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

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