qwt_plot_rasteritem.h

/******************************************************************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *
 * Modified by ChenZongYan in 2024 <czy.t@163.com>
 *   Summary of major modifications (see ChangeLog.md for full history):
 *   1. CMake build system & C++11 throughout.
 *   2. Core panner/ zoomer refactored:
 *        - QwtPanner → QwtCachePanner (pixmap-cache version)
 *        - New real-time QwtPlotPanner derived from QwtPicker.
 *   3. Zoomer supports multi-axis.
 *   4. Parasite-plot framework:
 *        - QwtFigure, QwtPlotParasiteLayout, QwtPlotTransparentCanvas,
 *        - QwtPlotScaleEventDispatcher, built-in pan/zoom on axis.
 *   5. New picker: QwtPlotSeriesDataPicker (works with date axis).
 *   6. Raster & color-map extensions:
 *        - QwtGridRasterData (2-D table + interpolation)
 *        - QwtLinearColorMap::stopColors(), stopPos() API rename.
 *   7. Bar-chart: expose pen/brush control.
 *   8. Amalgamated build: single QwtPlot.h / QwtPlot.cpp pair in src-amalgamate.
 *****************************************************************************/
 
#ifndef QWT_PLOT_RASTERITEM_H
#define QWT_PLOT_RASTERITEM_H
 
#include "qwt_global.h"
#include "qwt_plot_item.h"
 
#include <qstring.h>
 
class QwtInterval;
 
class QWT_EXPORT QwtPlotRasterItem : public QwtPlotItem
{
  public:
    enum CachePolicy
    {
        NoCache,
 
        PaintCache
    };
 
    enum PaintAttribute
    {
        PaintInDeviceResolution = 1
    };
 
    Q_DECLARE_FLAGS( PaintAttributes, PaintAttribute )
 
    // Constructor
    explicit QwtPlotRasterItem( const QString& title = QString() );
    // Constructor with title
    explicit QwtPlotRasterItem( const QwtText& title );
    // Destructor
    virtual ~QwtPlotRasterItem();
 
    // Set a paint attribute
    void setPaintAttribute( PaintAttribute, bool on = true );
    // Test a paint attribute
    bool testPaintAttribute( PaintAttribute ) const;
 
    // Set the alpha value
    void setAlpha( int alpha );
    // Get the alpha value
    int alpha() const;
 
    // Set the cache policy
    void setCachePolicy( CachePolicy );
    // Get the cache policy
    CachePolicy cachePolicy() const;
 
    // Invalidate the cache
    void invalidateCache();
 
    // Draw the raster item
    virtual void draw( QPainter*,
        const QwtScaleMap& xMap, const QwtScaleMap& yMap,
        const QRectF& canvasRect ) const override;
 
    // Get the pixel hint
    virtual QRectF pixelHint( const QRectF& ) const;
 
    // Get the interval for a specific axis
    virtual QwtInterval interval(Qt::Axis) const;
    // Get the bounding rectangle
    virtual QRectF boundingRect() const override;
 
  protected:
    virtual QImage renderImage( const QwtScaleMap& xMap,
        const QwtScaleMap& yMap, const QRectF& area,
        const QSize& imageSize ) const = 0;
 
    virtual QwtScaleMap imageMap( Qt::Orientation,
        const QwtScaleMap& map, const QRectF& area,
        const QSize& imageSize, double pixelSize) const;
 
  private:
    explicit QwtPlotRasterItem( const QwtPlotRasterItem& );
    QwtPlotRasterItem& operator=( const QwtPlotRasterItem& );
 
    void init();
 
    QImage compose( const QwtScaleMap&, const QwtScaleMap&,
        const QRectF& imageArea, const QRectF& paintRect,
        const QSize& imageSize, bool doCache) const;
 
 
    class PrivateData;
    PrivateData* m_data;
};
 
Q_DECLARE_OPERATORS_FOR_FLAGS( QwtPlotRasterItem::PaintAttributes )
 
#endif