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

   1 /* Header for fontset handler.
   2    Copyright (C) 1995, 1997, 2000 Electrotechnical Laboratory, JAPAN.
   3      Licensed to the Free Software Foundation.
   4    Copyright (C) 2003
   5      National Institute of Advanced Industrial Science and Technology (AIST)
   6      Registration Number H13PRO009
   7
   8 This file is part of GNU Emacs.
   9
  10 GNU Emacs is free software; you can redistribute it and/or modify
  11 it under the terms of the GNU General Public License as published by
  12 the Free Software Foundation; either version 2, or (at your option)
  13 any later version.
  14
  15 GNU Emacs is distributed in the hope that it will be useful,
  16 but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 GNU General Public License for more details.
  19
  20 You should have received a copy of the GNU General Public License
  21 along with GNU Emacs; see the file COPYING.  If not, write to
  22 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 Boston, MA 02111-1307, USA.  */
  24
  25 #ifndef EMACS_FONTSET_H
  26 #define EMACS_FONTSET_H
  27
  28 /* This data type is used for the font_table field of window system
  29    depending data area (e.g. struct x_display_info on X window).  */
  30
  31 struct font_info
  32 {
  33   /* Pointer to window system dependent font structure.  On X window,
  34      this value should be coerced to (XFontStruct *).  */
  35   void *font;
  36
  37   /* Index number of the font.  */
  38   int font_idx;
  39
  40   /* Name to be used to find the font.  */
  41   char *name;
  42
  43   /* Full name of the font given by a window system.  */
  44   char *full_name;
  45
  46   /* Charset to encode a character code into a glyph code of the
  47      font.  */
  48   int charset;
  49
  50 #ifdef WINDOWSNT
  51   /* Codepage of characters that will be displayed by the font.  */
  52   int codepage;
  53 #endif
  54
  55   /* Maximum bound width over all existing characters of the font.  On
  56      X window, this is same as (font->max_bounds.width) */
  57   int size;
  58
  59   /* Height of the font.  On X window, this is the same as
  60      (font->ascent + font->descent).  */
  61   int height;
  62
  63   /* Width of the space glyph of the font.  */
  64   int space_width;
  65
  66   /* Average width of glyphs in the font.  */
  67   int average_width;
  68
  69   /* 1 iff `vertical-centering-font-regexp' matches this font name.
  70      In this case, we render characters at vartical center positions
  71      of lines.  */
  72   int vertical_centering;
  73
  74   /* Encoding type of the font.  The value is one of
  75      0, 1, 2, or 3:
  76         0: code points 0x20..0x7F or 0x2020..0x7F7F are used
  77         1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
  78         2: code points 0x20A0..0x7FFF are used
  79         3: code points 0xA020..0xFF7F are used
  80      If the member `font_encoder' is not NULL, this member is ignored.
  81   */
  82   unsigned char encoding_type;
  83
  84   /* The baseline position of a font is normally `ascent' value of the
  85      font.  However, there exists many fonts which don't set `ascent'
  86      an appropriate value to be used as baseline position.  This is
  87      typical in such ASCII fonts which are designed to be used with
  88      Chinese, Japanese, Korean characters.  When we use mixture of
  89      such fonts and normal fonts (having correct `ascent' value), a
  90      display line gets very ugly.  Since we have no way to fix it
  91      automatically, it is users responsibility to supply well designed
  92      fonts or correct `ascent' value of fonts.  But, the latter
  93      requires heavy work (modifying all bitmap data in BDF files).
  94      So, Emacs accepts a private font property
  95      `_MULE_BASELINE_OFFSET'.  If a font has this property, we
  96      calculate the baseline position by subtracting the value from
  97      `ascent'.  In other words, the value indicates how many bits
  98      higher we should draw a character of the font than normal ASCII
  99      text for a better looking.
 100
 101      We also have to consider the fact that the concept of `baseline'
 102      differs among languages to which each character belongs.  For
 103      instance, baseline should be at the bottom most position of all
 104      glyphs for Chinese, Japanese, and Korean.  But, many of existing
 105      fonts for those characters doesn't have correct `ascent' values
 106      because they are designed to be used with ASCII fonts.  To
 107      display characters of different language on the same line, the
 108      best way will be to arrange them in the middle of the line.  So,
 109      in such a case, again, we utilize the font property
 110      `_MULE_BASELINE_OFFSET'.  If the value is larger than `ascent' we
 111      calculate baseline so that a character is arranged in the middle
 112      of a line.  */
 113
 114   int baseline_offset;
 115
 116   /* Non zero means a character should be composed at a position
 117      relative to the height (or depth) of previous glyphs in the
 118      following cases:
 119         (1) The bottom of the character is higher than this value.  In
 120         this case, the character is drawn above the previous glyphs.
 121         (2) The top of the character is lower than 0 (i.e. baseline
 122         height).  In this case, the character is drawn beneath the
 123         previous glyphs.
