153 lines
4.7 KiB
C++
153 lines
4.7 KiB
C++
/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
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* Qwt Widget Library
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* Copyright (C) 1997 Josef Wilgen
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* Copyright (C) 2002 Uwe Rathmann
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the Qwt License, Version 1.0
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*****************************************************************************/
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#ifndef QWT_PLOT_RASTERITEM_H
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#define QWT_PLOT_RASTERITEM_H
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#include "qwt_global.h"
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#include "qwt_plot_item.h"
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#include "qwt_interval.h"
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#include <qglobal.h>
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#include <qstring.h>
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#include <qimage.h>
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/*!
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\brief A class, which displays raster data
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Raster data is a grid of pixel values, that can be represented
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as a QImage. It is used for many types of information like
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spectrograms, cartograms, geographical maps ...
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Often a plot has several types of raster data organized in layers.
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( f.e a geographical map, with weather statistics ).
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Using setAlpha() raster items can be stacked easily.
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QwtPlotRasterItem is only implemented for images of the following formats:
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QImage::Format_Indexed8, QImage::Format_ARGB32.
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\sa QwtPlotSpectrogram
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*/
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class QWT_EXPORT QwtPlotRasterItem: public QwtPlotItem
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{
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public:
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/*!
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\brief Cache policy
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The default policy is NoCache
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*/
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enum CachePolicy
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{
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/*!
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renderImage() is called each time the item has to be repainted
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*/
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NoCache,
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/*!
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renderImage() is called, whenever the image cache is not valid,
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or the scales, or the size of the canvas has changed.
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This type of cache is useful for improving the performance
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of hide/show operations or manipulations of the alpha value.
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All other situations are handled by the canvas backing store.
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*/
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PaintCache
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};
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/*!
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Attributes to modify the drawing algorithm.
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\sa setPaintAttribute(), testPaintAttribute()
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*/
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enum PaintAttribute
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{
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/*!
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When the image is rendered according to the data pixels
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( QwtRasterData::pixelHint() ) it can be expanded to paint
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device resolution before it is passed to QPainter.
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The expansion algorithm rounds the pixel borders in the same
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way as the axis ticks, what is usually better than the
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scaling algorithm implemented in Qt.
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Disabling this flag might make sense, to reduce the size of a
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document/file. If this is possible for a document format
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depends on the implementation of the specific QPaintEngine.
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*/
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PaintInDeviceResolution = 1
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};
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//! Paint attributes
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typedef QFlags<PaintAttribute> PaintAttributes;
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explicit QwtPlotRasterItem( const QString& title = QString::null );
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explicit QwtPlotRasterItem( const QwtText& title );
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virtual ~QwtPlotRasterItem();
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void setPaintAttribute( PaintAttribute, bool on = true );
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bool testPaintAttribute( PaintAttribute ) const;
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void setAlpha( int alpha );
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int alpha() const;
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void setCachePolicy( CachePolicy );
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CachePolicy cachePolicy() const;
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void invalidateCache();
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virtual void draw( QPainter *p,
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const QwtScaleMap &xMap, const QwtScaleMap &yMap,
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const QRectF &rect ) const;
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virtual QRectF pixelHint( const QRectF & ) const;
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virtual QwtInterval interval(Qt::Axis) const;
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virtual QRectF boundingRect() const;
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protected:
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/*!
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\brief Render an image
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An implementation of render() might iterate over all
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pixels of imageRect. Each pixel has to be translated into
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the corresponding position in scale coordinates using the maps.
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This position can be used to look up a value in a implementation
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specific way and to map it into a color.
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\param xMap X-Scale Map
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\param yMap Y-Scale Map
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\param area Requested area for the image in scale coordinates
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\param imageSize Requested size of the image
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\return Rendered image
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*/
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virtual QImage renderImage( const QwtScaleMap &xMap,
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const QwtScaleMap &yMap, const QRectF &area,
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const QSize &imageSize ) const = 0;
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virtual QwtScaleMap imageMap( Qt::Orientation,
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const QwtScaleMap &map, const QRectF &area,
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const QSize &imageSize, double pixelSize) const;
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private:
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QwtPlotRasterItem( const QwtPlotRasterItem & );
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QwtPlotRasterItem &operator=( const QwtPlotRasterItem & );
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void init();
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QImage compose( const QwtScaleMap &, const QwtScaleMap &,
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const QRectF &imageArea, const QRectF &paintRect,
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const QSize &imageSize, bool doCache) const;
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class PrivateData;
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PrivateData *d_data;
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};
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Q_DECLARE_OPERATORS_FOR_FLAGS( QwtPlotRasterItem::PaintAttributes )
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#endif
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