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   /* 1 iff `vertical-centering-font-regexp' matches this font name.
  64      In this case, we render characters at vartical center positions
  65      of lines.  */
  66   int vertical_centering;
  67
  68   /* Encoding type of the font.  The value is one of
  69      0, 1, 2, or 3:
  70         0: code points 0x20..0x7F or 0x2020..0x7F7F are used
  71         1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
  72         2: code points 0x20A0..0x7FFF are used
  73         3: code points 0xA020..0xFF7F are used
  74      If the member `font_encoder' is not NULL, this member is ignored.
  75   */
  76   unsigned char encoding_type;
  77
  78   /* The baseline position of a font is normally `ascent' value of the
  79      font.  However, there exists many fonts which don't set `ascent'
  80      an appropriate value to be used as baseline position.  This is
  81      typical in such ASCII fonts which are designed to be used with
  82      Chinese, Japanese, Korean characters.  When we use mixture of
  83      such fonts and normal fonts (having correct `ascent' value), a
  84      display line gets very ugly.  Since we have no way to fix it
  85      automatically, it is users responsibility to supply well designed
  86      fonts or correct `ascent' value of fonts.  But, the latter
  87      requires heavy work (modifying all bitmap data in BDF files).
  88      So, Emacs accepts a private font property
  89      `_MULE_BASELINE_OFFSET'.  If a font has this property, we
  90      calculate the baseline position by subtracting the value from
  91      `ascent'.  In other words, the value indicates how many bits
  92      higher we should draw a character of the font than normal ASCII
  93      text for a better looking.
  94
  95      We also have to consider the fact that the concept of `baseline'
  96      differs among languages to which each character belongs.  For
  97      instance, baseline should be at the bottom most position of all
  98      glyphs for Chinese, Japanese, and Korean.  But, many of existing
  99      fonts for those characters doesn't have correct `ascent' values
 100      because they are designed to be used with ASCII fonts.  To
 101      display characters of different language on the same line, the
 102      best way will be to arrange them in the middle of the line.  So,
 103      in such a case, again, we utilize the font property
 104      `_MULE_BASELINE_OFFSET'.  If the value is larger than `ascent' we
 105      calculate baseline so that a character is arranged in the middle
 106      of a line.  */
 107
 108   int baseline_offset;
 109
 110   /* Non zero means a character should be composed at a position
 111      relative to the height (or depth) of previous glyphs in the
 112      following cases:
 113         (1) The bottom of the character is higher than this value.  In
 114         this case, the character is drawn above the previous glyphs.
 115         (2) The top of the character is lower than 0 (i.e. baseline
 116         height).  In this case, the character is drawn beneath the
 117         previous glyphs.
 118
 119      This value is taken from a private font property
 120      `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs.  */
 121   int relative_compose;
 122
 123   /* Non zero means an ascent value to be used for a character
 124      registered in char-table `use-default-ascent'.  */
 125   int default_ascent;
 126
 127   /* CCL program to calculate code points of the font.  */
 128   struct ccl_program *font_encoder;
 129 };
 130
 131 /* A value which may appear in the member `encoding' of struch
 132    font_info indicating that a font itself doesn't tell which encoding
 133    to be used.  */
 134 #define FONT_ENCODING_NOT_DECIDED 255
 135
 136 enum FONT_SPEC_INDEX
 137   {
 138     FONT_SPEC_FAMILY_INDEX,
 139     FONT_SPEC_WEIGHT_INDEX,
 140     FONT_SPEC_SLANT_INDEX,
 141     FONT_SPEC_SWIDTH_INDEX,
 142     FONT_SPEC_ADSTYLE_INDEX,
 143     FONT_SPEC_REGISTRY_INDEX,
 144     FONT_SPEC_MAX_INDEX
 145   };
 146
 147 /* Forward declaration for prototypes.  */
 148 struct frame;
 149
 150 /* The following six are window system dependent functions.
