1 /* Header for fontset handler.
2 Copyright (C) 1995, 1997 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)
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. */
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). */
30 /* Pointer to window system dependent font structure. On X window,
31 this value should be coerced to (XFontStruct *). */
34 /* Index number of the font. */
37 /* Name to be used to find the font. */
40 /* Full name of the font given by a window system. */
43 /* Charset of characters displayed by the font. */
46 /* Maximum bound width over all existing characters of the font. On
47 X window, this is same as (font->max_bounds.width) */
50 /* Height of the font. On X window, this is same as (font->ascent
54 /* Encodings of the font indexed by CHARSET. The value an integer
56 0: code points 0x20..0x7F or 0x2020..0x7F7F are used
57 1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
58 2: code points 0x20A0..0x7FFF are used
59 3: code points 0xA020..0xFF7F are used
60 For instance, ASCII and Latin-1 characters may use the same font
61 but different code points (ASCII uses 0x20..0x7F and Latin-1 uses
64 If the value can't be decided from information of the font, we
65 consult `font-encoding-alist' to get of the corresponding charset
66 whose default value is defined in lisp/fontset.el. Since there's
67 no charset whose id is 1, we use encoding[1] to store the
68 encoding information decided by the font itself. */
69 unsigned char encoding
[MAX_CHARSET
+ 1];
71 /* The baseline position of a font is normally `ascent' value of the
72 font. However, there exists many fonts which don't set `ascent'
73 an appropriate value to be used as baseline position. This is
74 typical in such ASCII fonts which are designed to be used with
75 Chinese, Japanese, Korean characters. When we use mixture of
76 such fonts and normal fonts (having correct `ascent' value), a
77 display line gets very ugly. Since we have no way to fix it
78 automatically, it is users responsibility to supply well designed
79 fonts or correct `ascent' value of fonts. But, the latter
80 requires heavy work (modifying all bitmap data in BDF files).
81 So, Emacs accepts a private font property
82 `_MULE_BASELINE_OFFSET'. If a font has this property, we
83 calculate the baseline position by subtracting the value from
84 `ascent'. In other words, the value indicates how many bits
85 higher we should draw a character of the font than normal ASCII
86 text for a better looking.
88 We also have to consider the fact that the concept of `baseline'
89 differs among languages to which each character belongs. For
90 instance, baseline should be at the bottom most position of all
91 glyphs for Chinese, Japanese, and Korean. But, many of existing
92 fonts for those characters doesn't have correct `ascent' values
93 because they are designed to be used with ASCII fonts. To
94 display characters of different language on the same line, the
95 best way will be to arrange them in the middle of the line. So,
96 in such a case, again, we utilize the font property
97 `_MULE_BASELINE_OFFSET'. If the value is larger than `ascent' we
98 calculate baseline so that a character is arranged in the middle
103 /* Non zero means a character should be composed at a position
104 relative to the height (or depth) of previous glyphs in the
106 (1) The bottom of the character is higher than this value. In
107 this case, the character is drawn above the previous glyphs.
108 (2) The top of the character is lower than 0 (i.e. baseline
109 height). In this case, the character is drawn beneath the
112 This value is taken from a private font property
113 `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs. */
114 int relative_compose
;
116 /* Non zero means an ascent value to be used for a character
117 registered in char-table `use-default-ascent'. */
120 /* CCL program to calculate code points of the font. */
121 struct ccl_program
*font_encoder
;
124 /* A value which may appear in the member encoding of struch font_info
125 indicating that a font itself doesn't tell which encoding to be
127 #define FONT_ENCODING_NOT_DECIDED 4
129 #define FONT_NOT_OPENED -1
130 #define FONT_NOT_FOUND -2
134 /* Name of the fontset. */
137 /* Size of the fontset. This is the same as the size of ASCII font
141 /* Height of the tallest font in the fontset. */
144 /* Table of font name for each character set. */
145 char *fontname
[MAX_CHARSET
+ 1];
147 /* Table of index numbers of fonts indexed by charset. If a font is
148 not yet loaded, the value is -1 (FONT_NOT_OPENED). If font
149 loading is failed, the value is -2 (FONT_NOT_FOUND). */
150 int font_indexes
[MAX_CHARSET
+ 1];
153 /* This data type is used for the fontset_data field of struct frame. */
157 /* A table of pointers to all the fontsets. */
158 struct fontset_info
**fontset_table
;
160 /* The current capacity of fontset_table. */
161 int fontset_table_size
;
163 /* The number of fontsets actually stored in fontset_table.