 124
 125      This value is taken from a private font property
 126      `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs.  */
 127   int relative_compose;
 128
 129   /* Non zero means an ascent value to be used for a character
 130      registered in char-table `use-default-ascent'.  */
 131   int default_ascent;
 132
 133   /* CCL program to calculate code points of the font.  */
 134   struct ccl_program *font_encoder;
 135 };
 136
 137 /* A value which may appear in the member `encoding' of struch
 138    font_info indicating that a font itself doesn't tell which encoding
 139    to be used.  */
 140 #define FONT_ENCODING_NOT_DECIDED 255
 141
 142 enum FONT_SPEC_INDEX
 143   {
 144     FONT_SPEC_FAMILY_INDEX,
 145     FONT_SPEC_WEIGHT_INDEX,
 146     FONT_SPEC_SLANT_INDEX,
 147     FONT_SPEC_SWIDTH_INDEX,
 148     FONT_SPEC_ADSTYLE_INDEX,
 149     FONT_SPEC_REGISTRY_INDEX,
 150     FONT_SPEC_MAX_INDEX
 151   };
 152
 153 /* Forward declaration for prototypes.  */
 154 struct frame;
 155
 156 /* The following six are window system dependent functions.
 157    Initialization routine of each window system should set appropriate
 158    functions to these variables.  For instance, in case of X window,
 159    x_term_init does this.  */
 160
 161 /* Return a pointer to struct font_info of font FONT_IDX of frame F.  */
 162 extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
 163                                                     int font_idx));
 164
 165 /* Return a list of font names which matches PATTERN.  See the document of
 166    `x-list-fonts' for more detail.  */
 167 extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
 168                                            Lisp_Object pattern,
 169                                            int size,
 170                                            int maxnames));
 171
 172 /* Load a font named NAME for frame F and return a pointer to the
 173    information of the loaded font.  If loading is failed, return -1.  */
 174 extern struct font_info *(*load_font_func) P_ ((struct frame *f,
 175                                                 char *name, int));
 176
 177 /* Return a pointer to struct font_info of a font named NAME for frame F.
 178    If no such font is loaded, return NULL.  */
 179 extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
 180
 181 /* Additional function for setting fontset or changing fontset
 182    contents of frame F.  This function may change the coordinate of
 183    the frame.  */
 184 extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
 185                                            Lisp_Object oldval));
 186
 187 /* To find a CCL program, fs_load_font calls this function.
 188    The argument is a pointer to the struct font_info.
 189    This function set the memer `encoder' of the structure.  */
 190 extern void (*find_ccl_program_func) P_ ((struct font_info *));
 191
 192 extern Lisp_Object (*get_font_repertory_func) P_ ((struct frame *,
 193                                                    struct font_info *));
 194
 195 /* Check if any window system is used now.  */
 196 extern void (*check_window_system_func) P_ ((void));
 197
 198 struct face;
 199
 200 extern void free_face_fontset P_ ((FRAME_PTR, struct face *));
 201 extern Lisp_Object fontset_font_pattern P_ ((FRAME_PTR, struct face *, int));
 202 extern int face_suitable_for_char_p P_ ((struct face *, int));
 203 extern int face_for_char P_ ((FRAME_PTR, struct face *, int,
 204                               int, Lisp_Object));
 205 extern int make_fontset_for_ascii_face P_ ((FRAME_PTR, int, struct face *));
 206 extern int new_fontset_from_font_name P_ ((Lisp_Object));
 207 extern void set_default_ascii_font P_ ((Lisp_Object));
 208 extern struct font_info *fs_load_font P_ ((struct frame *, char *, int));
 209 extern int fs_query_fontset P_ ((Lisp_Object, int));
 210 EXFUN (Fquery_fontset, 2);
 211 extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
 212
 213 extern Lisp_Object Vuse_default_ascent;
 214 extern Lisp_Object Vignore_relative_composition;
 215 extern Lisp_Object Valternate_fontname_alist;
 216 extern Lisp_Object Vfontset_alias_alist;
 217 extern Lisp_Object Vvertical_centering_font_regexp;
 218
 219 /* Load a font named FONTNAME on frame F.  All fonts for frame F is
 220    stored in a table pointed by FONT_TABLE.  Return a pointer to the
 221    struct font_info of the loaded font.  If loading fails, return
 222    NULL.  */
 223
 224 #define FS_LOAD_FONT(f, fontname) fs_load_font (f, fontname, -1)
 225
 226
 227 /* Return an immutable id for font_info FONT_INFO on frame F.  The
 228    reason for this macro is hat one cannot hold pointers to font_info
 229    structures in other data structures, because the table is
 230    reallocated in x_list_fonts.  */
 231
 232 #define FONT_INFO_ID(F, FONT_INFO) \
 233      (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
 234
 235 /* Given a font_info id ID, return a pointer to the font_info
 236    structure on frame F.  If ID is invalid, return null.  */
 237
 238 #define FONT_INFO_FROM_ID(F, ID)                                        \
 239      (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size) \
 240       ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID))                 \
 241       : 0)
 242
 243 extern Lisp_Object fontset_name P_ ((int));
 244 extern Lisp_Object fontset_ascii P_ ((int));
 245 extern int fontset_height P_ ((int));
 246
 247 #endif /* EMACS_FONTSET_H */
 248
 249 /* arch-tag: c27cef7b-3cab-488a-8398-7a4daa96bb77
 250    (do not change this comment) */