src/fontset.h

   1 /* Header for fontset handler.
   2    Copyright (C) 1995, 1997 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 _FONTSET_H
  23 #define _FONTSET_H
  24
  25 /* This data type is used for the font_table field of window system
  26    depending data area (e.g. struct x_display_info on X window).  */
  27
  28 struct font_info
  29 {
  30   /* Pointer to window system dependent font structure.  On X window,
  31      this value should be coerced to (XFontStruct *).  */
  32   void *font;
  33
  34   /* Index number of the font.  */
  35   int font_idx;
  36
  37   /* Name to be used to find the font.  */
  38   char *name;
  39
  40   /* Full name of the font given by a window system.  */
  41   char *full_name;
  42
  43   /* Charset of characters displayed by the font.  */
  44   int charset;
  45
  46   /* Maximum bound width over all existing characters of the font.  On
  47      X window, this is same as (font->max_bounds.width) */
  48   int size;
  49
  50   /* Height of the font.  On X window, this is same as (font->ascent
  51      + font->descent).  */
  52   int height;
  53
  54   /* 1 iff we render characters at vartical center positions of lines.  */
  55   int vertical_centering;
  56
  57   /* Encodings of the font indexed by CHARSET.  The value an integer
  58      0, 1, 2, or 3:
  59         0: code points 0x20..0x7F or 0x2020..0x7F7F are used
  60         1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
  61         2: code points 0x20A0..0x7FFF are used
  62         3: code points 0xA020..0xFF7F are used
  63      For instance, ASCII and Latin-1 characters may use the same font
  64      but different code points (ASCII uses 0x20..0x7F and Latin-1 uses
  65      0xA0..0xFF).
  66
  67      If the value can't be decided from information of the font, we
  68      consult `font-encoding-alist' to get of the corresponding charset
  69      whose default value is defined in lisp/fontset.el.  Since there's
  70      no charset whose id is 1, we use encoding[1] to store the
  71      encoding information decided by the font itself.  */
  72   unsigned char encoding[MAX_CHARSET + 1];
  73
  74   /* The baseline position of a font is normally `ascent' value of the
  75      font.  However, there exists many fonts which don't set `ascent'
  76      an appropriate value to be used as baseline position.  This is
  77      typical in such ASCII fonts which are designed to be used with
  78      Chinese, Japanese, Korean characters.  When we use mixture of
  79      such fonts and normal fonts (having correct `ascent' value), a
  80      display line gets very ugly.  Since we have no way to fix it
  81      automatically, it is users responsibility to supply well designed
  82      fonts or correct `ascent' value of fonts.  But, the latter
  83      requires heavy work (modifying all bitmap data in BDF files).
  84      So, Emacs accepts a private font property
  85      `_MULE_BASELINE_OFFSET'.  If a font has this property, we
  86      calculate the baseline position by subtracting the value from
  87      `ascent'.  In other words, the value indicates how many bits
  88      higher we should draw a character of the font than normal ASCII
  89      text for a better looking.
  90
  91      We also have to consider the fact that the concept of `baseline'
  92      differs among languages to which each character belongs.  For
  93      instance, baseline should be at the bottom most position of all
  94      glyphs for Chinese, Japanese, and Korean.  But, many of existing
  95      fonts for those characters doesn't have correct `ascent' values
  96      because they are designed to be used with ASCII fonts.  To
  97      display characters of different language on the same line, the
  98      best way will be to arrange them in the middle of the line.  So,
  99      in such a case, again, we utilize the font property
 100      `_MULE_BASELINE_OFFSET'.  If the value is larger than `ascent' we
 101      calculate baseline so that a character is arranged in the middle
 102      of a line.  */
 103
 104   int baseline_offset;
 105
 106   /* Non zero means a character should be composed at a position
 107      relative to the height (or depth) of previous glyphs in the
 108      following cases:
 109         (1) The bottom of the character is higher than this value.  In
 110         this case, the character is drawn above the previous glyphs.
 111         (2) The top of the character is lower than 0 (i.e. baseline
 112         height).  In this case, the character is drawn beneath the
 113         previous glyphs.
 114
 115      This value is taken from a private font property
 116      `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs.  */
 117   int relative_compose;
 118
 119   /* Non zero means an ascent value to be used for a character
 120      registered in char-table `use-default-ascent'.  */
 121   int default_ascent;
 122
 123   /* CCL program to calculate code points of the font.  */
 124   struct ccl_program *font_encoder;
 125 };
 126
 127 /* A value which may appear in the member encoding of struch font_info
 128    indicating that a font itself doesn't tell which encoding to be
 129    used.  */
 130 #define FONT_ENCODING_NOT_DECIDED 255
 131
 132 #define FONT_NOT_OPENED -1
 133 #define FONT_NOT_FOUND  -2
 134
 135 struct fontset_info
 136 {
 137   /* Name of the fontset.  */
 138   char *name;
 139
 140   /* Size of the fontset.  This is the same as the size of ASCII font
 141      of this fontset.  */
 142   int size;
 143
 144   /* Height of the tallest font in the fontset.  */
 145   int height;
 146
 147   /* Table of font name for each character set.  */
 148   char *fontname[MAX_CHARSET + 1];
 149
 150   /* Table of index numbers of fonts indexed by charset.  If a font is
 151      not yet loaded, the value is -1 (FONT_NOT_OPENED).  If font
 152      loading is failed, the value is -2 (FONT_NOT_FOUND).  */
 153   int font_indexes[MAX_CHARSET + 1];
 154 };
 155
 156 /* This data type is used for the fontset_data field of struct frame.  */
 157
 158 struct fontset_data
 159 {
 160   /* A table of pointers to all the fontsets.  */
 161   struct fontset_info **fontset_table;
 162
 163   /* The current capacity of fontset_table.  */
 164   int fontset_table_size;
 165
 166   /* The number of fontsets actually stored in fontset_table.
