1User manual for old pbm funcLtiibornasr(y3)FunctionUsseMranmuaanlual for old pbm functions(3)
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6 libpbm - libnetpbm functions to read and write PBM image files
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10 #include <netpbm/pbm.h>
11 bit **pbm_allocarray(int cols, int rows);
13 bit *pbm_allocrow(int cols);
15 pbm_freearray(bit **bits, int rows);
17 pbm_freerow(bit *bitrow);
19 void pbm_readpbminit(FILE * fp, int *colsP, int *rowsP, int *formatP);
21 void pbm_readpbmrow(FILE * fp, bit *bitrow, int cols, int format);
23 void pbm_readpbmrow_packed(FILE * fp, unsigned char * const
25 packed_bits, const int cols, const int format);
26 void bit** pbm_readpbm(FILE * fp, int *colsP, int *rowsP);
28 void pbm_writepbminit(FILE * fp, int cols, int rows, int forceplain);
30 void pbm_writepbmrow(FILE * fp, bit *bitrow, int cols, int forceplain);
32 void pbm_writepbmrow_packed(FILE * fp, unsigned char * const
34 packed_bits, const int cols, const int forceplain);
35 void pbm_writepbm(FILE * fp, bit **bits, int cols, int rows, int force‐
37 plain);
38 #define pbm_packed_bytes(cols) ...
40 void pbm_nextimage( FILE *file, int * const eofP);
42 void pbm_check( FILE * file, const enum pm_check_type check_type, const
44 int format, const int cols, const int rows, enum pm_check_code * const
45 retval);
46
50 These library functions are part of Netpbm(1).
51 TYPES AND CONSTANTS
54 typedef ... bit;
55 #define PBM_WHITE ...
57 #define PBM_BLACK ...
59 Each bit should contain only the values of PBM_WHITE or PBM_BLACK.
61 #define PBM_FORMAT ...
63 #define RPBM_FORMAT ...
65 #define PBM_TYPE PBM_FORMAT
67 #define PBM_FORMAT_TYPE(f) ...
69 These are for distinguishing different file formats and types.
71 INITIALIZATION
74 pbm_init() is identical to pm_proginit.
75 pbm_init() is obsolete. Use pm_proginit() instead.
77 MEMORY MANAGEMENT
80 pbm_allocarray() allocates an array of bits. pbm_allocrow() allocates
81 a row of the given number of bits. pbm_freearray() frees the array
82 allocated with pbm_allocarray() containing the given number of rows.
83 pbm_freerow() frees a row of bits.
84 READING PBM IMAGE FILES
88 pbm_readpbminit() reads the header from a PBM image in a PBM file,
89 filling in the rows, cols and format variables. pbm_readpbmrow() reads
90 a row of bits into the bitrow array. Format and cols were filled in by
91 pbm_readpbminit().
92 pbm_readpbmrow_packed() is like pbm_readpbmrow() except instead of
94 returning a bits array, it returns an array packed_bits of bytes with
95 the pixels of the image row packed into them. The pixels are in order
96 from left to right across the row and from the beginning of the array
97 to the end. Within a byte, the bits are in order from the most signif‐
98 icant bit to the least significant bit. If the number of pixels in the
99 row is not a multiple of 8, the last byte returned is padded on the
100 least signficant bit side with undefined bits. White is represented by
101 a PBM_WHITE bit; black by PBM_BLACK.
102 pbm_readpbm() reads an entire bitmap file into memory, returning the
104 allocated array and filling in the rows and cols variables. This func‐
105 tion combines pbm_readpbminit(), pbm_allocarray() and pbm_readpbmrow().
106 pbm_readpbminit() and pbm_readpbm abort the program with a message to
108 Standard Error if the PBM image header is not syntactically valid,
109 including if it contains a number too large to be processed using the
110 system's normal data structures (to wit, a number that won't fit in a C
111 'int').
112 ppm_readppminit() and ppm_readppm abort the program with a message to
114 Standard Error if the PPM image header is not syntactically valid,
115 including if it contains a number too large to be processed using the
116 system's normal data structures (to wit, a number that won't fit in a C
117 'int').
118 WRITING PBM IMAGE FILES
121 pbm_writepbminit() writes the header for a PBM image in a PBM file.
122 forceplain is a boolean value specifying that a plain format (text)
123 file to be written, as opposed to a raw format (binary) one.
124 pbm_writepbmrow() writes a row to a PBM file. pbm_writepbmrow_packed()
125 is the same as pbm_writepbmrow() except that you supply the row to
126 write as an array of bytes packed with bits instead of as a bits array.
127 The format of packed_bits is the same as that returned by pbm_readpbm‐
128 row().
129 pbm_writepbm() writes the header and all data for a PBM image to a PBM
131 file. This function combines pbm_writepbminit() and pbm_writepbmrow().
132 MISCELLANEOUS
135 pbm_nextimage() positions a PBM input file to the next image in it (so
136 that a subsequent pbm_readpbminit() reads its header).
137 Immediately before a call to pbm_nextimage(), the file must be posi‐
139 tioned either at its beginning (i.e. nothing has been read from the
140 file yet) or just after an image (i.e. as left by a pbm_readpbmrow()
141 of the last row in the image).
142 Note that in the raw PNM and PAM format, the next image always starts
144 immediately after the previous image, so all pbm_nextimage() really
145 does is test whether there is a next image or the file is positioned at
146 end-of-file. In plain PNM, though, there may be white space between
147 images.
148 If pbm_nextimage() successfully positions to the next image, it
150 returns *eofP false (0). If there is no next image in the file, it
151 returns *eofP true . If it can't position or determine the file status
152 due to a file error, it throws an error ⟨liberror.html#error⟩ .
153 pbm_check() checks for the common file integrity error where the file
155 is the wrong size to contain all the image data. pbm_check() assumes
156 the file is positioned after an image header (as if pbm_readpbminit()
157 was the last operation on the file). It checks the file size to see if
158 the number of bytes left in the file are the number required to contain
159 the image raster. If the file is too short, pbm_check() causes the
160 program t throws an error ⟨liberror.html#error⟩ . Otherwise, it
161 returns one of the following values (enumerations of the enum
162 pm_check_code type) as *retval:
163 PM_CHECK_OK
167 The file's size is exactly what is required to hold the image
168 raster.
169 PM_CHECK_UNKNOWN_TYPE
172 format is not a format whose size pbm_check() can anticipate.
173 The only format with which pbm_check() can deal is raw PBM for‐
174 mat.
175 PM_CHECK_TOO_LONG
178 The file is longer than it needs to be to contain the image
179 raster. The extra data might be another image.
180 PM_CHECK_UNCHECKABLE
183 The file is not a kind that has a predictable size, so there is
184 no simple way for pbm_check() to know if it is the right size.
185 Only a regular file has predictable size. A pipe is a common
186 example of a file that does not.
187 check_type must have the value PM_CHECK_BASIC (an enumerated value of
191 the pm_check_type enumerated type). Otherwise, the effect of
192 pbm_check() is unpredictable. This argument exists for future backward
193 compatible expansion of the function of pbm_check().
194
197 libpgm(1), libppm(1), libpnm(1), pbm(1)
198
201 Copyright (C) 1989, 1991 by Tony Hansen and Jef Poskanzer.
202netpbm documentation 8 SeptemberU2s0e0r7manual for old pbm functions(3)