1/* Header for fontset handler.
2   Copyright (C) 1998, 2001, 2002, 2003, 2004, 2005,
3                 2006, 2007  Free Software Foundation, Inc.
4   Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
5     2005, 2006, 2007
6     National Institute of Advanced Industrial Science and Technology (AIST)
7     Registration Number H14PRO021
8
9This file is part of GNU Emacs.
10
11GNU Emacs is free software; you can redistribute it and/or modify
12it under the terms of the GNU General Public License as published by
13the Free Software Foundation; either version 2, or (at your option)
14any later version.
15
16GNU Emacs is distributed in the hope that it will be useful,
17but WITHOUT ANY WARRANTY; without even the implied warranty of
18MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19GNU General Public License for more details.
20
21You should have received a copy of the GNU General Public License
22along with GNU Emacs; see the file COPYING.  If not, write to
23the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
24Boston, 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
32struct 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 of characters displayed by the 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  /* Width of the space glyph of the font.  */
64  int space_width;
65
66  /* Average width of glyphs in the font.  */
67  int average_width;
68
69  /* 1 iff `vertical-centering-font-regexp' matches this font name.
70     In this case, we render characters at vartical center positions
71     of lines.  */
72  int vertical_centering;
73
74  /* Encodings of the font indexed by CHARSET.  The value is one of
75     0, 1, 2, or 3:
76	0: code points 0x20..0x7F or 0x2020..0x7F7F are used
77	1: code points 0xA0..0xFF or 0xA0A0..0xFFFF are used
78	2: code points 0x20A0..0x7FFF are used
79	3: code points 0xA020..0xFF7F are used
80     For instance, ASCII and Latin-1 characters may use the same font
81     but different code points (ASCII uses 0x20..0x7F and Latin-1 uses
82     0xA0..0xFF).
83
84     If the value can't be decided from information of the font, we
85     consult `font-encoding-alist' to get of the corresponding charset
86     whose default value is defined in lisp/fontset.el.  Since there's
87     no charset whose id is 1, we use encoding[1] to store the
88     encoding information decided by the font itself.
89
90     If the member `font_encoder' is not NULL, this member is ignored.
91  */
92  unsigned char encoding[MAX_CHARSET + 1];
93
94  /* The baseline position of a font is normally `ascent' value of the
95     font.  However, there exists many fonts which don't set `ascent'
96     an appropriate value to be used as baseline position.  This is
97     typical in such ASCII fonts which are designed to be used with
98     Chinese, Japanese, Korean characters.  When we use mixture of
99     such fonts and normal fonts (having correct `ascent' value), a
100     display line gets very ugly.  Since we have no way to fix it
101     automatically, it is users responsibility to supply well designed
102     fonts or correct `ascent' value of fonts.  But, the latter
103     requires heavy work (modifying all bitmap data in BDF files).
104     So, Emacs accepts a private font property
105     `_MULE_BASELINE_OFFSET'.  If a font has this property, we
106     calculate the baseline position by subtracting the value from
107     `ascent'.  In other words, the value indicates how many bits
108     higher we should draw a character of the font than normal ASCII
109     text for a better looking.
110
111     We also have to consider the fact that the concept of `baseline'
112     differs among languages to which each character belongs.  For
113     instance, baseline should be at the bottom most position of all
114     glyphs for Chinese, Japanese, and Korean.  But, many of existing
115     fonts for those characters doesn't have correct `ascent' values
116     because they are designed to be used with ASCII fonts.  To
117     display characters of different language on the same line, the
118     best way will be to arrange them in the middle of the line.  So,
119     in such a case, again, we utilize the font property
120     `_MULE_BASELINE_OFFSET'.  If the value is larger than `ascent' we
121     calculate baseline so that a character is arranged in the middle
122     of a line.  */
123
124  int baseline_offset;
125
126  /* Non zero means a character should be composed at a position
127     relative to the height (or depth) of previous glyphs in the
128     following cases:
129	(1) The bottom of the character is higher than this value.  In
130	this case, the character is drawn above the previous glyphs.
131	(2) The top of the character is lower than 0 (i.e. baseline
132	height).  In this case, the character is drawn beneath the
133	previous glyphs.
134
135     This value is taken from a private font property
136     `_MULE_RELATIVE_COMPOSE' which is introduced by Emacs.  */
137  int relative_compose;
138
139  /* Non zero means an ascent value to be used for a character
140     registered in char-table `use-default-ascent'.  */
141  int default_ascent;
142
143  /* CCL program to calculate code points of the font.  */
144  struct ccl_program *font_encoder;
145};
146
147/* A value which may appear in the member `encoding' of struch
148   font_info indicating that a font itself doesn't tell which encoding
149   to be used.  */
150#define FONT_ENCODING_NOT_DECIDED 255
151
152/* Forward declaration for prototypes.  */
153struct frame;
154
155/* The following six are window system dependent functions.
