qwt_text_engine.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_TEXT_ENGINE_H
#define QWT_TEXT_ENGINE_H
 
#include "qwt_global.h"
#include <qsize.h>
 
class QFont;
class QRectF;
class QString;
class QPainter;
 
class QWT_EXPORT QwtTextEngine
{
  public:
    // Virtual destructor
    virtual ~QwtTextEngine();
 
    virtual double heightForWidth( const QFont& font, int flags,
        const QString& text, double width ) const = 0;
 
    virtual QSizeF textSize( const QFont& font, int flags,
        const QString& text ) const = 0;
 
    virtual bool mightRender( const QString& text ) const = 0;
 
    virtual void textMargins( const QFont& font, const QString& text,
        double& left, double& right, double& top, double& bottom ) const = 0;
 
    virtual void draw( QPainter* painter, const QRectF& rect,
        int flags, const QString& text ) const = 0;
 
  protected:
    QwtTextEngine();
 
  private:
    Q_DISABLE_COPY(QwtTextEngine)
};
 
 
class QWT_EXPORT QwtPlainTextEngine : public QwtTextEngine
{
  public:
    // Constructor
    QwtPlainTextEngine();
    // Destructor
    virtual ~QwtPlainTextEngine();
 
    // Calculate height for a given width
    virtual double heightForWidth( const QFont& font, int flags,
        const QString& text, double width ) const override;
 
    // Return the size needed to render text
    virtual QSizeF textSize( const QFont& font, int flags,
        const QString& text ) const override;
 
    // Draw the text
    virtual void draw( QPainter*, const QRectF& rect,
        int flags, const QString& text ) const override;
 
    // Test if a string can be rendered
    virtual bool mightRender( const QString& ) const override;
 
    // Return text margins
    virtual void textMargins(
        const QFont&, const QString&,
        double& left, double& right,
        double& top, double& bottom ) const override;
 
  private:
    class PrivateData;
    PrivateData* m_data;
};
 
 
#ifndef QT_NO_RICHTEXT
 
class QWT_EXPORT QwtRichTextEngine : public QwtTextEngine
{
  public:
    // Constructor
    QwtRichTextEngine();
 
    // Calculate height for a given width
    virtual double heightForWidth( const QFont& font, int flags,
        const QString& text, double width ) const override;
 
    // Return the size needed to render text
    virtual QSizeF textSize( const QFont& font, int flags,
        const QString& text ) const override;
 
    // Draw the text
    virtual void draw( QPainter*, const QRectF& rect,
        int flags, const QString& text ) const override;
 
    // Test if a string can be rendered
    virtual bool mightRender( const QString& ) const override;
 
    // Return text margins
    virtual void textMargins(
        const QFont&, const QString&,
        double& left, double& right,
        double& top, double& bottom ) const override;
 
  private:
    QString taggedText( const QString&, int flags ) const;
};
 
#endif // !QT_NO_RICHTEXT
 
#endif