src/composite.h

   1 /* Header for composite sequence handler.
   2    Copyright (C) 1999 Electrotechnical Laboratory, JAPAN.
   3    Licensed to the Free Software Foundation.
   4    Copyright (C) 2001 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Emacs.
   7
   8 GNU Emacs is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2, or (at your option)
  11 any later version.
  12
  13 GNU Emacs is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GNU Emacs; see the file COPYING.  If not, write to
  20 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.  */
  22
  23 #ifndef EMACS_COMPOSITE_H
  24 #define EMACS_COMPOSITE_H
  25
  26 /* Methods to display a sequence of components a composition.  */
  27 enum composition_method {
  28   /* The first two are actually not methods, but used in code
  29      conversion to specify the current composing status.  */
  30   COMPOSITION_DISABLED,         /* Never handle composition data */
  31   COMPOSITION_NO,               /* Not processing composition data */
  32   /* Compose relatively without alternate characters.  */
  33   COMPOSITION_RELATIVE,
  34   /* Compose by specified composition rule.  This is not used in Emacs
  35      21 but we need it to decode files saved in the older versions of
  36      Emacs.  */
  37   COMPOSITION_WITH_RULE,
  38   /* Compose relatively with alternate characters.  */
  39   COMPOSITION_WITH_ALTCHARS,
  40   /* Compose by specified composition rule with alternate characters.  */
  41   COMPOSITION_WITH_RULE_ALTCHARS
  42 };
  43
  44 /* Maximum number of compoments a single composition can have.  */
  45 #define MAX_COMPOSITION_COMPONENTS 16
  46
  47 /* These macros access information about a composition that
  48    has `composition' property PROP.  PROP is:
  49         ((LENGTH . COMPONENTS) . MODIFICATION-FUNC)
  50    or
  51         (COMPOSITION-ID . (LENGTH COMPONENTS . MODIFICATION-FUNC))
  52    They don't check validity of PROP.  */
  53
  54 /* Temporary variable used only in the following macros.  */
  55 extern Lisp_Object composition_temp;
  56
  57 /* Return 1 iff the composition is already registered.  */
  58 #define COMPOSITION_REGISTERD_P(prop) INTEGERP (XCAR (prop))
  59
  60 /* Return ID number of the already registered composition.  */
  61 #define COMPOSITION_ID(prop) XINT (XCAR (prop))
  62
  63 /* Return length of the composition.  */
  64 #define COMPOSITION_LENGTH(prop)        \
  65   (COMPOSITION_REGISTERD_P (prop)       \
  66    ? XINT (XCAR (XCDR (prop)))          \
  67    : XINT (XCAR (XCAR (prop))))
  68
  69 /* Return components of the composition.  */
  70 #define COMPOSITION_COMPONENTS(prop)    \
  71   (COMPOSITION_REGISTERD_P (prop)       \
  72    ? XCAR (XCDR (XCDR (prop)))          \
  73    : XCDR (XCAR (prop)))
  74
  75 /* Return modification function of the composition.  */
  76 #define COMPOSITION_MODIFICATION_FUNC(prop)     \
  77   (COMPOSITION_REGISTERD_P (prop)               \
  78    ? XCDR (XCDR (XCDR (prop)))                  \
  79    : CONSP (prop) ? XCDR (prop) : Qnil)
  80
  81 /* Return the method of composition.  */
  82 #define COMPOSITION_METHOD(prop)                                        \
  83   (COMPOSITION_REGISTERD_P (prop)                                       \
  84    ? composition_table[COMPOSITION_ID (prop)]->method                   \
  85    : (composition_temp = XCDR (XCAR (prop)),                            \
  86       (NILP (composition_temp)                                          \
  87        ? COMPOSITION_RELATIVE                                           \
  88        : ((INTEGERP (composition_temp) || STRINGP (composition_temp))   \
  89           ? COMPOSITION_WITH_ALTCHARS                                   \
  90           : COMPOSITION_WITH_RULE_ALTCHARS))))
  91
  92 /* Return 1 iff the composition is valid.  It is valid if length of
  93    the composition equals to (END - START).  */
  94 #define COMPOSITION_VALID_P(start, end, prop)                   \
  95   (CONSP (prop)                                                 \
  96    && (COMPOSITION_REGISTERD_P (prop)                           \
  97        ? (COMPOSITION_ID (prop) >= 0                            \
  98           && COMPOSITION_ID (prop) <= n_compositions            \
  99           && CONSP (XCDR (prop)))                               \
 100        : (composition_temp = XCAR (prop),                       \
 101           (CONSP (composition_temp)                             \
 102            && (composition_temp = XCDR (composition_temp),      \
 103                (NILP (composition_temp)                         \
 104                 || STRINGP (composition_temp)                   \
 105                 || VECTORP (composition_temp)                   \
 106                 || INTEGERP (composition_temp)                  \
 107                 || CONSP (composition_temp))))))                \
 108    && (end - start) == COMPOSITION_LENGTH (prop))
 109
