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