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1 | ;;; composite.el --- Support character composition. |
2 | ||
3 | ;; Copyright (C) 1999 Electrotechnical Laboratory, JAPAN. | |
4 | ;; Licensed to the Free Software Foundation. | |
5 | ||
6 | ;; Keywords: mule, multilingual, character composition | |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
10 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
11 | ;; it under the terms of the GNU General Public License as published by | |
12 | ;; the Free Software Foundation; either version 2, or (at your option) | |
13 | ;; any later version. | |
14 | ||
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | ;; GNU General Public License for more details. | |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
23 | ;; Boston, MA 02111-1307, USA. | |
24 | ||
25 | ;;; Code: | |
26 | ||
27 | ;;;###autoload | |
28 | (defconst reference-point-alist | |
29 | '((tl . 0) (tc . 1) (tr . 2) | |
30 | (Bl . 3) (Bc . 4) (Br . 5) | |
31 | (bl . 6) (bc . 7) (br . 8) | |
32 | (cl . 9) (cc . 10) (cr . 11) | |
33 | (top-left . 0) (top-center . 1) (top-right . 2) | |
34 | (base-left . 3) (base-center . 4) (base-right . 5) | |
35 | (bottom-left . 6) (bottom-center . 7) (bottom-right . 8) | |
36 | (center-left . 9) (center-center . 10) (center-right . 11) | |
37 | ;; For backward compatibility... | |
38 | (ml . 3) (mc . 10) (mr . 5) | |
39 | (mid-left . 3) (mid-center . 10) (mid-right . 5)) | |
40 | "Alist of symbols vs integer codes of glyph reference points. | |
41 | A glyph reference point symbol is to be used to specify a composition | |
42 | rule in COMPONENTS argument to such functions as `compose-region' and | |
43 | `make-composition'. | |
44 | ||
45 | Meanings of glyph reference point codes are as follows: | |
46 | ||
47 | 0----1----2 <---- ascent 0:tl or top-left | |
48 | | | 1:tc or top-center | |
49 | | | 2:tr or top-right | |
50 | | | 3:Bl or base-left 9:cl or center-left | |
51 | 9 10 11 <---- center 4:Bc or base-center 10:cc or center-center | |
52 | | | 5:Br or base-right 11:cr or center-right | |
53 | --3----4----5-- <-- baseline 6:bl or bottom-left | |
54 | | | 7:bc or bottom-center | |
55 | 6----7----8 <---- descent 8:br or bottom-right | |
56 | ||
57 | Glyph reference point symbols are to be used to specify composition | |
58 | rule of the form \(GLOBAL-REF-POINT . NEW-REF-POINT), where | |
59 | GLOBAL-REF-POINT is a reference point in the overall glyphs already | |
60 | composed, and NEW-REF-POINT is a reference point in the new glyph to | |
61 | be added. | |
62 | ||
63 | For instance, if GLOBAL-REF-POINT is `br' (bottom-right) and | |
64 | NEW-REF-POINT is `tl' (top-left), the overall glyph is updated as | |
65 | follows (the point `*' corresponds to both reference points): | |
66 | ||
67 | +-------+--+ <--- new ascent | |
68 | | | | | |
69 | | global| | | |
70 | | glyph | | | |
71 | -- | | |-- <--- baseline \(doesn't change) | |
72 | +----+--*--+ | |
73 | | | new | | |
74 | | |glyph| | |
75 | +----+-----+ <--- new descent | |
76 | ") | |
77 | ||
78 | ;; Encode composition rule RULE into an integer value. RULE is a cons | |
79 | ;; of global and new reference point symbols. | |
80 | ;; This must be compatible with C macro COMPOSITION_ENCODE_RULE | |
81 | ;; defined in composite.h. | |
82 | ||
83 | (defun encode-composition-rule (rule) | |
84 | (if (and (integerp rule) (< rule 144)) | |
85 | ;; Already encoded. | |
86 | rule | |
87 | (or (consp rule) | |
88 | (error "Invalid composition rule: %S" rule)) | |
89 | (let ((gref (car rule)) | |
90 | (nref (cdr rule))) | |
91 | (or (integerp gref) | |
92 | (setq gref (cdr (assq gref reference-point-alist)))) | |
93 | (or (integerp nref) | |
94 | (setq nref (cdr (assq nref reference-point-alist)))) | |
95 | (or (and (>= gref 0) (< gref 12) (>= nref 0) (< nref 12)) | |
96 | (error "Invalid composition rule: %S" rule)) | |
97 | (+ (* gref 12) nref)))) | |
98 | ||
99 | ;; Decode encoded composition rule RULE-CODE. The value is a cons of | |
100 | ;; global and new reference point symbols. | |
101 | ;; This must be compatible with C macro COMPOSITION_DECODE_RULE | |
102 | ;; defined in composite.h. | |
103 | ||
104 | (defun decode-composition-rule (rule-code) | |
105 | (or (and (natnump rule-code) (< rule-code 144)) | |
106 | (error "Invalid encoded composition rule: %S" rule-code)) | |
107 | (let ((gref (car (rassq (/ rule-code 12) reference-point-alist))) | |
