code.delx.au - gnu-emacs/blob - src/fontset.h

   1 /* Header for fontset handler.
   2    Copyright (C) 1998, 2001, 2002, 2003, 2004, 2005,
   3                  2006, 2007  Free Software Foundation, Inc.
   4    Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   5      2005, 2006, 2007
   6      National Institute of Advanced Industrial Science and Technology (AIST)
   7      Registration Number H14PRO021
   8    Copyright (C) 2003, 2006
   9      National Institute of Advanced Industrial Science and Technology (AIST)
  10      Registration Number H13PRO009
  11
  12 This file is part of GNU Emacs.
  13
  14 GNU Emacs is free software; you can redistribute it and/or modify
  15 it under the terms of the GNU General Public License as published by
  16 the Free Software Foundation; either version 3, or (at your option)
  17 any later version.
  18
  19 GNU Emacs is distributed in the hope that it will be useful,
  20 but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22 GNU General Public License for more details.
  23
  24 You should have received a copy of the GNU General Public License
  25 along with GNU Emacs; see the file COPYING.  If not, write to
  26 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  27 Boston, MA 02110-1301, USA.  */
  28
  29 #ifndef EMACS_FONTSET_H
  30 #define EMACS_FONTSET_H
  31
  32 /* This data type is used for the font_table field of window system
  33    depending data area (e.g. struct x_display_info on X window).  */
  34
  35 struct font_info
  36 {
  37   /* Pointer to window system dependent font structure.  On X window,
  38      this value should be coerced to (XFontStruct *).  */
  39   void *font;
  40
  41   /* Index number of the font.  */
  42   int font_idx;
  43
  44   /* Name to be used to find the font.  */
  45   char *name;
  46
  47   /* Full name of the font given by a window system.  */
  48   char *full_name;
  49
  50   /* Charset to encode a character code into a glyph code of the
  51      font.  */
  52   int charset;
  53
  54 #ifdef WINDOWSNT
  55   /* Codepage of characters that will be displayed by the font.  */
  56   int codepage;
  57 #endif
  58
  59   /* Maximum bound width over all existing characters of the font.  On
  60      X window, this is same as (font->max_bounds.width) */
  61   int size;
  62
  63   /* Height of the font.  On X window, this is the same as
  64      (font->ascent + font->descent).  */
  65   int height;
  66
  67   /* Width of the space glyph of the font.  */
  68   int space_width;
  69
  70   /* Average width of glyphs in the font.  */
  71   int average_width;
  72
  73   /* 1 if `vertical-centering-font-regexp' matches this font name.
  74      In this case, we render characters at vartical center positions
  75      of lines.  */
  76   int vertical_centering;
  77
  78   /* Encoding type of the font.  The value is one of
  79      0, 1, 2, or 3:
  80         0: code points 0x20..0x7F or 0x2020..0x7F7F are used
  81         1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
  82         2: code points 0x20A0..0x7FFF are used
  83         3: code points 0xA020..0xFF7F are used
  84      If the member `font_encoder' is not NULL, this member is ignored.
  85   */
  86   unsigned char encoding_type;
  87
  88   /* The baseline position of a font is normally `ascent' value of the
  89      font.  However, there exists many fonts which don't set `ascent'
  90      an appropriate value to be used as baseline position.  This is
  91      typical in such ASCII fonts which are designed to be used with
  92      Chinese, Japanese, Korean characters.  When we use mixture of
  93      such fonts and normal fonts (having correct `ascent' value), a
  94      display line gets very ugly.  Since we have no way to fix it
  95      automatically, it is users responsibility to supply well designed
  96      fonts or correct `ascent' value of fonts.  But, the latter
  97      requires heavy work (modifying all bitmap data in BDF files).
