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2624e2ac35
Fix typos in docstrings.
396 lines
15 KiB
EmacsLisp
396 lines
15 KiB
EmacsLisp
;;; composite.el --- support character composition
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;; Copyright (C) 1999 Electrotechnical Laboratory, JAPAN.
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;; Licensed to the Free Software Foundation.
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;; Keywords: mule, multilingual, character composition
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;; Boston, MA 02110-1301, USA.
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;;; Commentary:
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;;; Code:
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;;;###autoload
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(defconst reference-point-alist
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'((tl . 0) (tc . 1) (tr . 2)
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(Bl . 3) (Bc . 4) (Br . 5)
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(bl . 6) (bc . 7) (br . 8)
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(cl . 9) (cc . 10) (cr . 11)
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(top-left . 0) (top-center . 1) (top-right . 2)
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(base-left . 3) (base-center . 4) (base-right . 5)
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(bottom-left . 6) (bottom-center . 7) (bottom-right . 8)
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(center-left . 9) (center-center . 10) (center-right . 11)
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;; For backward compatibility...
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(ml . 3) (mc . 10) (mr . 5)
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(mid-left . 3) (mid-center . 10) (mid-right . 5))
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"Alist of symbols vs integer codes of glyph reference points.
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A glyph reference point symbol is to be used to specify a composition
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rule in COMPONENTS argument to such functions as `compose-region' and
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`make-composition'.
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Meanings of glyph reference point codes are as follows:
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0----1----2 <---- ascent 0:tl or top-left
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| | 1:tc or top-center
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| | 2:tr or top-right
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| | 3:Bl or base-left 9:cl or center-left
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9 10 11 <---- center 4:Bc or base-center 10:cc or center-center
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| | 5:Br or base-right 11:cr or center-right
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--3----4----5-- <-- baseline 6:bl or bottom-left
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| | 7:bc or bottom-center
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6----7----8 <---- descent 8:br or bottom-right
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Glyph reference point symbols are to be used to specify composition
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rule of the form \(GLOBAL-REF-POINT . NEW-REF-POINT), where
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GLOBAL-REF-POINT is a reference point in the overall glyphs already
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composed, and NEW-REF-POINT is a reference point in the new glyph to
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be added.
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For instance, if GLOBAL-REF-POINT is `br' (bottom-right) and
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NEW-REF-POINT is `tc' (top-center), the overall glyph is updated as
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follows (the point `*' corresponds to both reference points):
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+-------+--+ <--- new ascent
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| | |
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| global| |
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| glyph | |
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-- | | |-- <--- baseline \(doesn't change)
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+----+--*--+
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| | new |
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| |glyph|
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+----+-----+ <--- new descent
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")
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;;;###autoload
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(defun encode-composition-rule (rule)
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"Encode composition rule RULE into an integer value.
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RULE is a cons of global and new reference point symbols
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\(see `reference-point-alist')."
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;; This must be compatible with C macro COMPOSITION_ENCODE_RULE
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;; defined in composite.h.
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(if (and (integerp rule) (< rule 144))
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;; Already encoded.
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rule
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(or (consp rule)
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(error "Invalid composition rule: %S" rule))
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(let ((gref (car rule))
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(nref (cdr rule)))
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(or (integerp gref)
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(setq gref (cdr (assq gref reference-point-alist))))
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(or (integerp nref)
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(setq nref (cdr (assq nref reference-point-alist))))
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(or (and (>= gref 0) (< gref 12) (>= nref 0) (< nref 12))
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(error "Invalid composition rule: %S" rule))
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(+ (* gref 12) nref))))
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;; Decode encoded composition rule RULE-CODE. The value is a cons of
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;; global and new reference point symbols.
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;; This must be compatible with C macro COMPOSITION_DECODE_RULE
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;; defined in composite.h.
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(defun decode-composition-rule (rule-code)
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(or (and (natnump rule-code) (< rule-code 144))
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(error "Invalid encoded composition rule: %S" rule-code))
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(let ((gref (car (rassq (/ rule-code 12) reference-point-alist)))
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(nref (car (rassq (% rule-code 12) reference-point-alist))))
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(or (and gref (symbolp gref) nref (symbolp nref))
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(error "Invalid composition rule code: %S" rule-code))
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(cons gref nref)))
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;; Encode composition rules in composition components COMPONENTS. The
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;; value is a copy of COMPONENTS, where composition rules (cons of
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;; global and new glyph reference point symbols) are replaced with
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;; encoded composition rules. Optional 2nd argument NOCOPY non-nil
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;; means don't make a copy but modify COMPONENTS directly.