108 | (nref (car (rassq (% rule-code 12) reference-point-alist)))) | |
109 | (or (and gref (symbolp gref) nref (symbolp nref)) | |
110 | (error "Invalid composition rule code: %S" rule-code)) | |
111 | (cons gref nref))) | |
112 | ||
113 | ;; Encode composition rules in composition components COMPONENTS. The | |
114 | ;; value is a copy of COMPONENTS, where composition rules (cons of | |
115 | ;; global and new glyph reference point symbols) are replaced with | |
116 | ;; encoded composition rules. Optional 2nd argument NOCOPY non-nil | |
117 | ;; means don't make a copy but modify COMPONENTS directly. | |
118 | ||
119 | (defun encode-composition-components (components &optional nocopy) | |
120 | (or nocopy | |
121 | (setq components (copy-sequence components))) | |
122 | (if (vectorp components) | |
123 | (let ((len (length components)) | |
124 | (i 1)) | |
125 | (while (< i len) | |
126 | (aset components i | |
127 | (encode-composition-rule (aref components i))) | |
128 | (setq i (+ i 2)))) | |
129 | (let ((tail (cdr components))) | |
130 | (while tail | |
131 | (setcar tail | |
132 | (encode-composition-rule (car tail))) | |
133 | (setq tail (nthcdr 2 tail))))) | |
134 | components) | |
135 | ||
136 | ;; Decode composition rule codes in composition components COMPONENTS. | |
137 | ;; The value is a copy of COMPONENTS, where composition rule codes are | |
138 | ;; replaced with composition rules (cons of global and new glyph | |
139 | ;; reference point symbols). Optional 2nd argument NOCOPY non-nil | |
140 | ;; means don't make a copy but modify COMPONENTS directly. | |
141 | ;; It is assumed that COMPONENTS is a vector and is for rule-base | |
142 | ;; composition, thus (2N+1)th elements are rule codes. | |
143 | ||
144 | (defun decode-composition-components (components &optional nocopy) | |
145 | (or nocopy | |
146 | (setq components (copy-sequence components))) | |
147 | (let ((len (length components)) | |
148 | (i 1)) | |
149 | (while (< i len) | |
150 | (aset components i | |
151 | (decode-composition-rule (aref components i))) | |
152 | (setq i (+ i 2)))) | |
153 | components) | |
154 | ||
155 | ;;;###autoload | |
156 | (defun compose-region (start end &optional components modification-func) | |
157 | "Compose characters in the current region. | |
158 | ||
159 | When called from a program, expects these four arguments. | |
160 | ||
161 | First two arguments START and END are positions (integers or markers) | |
162 | specifying the region. | |
163 | ||
164 | Optional 3rd argument COMPONENTS, if non-nil, is a character or a | |
165 | sequence (vector, list, or string) of integers. | |
166 | ||
167 | If it is a character, it is an alternate character to display instead | |
168 | of the text in the region. | |
169 | ||
170 | If it is a string, the elements are alternate characters. | |
171 | ||
172 | If it is a vector or list, it is a sequence of alternate characters and | |
173 | composition rules, where (2N)th elements are characters and (2N+1)th | |
174 | elements are composition rules to specify how to compose (2N+2)th | |
175 | elements with previously composed N glyphs. | |
176 | ||
177 | A composition rule is a cons of global and new glyph reference point | |
178 | symbols. See the documentation of `reference-point-alist' for more | |
179 | detail. | |
180 | ||
181 | Optional 4th argument MODIFICATION-FUNC is a function to call to | |
182 | adjust the composition when it gets invalid because of a change of | |
183 | text in the composition." | |
184 | (interactive "r") | |
185 | (let ((modified-p (buffer-modified-p)) | |
186 | (buffer-read-only nil)) | |
187 | (if (or (vectorp components) (listp components)) | |
188 | (setq components (encode-composition-components components))) | |
189 | (compose-region-internal start end components modification-func) | |
190 | (set-buffer-modified-p modified-p))) | |
191 | ||
192 | ;;;###autoload | |
193 | (defun decompose-region (start end) | |
194 | "Decompose text in the current region. | |
195 | ||
196 | When called from a program, expects two arguments, | |
197 | positions (integers or markers) specifying the region." | |
198 | (interactive "r") | |
199 | (let ((modified-p (buffer-modified-p)) | |
200 | (buffer-read-only nil)) | |
201 | (remove-text-properties start end '(composition nil)) | |
202 | (set-buffer-modified-p modified-p))) | |
203 | ||
