gray scale images the color value of a single pixel is described
79 via a uchar (1 byte) while for RGB(A) images uint (4 bytes) are used.
80*/
81 uint pixel( int x, int y ) const;
82
83/*!
84 \brief Returns the color value of the result tile at a given floating point position.
85 \return The uint that describes the color value of the given pixel
86
87 Subpixel calculation is done via bilinear interpolation.
88
89 Note: for gray scale images the color value of a single pixel is described
90 via a uchar (1 byte) while for RGB(A) images uint (4 bytes) are used.
91*/
92 uint pixelF( qreal x, qreal y ) const;
93 // This method passes the top left pixel (if known already) for better performance
94 uint pixelF( qreal x, qreal y, const QRgb& pixel ) const;
95
96 private:
97 Q_DISABLE_COPY( StackedTile )
98
99 const QImage m_resultImage;
100 const int m_depth;
101 const bool m_isGrayscale;
103 const uchar **const jumpTable8;
104 const uint **const jumpTable32;
105 const int m_byteCount;
106 bool m_isUsed;
107
108 static int calcByteCount( const QImage &resultImage, const QVector<QSharedPointer<TextureTile> > &tiles );
109};
110
111}
112
113#endif
A single tile that consists of a stack of Tile layers.
Definition StackedTile.h:51
QVector< QSharedPointer< TextureTile > > tiles() const
Returns the stack of Tiles.
uint pixelF(qreal x, qreal y) const
Returns the color value of the result tile at a given floating point position.
QImage const * resultImage() const
Returns the QImage that describes the merged stack of Tiles.
uint pixel(int x, int y) const
Returns the color value of the result tile at the given integer position.
A class that resembles a tile (then it is extended to TextureTile or Vectortile).
Definition Tile.h:43
Binds a QML item to a specific geodetic location in screen coordinates.
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