From e88a2ed3719bc74be5f13d297d9370dde777c6f5 Mon Sep 17 00:00:00 2001 From: Glenn Morris Date: Thu, 21 Feb 2008 04:00:22 +0000 Subject: [PATCH] Split off from README.unicode --- admin/notes/font-backend | 77 +++++++++++++++++++++ admin/notes/unicode | 146 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 223 insertions(+) create mode 100644 admin/notes/font-backend create mode 100644 admin/notes/unicode diff --git a/admin/notes/font-backend b/admin/notes/font-backend new file mode 100644 index 00000000000..7abe8f1a9e8 --- /dev/null +++ b/admin/notes/font-backend @@ -0,0 +1,77 @@ +Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008 + Free Software Foundation, Inc. +See the end of the file for license conditions. + + +New font handling mechanism with font backend method +---------------------------------------------------- + +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 existence 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 +has 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")) + + +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. diff --git a/admin/notes/unicode b/admin/notes/unicode new file mode 100644 index 00000000000..0f76a3d36f9 --- /dev/null +++ b/admin/notes/unicode @@ -0,0 +1,146 @@ + -*-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. + + +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. -- 2.39.2