164 fontset_table[n] is used and valid iff 0 <= n < n_fontsets.
165 0 <= n_fontsets <= fontset_table_size. */
169 /* Forward declaration for prototypes. */
172 /* The following six are window system dependent functions.
173 Initialization routine of each window system should set appropriate
174 functions to these variables. For instance, in case of X window,
175 x_term_init does this. */
177 /* Return a pointer to struct font_info of font FONT_IDX of frame F. */
178 extern struct font_info
*(*get_font_info_func
) P_ ((struct frame
*f
,
181 /* Return a list of font names which matches PATTERN. See the document of
182 `x-list-fonts' for more detail. */
183 extern Lisp_Object (*list_fonts_func
) P_ ((Lisp_Object pattern
,
188 /* Load a font named NAME for frame F and return a pointer to the
189 information of the loaded font. If loading is failed, return -1. */
190 extern struct font_info
*(*load_font_func
) P_ ((struct frame
*f
,
193 /* Return a pointer to struct font_info of a font named NAME for frame F.
194 If no such font is loaded, return NULL. */
195 extern struct font_info
*(*query_font_func
) P_ ((struct frame
*f
, char *name
));
197 /* Additional function for setting fontset or changing fontset
198 contents of frame F. This function may change the coordinate of
200 extern void (*set_frame_fontset_func
) P_ ((struct frame
*f
, Lisp_Object arg
,
201 Lisp_Object oldval
));
203 /* Check if any window system is used now. */
204 extern void (*check_window_system_func
) P_ ((void));
206 extern struct fontset_data
*alloc_fontset_data
P_ ((void));
207 extern void free_fontset_data
P_ ((struct fontset_data
*));
208 extern struct font_info
*fs_load_font
P_ ((struct frame
*, struct font_info
*,
210 extern int fs_query_fontset
P_ ((struct frame
*, char *));
211 extern int fs_register_fontset
P_ ((struct frame
*, Lisp_Object
));
212 EXFUN (Fquery_fontset
, 1);
213 extern Lisp_Object list_fontsets
P_ ((struct frame
*, Lisp_Object
, int));
214 extern Lisp_Object Vglobal_fontset_alist
;
216 extern Lisp_Object Qfontset
;
217 extern Lisp_Object Vuse_default_ascent
;
218 extern Lisp_Object Vignore_relative_composition
;
219 extern Lisp_Object Valternate_fontname_alist
;
220 extern Lisp_Object Vhighlight_wrong_size_font
;
221 extern Lisp_Object Vclip_large_size_font
;
223 extern int font_idx_temp
;
225 /* Load a font named FONTNAME for displaying CHARSET on frame F.
226 All fonts for frame F is stored in a table pointed by FONT_TABLE.
227 Return a pointer to the struct font_info of the loaded font.
228 If loading fails, return 0;
229 If FONTNAME is NULL, the name is taken from the information of FONTSET.
230 If FONTSET is given, try to load a font whose size matches that of
231 FONTSET, and, the font index is stored in the table for FONTSET. */
233 #define FS_LOAD_FONT(f, font_table, charset, fontname, fontset) \
234 (fontset >= 0 && fontset < FRAME_FONTSET_DATA (f)->n_fontsets \
235 && (font_idx_temp = (FRAME_FONTSET_DATA (f) \
236 ->fontset_table[fontset]->font_indexes[charset]), \
237 font_idx_temp >= 0) \
238 ? font_table + font_idx_temp \
239 : fs_load_font (f, font_table, charset, fontname, fontset))
241 #endif /* _FONTSET_H */