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(defun encode-composition-components (components &optional nocopy)
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(or nocopy
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(setq components (copy-sequence components)))
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(if (vectorp components)
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(let ((len (length components))
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(i 1))
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(while (< i len)
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(aset components i
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(encode-composition-rule (aref components i)))
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(setq i (+ i 2))))
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(let ((tail (cdr components)))
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(while tail
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(setcar tail
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(encode-composition-rule (car tail)))
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(setq tail (nthcdr 2 tail)))))
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components)
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;; Decode composition rule codes in composition components COMPONENTS.
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;; The value is a copy of COMPONENTS, where composition rule codes are
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;; replaced with composition rules (cons of global and new glyph
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;; reference point symbols). Optional 2nd argument NOCOPY non-nil
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;; means don't make a copy but modify COMPONENTS directly.
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;; It is assumed that COMPONENTS is a vector and is for rule-base
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;; composition, thus (2N+1)th elements are rule codes.
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(defun decode-composition-components (components &optional nocopy)
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(or nocopy
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(setq components (copy-sequence components)))
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(let ((len (length components))
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(i 1))
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(while (< i len)
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(aset components i
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(decode-composition-rule (aref components i)))
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(setq i (+ i 2))))
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components)
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;;;###autoload
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(defun compose-region (start end &optional components modification-func)
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"Compose characters in the current region.
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Characters are composed relatively, i.e. composed by overstricking or
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stacking depending on ascent, descent and other properties.
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When called from a program, expects these four arguments.
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First two arguments START and END are positions (integers or markers)
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specifying the region.
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Optional 3rd argument COMPONENTS, if non-nil, is a character or a
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sequence (vector, list, or string) of integers. In this case,
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characters are composed not relatively but according to COMPONENTS.
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If it is a character, it is an alternate character to display instead
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of the text in the region.
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If it is a string, the elements are alternate characters.
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If it is a vector or list, it is a sequence of alternate characters and
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composition rules, where (2N)th elements are characters and (2N+1)th
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elements are composition rules to specify how to compose (2N+2)th
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elements with previously composed N glyphs.
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A composition rule is a cons of global and new glyph reference point
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symbols. See the documentation of `reference-point-alist' for more
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detail.
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Optional 4th argument MODIFICATION-FUNC is a function to call to
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adjust the composition when it gets invalid because of a change of
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text in the composition."
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(interactive "r")
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(let ((modified-p (buffer-modified-p))
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(buffer-read-only nil))
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(if (or (vectorp components) (listp components))
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(setq components (encode-composition-components components)))
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(compose-region-internal start end components modification-func)
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(restore-buffer-modified-p modified-p)))
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;;;###autoload
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(defun decompose-region (start end)
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"Decompose text in the current region.
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When called from a program, expects two arguments,
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positions (integers or markers) specifying the region."
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(interactive "r")
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(let ((modified-p (buffer-modified-p))
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(buffer-read-only nil))
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(remove-text-properties start end '(composition nil))
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(set-buffer-modified-p modified-p)))
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;;;###autoload
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(defun compose-string (string &optional start end components modification-func)
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"Compose characters in string STRING.
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The return value is STRING where `composition' property is put on all
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the characters in it.
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Optional 2nd and 3rd arguments START and END specify the range of
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STRING to be composed. They default to the beginning and the end of
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STRING respectively.
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Optional 4th argument COMPONENTS, if non-nil, is a character or a
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sequence (vector, list, or string) of integers. See the function
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`compose-region' for more detail.
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Optional 5th argument MODIFICATION-FUNC is a function to call to
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adjust the composition when it gets invalid because of a change of
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text in the composition."
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(if (or (vectorp components) (listp components))
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(setq components (encode-composition-components components)))
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(or start (setq start 0))
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(or end (setq end (length string)))
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(compose-string-internal string start end components modification-func)
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string)
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;;;###autoload
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(defun decompose-string (string)
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"Return STRING where `composition' property is removed."
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(remove-text-properties 0 (length string) '(composition nil) string)
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string)
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;;;###autoload
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(defun compose-chars (&rest args)
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"Return a string from arguments in which all characters are composed.
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For relative composition, arguments are characters.
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For rule-based composition, Mth \(where M is odd) arguments are
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characters, and Nth \(where N is even) arguments are composition rules.
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A composition rule is a cons of glyph reference points of the form
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\(GLOBAL-REF-POINT . NEW-REF-POINT). See the documentation of
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`reference-point-alist' for more detail."
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(let (str components)
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(if (consp (car (cdr args)))
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;; Rule-base composition.
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(let ((len (length args))
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(tail (encode-composition-components args 'nocopy)))
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(while tail
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(setq str (cons (car tail) str))
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(setq tail (nthcdr 2 tail)))
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(setq str (concat (nreverse str))
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components args))
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;; Relative composition.
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(setq str (concat args)))
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(compose-string-internal str 0 (length str) components)))
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;;;###autoload
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(defun find-composition (pos &optional limit string detail-p)
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"Return information about a composition at or nearest to buffer position POS.
