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Diffstat (limited to 'include/font.h')
| -rw-r--r-- | include/font.h | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/include/font.h b/include/font.h new file mode 100644 index 0000000..886b3ce --- /dev/null +++ b/include/font.h @@ -0,0 +1,243 @@ +/* font.h: operations on fonts independent of a particular file format. + +Copyright (C) 1992 Free Software Foundation, Inc. + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ + +#ifndef FONT_LIBRARY_H +#define FONT_LIBRARY_H + +#include "bitmap.h" +#include "bounding-box.h" +#include "tfm.h" +#include <kpathsea/types.h> + + + +/* A font is a collection of characters, generally at a particular point + size and resolution. The `bitmap_font_type' structure holds + information that comes entirely from a bitmap file. */ +typedef struct +{ + real design_size; + string comment; + unsigned checksum; + string filename; +} bitmap_font_type; + +/* The design size is given in points. It is not necessarily + related to the actual dimensions of any of the characters in the + font; indeed, usually the design size is quite a bit larger than the + largest characters. */ +#define BITMAP_FONT_DESIGN_SIZE(f) ((f).design_size) + +/* Sometimes a font comes with a comment identifying its source, who + owns the trademark, or some such. */ +#define BITMAP_FONT_COMMENT(f) ((f).comment) + +/* The checksum found in the bitmap file. */ +#define BITMAP_FONT_CHECKSUM(f) ((f).checksum) + +/* The full pathname for the file that we opened. */ +#define BITMAP_FONT_FILENAME(f) ((f).filename) + + +/* Look for a font named FONT_NAME in PK or GF format, at resolution + DPI. This ignores any extension in FONT_NAME; it adds `.<dpi>gf' or + `.<dpi>pk'. The font is looked for using the PKFONTS, GFFONTS, and + TEXFONTS environment variables, just as with the TeX software. If + the font can't be found, this gives a fatal error. */ +extern bitmap_font_type get_bitmap_font (string font_name, unsigned dpi); + +/* `close_font', below, works for bitmap fonts, too. */ + +/* The `font_info_type' holds a `bitmap_font_type', and additional + information that we get from a font metric file. */ +typedef struct +{ + bitmap_font_type bitmap_font; + tfm_global_info_type tfm_font; + string tfm_filename; +} font_info_type; + +/* The bitmap information that is associated with this font. */ +#define FONT_BITMAP_FONT(f) ((f).bitmap_font) + +/* The TFM information. */ +#define FONT_TFM_FONT(f) ((f).tfm_font) + +/* The full pathname for the TFM file that we opened. */ +#define FONT_TFM_FILENAME(f) ((f).tfm_filename) + +/* The design size is given in points. It is not necessarily + related to the actual dimensions of any of the characters in the + font; indeed, usually the design size is quite a bit larger than the + largest characters. */ +#define FONT_DESIGN_SIZE(f) BITMAP_FONT_DESIGN_SIZE ((f).bitmap_font) + +/* Sometimes a font comes with a comment identifying its source, who + owns the trademark, or some such. */ +#define FONT_COMMENT(f) BITMAP_FONT_COMMENT ((f).bitmap_font) + + +/* This calls `get_bitmap_font'; in addition, it looks for FONT_NAME in + TFM format. If either the bitmap file or the metric file can't be + found, this gives a fatal error. */ +extern font_info_type get_font (string font_name, unsigned dpi); + +/* Close any open files associated with FONT_NAME, whether it was opened + with `get_bitmap_font' or `get_font'. */ +extern void close_font (string font_name); + +/* A character is a bitmap image, and is therefore at a particular size + and resolution. It is also at a particular position in a font. + Generally, characters also have `side bearings'---extra space at the + left and/or right of the character. (In some scripts, there is + also displacement above and/or below the character, but we don't take + that into account here.) */ + +typedef struct +{ + charcode_type code; + int set_width; + fix_word tfm_width; + bounding_box_type bb; + bitmap_type bitmap; +} char_info_type; + +/* The character code in our fonts is always between 0 and 255. */ +#define CHARCODE(c) ((c).code) + +/* The set width is given in pixels; it's the sum of the left side + bearing, the bitmap's width, and