Image::Leptonica::Func::bmf
version 0.04
bmf.c
bmf.c Acquisition and generation of bitmap fonts. L_BMF *bmfCreate() L_BMF *bmfDestroy() PIX *bmfGetPix() l_int32 bmfGetWidth() l_int32 bmfGetBaseline() PIXA *pixaGetFont() l_int32 pixaSaveFont() PIXA *pixaGenerateFont() static l_int32 pixGetTextBaseline() static l_int32 bmfMakeAsciiTables() This is not a very general utility, because it only uses bitmap representations of a single font, Palatino-Roman, with the normal style. It uses bitmaps generated for nine sizes, from 4 to 20 pts, rendered at 300 ppi. Generalization to different fonts, styles and sizes is straightforward. I chose Palatino-Roman is because I like it. The input font images were generated from a set of small PostScript files, such as chars-12.ps, which were rendered into the inputfont[] bitmap files using GhostScript. See, for example, the bash script prog/ps2tiff, which will "rip" a PostScript file into a set of ccitt-g4 compressed tiff files. The set of ascii characters from 32 through 126 are the 95 printable ascii chars. Palatino-Roman is missing char 92, '\'. I have substituted '/', char 47, for 92, so that there will be no missing printable chars in this set. The space is char 32, and I have given it a width equal to twice the width of '!'.
L_BMF * bmfCreate ( const char *dir, l_int32 size )
bmfCreate() Input: dir (directory holding pixa of character set) size (4, 6, 8, ... , 20) Return: bmf (holding the bitmap font and associated information) Notes: (1) This first tries to read a pre-computed pixa file with the 95 ascii chars in it. If the file is not found, it creates the pixa from the raw image. It then generates all associated data required to use the bmf.
void bmfDestroy ( L_BMF **pbmf )
bmfDestroy() Input: &bmf (<set to null>) Return: void
l_int32 bmfGetBaseline ( L_BMF *bmf, char chr, l_int32 *pbaseline )
bmfGetBaseline() Input: bmf chr (should be one of the 95 supported bitmaps) &baseline (<return>; distance below UL corner of bitmap char) Return: 0 if OK, 1 on error
PIX * bmfGetPix ( L_BMF *bmf, char chr )
bmfGetPix() Input: bmf chr (should be one of the 95 supported printable bitmaps) Return: pix (clone of pix in bmf), or null on error
l_int32 bmfGetWidth ( L_BMF *bmf, char chr, l_int32 *pw )
bmfGetWidth() Input: bmf chr (should be one of the 95 supported bitmaps) &w (<return> character width; -1 if not printable) Return: 0 if OK, 1 on error
PIXA * pixaGenerateFont ( const char *dir, l_int32 size, l_int32 *pbl0, l_int32 *pbl1, l_int32 *pbl2 )
pixaGenerateFont() Input: dir (directory holding image of character set) size (4, 6, 8, ... , 20, in pts at 300 ppi) &bl1 (<return> baseline of row 1) &bl2 (<return> baseline of row 2) &bl3 (<return> baseline of row 3) Return: pixa of font bitmaps for 95 characters, or null on error These font generation functions use 9 sets, each with bitmaps of 94 ascii characters, all in Palatino-Roman font. Each input bitmap has 3 rows of characters. The range of ascii values in each row is as follows: row 0: 32-57 (32 is a space) row 1: 58-91 (92, '\', is not represented in this font) row 2: 93-126 We LR flip the '/' char to generate a bitmap for the missing '\' character, so that we have representations of all 95 printable chars. Computation of the bitmaps and baselines for a single font takes from 40 to 200 msec on a 2 GHz processor, depending on the size. Use pixaGetFont() to read the generated character set directly from files that were produced in prog/genfonts.c using this function.
PIXA * pixaGetFont ( const char *dir, l_int32 size, l_int32 *pbl0, l_int32 *pbl1, l_int32 *pbl2 )
pixaGetFont() Input: dir (directory holding pixa of character set) size (4, 6, 8, ... , 20) &bl1 (<return> baseline of row 1) &bl2 (<return> baseline of row 2) &bl3 (<return> baseline of row 3) Return: pixa of font bitmaps for 95 characters, or null on error Notes: (1) This reads a pre-computed pixa file with the 95 ascii chars.
l_int32 pixaSaveFont ( const char *indir, const char *outdir, l_int32 size )
pixaSaveFont() Input: indir (directory holding image of character set) outdir (directory into which the output pixa file will be written) size (in pts, at 300 ppi) Return: 0 if OK, 1 on error Notes: (1) This saves a font of a particular size. (2) prog/genfonts calls this function for each of the nine font sizes, to generate all the font pixa files.
Zakariyya Mughal <zmughal@cpan.org>
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Image::Leptonica, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Image::Leptonica
CPAN shell
perl -MCPAN -e shell install Image::Leptonica
For more information on module installation, please visit the detailed CPAN module installation guide.