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[emacs.git] / src / fontset.h
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1 /* Header for fontset handler.
2 Copyright (C) 1995, 1997, 2000 Electrotechnical Laboratory, JAPAN.
3 Licensed to the Free Software Foundation.
5 This file is part of GNU Emacs.
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.
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.
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. */
22 #ifndef EMACS_FONTSET_H
23 #define EMACS_FONTSET_H
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). */
28 struct font_info
30 /* Pointer to window system dependent font structure. On X window,
31 this value should be coerced to (XFontStruct *). */
32 void *font;
34 /* Index number of the font. */
35 int font_idx;
37 /* Name to be used to find the font. */
38 char *name;
40 /* Full name of the font given by a window system. */
41 char *full_name;
43 /* Charset of characters displayed by the font. */
44 int charset;
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;
50 /* Height of the font. On X window, this is the same as
51 (font->ascent + font->descent). */
52 int height;
54 /* 1 iff `vertical-centering-font-regexp' matches this font name.
55 In this case, we render characters at vartical center positions
56 of lines. */
57 int vertical_centering;
59 /* Encodings of the font indexed by CHARSET. The value is one of
60 0, 1, 2, or 3:
61 0: code points 0x20..0x7F or 0x2020..0x7F7F are used
62 1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
63 2: code points 0x20A0..0x7FFF are used
64 3: code points 0xA020..0xFF7F are used
65 For instance, ASCII and Latin-1 characters may use the same font
66 but different code points (ASCII uses 0x20..0x7F and Latin-1 uses
67 0xA0..0xFF).
69 If the value can't be decided from information of the font, we
70 consult `font-encoding-alist' to get of the corresponding charset
71 whose default value is defined in lisp/fontset.el. Since there's
72 no charset whose id is 1, we use encoding[1] to store the
73 encoding information decided by the font itself.
75 If the member `font_encoder' is not NULL, this member is ignored.
77 unsigned char encoding[MAX_CHARSET + 1];
79 /* The baseline position of a font is normally `ascent' value of the
80 font. However, there exists many fonts which don't set `ascent'
81 an appropriate value to be used as baseline position. This is
82 typical in such ASCII fonts which are designed to be used with
83 Chinese, Japanese, Korean characters. When we use mixture of
84 such fonts and normal fonts (having correct `ascent' value), a
85 display line gets very ugly. Since we have no way to fix it
86 automatically, it is users responsibility to supply well designed
87 fonts or correct `ascent' value of fonts. But, the latter
88 requires heavy work (modifying all bitmap data in BDF files).
89 So, Emacs accepts a private font property
90 `_MULE_BASELINE_OFFSET'. If a font has this property, we
91 calculate the baseline position by subtracting the value from
92 `ascent'. In other words, the value indicates how many bits
93 higher we should draw a character of the font than normal ASCII
94 text for a better looking.
96 We also have to consider the fact that the concept of `baseline'
97 differs among languages to which each character belongs. For
98 instance, baseline should be at the bottom most position of all
99 glyphs for Chinese, Japanese, and Korean. But, many of existing
100 fonts for those characters doesn't have correct `ascent' values
101 because they are designed to be used with ASCII fonts. To
102 display characters of different language on the same line, the
103 best way will be to arrange them in the middle of the line. So,
104 in such a case, again, we utilize the font property
105 `_MULE_BASELINE_OFFSET'. If the value is larger than `ascent' we
106 calculate baseline so that a character is arranged in the middle
107 of a line. */
109 int baseline_offset;
111 /* Non zero means a character should be composed at a position
112 relative to the height (or depth) of previous glyphs in the
113 following cases:
114 (1) The bottom of the character is higher than this value. In
115 this case, the character is drawn above the previous glyphs.
116 (2) The top of the character is lower than 0 (i.e. baseline
117 height). In this case, the character is drawn beneath the
118 previous glyphs.
120 This value is taken from a private font property
121 `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs. */
122 int relative_compose;
124 /* Non zero means an ascent value to be used for a character
125 registered in char-table `use-default-ascent'. */
126 int default_ascent;
128 /* CCL program to calculate code points of the font. */
129 struct ccl_program *font_encoder;
132 /* A value which may appear in the member `encoding' of struch
133 font_info indicating that a font itself doesn't tell which encoding
134 to be used. */
135 #define FONT_ENCODING_NOT_DECIDED 255
137 /* Forward declaration for prototypes. */
138 struct frame;
140 /* The following six are window system dependent functions.
