interface/wx/fontmap.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        fontmap.h
   3 // Purpose:     interface of wxFontMapper
   4 // Author:      wxWidgets team
   5 // Licence:     wxWindows licence
   6 /////////////////////////////////////////////////////////////////////////////
   7
   8 /**
   9     @class wxFontMapper
  10
  11     wxFontMapper manages user-definable correspondence between logical font
  12     names and the fonts present on the machine.
  13
  14     The default implementations of all functions will ask the user if they are
  15     not capable of finding the answer themselves and store the answer in a
  16     config file (configurable via SetConfigXXX functions). This behaviour may
  17     be disabled by giving the value of @false to "interactive" parameter.
  18
  19     However, the functions will always consult the config file to allow the
  20     user-defined values override the default logic and there is no way to
  21     disable this - which shouldn't be ever needed because if "interactive" was
  22     never @true, the config file is never created anyhow.
  23
  24     In case everything else fails (i.e. there is no record in config file
  25     and "interactive" is @false or user denied to choose any replacement),
  26     the class queries wxEncodingConverter for "equivalent" encodings
  27     (e.g. iso8859-2 and cp1250) and tries them.
  28
  29
  30     @section fontmapper_mbconv Using wxFontMapper in conjunction with wxMBConv classes
  31
  32     If you need to display text in encoding which is not available at host
  33     system (see wxFontMapper::IsEncodingAvailable), you may use these two
  34     classes to find font in some similar encoding (see wxFontMapper::GetAltForEncoding)
  35     and convert the text to this encoding (wxMBConv classes).
  36     Following code snippet demonstrates it:
  37
  38     @code
  39     if (!wxFontMapper::Get()->IsEncodingAvailable(enc, facename))
  40     {
  41         wxFontEncoding alternative;
  42         if (wxFontMapper::Get()->GetAltForEncoding(enc, &alternative,
  43                                                     facename, false))
  44         {
  45             wxCSConv convFrom(wxFontMapper::Get()->GetEncodingName(enc));
  46             wxCSConv convTo(wxFontMapper::Get()->GetEncodingName(alternative));
  47             text = wxString(text.mb_str(convFrom), convTo);
  48         }
  49         else
  50             ...failure (or we may try iso8859-1/7bit ASCII)...
  51     }
  52     ...display text...
  53     @endcode
  54
  55     @library{wxcore}
  56     @category{cfg}
  57
  58     @see wxEncodingConverter, @ref overview_nonenglish
  59 */
  60 class wxFontMapper
  61 {
  62 public:
  63     /**
  64         Default ctor.
  65
  66         @note
  67         The preferred way of creating a wxFontMapper instance is to call wxFontMapper::Get().
  68     */
  69     wxFontMapper();
  70
  71     /**
  72         Virtual dtor.
  73     */
  74     virtual ~wxFontMapper();
  75
  76     /**
  77         Returns the encoding for the given charset (in the form of RFC 2046) or
  78         @c wxFONTENCODING_SYSTEM if couldn't decode it.
  79
  80         Be careful when using this function with @a interactive set to @true
  81         (default value) as the function then may show a dialog box to the user which
  82         may lead to unexpected reentrancies and may also take a significantly longer
  83         time than a simple function call. For these reasons, it is almost always a bad
  84         idea to call this function from the event handlers for repeatedly generated
  85         events such as @c EVT_PAINT.
  86     */
  87     virtual wxFontEncoding CharsetToEncoding(const wxString& charset,
  88                                              bool interactive = true);
  89
  90     /**
  91         Get the current font mapper object. If there is no current object, creates one.
  92
  93         @see Set()
  94     */
  95     static wxFontMapper* Get();
  96
  97     /**
  98         Returns the array of all possible names for the given encoding.
  99
 100         The array is @NULL-terminated. IF it isn't empty, the first name in it is
 101         the canonical encoding name, i.e. the same string as returned by
 102         GetEncodingName().
 103     */
 104     static const wxChar** GetAllEncodingNames(wxFontEncoding encoding);
 105
 106     //@{
 107     /**
 108         Find an alternative for the given encoding (which is supposed to not be
 109         available on this system). If successful, return @true and fill info
 110         structure with the parameters required to create the font, otherwise
 111         return @false.
 112
 113         The first form is for wxWidgets' internal use while the second one
 114         is better suitable for general use -- it returns wxFontEncoding which
 115         can consequently be passed to wxFont constructor.
 116     */
 117     bool GetAltForEncoding(wxFontEncoding encoding,
 118                            wxNativeEncodingInfo* info,
 119                            const wxString& facename = wxEmptyString,
 120                            bool interactive = true);
 121     bool GetAltForEncoding(wxFontEncoding encoding,
 122                            wxFontEncoding* alt_encoding,
 123                            const wxString& facename = wxEmptyString,
 124                            bool interactive = true);
 125     //@}
 126
 127     /**
 128         Returns the @e n-th supported encoding.
 129
 130         Together with GetSupportedEncodingsCount() this method may be used
 131         to get all supported encodings.
 132     */
 133     static wxFontEncoding GetEncoding(size_t n);
 134
 135     /**
 136         Return user-readable string describing the given encoding.
 137     */
 138     static wxString GetEncodingDescription(wxFontEncoding encoding);
 139
 140     /**
 141         Return the encoding corresponding to the given internal name.
 142
 143         This function is the inverse of GetEncodingName() and is intentionally
 144         less general than CharsetToEncoding(), i.e. it doesn't try to make any
 145         guesses nor ever asks the user. It is meant just as a way of restoring
 146         objects previously serialized using GetEncodingName().
 147     */
 148     static wxFontEncoding GetEncodingFromName(const wxString& encoding);
 149
 150     /**
 151         Return internal string identifier for the encoding (see also
 152         wxFontMapper::GetEncodingDescription).
 153
 154         @see GetEncodingFromName()
 155     */
 156     static wxString GetEncodingName(wxFontEncoding encoding);
 157
 158     /**
 159         Returns the number of the font encodings supported by this class.
 160         Together with GetEncoding() this method may be used to get
 161         all supported encodings.
 162     */
 163     static size_t GetSupportedEncodingsCount();
 164
 165     /**
 166         Check whether given encoding is available in given face or not.
 167         If no facename is given, find @e any font in this encoding.
 168     */
 169     virtual bool IsEncodingAvailable(wxFontEncoding encoding,
 170                                      const wxString& facename = wxEmptyString);
 171
 172     /**
 173         Set the current font mapper object and return previous one (may be @NULL).
 174         This method is only useful if you want to plug-in an alternative font mapper
 175         into wxWidgets.
 176
 177         @see Get()
 178     */
 179     static wxFontMapper* Set(wxFontMapper* mapper);
 180
 181     /**
 182         Set the root config path to use (should be an absolute path).
 183     */
 184     void SetConfigPath(const wxString& prefix);
 185
 186     /**
 187         The parent window for modal dialogs.
 188     */
 189     void SetDialogParent(wxWindow* parent);
 190
 191     /**
 192         The title for the dialogs (note that default is quite reasonable).
 193     */
 194     void SetDialogTitle(const wxString& title);
 195 };
 196