 167      fontset_table[n] is used and valid iff 0 <= n < n_fontsets.
 168      0 <= n_fontsets <= fontset_table_size.  */
 169   int n_fontsets;
 170 };
 171
 172 /* Forward declaration for prototypes.  */
 173 struct frame;
 174
 175 /* The following six are window system dependent functions.
 176    Initialization routine of each window system should set appropriate
 177    functions to these variables.  For instance, in case of X window,
 178    x_term_init does this.  */
 179
 180 /* Return a pointer to struct font_info of font FONT_IDX of frame F.  */
 181 extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
 182                                                     int font_idx));
 183
 184 /* Return a list of font names which matches PATTERN.  See the document of
 185    `x-list-fonts' for more detail.  */
 186 extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
 187                                            Lisp_Object pattern,
 188                                            int size,
 189                                            int maxnames));
 190
 191 /* Load a font named NAME for frame F and return a pointer to the
 192    information of the loaded font.  If loading is failed, return -1.  */
 193 extern struct font_info *(*load_font_func) P_ ((struct frame *f,
 194                                                 char *name, int));
 195
 196 /* Return a pointer to struct font_info of a font named NAME for frame F.
 197    If no such font is loaded, return NULL.  */
 198 extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
 199
 200 /* Additional function for setting fontset or changing fontset
 201    contents of frame F.  This function may change the coordinate of
 202    the frame.  */
 203 extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
 204                                            Lisp_Object oldval));
 205
 206 /* To find a CCL program, fs_load_font calls this function.
 207    The argument is a pointer to the struct font_info.
 208    This function set the memer `encoder' of the structure.  */
 209 extern void (*find_ccl_program_func) P_ ((struct font_info *));
 210
 211 /* Check if any window system is used now.  */
 212 extern void (*check_window_system_func) P_ ((void));
 213
 214 extern struct fontset_data *alloc_fontset_data P_ ((void));
 215 extern void free_fontset_data P_ ((struct fontset_data *));
 216 extern struct font_info *fs_load_font P_ ((struct frame *, struct font_info *,
 217                                            int, char *, int));
 218 extern int fs_query_fontset P_ ((struct frame *, char *));
 219 extern int fs_register_fontset P_ ((struct frame *, Lisp_Object));
 220 EXFUN (Fquery_fontset, 2);
 221 extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
 222 extern Lisp_Object Vglobal_fontset_alist;
 223 struct frame;
 224 int fs_query_fontset P_ ((struct frame *f, char *name));
 225
 226 extern Lisp_Object Qfontset;
 227 extern Lisp_Object Vuse_default_ascent;
 228 extern Lisp_Object Vignore_relative_composition;
 229 extern Lisp_Object Valternate_fontname_alist;
 230 extern Lisp_Object Vhighlight_wrong_size_font;
 231 extern Lisp_Object Vclip_large_size_font;
 232 extern Lisp_Object Vvertical_centering_font_regexp;
 233 extern int font_idx_temp;
 234
 235 /* Load a font named FONTNAME for displaying CHARSET on frame F.
 236    All fonts for frame F is stored in a table pointed by FONT_TABLE.
 237    Return a pointer to the struct font_info of the loaded font.
 238    If loading fails, return 0;
 239    If FONTNAME is NULL, the name is taken from the information of FONTSET.
 240    If FONTSET is given, try to load a font whose size matches that of
 241    FONTSET, and, the font index is stored in the table for FONTSET.  */
 242
 243 #define FS_LOAD_FONT(f, font_table, charset, fontname, fontset)           \
 244   (fontset >= 0 && fontset < FRAME_FONTSET_DATA (f)->n_fontsets           \
 245    && (font_idx_temp = (FRAME_FONTSET_DATA (f)                            \
 246                         ->fontset_table[fontset]->font_indexes[charset]), \
 247        font_idx_temp >= 0)                                                \
 248    ? font_table + font_idx_temp                                           \
 249    : fs_load_font (f, font_table, charset, fontname, fontset))
 250
 251 extern Lisp_Object Vfontset_alias_alist;
 252 extern Lisp_Object Vglobal_fontset_alist;
 253
 254
 255 /* Return an immutable id for font_info FONT_INFO on frame F.  The
 256    reason for this macro is hat one cannot hold pointers to font_info
 257    structures in other data structures, because the table is
 258    reallocated in x_list_fonts.  */
 259
 260 #define FONT_INFO_ID(F, FONT_INFO) \
 261      (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
 262
 263 /* Given a font_info id ID, return a pointer to the font_info
 264    structure on frame F.  If ID is invalid, return null.  */
 265
 266 #define FONT_INFO_FROM_ID(F, ID)                                        \
 267      (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size) \
 268       ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID))                 \
 269       : 0)
 270
 271 #endif /* _FONTSET_H */