156   Initialization routine of each window system should set appropriate
157   functions to these variables.  For instance, in case of X window,
158   x_term_init does this.  */
159
160/* Return a pointer to struct font_info of font FONT_IDX of frame F.  */
161extern struct font_info *(*get_font_info_func) P_ ((struct frame *f,
162						    int font_idx));
163
164/* Return a list of font names which matches PATTERN.  See the document of
165   `x-list-fonts' for more detail.  */
166extern Lisp_Object (*list_fonts_func) P_ ((struct frame *f,
167					   Lisp_Object pattern,
168					   int size,
169					   int maxnames));
170
171/* Load a font named NAME for frame F and return a pointer to the
172   information of the loaded font.  If loading is failed, return -1.  */
173extern struct font_info *(*load_font_func) P_ ((struct frame *f,
174						char *name, int));
175
176/* Return a pointer to struct font_info of a font named NAME for frame F.
177   If no such font is loaded, return NULL.  */
178extern struct font_info *(*query_font_func) P_ ((struct frame *f, char *name));
179
180/* Additional function for setting fontset or changing fontset
181   contents of frame F.  This function may change the coordinate of
182   the frame.  */
183extern void (*set_frame_fontset_func) P_ ((struct frame *f, Lisp_Object arg,
184					   Lisp_Object oldval));
185
186/* To find a CCL program, fs_load_font calls this function.
187   The argument is a pointer to the struct font_info.
188   This function set the memer `encoder' of the structure.  */
189extern void (*find_ccl_program_func) P_ ((struct font_info *));
190
191/* Check if any window system is used now.  */
192extern void (*check_window_system_func) P_ ((void));
193
194struct face;
195
196extern void free_face_fontset P_ ((FRAME_PTR, struct face *));
197extern Lisp_Object fontset_font_pattern P_ ((FRAME_PTR, int, int));
198extern int face_suitable_for_char_p P_ ((struct face *, int));
199extern int face_for_char P_ ((FRAME_PTR, struct face *, int));
200extern int make_fontset_for_ascii_face P_ ((FRAME_PTR, int));
201extern void set_default_ascii_font P_ ((Lisp_Object));
202extern struct font_info *fs_load_font P_ ((struct frame *, int, char *, int,
203					   struct face *));
204extern int fs_query_fontset P_ ((Lisp_Object, int));
205EXFUN (Fquery_fontset, 2);
206extern Lisp_Object list_fontsets P_ ((struct frame *, Lisp_Object, int));
207
208extern Lisp_Object Qfontset;
209extern Lisp_Object Vuse_default_ascent;
210extern Lisp_Object Vignore_relative_composition;
211extern Lisp_Object Valternate_fontname_alist;
212extern Lisp_Object Vfontset_alias_alist;
213extern Lisp_Object Vvertical_centering_font_regexp;
214
215/* Load a font named FONTNAME for displaying character C.  All fonts
216   for frame F is stored in a table pointed by FONT_TABLE.  Return a
217   pointer to the struct font_info of the loaded font.  If loading
218   fails, return 0; If FONTNAME is NULL, the name is taken from the
219   information of FONTSET.  If FONTSET is given, try to load a font
220   whose size matches that of FONTSET, and, the font index is stored
221   in the table for FONTSET.  */
222
223#define FS_LOAD_FONT(f, c, fontname, fontset)  \
224  fs_load_font (f, c, fontname, fontset, NULL)
225
226#define FS_LOAD_FACE_FONT(f, c, fontname, face) \
227  fs_load_font (f, c, fontname, -1, face)
228
229/* Return an immutable id for font_info FONT_INFO on frame F.  The
230   reason for this macro is hat one cannot hold pointers to font_info
231   structures in other data structures, because the table is
232   reallocated in x_list_fonts.  */
233
234#define FONT_INFO_ID(F, FONT_INFO) \
235     (FONT_INFO) - (FRAME_X_DISPLAY_INFO ((F))->font_table)
236
237/* Given a font_info id ID, return a pointer to the font_info
238   structure on frame F.  If ID is invalid, return null.  */
239
240#define FONT_INFO_FROM_ID(F, ID)					\
241     (((ID) >= 0 && (ID) < FRAME_X_DISPLAY_INFO ((F))->font_table_size)	\
242      ? (FRAME_X_DISPLAY_INFO ((F))->font_table + (ID))			\
243      : 0)
244
245extern Lisp_Object fontset_name P_ ((int));
246extern Lisp_Object fontset_ascii P_ ((int));
247extern int fontset_height P_ ((int));
248
249#endif /* EMACS_FONTSET_H */
250
251/* arch-tag: c27cef7b-3cab-488a-8398-7a4daa96bb77
252   (do not change this comment) */
253