1 | /* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
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2 | * Qwt Widget Library
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3 | * Copyright (C) 1997 Josef Wilgen
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4 | * Copyright (C) 2002 Uwe Rathmann
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5 | *
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6 | * This library is free software; you can redistribute it and/or
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7 | * modify it under the terms of the Qwt License, Version 1.0
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8 | *****************************************************************************/
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9 |
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10 | #ifndef QWT_PLOT_RASTERITEM_H
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11 | #define QWT_PLOT_RASTERITEM_H
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12 |
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13 | #include "qwt_global.h"
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14 | #include "qwt_plot_item.h"
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15 | #include "qwt_interval.h"
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16 | #include <qglobal.h>
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17 | #include <qstring.h>
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18 | #include <qimage.h>
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19 |
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20 | /*!
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21 | \brief A class, which displays raster data
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22 |
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23 | Raster data is a grid of pixel values, that can be represented
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24 | as a QImage. It is used for many types of information like
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25 | spectrograms, cartograms, geographical maps ...
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26 |
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27 | Often a plot has several types of raster data organized in layers.
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28 | ( f.e a geographical map, with weather statistics ).
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29 | Using setAlpha() raster items can be stacked easily.
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30 |
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31 | QwtPlotRasterItem is only implemented for images of the following formats:
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32 | QImage::Format_Indexed8, QImage::Format_ARGB32.
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33 |
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34 | \sa QwtPlotSpectrogram
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35 | */
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36 |
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37 | class QWT_EXPORT QwtPlotRasterItem: public QwtPlotItem
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38 | {
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39 | public:
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40 | /*!
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41 | - NoCache\n
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42 | renderImage() is called, whenever the item has to be repainted
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43 | - PaintCache\n
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44 | renderImage() is called, whenever the image cache is not valid,
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45 | or the scales, or the size of the canvas has changed. This type
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46 | of cache is only useful for improving the performance of hide/show
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47 | operations. All other situations are already handled by the
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48 | plot canvas cache.
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49 |
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50 | The default policy is NoCache
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51 | */
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52 | enum CachePolicy
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53 | {
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54 | NoCache,
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55 | PaintCache
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56 | };
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57 |
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58 | /*!
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59 | Attributes to modify the drawing algorithm.
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60 | \sa setPaintAttribute(), testPaintAttribute()
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61 | */
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62 | enum PaintAttribute
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63 | {
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64 | /*!
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65 | When the image is rendered according to the data pixels
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66 | ( QwtRasterData::pixelHint() ) it can be expanded to paint
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67 | device resolution before it is passed to QPainter.
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68 | The expansion algorithm rounds the pixel borders in the same
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69 | way as the axis ticks, what is usually better than the
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70 | scaling algorithm implemented in Qt.
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71 | Disabling this flag might make sense, to reduce the size of a
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72 | document/file. If this is possible for a document format
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73 | depends on the implementation of the specific QPaintEngine.
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74 | */
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75 |
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76 | PaintInDeviceResolution = 1
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77 | };
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78 |
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79 | //! Paint attributes
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80 | typedef QFlags<PaintAttribute> PaintAttributes;
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81 |
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82 | explicit QwtPlotRasterItem( const QString& title = QString::null );
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83 | explicit QwtPlotRasterItem( const QwtText& title );
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84 | virtual ~QwtPlotRasterItem();
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85 |
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86 | void setPaintAttribute( PaintAttribute, bool on = true );
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87 | bool testPaintAttribute( PaintAttribute ) const;
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88 |
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89 | void setAlpha( int alpha );
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90 | int alpha() const;
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91 |
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92 | void setCachePolicy( CachePolicy );
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93 | CachePolicy cachePolicy() const;
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94 |
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95 | void invalidateCache();
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96 |
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97 | virtual void draw( QPainter *p,
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98 | const QwtScaleMap &xMap, const QwtScaleMap &yMap,
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99 | const QRectF &rect ) const;
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100 |
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101 | virtual QRectF pixelHint( const QRectF & ) const;
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102 |
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103 | virtual QwtInterval interval(Qt::Axis) const;
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104 | virtual QRectF boundingRect() const;
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105 |
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106 | protected:
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107 | /*!
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108 | \brief Render an image
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109 |
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110 | An implementation of render() might iterate over all
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111 | pixels of imageRect. Each pixel has to be translated into
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112 | the corresponding position in scale coordinates using the maps.
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113 | This position can be used to look up a value in a implementation
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114 | specific way and to map it into a color.
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115 |
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116 | \param xMap X-Scale Map
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117 | \param yMap Y-Scale Map
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118 | \param area Requested area for the image in scale coordinates
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119 | \param imageSize Requested size of the image
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120 | */
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121 | virtual QImage renderImage( const QwtScaleMap &xMap,
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122 | const QwtScaleMap &yMap, const QRectF &area,
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123 | const QSize &imageSize ) const = 0;
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124 |
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125 | virtual QwtScaleMap imageMap( Qt::Orientation,
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126 | const QwtScaleMap &map, const QRectF &area,
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127 | const QSize &imageSize, double pixelSize) const;
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128 |
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129 | private:
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130 | QwtPlotRasterItem( const QwtPlotRasterItem & );
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131 | QwtPlotRasterItem &operator=( const QwtPlotRasterItem & );
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132 |
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133 | void init();
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134 |
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135 | QImage compose( const QwtScaleMap &, const QwtScaleMap &,
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136 | const QRectF &imageArea, const QRectF &paintRect,
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137 | const QSize &imageSize, bool doCache) const;
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138 |
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139 |
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140 | class PrivateData;
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141 | PrivateData *d_data;
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142 | };
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143 |
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144 | Q_DECLARE_OPERATORS_FOR_FLAGS( QwtPlotRasterItem::PaintAttributes )
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145 |
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146 | #endif
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