141 Initialization routine of each window system should set appropriate
142 functions to these variables. For instance, in case of X window,
143 x_term_init does this. */
145 /* Return a pointer to struct font_info of font FONT_IDX of frame F. */
146 extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
147 int font_idx));
149 /* Return a list of font names which matches PATTERN. See the document of
150 `x-list-fonts' for more detail. */
151 extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
152 Lisp_Object pattern,
153 int size,
154 int maxnames));
156 /* Load a font named NAME for frame F and return a pointer to the
157 information of the loaded font. If loading is failed, return -1. */
158 extern struct font_info *(*load_font_func) P_ ((struct frame *f,
159 char *name, int));
161 /* Return a pointer to struct font_info of a font named NAME for frame F.
162 If no such font is loaded, return NULL. */
163 extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
165 /* Additional function for setting fontset or changing fontset
166 contents of frame F. This function may change the coordinate of
167 the frame. */
168 extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
169 Lisp_Object oldval));
171 /* To find a CCL program, fs_load_font calls this function.
172 The argument is a pointer to the struct font_info.
173 This function set the memer `encoder' of the structure. */
174 extern void (*find_ccl_program_func) P_ ((struct font_info *));
176 /* Check if any window system is used now. */
177 extern void (*check_window_system_func) P_ ((void));
179 struct face;
181 extern void free_face_fontset P_ ((FRAME_PTR, struct face *));
182 extern Lisp_Object fontset_font_pattern P_ ((FRAME_PTR, int, int));
183 extern int face_suitable_for_char_p P_ ((struct face *, int));
184 extern int face_for_char P_ ((FRAME_PTR, struct face *, int));
185 extern int make_fontset_for_ascii_face P_ ((FRAME_PTR, int));
186 extern struct font_info *fs_load_font P_ ((struct frame *, int, char *, int,
187 struct face *));
188 extern int fs_query_fontset P_ ((Lisp_Object, int));
189 EXFUN (Fquery_fontset, 2);
190 extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
192 extern Lisp_Object Qfontset;
193 extern Lisp_Object Vuse_default_ascent;
194 extern Lisp_Object Vignore_relative_composition;
195 extern Lisp_Object Valternate_fontname_alist;
196 extern Lisp_Object Vfontset_alias_alist;
197 extern Lisp_Object Vhighlight_wrong_size_font;
198 extern Lisp_Object Vclip_large_size_font;
199 extern Lisp_Object Vvertical_centering_font_regexp;
201 /* Load a font named FONTNAME for displaying character C. All fonts
202 for frame F is stored in a table pointed by FONT_TABLE. Return a
203 pointer to the struct font_info of the loaded font. If loading
204 fails, return 0; If FONTNAME is NULL, the name is taken from the
205 information of FONTSET. If FONTSET is given, try to load a font
206 whose size matches that of FONTSET, and, the font index is stored
207 in the table for FONTSET. */
209 #define FS_LOAD_FONT(f, c, fontname, fontset) \
210 fs_load_font (f, c, fontname, fontset, NULL)
212 #define FS_LOAD_FACE_FONT(f, c, fontname, face) \
213 fs_load_font (f, c, fontname, -1, face)
215 /* Return an immutable id for font_info FONT_INFO on frame F. The
216 reason for this macro is hat one cannot hold pointers to font_info
217 structures in other data structures, because the table is
218 reallocated in x_list_fonts. */
220 #define FONT_INFO_ID(F, FONT_INFO) \
221 (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
223 /* Given a font_info id ID, return a pointer to the font_info
224 structure on frame F. If ID is invalid, return null. */
226 #define FONT_INFO_FROM_ID(F, ID) \
227 (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size) \
228 ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID)) \
229 : 0)
231 extern Lisp_Object fontset_name P_ ((int));
232 extern Lisp_Object fontset_ascii P_ ((int));
233 extern int fontset_height P_ ((int));
235 #endif /* EMACS_FONTSET_H */