  98      So, Emacs accepts a private font property
  99      `_MULE_BASELINE_OFFSET'.  If a font has this property, we
 100      calculate the baseline position by subtracting the value from
 101      `ascent'.  In other words, the value indicates how many bits
 102      higher we should draw a character of the font than normal ASCII
 103      text for a better looking.
 104
 105      We also have to consider the fact that the concept of `baseline'
 106      differs among languages to which each character belongs.  For
 107      instance, baseline should be at the bottom most position of all
 108      glyphs for Chinese, Japanese, and Korean.  But, many of existing
 109      fonts for those characters doesn't have correct `ascent' values
 110      because they are designed to be used with ASCII fonts.  To
 111      display characters of different language on the same line, the
 112      best way will be to arrange them in the middle of the line.  So,
 113      in such a case, again, we utilize the font property
 114      `_MULE_BASELINE_OFFSET'.  If the value is larger than `ascent' we
 115      calculate baseline so that a character is arranged in the middle
 116      of a line.  */
 117
 118   int baseline_offset;
 119
 120   /* Non zero means a character should be composed at a position
 121      relative to the height (or depth) of previous glyphs in the
 122      following cases:
 123         (1) The bottom of the character is higher than this value.  In
 124         this case, the character is drawn above the previous glyphs.
 125         (2) The top of the character is lower than 0 (i.e. baseline
 126         height).  In this case, the character is drawn beneath the
 127         previous glyphs.
 128
 129      This value is taken from a private font property
 130      `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs.  */
 131   int relative_compose;
 132
 133   /* Non zero means an ascent value to be used for a character
 134      registered in char-table `use-default-ascent'.  */
 135   int default_ascent;
 136
 137   /* CCL program to calculate code points of the font.  */
 138   struct ccl_program *font_encoder;
 139 };
 140
 141 /* A value which may appear in the member `encoding' of struch
 142    font_info indicating that a font itself doesn't tell which encoding
 143    to be used.  */
 144 #define FONT_ENCODING_NOT_DECIDED 255
 145
 146 enum FONT_SPEC_INDEX
 147   {
 148     FONT_SPEC_FAMILY_INDEX,
 149     FONT_SPEC_WEIGHT_INDEX,
 150     FONT_SPEC_SLANT_INDEX,
 151     FONT_SPEC_SWIDTH_INDEX,
 152     FONT_SPEC_ADSTYLE_INDEX,
 153     FONT_SPEC_REGISTRY_INDEX,
 154     FONT_SPEC_MAX_INDEX
 155   };
 156
 157 /* Forward declaration for prototypes.  */
 158 struct frame;
 159
 160 /* The following six are window system dependent functions.
 161    Initialization routine of each window system should set appropriate
 162    functions to these variables.  For instance, in case of X window,
 163    x_term_init does this.  */
 164
 165 /* Return a pointer to struct font_info of font FONT_IDX of frame F.  */
 166 extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
 167                                                     int font_idx));
 168
 169 /* Return a list of font names which matches PATTERN.  See the document of
 170    `x-list-fonts' for more detail.  */
 171 extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
 172                                            Lisp_Object pattern,
 173                                            int size,
 174                                            int maxnames));
 175
 176 /* Load a font named NAME for frame F and return a pointer to the
 177    information of the loaded font.  If loading is failed, return -1.  */
 178 extern struct font_info *(*load_font_func) P_ ((struct frame *f,
 179                                                 char *name, int));
 180
 181 /* Return a pointer to struct font_info of a font named NAME for frame F.
 182    If no such font is loaded, return NULL.  */
 183 extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
 184
 185 /* Additional function for setting fontset or changing fontset
 186    contents of frame F.  This function may change the coordinate of
 187    the frame.  */
 188 extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
 189                                            Lisp_Object oldval));
 190
 191 /* To find a CCL program, fs_load_font calls this function.
