+++ /dev/null
- -*-mode: text; coding: latin-1;-*-
-
-Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
- Free Software Foundation, Inc.
-See the end of the file for license conditions.
-
-Problems, fixmes and other unicode-related issues
--------------------------------------------------------------
-
-Notes by fx to record various things of variable importance. handa
-needs to check them -- don't take too seriously, especially with
-regard to completeness.
-
- * SINGLE_BYTE_CHAR_P returns true for Latin-1 characters, which has
- undesirable effects. E.g.:
- (multibyte-string-p (let ((s "x")) (aset s 0 ?£) s)) => nil
- (multibyte-string-p (concat [?£])) => nil
- (text-char-description ?£) => "M-#"
-
- These examples are all fixed by the change of 2002-10-14, but
- there still exist questionable SINGLE_BYTE_CHAR_P in the
- code (keymap.c and print.c).
-
- * Rationalize character syntax and its relationship to the Unicode
- database. (Applies mainly to symbol an punctuation syntax.)
-
- * Fontset handling and customization needs work. We want to relate
- fonts to scripts, probably based on the Unicode blocks. The
- presence of small-repertoire 10646-encoded fonts in XFree 4 is a
- pain, not currently worked round.
-
- With the change on 2002-07-26, multiple fonts can be
- specified in a fontset for a specific range of characters.
- Each range can also be specified by script. Before using
- ISO10646 fonts, Emacs checks their repertories to avoid such
- fonts that don't have a glyph for a specific character.
-
- fx has worked on fontset customization, but was stymied by
- basic problems with the way the default face is dealt with
- (and something else, I think). This needs revisiting.
-
- * Work is also needed on charset and coding system priorities.
-
- * The relevant bits of latin1-disp.el need porting (and probably
- re-naming/updating). See also cyril-util.el.
-
- * Quail files need more work now the encoding is largely irrelevant.
-
- * What to do with the old coding categories stuff?
-
- * The preferred-coding-system property of charsets should probably be
- junked unless it can be made more useful now.
-
- * find-multibyte-characters needs looking at.
-
- * Implement Korean cp949/UHC, BIG5-HKSCS and any other important missing
- charsets.
-
- * Lazy-load tables for unify-charset somehow?
-
- Actually, Emacs clears out all charset maps and unify-map just
- before dumping, and they are loaded again on demand by the
- dumped emacs. But, those maps (char tables) generated while
- temacs is running can't be removed from the dumped emacs.
-
- * Translation tables for {en,de}code currently aren't supported.
-
- This should be fixed by the changes of 2002-10-14.
-
- * Defining CCL coding systems currently doesn't work.
-
- This should be fixed by the changes of 2003-01-30.
-
- * iso-2022 charsets get unified on i/o.
-
- With the change on 2003-01-06, decoding routines put `charset'
- property to decoded text, and iso-2022 encoder pay attention
- to it. Thus, for instance, reading and writing by
- iso-2022-7bit preserve the original designation sequences.
- The property name `preferred-charset' may be better?
-
- We may have to utilize this property to decide a font.
-
- * Revisit locale processing: look at treating the language and
- charset parts separately. (Language should affect things like
- spelling and calendar, but that's not a Unicode issue.)
-
- * Handle Unicode combining characters usefully, e.g. diacritics, and
- handle more scripts specifically (à la Devanagari). There are
- issues with canonicalization.
-
- * Bidi is a separate issue with no support currently.
-
- * We need tabular input methods, e.g. for maths symbols. (Not
- specific to Unicode.)
-
- * Need multibyte text in menus, e.g. for the above. (Not specific to
- Unicode -- see Emacs etc/TODO, but now mostly works with gtk.)
-
- * There's currently no support for Unicode normalization.
-
- * Populate char-width-table correctly for Unicode characters and
- worry about what happens when double-width charsets covering
- non-CJK characters are unified.
-
- * Emacs 20/21 .elc files are currently not loadable. It may or may
- not be possible to do this properly.
