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1/*
2 * font.h -- `Soft' font definitions
3 *
4 * Created 1995 by Geert Uytterhoeven
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11#ifndef _VIDEO_FONT_H
12#define _VIDEO_FONT_H
13
14#include <linux/math.h>
15#include <linux/types.h>
16
17struct console_font;
18
19/*
20 * Glyphs
21 */
22
23/**
24 * font_glyph_pitch - Calculates the number of bytes per scanline
25 * @width: The glyph width in bits per scanline
26 *
27 * A glyph's pitch is the number of bytes in a single scanline, rounded
28 * up to the next full byte. The parameter @width receives the number
29 * of visible bits per scanline. For example, if width is 14 bytes per
30 * scanline, the pitch is 2 bytes per scanline. If width is 8 bits per
31 * scanline, the pitch is 1 byte per scanline.
32 *
33 * Returns:
34 * The number of bytes in a single scanline of the glyph
35 */
36static inline unsigned int font_glyph_pitch(unsigned int width)
37{
38 return DIV_ROUND_UP(width, 8);
39}
40
41/**
42 * font_glyph_size - Calculates the number of bytes per glyph
43 * @width: The glyph width in bits per scanline
44 * @vpitch: The number of scanlines in the glyph
45 *
46 * The number of bytes in a glyph depends on the pitch and the number
47 * of scanlines. font_glyph_size automatically calculates the pitch
48 * from the given width. The parameter @vpitch gives the number of
49 * scanlines, which is usually the glyph's height in scanlines. Fonts
50 * coming from user space can sometimes have a different vertical pitch
51 * with empty scanlines between two adjacent glyphs.
52 */
53static inline unsigned int font_glyph_size(unsigned int width, unsigned int vpitch)
54{
55 return font_glyph_pitch(width) * vpitch;
56}
57
58/*
59 * font_data_t and helpers
60 */
61
62/**
63 * font_data_t - Raw font data
64 *
65 * Values of type font_data_t store a pointer to raw font data. The format
66 * is monochrome. Each bit sets a pixel of a stored glyph. Font data does
67 * not store geometry information for the individual glyphs. Users of the
68 * font have to store glyph size, pitch and character count separately.
69 *
70 * Font data in font_data_t is not equivalent to raw u8. Each pointer stores
71 * an additional hidden header before the font data. The layout is
72 *
73 * +------+-----------------------------+
74 * | -16 | CRC32 Checksum (optional) |
75 * | -12 | <Unused> |
76 * | -8 | Number of data bytes |
77 * | -4 | Reference count |
78 * +------+-----------------------------+
79 * | 0 | Data buffer |
80 * | ... | |
81 * +------+-----------------------------+
82 *
83 * Use helpers to access font_data_t. Use font_data_buf() to get the stored data.
84 */
85typedef const unsigned char font_data_t;
86
87/**
88 * font_data_buf() - Returns the font data as raw bytes
89 * @fd: The font data
90 *
91 * Returns:
92 * The raw font data. The provided buffer is read-only.
93 */
94static inline const unsigned char *font_data_buf(font_data_t *fd)
95{
96 return (const unsigned char *)fd;
97}
98
99font_data_t *font_data_import(const struct console_font *font, unsigned int vpitch,
100 u32 (*calc_csum)(u32, const void *, size_t));
101void font_data_get(font_data_t *fd);
102bool font_data_put(font_data_t *fd);
103unsigned int font_data_size(font_data_t *fd);
104bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs);
105int font_data_export(font_data_t *fd, struct console_font *font, unsigned int vpitch);
106
107/* font_rotate.c */
108void font_glyph_rotate_90(const unsigned char *glyph, unsigned int width, unsigned int height,
109 unsigned char *out);
110void font_glyph_rotate_180(const unsigned char *glyph, unsigned int width, unsigned int height,
111 unsigned char *out);
112void font_glyph_rotate_270(const unsigned char *glyph, unsigned int width, unsigned int height,
113 unsigned char *out);
114unsigned char *font_data_rotate(font_data_t *fd, unsigned int width, unsigned int height,
115 unsigned int charcount, unsigned int steps,
116 unsigned char *buf, size_t *bufsize);
117
118/*
119 * Font description
120 */
121
122struct font_desc {
123 int idx;
124 const char *name;
125 unsigned int width, height;
126 unsigned int charcount;
127 font_data_t *data;
128 int pref;
129};
130
131/* Find a font with a specific name */
132
133extern const struct font_desc *find_font(const char *name);
134
135/* Get the default font for a specific screen size */
136
137extern const struct font_desc *get_default_font(int xres, int yres,
138 unsigned long *font_w,
139 unsigned long *font_h);
140
141/* Max. length for the name of a predefined font */
142#define MAX_FONT_NAME 32
143
144/*
145 * Built-in fonts
146 */
147
148extern const struct font_desc font_10x18;
149extern const struct font_desc font_6x10;
150extern const struct font_desc font_6x8;
151extern const struct font_desc font_7x14;
152extern const struct font_desc font_acorn_8x8;
153extern const struct font_desc font_mini_4x6;
154extern const struct font_desc font_pearl_8x8;
155extern const struct font_desc font_sun_12x22;
156extern const struct font_desc font_sun_8x16;
157extern const struct font_desc font_ter_10x18;
158extern const struct font_desc font_ter_16x32;
159extern const struct font_desc font_vga_6x11;
160extern const struct font_desc font_vga_8x16;
161extern const struct font_desc font_vga_8x8;
162
163#endif /* _VIDEO_FONT_H */