[89] | 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) 2003 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 | // vim: expandtab
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| 11 |
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| 12 | #ifndef QWT_TEXT_ENGINE_H
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| 13 | #define QWT_TEXT_ENGINE_H 1
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| 14 |
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| 15 | #include <qsize.h>
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| 16 | #include "qwt_global.h"
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| 17 |
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| 18 | class QFont;
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| 19 | class QRect;
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| 20 | class QString;
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| 21 | class QPainter;
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| 22 |
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| 23 | /*!
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| 24 | \brief Abstract base class for rendering text strings
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| 25 |
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| 26 | A text engine is responsible for rendering texts for a
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| 27 | specific text format. They are used by QwtText to render a text.
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| 28 |
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| 29 | QwtPlainTextEngine and QwtRichTextEngine are part of the Qwt library.
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| 30 |
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| 31 | QwtMathMLTextEngine can be found in Qwt MathML extension, that
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| 32 | needs the MathML renderer of the Qt solutions package. Unfortunately
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| 33 | it is only available with a commercial Qt license.
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| 34 |
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| 35 | \sa QwtText::setTextEngine()
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| 36 | */
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| 37 |
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| 38 | class QWT_EXPORT QwtTextEngine
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| 39 | {
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| 40 | public:
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| 41 | virtual ~QwtTextEngine();
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| 42 |
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| 43 | /*!
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| 44 | Find the height for a given width
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| 45 |
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| 46 | \param font Font of the text
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| 47 | \param flags Bitwise OR of the flags used like in QPainter::drawText
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| 48 | \param text Text to be rendered
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| 49 | \param width Width
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| 50 |
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| 51 | \return Calculated height
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| 52 | */
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| 53 | virtual int heightForWidth(const QFont &font, int flags,
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| 54 | const QString &text, int width) const = 0;
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| 55 |
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| 56 | /*!
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| 57 | Returns the size, that is needed to render text
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| 58 |
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| 59 | \param font Font of the text
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| 60 | \param flags Bitwise OR of the flags like in for QPainter::drawText
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| 61 | \param text Text to be rendered
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| 62 |
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| 63 | \return Caluclated size
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| 64 | */
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| 65 | virtual QSize textSize(const QFont &font, int flags,
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| 66 | const QString &text) const = 0;
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| 67 |
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| 68 | /*!
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| 69 | Test if a string can be rendered by this text engine
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| 70 |
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| 71 | \param text Text to be tested
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| 72 | \return true, if it can be rendered
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| 73 | */
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| 74 | virtual bool mightRender(const QString &text) const = 0;
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| 75 |
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| 76 | /*!
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| 77 | Return margins around the texts
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| 78 |
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| 79 | The textSize might include margins around the
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| 80 | text, like QFontMetrics::descent. In situations
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| 81 | where texts need to be aligend in detail, knowing
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| 82 | these margins might improve the layout calculations.
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| 83 |
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| 84 | \param font Font of the text
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| 85 | \param text Text to be rendered
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| 86 | \param left Return value for the left margin
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| 87 | \param right Return value for the right margin
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| 88 | \param top Return value for the top margin
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| 89 | \param bottom Return value for the bottom margin
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| 90 | */
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| 91 | virtual void textMargins(const QFont &font, const QString &text,
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| 92 | int &left, int &right, int &top, int &bottom) const = 0;
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| 93 |
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| 94 | /*!
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| 95 | Draw the text in a clipping rectangle
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| 96 |
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| 97 | \param painter Painter
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| 98 | \param rect Clipping rectangle
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| 99 | \param flags Bitwise OR of the flags like in for QPainter::drawText
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| 100 | \param text Text to be rendered
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| 101 | */
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| 102 | virtual void draw(QPainter *painter, const QRect &rect,
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| 103 | int flags, const QString &text) const = 0;
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| 104 |
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| 105 | protected:
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| 106 | QwtTextEngine();
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| 107 | };
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| 108 |
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| 109 |
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| 110 | /*!
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| 111 | \brief A text engine for plain texts
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| 112 |
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| 113 | QwtPlainTextEngine renders texts using the basic Qt classes
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| 114 | QPainter and QFontMetrics.
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| 115 | */
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| 116 | class QWT_EXPORT QwtPlainTextEngine: public QwtTextEngine
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| 117 | {
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| 118 | public:
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| 119 | QwtPlainTextEngine();
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| 120 | virtual ~QwtPlainTextEngine();
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| 121 |
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| 122 | virtual int heightForWidth(const QFont &font, int flags,
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| 123 | const QString &text, int width) const;
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| 124 |
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| 125 | virtual QSize textSize(const QFont &font, int flags,
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| 126 | const QString &text) const;
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| 127 |
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| 128 | virtual void draw(QPainter *painter, const QRect &rect,
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| 129 | int flags, const QString &text) const;
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| 130 |
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| 131 | virtual bool mightRender(const QString &) const;
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| 132 |
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| 133 | virtual void textMargins(const QFont &, const QString &,
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| 134 | int &left, int &right, int &top, int &bottom) const;
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| 135 |
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| 136 | private:
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| 137 | class PrivateData;
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| 138 | PrivateData *d_data;
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| 139 | };
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| 140 |
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| 141 |
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| 142 | #ifndef QT_NO_RICHTEXT
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| 143 |
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| 144 | /*!
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| 145 | \brief A text engine for Qt rich texts
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| 146 |
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| 147 | QwtRichTextEngine renders Qt rich texts using the classes
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| 148 | of the Scribe framework of Qt.
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| 149 | */
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| 150 | class QWT_EXPORT QwtRichTextEngine: public QwtTextEngine
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| 151 | {
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| 152 | public:
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| 153 | QwtRichTextEngine();
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| 154 |
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| 155 | virtual int heightForWidth(const QFont &font, int flags,
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| 156 | const QString &text, int width) const;
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| 157 |
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| 158 | virtual QSize textSize(const QFont &font, int flags,
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| 159 | const QString &text) const;
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| 160 |
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| 161 | virtual void draw(QPainter *painter, const QRect &rect,
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| 162 | int flags, const QString &text) const;
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| 163 |
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| 164 | virtual bool mightRender(const QString &) const;
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| 165 |
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| 166 | virtual void textMargins(const QFont &, const QString &,
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| 167 | int &left, int &right, int &top, int &bottom) const;
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| 168 | private:
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| 169 | QString taggedText(const QString &, int flags) const;
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| 170 | };
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| 171 |
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| 172 | #endif // !QT_NO_RICHTEXT
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| 173 |
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| 174 | #endif
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