-
- With the change on 2002-07-24, elc files generated by Emacs
- 20.3 and later are correctly loaded (including those
- containing multibyte characters and compressed). But, elc
- files generated by 20.2 and the primer are still not loadable.
- Is it really worth working on it?
-
- * Rmail won't work with non-ASCII text. Encoding issues for Babyl
- files need sorting out, but rms says Babyl will go before this is
- released.
-
- * Gnus still needs some attention, and we need to get changes
- accepted by Gnus maintainers...
-
- * There are type errors lurking, e.g. in
- Fcheck_coding_systems_region. Define ENABLE_CHECKING to find them.
-
- * You can grep the code for lots of fixmes.
-
- * Old auto-save files, and similar files, such as Gnus drafts,
- containing non-ASCII characters probably won't be re-read correctly.
-
-
-
-New font handling mechanism with font backend method
-----------------------------------------------------
-
-Emacs now contains new codes for handling fonts by multiple font
-backends. The old font handling codes still exist completely parallel
-to the new codes, and the new codes are used only when you configure
-Emacs with the argument "--enable-font-backend".
-
-Which font backends to use can be specified by X resource
-"FontBackend". For instance, if you want to use Xft fonts only,
-
-Emacs.FontBackend: xft
-
-will work. If this resource is not set, Emacs tries to use all font
-backends available on your graphic device.
-
-The configure script, if invoked with "--enable-font-backend", checks
-if libraries freetype and fontconfig exist. If they are both
-available, macro "USE_FONT_BACKEND" is defined in src/config.h. In
-that case, the existing of Xft library is checked too.
-
-The new files are:
- font.h -- header providing font-backend related structures
- (most important ones are "struct font" and "struct
- font_driver"), macros, and etc.
- font.c -- main font handling code.
- xfont.c -- font-driver on X for X core fonts.
- ftfont.c -- generic font-driver for FreeType fonts providing
- device-independent methods of struct font_driver.
- xftfont.c -- font-driver on X using Xft for FreeType fonts
- utilizing methods provided by ftfont.c.
- ftxfont.c -- font-driver on X directly using FreeType fonts
- utilizing methods provided by ftfont.c.
- w32font.c -- font driver on w32 using Windows native fonts,
- corresponding to xfont.c
-
-So we already have codes for X. For the other systems (w32 and mac),
-it seems that we need these files:
- atmfont.c -- font-driver on mac using ATM fonts, corresponding
- to xfont.c
-As BDF fonts are currently used on w32, we may also implement these:
- bdffont.c -- generic font-driver for BDF fonts, corresponding to
- ftfont.c
- bdfw32font.c -- font-driver on w32 using BDF fonts,
- corresponding to ftxfont.c
-But, as FreeType already supports BDF fonts, if FreeType and
-Fontconfig are also available on w32, what we need may be:
- ftw32font.c -- font-driver on w32 directly using FreeType fonts
- utilizing methods provided by ftfont.c.
-
-And, for those to work, macterm.c and macfns.c must be changed by the
-similar way as xterm.c and xfns.c (the parts "#ifdef USE_FONT_BACKEND"
-... "#endif" should be checked).
-
-It may be interesting if Emacs supports a frame buffer directly and
-have these font driver.
- ftfbfont.c -- font-driver on FB for FreeType fonts.
- bdffbfont.c -- font-driver on FB for BDF fonts.
-
-Note: The fontset related codes are not yet matured to work well with
-the font backend method. So, for instance, even if you start Emacs
-as something like this:
- % emacs -fn tahoma
-Non-ASCII Latin characters will not be displayed by the font "tahoma".
-In such a case, please try this:
-
-(set-fontset-font "fontset-default" 'latin '("tahoma" . "unicode-bmp"))
-
-\f
-This file is part of GNU Emacs.
-
-GNU Emacs is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 3, or (at your option)
-any later version.
-
-GNU Emacs is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with GNU Emacs; see the file COPYING. If not, write to the
-Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA.
projects / emacs.git / commitdiff