diff options
Diffstat (limited to 'converter/other/pbmtopgm.c')
-rw-r--r-- | converter/other/pbmtopgm.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/converter/other/pbmtopgm.c b/converter/other/pbmtopgm.c new file mode 100644 index 00000000..69b20fb2 --- /dev/null +++ b/converter/other/pbmtopgm.c @@ -0,0 +1,80 @@ +/* pbmtopgm.c - convert PBM to PGM by totalling pixels over sample area + * AJCD 12/12/90 + */ + +#include <stdio.h> + +#include "pm_c_util.h" +#include "pgm.h" + +int +main(int argc, char *argv[]) { + + gray *outrow, maxval; + int right, left, down, up; + bit **inbits; + int rows, cols; + FILE *ifd; + int row; + int width, height; + const char * const usage = "<w> <h> [pbmfile]"; + + + pgm_init( &argc, argv ); + + if (argc > 4 || argc < 3) + pm_usage(usage); + + width = atoi(argv[1]); + height = atoi(argv[2]); + if (width < 1 || height < 1) + pm_error("width and height must be > 0"); + left=width/2; right=width-left; + up=width/2; down=height-up; + + if (argc == 4) + ifd = pm_openr(argv[3]); + else + ifd = stdin ; + + inbits = pbm_readpbm(ifd, &cols, &rows) ; + + if (width > cols) + pm_error("You specified a sample width (%u columns) which is greater " + "than the image width (%u columns)", height, rows); + if (height > rows) + pm_error("You specified a sample height (%u rows) which is greater " + "than the image height (%u rows)", height, rows); + + outrow = pgm_allocrow(cols) ; + maxval = MIN(PGM_OVERALLMAXVAL, width*height); + pgm_writepgminit(stdout, cols, rows, maxval, 0) ; + + for (row = 0; row < rows; row++) { + int const t = (row > up) ? (row-up) : 0; + int const b = (row+down < rows) ? (row+down) : rows; + int const onv = height - (t-row+up) - (row+down-b); + unsigned int col; + for (col = 0; col < cols; col++) { + int const l = (col > left) ? (col-left) : 0; + int const r = (col+right < cols) ? (col+right) : cols; + int const onh = width - (l-col+left) - (col+right-r); + int value; + int x; + + value = 0; /* initial value */ + + for (x = l; x < r; ++x) { + int y; + for (y = t; y < b; ++y) + if (inbits[y][x] == PBM_WHITE) + ++value; + } + outrow[col] = maxval*value/(onh*onv); + } + pgm_writepgmrow(stdout, outrow, cols, maxval, 0) ; + } + pm_close(ifd); + + return 0; +} |