src/composite.h

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