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

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