the right side bearing. */ +#define CHAR_SET_WIDTH(c) ((c).set_width) + +/* The TFM width is the character's true width divided by the design + size (expressed as a fix_word). */ +#define CHAR_TFM_WIDTH(c) ((c).tfm_width) + +/* Unlike the font's bounding box, the character bounding box is + guaranteed to be the tightest possible; i.e., no all-blank rows occur + at the top or bottom, and no all-blank columns occur at the left or + right. */ +#define CHAR_BB(c) ((c).bb) + +/* The pixels. See `bitmap.h'. */ +#define CHAR_BITMAP(c) ((c).bitmap) + + +/* Abbreviations for the width and height of a character's bitmap. */ +#define CHAR_BITMAP_WIDTH(c) BITMAP_WIDTH (CHAR_BITMAP (c)) +#define CHAR_BITMAP_HEIGHT(c) BITMAP_HEIGHT (CHAR_BITMAP (c)) + +/* Abbreviations for the parts of the character's bounding box. */ +#define CHAR_MIN_COL(c) MIN_COL (CHAR_BB (c)) +#define CHAR_MAX_COL(c) MAX_COL (CHAR_BB (c)) +#define CHAR_MIN_ROW(c) MIN_ROW (CHAR_BB (c)) +#define CHAR_MAX_ROW(c) MAX_ROW (CHAR_BB (c)) + + +/* The height of a character is how far it extends above the baseline. */ +#define CHAR_HEIGHT(c) (CHAR_MAX_ROW (c) >= 0 ? CHAR_MAX_ROW (c) : 0) + +/* The depth is far it extends below the baseline (but as a positive + number, e.g., if a character's bitmap goes down to row -4, the depth + is 4). */ +#define CHAR_DEPTH(c) (CHAR_MIN_ROW (c) < 0 ? -CHAR_MIN_ROW (c) : 0) + + +/* Abbreviations for the left and right side bearings, unless someone + else has already defined such macros (in which case they presumably + don't want ours). */ +#ifndef CHAR_LSB +#define CHAR_LSB CHAR_MIN_COL +#endif +#ifndef CHAR_RSB +#define CHAR_RSB(c) (CHAR_SET_WIDTH (c) - CHAR_MAX_COL (c)) +#endif + +/* Return the character numbered CODE in the font FONT_NAME, or NULL if + that character doesn't exist in that font. If `get_font' or + `get_bitmap_font' has not been previously called on FONT_NAME, + `get_char' gives a fatal error. */ +extern char_info_type *get_char (string font_name, charcode_type code); + + +/* Print a plain text representation of the character C to the file F. */ +extern void print_char (FILE *f, char_info_type c); + + +/* Typeset the TEXT in the font FONT_NAME, at a resolution of DPI. */ +extern bitmap_type string_to_bitmap (string text, + string font_name, unsigned dpi); + +/* A raw character is the byte string that defines the character in the + font file, in some format. */ + +typedef enum { pk_format, gf_format } bitmap_format_type; + +typedef struct +{ + bitmap_format_type bitmap_format; + charcode_type code; + one_byte *bytes; + unsigned allocated; + unsigned used; + bounding_box_type bb; + signed_4_bytes h_escapement; + fix_word tfm_width; +} raw_char_type; + +/* CHARCODE works to access the character code of a `raw_char_type' + variable. Likewise for the bounding box, horizontal escapement, and + TFM width. */ + +/* The file format the character definition was read from. */ +#define RAW_CHAR_BITMAP_FORMAT(rc) ((rc).bitmap_format) + +/* The bytes in the file that comprise the character definition. */ +#define RAW_CHAR_BYTES(rc) ((rc).bytes) + +/* The number of allocated bytes to which the buffer points. */ +#define RAW_CHAR_ALLOCATED(rc) ((rc).allocated) + +/* The number of bytes actually used. */ +#define RAW_CHAR_USED(rc) ((rc).used) + +/* A convenience macro for the first unused byte. */ +#define RAW_CHAR_UNUSED_START(rc) RAW_CHAR_BYTES (rc)[RAW_CHAR_USED (rc)] + + +/* Return the raw character numbered CODE in the font named FONT_NAME, + or NULL. The only useful operation on a raw character is to write it + to an output file with the appropriate format. */ +extern raw_char_type *get_raw_char (string font_name, + charcode_type code); + +/* Free all allocated storage in the raw character RAW_CHAR, including + the character itself. */ +extern void free_raw_char (raw_char_type *raw_char); + +/* Miscellanous constants. */ + +/* We will only deal with fonts that have at most this many characters, + although the bitmap formats allow more. */ +#define MAX_CHARCODE 255 + +/* Some font formats have pointers within the file (to other places in + the file). The null value for such pointers is -1. */ +#define NULL_BYTE_PTR (-1) + +#endif /* not FONT_LIBRARY_H */ |