 110 /* Return the Nth glyph of composition specified by CMP.  CMP is a
 111    pointer to `struct composition'. */
 112 #define COMPOSITION_GLYPH(cmp, n)                                       \
 113   XINT (XVECTOR (XVECTOR (XHASH_TABLE (composition_hash_table)          \
 114                           ->key_and_value)                              \
 115                  ->contents[cmp->hash_index * 2])                       \
 116         ->contents[cmp->method == COMPOSITION_WITH_RULE_ALTCHARS        \
 117                   ? (n) * 2 : (n)])
 118
 119 /* Return the encoded composition rule to compose the Nth glyph of
 120    rule-base composition specified by CMP.  CMP is a pointer to
 121    `struct composition'. */
 122 #define COMPOSITION_RULE(cmp, n)                                \
 123   XINT (XVECTOR (XVECTOR (XHASH_TABLE (composition_hash_table)  \
 124                           ->key_and_value)                      \
 125                  ->contents[cmp->hash_index * 2])               \
 126         ->contents[(n) * 2 - 1])
 127
 128 /* Decode encoded composition rule RULE_CODE into GREF (global
 129    reference point code) and NREF (new reference point code).  Don't
 130    check RULE_CODE, always set GREF and NREF to valid values.  */
 131 #define COMPOSITION_DECODE_RULE(rule_code, gref, nref)  \
 132   do {                                                  \
 133     gref = (rule_code) / 12;                            \
 134     if (gref > 12) gref = 11;                           \
 135     nref = (rule_code) % 12;                            \
 136   } while (0)
 137
 138 /* Return encoded composition rule for the pair of global reference
 139    point GREF and new reference point NREF.  If arguments are invalid,
 140    return -1. */
 141 #define COMPOSITION_ENCODE_RULE(gref, nref)             \
 142   ((unsigned) (gref) < 12 && (unsigned) (nref) < 12     \
 143    ? (gref) * 12 + (nref) : -1)
 144
 145 /* Data structure that records information about a composition
 146    currently used in some buffers or strings.
 147
 148    When a composition is assigned an ID number (by
 149    get_composition_id), this structure is allocated for the
 150    composition and linked in composition_table[ID].
 151
 152    Identical compositions appearing at different places have the same
 153    ID, and thus share the same instance of this structure.  */
 154
 155 struct composition {
 156   /* Number of glyphs of the composition components.  */
 157   unsigned glyph_len;
 158
 159   /* Width, ascent, and descent pixels of the composition.  */
 160   short pixel_width, ascent, descent;
 161
 162   /* How many columns the overall glyphs occupy on the screen.  This
 163      gives an approximate value for column calculation in
 164      Fcurrent_column, and etc.  */
 165   unsigned short width;
 166
 167   /* Method of the composition.  */
 168   enum composition_method method;
 169
 170   /* Index to the composition hash table.  */
 171   int hash_index;
 172
 173   /* For which font we have calculated the remaining members.  The
 174      actual type is device dependent.  */
 175   void *font;
 176
 177   /* Pointer to an array of x-offset and y-offset (by pixels) of
 178      glyphs.  This points to a sufficient memory space (sizeof (int) *
 179      glyph_len * 2) that is allocated when the composition is
 180      registered in composition_table.  X-offset and Y-offset of Nth
 181      glyph are (2N)th and (2N+1)th elements respectively.  */
 182   short *offsets;
 183 };
 184
 185 /* Table of pointers to the structure `composition' indexed by
 186    COMPOSITION-ID.  */
 187 extern struct composition **composition_table;
 188 /* Number of the currently registered compositions.  */
 189 extern int n_compositions;
 190
 191 /* Mask bits for CHECK_MASK arg to update_compositions.
 192    For a change in the region FROM and TO, check compositions ... */
 193 #define CHECK_HEAD      1       /* adjacent to FROM */
 194 #define CHECK_TAIL      2       /* adjacent to TO */
 195 #define CHECK_INSIDE    4       /* between FROM and TO */
 196 #define CHECK_BORDER    (CHECK_HEAD | CHECK_TAIL)
 197 #define CHECK_ALL       (CHECK_BORDER | CHECK_INSIDE)
 198
 199 extern Lisp_Object Qcomposition;
 200 extern Lisp_Object composition_hash_table;
 201
 202 extern int get_composition_id P_ ((int, int, int, Lisp_Object, Lisp_Object));
 203 extern int find_composition P_ ((int, int, int *, int *, Lisp_Object *,
 204                                  Lisp_Object));
 205 extern void update_compositions P_ ((int, int, int));
 206 extern void make_composition_value_copy P_ ((Lisp_Object));
 207 extern void compose_region P_ ((int, int, Lisp_Object, Lisp_Object,
 208                                 Lisp_Object));
 209 extern void syms_of_composite P_ ((void));
 210 extern void compose_text P_ ((int, int, Lisp_Object, Lisp_Object,
 211                               Lisp_Object));
 212 extern void compose_chars_in_text P_ ((int, int, Lisp_Object));
 213
 214 #endif /* not EMACS_COMPOSITE_H */