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If the character at POS has `composition' property, the value is a list
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of FROM, TO, and VALID-P.
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FROM and TO specify the range of text that has the same `composition'
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property, VALID-P is non-nil if and only if this composition is valid.
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If there's no composition at POS, and the optional 2nd argument LIMIT
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is non-nil, search for a composition toward LIMIT.
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If no composition is found, return nil.
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Optional 3rd argument STRING, if non-nil, is a string to look for a
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composition in; nil means the current buffer.
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If a valid composition is found and the optional 4th argument DETAIL-P
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is non-nil, the return value is a list of FROM, TO, COMPONENTS,
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RELATIVE-P, MOD-FUNC, and WIDTH.
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COMPONENTS is a vector of integers, the meaning depends on RELATIVE-P.
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RELATIVE-P is t if the composition method is relative, else nil.
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If RELATIVE-P is t, COMPONENTS is a vector of characters to be
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composed. If RELATIVE-P is nil, COMPONENTS is a vector of characters
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and composition rules as described in `compose-region'.
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MOD-FUNC is a modification function of the composition.
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WIDTH is a number of columns the composition occupies on the screen."
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(let ((result (find-composition-internal pos limit string detail-p)))
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(if (and detail-p result (nth 2 result) (not (nth 3 result)))
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;; This is a valid rule-base composition.
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(decode-composition-components (nth 2 result) 'nocopy))
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result))
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;;;###autoload
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(defun compose-chars-after (pos &optional limit object)
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"Compose characters in current buffer after position POS.
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It looks up the char-table `composition-function-table' (which see) by
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a character after POS. If non-nil value is found, the format of the
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value should be an alist of PATTERNs vs FUNCs, where PATTERNs are
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regular expressions and FUNCs are functions. If the text after POS
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matches one of PATTERNs, call the corresponding FUNC with three
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arguments POS, TO, and PATTERN, where TO is the end position of text
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matching PATTERN, and return what FUNC returns. Otherwise, return
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nil.
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FUNC is responsible for composing the text properly. The return value
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is:
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nil -- if no characters were composed.
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CHARS (integer) -- if CHARS characters were composed.
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Optional 2nd arg LIMIT, if non-nil, limits the matching of text.
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Optional 3rd arg OBJECT, if non-nil, is a string that contains the
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text to compose. In that case, POS and LIMIT index to the string.
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This function is the default value of `compose-chars-after-function'."
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(let ((tail (aref composition-function-table (char-after pos)))
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pattern func result)
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(when tail
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(save-match-data
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(save-excursion
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(while (and tail (not func))
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(setq pattern (car (car tail))
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func (cdr (car tail)))
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(goto-char pos)
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(if (if limit
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(and (re-search-forward pattern limit t)
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(= (match-beginning 0) pos))
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(looking-at pattern))
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(setq result (funcall func pos (match-end 0) pattern nil))
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(setq func nil tail (cdr tail)))))))
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result))
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;;;###autoload
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(defun compose-last-chars (args)
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"Compose last characters.
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The argument is a parameterized event of the form
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\(compose-last-chars N COMPONENTS),
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where N is the number of characters before point to compose,
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COMPONENTS, if non-nil, is the same as the argument to `compose-region'
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\(which see). If it is nil, `compose-chars-after' is called,
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and that function finds a proper rule to compose the target characters.
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This function is intended to be used from input methods.
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The global keymap binds special event `compose-last-chars' to this
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function. Input method may generate an event (compose-last-chars N COMPONENTS)
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after a sequence of character events."
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(interactive "e")
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(let ((chars (nth 1 args)))
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(if (and (numberp chars)
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(>= (- (point) (point-min)) chars))
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(if (nth 2 args)
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(compose-region (- (point) chars) (point) (nth 2 args))
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(compose-chars-after (- (point) chars) (point))))))
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;;;###autoload(global-set-key [compose-last-chars] 'compose-last-chars)
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;;; The following codes are only for backward compatibility with Emacs
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;;; 20.4 and earlier.
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;;;###autoload
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(defun decompose-composite-char (char &optional type with-composition-rule)
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"Convert CHAR to string.
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If optional 2nd arg TYPE is non-nil, it is `string', `list', or
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`vector'. In this case, CHAR is converted to string, list of CHAR, or
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vector of CHAR respectively.
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Optional 3rd arg WITH-COMPOSITION-RULE is ignored."
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(cond ((or (null type) (eq type 'string)) (char-to-string char))
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((eq type 'list) (list char))
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(t (vector char))))
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;;;###autoload
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(make-obsolete 'decompose-composite-char 'char-to-string "21.1")
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;;; arch-tag: ee703d77-1723-45d4-a31f-e9f0f867aa33
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;;; composite.el ends here
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