 192    The argument is a pointer to the struct font_info.
 193    This function set the memer `encoder' of the structure.  */
 194 extern void (*find_ccl_program_func) P_ ((struct font_info *));
 195
 196 extern Lisp_Object (*get_font_repertory_func) P_ ((struct frame *,
 197                                                    struct font_info *));
 198
 199 /* Check if any window system is used now.  */
 200 extern void (*check_window_system_func) P_ ((void));
 201
 202 struct face;
 203
 204 extern void free_face_fontset P_ ((FRAME_PTR, struct face *));
 205 extern Lisp_Object fontset_font_pattern P_ ((FRAME_PTR, struct face *, int));
 206 extern int face_suitable_for_char_p P_ ((struct face *, int));
 207 extern int face_for_char P_ ((FRAME_PTR, struct face *, int,
 208                               int, Lisp_Object));
 209 extern int make_fontset_for_ascii_face P_ ((FRAME_PTR, int, struct face *));
 210 extern int new_fontset_from_font_name P_ ((Lisp_Object));
 211 extern void set_default_ascii_font P_ ((Lisp_Object));
 212 extern struct font_info *fs_load_font P_ ((struct frame *, char *, int));
 213 extern int fs_query_fontset P_ ((Lisp_Object, int));
 214 EXFUN (Fquery_fontset, 2);
 215 extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
 216
 217 extern Lisp_Object Vuse_default_ascent;
 218 extern Lisp_Object Vignore_relative_composition;
 219 extern Lisp_Object Valternate_fontname_alist;
 220 extern Lisp_Object Vfontset_alias_alist;
 221 extern Lisp_Object Vvertical_centering_font_regexp;
 222 extern Lisp_Object Votf_script_alist;
 223
 224 /* Load a font named FONTNAME on frame F.  All fonts for frame F is
 225    stored in a table pointed by FONT_TABLE.  Return a pointer to the
 226    struct font_info of the loaded font.  If loading fails, return
 227    NULL.  */
 228
 229 #define FS_LOAD_FONT(f, fontname) fs_load_font (f, fontname, -1)
 230
 231
 232 /* Return an immutable id for font_info FONT_INFO on frame F.  The
 233    reason for this macro is hat one cannot hold pointers to font_info
 234    structures in other data structures, because the table is
 235    reallocated in x_list_fonts.  */
 236
 237 #define FONT_INFO_ID(F, FONT_INFO) \
 238      (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
 239
 240 /* Given a font_info id ID, return a pointer to the font_info
 241    structure on frame F.  If ID is invalid, return null.  */
 242
 243 #define FONT_INFO_FROM_ID(F, ID)                                        \
 244      (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size) \
 245       ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID))                 \
 246       : 0)
 247
 248 #ifdef USE_FONT_BACKEND
 249 #define FONT_INFO_FROM_FACE(F, FACE)            \
 250   (enable_font_backend ? (FACE)->font_info      \
 251    : FONT_INFO_FROM_ID ((F), (FACE)->font_info_id))
 252 #else  /* not USE_FONT_BACKEND */
 253 #define FONT_INFO_FROM_FACE(F, FACE)    \
 254   FONT_INFO_FROM_ID ((F), (FACE)->font_info_id)
 255 #endif  /* not USE_FONT_BACKEND */
 256
 257 extern Lisp_Object fontset_name P_ ((int));
 258 extern Lisp_Object fontset_ascii P_ ((int));
 259 extern int fontset_height P_ ((int));
 260
 261 #ifdef USE_FONT_BACKEND
 262 struct font;
 263 extern int face_for_font P_ ((struct frame *, struct font *, struct face *));
 264 extern int new_fontset_from_font P_ ((Lisp_Object));
 265 extern struct font *fontset_ascii_font P_ ((FRAME_PTR, int));
 266 #endif  /* USE_FONT_BACKEND */
 267
 268 #endif /* EMACS_FONTSET_H */
 269
 270 /* arch-tag: c27cef7b-3cab-488a-8398-7a4daa96bb77
 271    (do not change this comment) */