204 | ;;;###autoload | |
205 | (defun compose-string (string &optional start end components modification-func) | |
206 | "Compose characters in string STRING. | |
207 | ||
208 | The return value is STRING where `composition' property is put on all | |
209 | the characters in it. | |
210 | ||
211 | Optional 2nd and 3rd arguments START and END specify the range of | |
212 | STRING to be composed. They defaults to the beginning and the end of | |
213 | STRING respectively. | |
214 | ||
215 | Optional 4th argument COMPONENTS, if non-nil, is a character or a | |
216 | sequence (vector, list, or string) of integers. See the function | |
217 | `compose-region' for more detail. | |
218 | ||
219 | Optional 5th argument MODIFICATION-FUNC is a function to call to | |
220 | adjust the composition when it gets invalid because of a change of | |
221 | text in the composition." | |
222 | (if (or (vectorp components) (listp components)) | |
223 | (setq components (encode-composition-components components))) | |
224 | (or start (setq start 0)) | |
225 | (or end (setq end (length string))) | |
226 | (compose-string-internal string start end components modification-func) | |
227 | string) | |
228 | ||
229 | ;;;###autoload | |
230 | (defun decompose-string (string) | |
231 | "Return STRING where `composition' property is removed." | |
232 | (remove-text-properties 0 (length string) '(composition nil) string) | |
233 | string) | |
234 | ||
235 | ;;;###autoload | |
236 | (defun compose-chars (&rest args) | |
237 | "Return a string from arguments in which all characters are composed. | |
238 | For relative composition, arguments are characters. | |
239 | For rule-based composition, Mth \(where M is odd) arguments are | |
240 | characters, and Nth \(where N is even) arguments are composition rules. | |
241 | A composition rule is a cons of glyph reference points of the form | |
242 | \(GLOBAL-REF-POINT . NEW-REF-POINT). See the documentation of | |
243 | `reference-point-alist' for more detail." | |
244 | (let (str components) | |
245 | (if (consp (car (cdr args))) | |
246 | ;; Rule-base composition. | |
247 | (let ((len (length args)) | |
248 | (tail (encode-composition-components args 'nocopy))) | |
249 | ||
250 | (while tail | |
251 | (setq str (cons (car tail) str)) | |
252 | (setq tail (nthcdr 2 tail))) | |
253 | (setq str (concat (nreverse str)) | |
254 | components args)) | |
255 | ;; Relative composition. | |
256 | (setq str (concat args))) | |
257 | (compose-string-internal str 0 (length str) components))) | |
258 | ||
259 | ;;;###autoload | |
260 | (defun find-composition (pos &optional limit string detail-p) | |
261 | "Return information about a composition at or nearest to buffer position POS. | |
262 | ||
263 | If the character at POS has `composition' property, the value is a list | |
264 | of FROM, TO, and VALID-P. | |
265 | ||
266 | FROM and TO specify the range of text that has the same `composition' | |
267 | property, VALID-P is non-nil if and only if this composition is valid. | |
268 | ||
269 | If there's no composition at POS, and the optional 2nd argument LIMIT | |
270 | is non-nil, search for a composition toward LIMIT. | |
271 | ||
272 | If no composition is found, return nil. | |
273 | ||
274 | Optional 3rd argument STRING, if non-nil, is a string to look for a | |
275 | composition in; nil means the current buffer. | |
276 | ||
277 | If a valid composition is found and the optional 4th argument DETAIL-P | |
278 | is non-nil, the return value is a list of FROM, TO, COMPONENTS, | |
279 | RELATIVE-P, MOD-FUNC, and WIDTH. | |
280 | ||
281 | COMPONENTS is a vector of integers, the meaning depends on RELATIVE-P. | |
282 | ||
283 | RELATIVE-P is t if the composition method is relative, else nil. | |
284 | ||
285 | If RELATIVE-P is t, COMPONENTS is a vector of characters to be | |
286 | composed. If RELATIVE-P is nil, COMPONENTS is a vector of characters | |
287 | and composition rules as described in `compose-region'. | |
288 | ||
289 | MOD-FUNC is a modification function of the composition. | |
290 | ||
291 | WIDTH is a number of columns the composition occupies on the screen." | |
292 | (let ((result (find-composition-internal pos limit string detail-p))) | |
293 | (if (and detail-p result (nth 2 result) (not (nth 3 result))) | |
294 | ;; This is a valid rule-base composition. | |
295 | (decode-composition-components (nth 2 result) 'nocopy)) | |
