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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