1 /*
2  * Copyright (C) 2001-2015 Klaralvdalens Datakonsult AB.  All rights reserved.
3  *
4  * This file is part of the KD Chart library.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of
9  * the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
18  */
19 
20 #ifndef PLOTTERDIAGRAMCOMPRESSOR_H
21 #define PLOTTERDIAGRAMCOMPRESSOR_H
22 
23 #include <QObject>
24 #include <QAbstractItemModel>
25 #include <QPointer>
26 #include <QVector>
27 #include <QDateTime>
28 
29 #include <cmath>
30 #include <limits>
31 
32 namespace KChart
33 {
34 
35 
36 class PlotterDiagramCompressor : public QObject
37 {
38     Q_OBJECT
39 public:
40 
41     enum CompressionMode{ SLOPE = 0, DISTANCE, BOTH };
Q_ENUM(CompressionMode)42     Q_ENUM( CompressionMode )
43 
44     class DataPoint {
45     public:
46         DataPoint()
47             : key( std::numeric_limits< qreal >::quiet_NaN() ),
48               value( std::numeric_limits< qreal >::quiet_NaN() ),
49               hidden( false )
50               {}
51         inline qreal distance( const DataPoint &other )
52         {
53             const qreal dx = key - other.key;
54             const qreal dy = value - other.value;
55             return std::sqrt( dx * dx + dy * dy );
56         }
57 
58         inline bool operator==( const DataPoint &other )
59         {
60             return key == other.key && value == other.value;
61         }
62 
63         inline bool operator!=( const DataPoint &other )
64         {
65             return !( *this == other );
66         }
67 
68         qreal key;
69         qreal value;
70         bool hidden;
71         QModelIndex index;
72     };
73 
74     class Iterator
75     {
76         friend class PlotterDiagramCompressor;
77     public:
78         Iterator( int dataSet, PlotterDiagramCompressor *parent );
79         ~Iterator();
80         bool isValid() const;
81         Iterator& operator++();
82         Iterator operator++( int );
83         Iterator& operator += ( int value );
84         Iterator& operator--();
85         Iterator operator--( int );
86         Iterator& operator-=( int value );
87         DataPoint operator*();
88         bool operator==( const Iterator &other ) const;
89         bool operator!=( const Iterator &other ) const;
90         void invalidate();
91     protected:
92         Iterator( int dataSet, PlotterDiagramCompressor *parent, QVector< DataPoint > buffer );
93     private:
94         void handleSlopeForward( const DataPoint &dp );
95         QPointer< PlotterDiagramCompressor > m_parent;
96         QVector< DataPoint > m_buffer;
97         int m_index;
98         int m_dataset;
99         int m_bufferIndex;
100         int m_rebuffer;
101         QDateTime m_timeOfCreation;
102     };
103 
104     typedef QVector<DataPoint> DataPointVector;
105     class CachePosition {
106     public:
CachePosition()107         CachePosition()
108             : first( -1 ),
109               second( -1 )
110               {}
CachePosition(int first,int second)111         CachePosition( int first, int second )
112             : first( first ),
113               second( second )
114               {}
115         int first;
116         int second;
117 
118         bool operator==( const CachePosition& rhs ) const
119         {
120             return first == rhs.first &&
121                    second == rhs.second;
122         }
123     };
124     explicit PlotterDiagramCompressor(QObject *parent = nullptr);
125     ~PlotterDiagramCompressor();
126     Iterator begin( int dataSet );
127     Iterator end( int dataSet );
128     void setMergeRadius( qreal radius );
129     void setMergeRadiusPercentage( qreal radius );
130     void setModel( QAbstractItemModel *model );
131     QAbstractItemModel* model() const;
132     DataPoint data( const CachePosition& pos ) const;
133     int rowCount() const;
134     int datasetCount() const;
135     void setCompressionModel( CompressionMode value );
136     void setMaxSlopeChange( qreal value );
137     qreal maxSlopeChange() const;
138     void cleanCache();
139     QPair< QPointF, QPointF > dataBoundaries() const;
140     void setForcedDataBoundaries( const QPair< qreal, qreal > &bounds, Qt::Orientation direction );
141 Q_SIGNALS:
142     void boundariesChanged();
143     void rowCountChanged();
144 
145 private:
146     class Private;
147     Private *d;
148 };
149 
150 }
151 
152 #endif // PLOTTERDIAGRAMCOMPRESSOR_H
153