 151    Initialization routine of each window system should set appropriate
 152    functions to these variables.  For instance, in case of X window,
 153    x_term_init does this.  */
 154
 155 /* Return a pointer to struct font_info of font FONT_IDX of frame F.  */
 156 extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
 157                                                     int font_idx));
 158
 159 /* Return a list of font names which matches PATTERN.  See the document of
 160    `x-list-fonts' for more detail.  */
 161 extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
 162                                            Lisp_Object pattern,
 163                                            int size,
 164                                            int maxnames));
 165
 166 /* Load a font named NAME for frame F and return a pointer to the
 167    information of the loaded font.  If loading is failed, return -1.  */
 168 extern struct font_info *(*load_font_func) P_ ((struct frame *f,
 169                                                 char *name, int));
 170
 171 /* Return a pointer to struct font_info of a font named NAME for frame F.
 172    If no such font is loaded, return NULL.  */
 173 extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
 174
 175 /* Additional function for setting fontset or changing fontset
 176    contents of frame F.  This function may change the coordinate of
 177    the frame.  */
 178 extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
 179                                            Lisp_Object oldval));
 180
 181 /* To find a CCL program, fs_load_font calls this function.
 182    The argument is a pointer to the struct font_info.
 183    This function set the memer `encoder' of the structure.  */
 184 extern void (*find_ccl_program_func) P_ ((struct font_info *));
 185
 186 extern Lisp_Object (*get_font_repertory_func) P_ ((struct frame *,
 187                                                    struct font_info *));
 188
 189 /* Check if any window system is used now.  */
 190 extern void (*check_window_system_func) P_ ((void));
 191
 192 struct face;
 193
 194 extern void free_face_fontset P_ ((FRAME_PTR, struct face *));
 195 extern Lisp_Object fontset_font_pattern P_ ((FRAME_PTR, struct face *, int));
 196 extern int face_suitable_for_char_p P_ ((struct face *, int));
 197 extern int face_for_char P_ ((FRAME_PTR, struct face *, int,
 198                               int, Lisp_Object));
 199 extern int make_fontset_for_ascii_face P_ ((FRAME_PTR, int, struct face *));
 200 extern int new_fontset_from_font_name P_ ((Lisp_Object));
 201 extern struct font_info *fs_load_font P_ ((struct frame *, char *, int));
 202 extern int fs_query_fontset P_ ((Lisp_Object, int));
 203 EXFUN (Fquery_fontset, 2);
 204 extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
 205
 206 extern Lisp_Object Vuse_default_ascent;
 207 extern Lisp_Object Vignore_relative_composition;
 208 extern Lisp_Object Valternate_fontname_alist;
 209 extern Lisp_Object Vfontset_alias_alist;
 210 extern Lisp_Object Vvertical_centering_font_regexp;
 211
 212 /* Load a font named FONTNAME on frame F.  All fonts for frame F is
 213    stored in a table pointed by FONT_TABLE.  Return a pointer to the
 214    struct font_info of the loaded font.  If loading fails, return
 215    NULL.  */
 216
 217 #define FS_LOAD_FONT(f, fontname) fs_load_font (f, fontname, -1)
 218
 219
 220 /* Return an immutable id for font_info FONT_INFO on frame F.  The
 221    reason for this macro is hat one cannot hold pointers to font_info
 222    structures in other data structures, because the table is
 223    reallocated in x_list_fonts.  */
 224
 225 #define FONT_INFO_ID(F, FONT_INFO) \
 226      (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
 227
 228 /* Given a font_info id ID, return a pointer to the font_info
 229    structure on frame F.  If ID is invalid, return null.  */
 230
 231 #define FONT_INFO_FROM_ID(F, ID)                                        \
 232      (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size) \
 233       ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID))                 \
 234       : 0)
 235
 236 extern Lisp_Object fontset_name P_ ((int));
 237 extern Lisp_Object fontset_ascii P_ ((int));
 238 extern int fontset_height P_ ((int));
 239
 240 #endif /* EMACS_FONTSET_H */
 241
 242 /* arch-tag: c27cef7b-3cab-488a-8398-7a4daa96bb77
 243    (do not change this comment) */