8f1337ed68
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@59609 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
89 lines
4.3 KiB
C++
89 lines
4.3 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: fontencoding.h
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// Purpose: topic overview
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// Author: wxWidgets team
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// RCS-ID: $Id$
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// Licence: wxWindows license
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/////////////////////////////////////////////////////////////////////////////
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/**
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@page overview_fontencoding Font Encodings
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wxWidgets has support for multiple font encodings.
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By encoding we mean here the mapping between the character codes and the
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letters. Probably the most well-known encoding is (7 bit) ASCII one which is
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used almost universally now to represent the letters of the English alphabet
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and some other common characters. However, it is not enough to represent the
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letters of foreign alphabets and here other encodings come into play. Please
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note that we will only discuss 8-bit fonts here and not Unicode
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(see @ref overview_unicode).
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Font encoding support is ensured by several classes:
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wxFont itself, but also wxFontEnumerator and wxFontMapper. wxFont encoding
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support is reflected by a (new) constructor parameter @e encoding which takes
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one of the following values (elements of enumeration type @c wxFontEncoding):
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@beginDefList
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@itemdef{wxFONTENCODING_SYSTEM,
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The default encoding of the underlying
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operating system (notice that this might be a "foreign" encoding for foreign
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versions of Windows 9x/NT).}
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@itemdef{wxFONTENCODING_DEFAULT,
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The applications default encoding as returned by wxFont::GetDefaultEncoding.
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On program startup, the applications default encoding is the same as
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wxFONTENCODING_SYSTEM, but may be changed to make all the fonts created later
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to use it (by default).}
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@itemdef{wxFONTENCODING_ISO8859_1..15,
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ISO8859 family encodings which are
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usually used by all non-Microsoft operating systems.}
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@itemdef{wxFONTENCODING_KOI8,
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Standard Cyrillic encoding for the Internet
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(but see also wxFONTENCODING_ISO8859_5 and wxFONTENCODING_CP1251).}
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@itemdef{wxFONTENCODING_CP1250, Microsoft analogue of ISO8859-2}
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@itemdef{wxFONTENCODING_CP1251, Microsoft analogue of ISO8859-5}
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@itemdef{wxFONTENCODING_CP1252, Microsoft analogue of ISO8859-1}
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@endDefList
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As you may see, Microsoft's encoding partly mirror the standard ISO8859 ones,
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but there are (minor) differences even between ISO8859-1 (Latin1, ISO encoding
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for Western Europe) and CP1251 (WinLatin1, standard code page for English
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versions of Windows) and there are more of them for other encodings.
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The situation is particularly complicated with Cyrillic encodings for which
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(more than) three incompatible encodings exist: KOI8 (the old standard, widely
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used on the Internet), ISO8859-5 (ISO standard for Cyrillic) and CP1251
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(WinCyrillic).
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This abundance of (incompatible) encodings should make it clear that using
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encodings is less easy than it might seem. The problems arise both from the
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fact that the standard encodings for the given language (say Russian, which is
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written in Cyrillic) are different on different platforms and because the
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fonts in the given encoding might just not be installed (this is especially a
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problem with Unix, or, in general, non-Win32 systems).
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To clarify, the wxFontEnumerator
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class may be used to enumerate both all available encodings and to find the
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facename(s) in which the given encoding exists. If you can find the font in
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the correct encoding with wxFontEnumerator then your troubles are over, but,
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unfortunately, sometimes this is not enough. For example, there is no standard
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way (that I know of, please tell me if you do!) to find a font on a Windows system
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for KOI8 encoding (only for WinCyrillic one which is quite different), so
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wxFontEnumerator will never return one, even if the user has installed a KOI8
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font on his system.
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To solve this problem, a wxFontMapper class is provided.
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This class stores the mapping between the encodings and the font face
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names which support them in wxConfigBase object.
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Of course, it would be fairly useless if it tried to determine these mappings by
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itself, so, instead, it (optionally) asks the user and remembers his answers
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so that the next time the program will automatically choose the correct font.
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All these topics are illustrated by the @ref page_samples_font;
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please refer to it and the documentation of the classes mentioned here for
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further explanations.
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*/
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