296 | result)) | |
297 | ||
298 | \f | |
299 | ;; A char-table of functions to call for compositions. | |
61dc47f5 SM |
300 | ;;;###autoload |
301 | (put 'composition-function-table 'char-table-extra-slots 0) | |
c674f351 KH |
302 | |
303 | ;;;###autoload | |
304 | (defvar composition-function-table | |
305 | (make-char-table 'composition-function-table) | |
306 | "Char table of patterns and functions to make a composition. | |
307 | ||
308 | Each element is nil or an alist of PATTERNs vs FUNCs, where PATTERNs | |
309 | are regular expressions and FUNCs are functions. FUNC is responsible | |
310 | for composing text matching the corresponding PATTERN. FUNC is called | |
311 | with three arguments FROM, TO, and PATTERN. See the function | |
312 | `compose-chars-after' for more detail. | |
313 | ||
314 | This table is looked up by the first character of a composition when | |
315 | the composition gets invalid after a change in a buffer.") | |
316 | ||
317 | ;;;###autoload | |
318 | (defun compose-chars-after (pos &optional limit) | |
319 | "Compose characters in current buffer after position POS. | |
320 | ||
321 | It looks up the char-table `composition-function-table' (which see) by | |
322 | a character after POS. If non-nil value is found, the format of the | |
323 | value should be an alist of PATTERNs vs FUNCs, where PATTERNs are | |
324 | regular expressions and FUNCs are functions. If the text after POS | |
325 | matches one of PATTERNs, call the corresponding FUNC with three | |
326 | arguments POS, TO, and PATTERN, where TO is the end position of text | |
327 | matching PATTERN, and return what FUNC returns. Otherwise, return | |
328 | nil. | |
329 | ||
330 | FUNC is responsible for composing the text properly. The return value | |
331 | is: | |
332 | nil -- if no characters were composed. | |
333 | CHARS (integer) -- if CHARS characters were composed. | |
334 | ||
335 | Optional 2nd arg LIMIT, if non-nil, limits the matching of text. | |
336 | ||
337 | This function is the default value of `compose-chars-after-function'." | |
338 | (let ((tail (aref composition-function-table (char-after pos))) | |
339 | pattern func result) | |
340 | (when tail | |
339cebdc KH |
341 | (save-match-data |
342 | (save-excursion | |
343 | (while (and tail (not func)) | |
344 | (setq pattern (car (car tail)) | |
345 | func (cdr (car tail))) | |
346 | (goto-char pos) | |
347 | (if (if limit | |
348 | (and (re-search-forward pattern limit t) | |
349 | (= (match-beginning 0) pos)) | |
350 | (looking-at pattern)) | |
351 | (setq result (funcall func pos (match-end 0) pattern nil)) | |
352 | (setq func nil tail (cdr tail))))))) | |
c674f351 KH |
353 | result)) |
354 | ||
355 | ;;;###autoload | |
356 | (defun compose-last-chars (args) | |
357 | "Compose last characters. | |
358 | The argument is a parameterized event of the form (compose-last-chars N), | |
359 | where N is the number of characters before point to compose. | |
360 | This function is intended to be used from input methods. | |
361 | The global keymap binds special event `compose-last-chars' to this | |
362 | function. Input method may generate an event (compose-last-chars N) | |
363 | after a sequence character events." | |
364 | (interactive "e") | |
365 | (let ((chars (nth 1 args))) | |
366 | (if (and (numberp chars) | |
367 | (>= (- (point) (point-min)) chars)) | |
368 | (compose-chars-after (- (point) chars) (point))))) | |
369 | ||
370 | ;;;###autoload(global-set-key [compose-last-chars] 'compose-last-chars) | |
371 | ||
372 | \f | |
373 | ;;; The following codes are only for backward compatibility with Emacs | |
374 | ;;; 20.4 and the earlier. | |
375 | ||
376 | ;;;###autoload | |
377 | (defun decompose-composite-char (char &optional type with-composition-rule) | |
378 | "Convert CHAR to string. | |
379 | This is only for backward compatibility with Emacs 20.4 and the earlier. | |
380 | ||
381 | If optional 2nd arg TYPE is non-nil, it is `string', `list', or | |
382 | `vector'. In this case, CHAR is converted string, list of CHAR, or | |
383 | vector of CHAR respectively." | |
384 | (cond ((or (null type) (eq type 'string)) (char-to-string char)) | |
385 | ((eq type 'list) (list char)) | |
386 | (t (vector char)))) | |
387 | ||
8d787845 KH |
388 | (make-obsolete 'decompose-composite-char 'char-to-string "21.1") |
389 | ||
c674f351 KH |
390 | \f |
391 | ;;; composite.el ends here |