/****************************************************************************** Pnmnorm ******************************************************************************* This program normalizes the contrast in a Netpbm image. by Bryan Henderson bryanh@giraffe-data.com San Jose CA March 2002. Adapted from Ppmnorm. Ppmnorm is by Wilson H. Bent, Jr. (whb@usc.edu) Extensively hacked from pgmnorm.c, which carries the following note: Copyright (C) 1989, 1991 by Jef Poskanzer. Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. This software is provided "as is" without express or implied warranty. (End of note from pgmnorm.c) Pgmnorm's man page also said: Partially based on the fbnorm filter in Michael Mauldin's "Fuzzy Pixmap" package. *****************************************************************************/ #include "pnm.h" #include "shhopt.h" #include "mallocvar.h" enum brightMethod {BRIGHT_MAX, BRIGHT_LUMIN}; struct cmdlineInfo { /* All the information the user supplied in the command line, in a form easy for the program to use. */ const char *inputFilespec; /* Filespec of input file */ unsigned int bvalueSpec; xelval bvalue; float bpercent; unsigned int wvalueSpec; xelval wvalue; float wpercent; enum brightMethod brightMethod; unsigned int keephues; }; static void parseCommandLine (int argc, char ** argv, struct cmdlineInfo *cmdlineP) { /*---------------------------------------------------------------------------- parse program command line described in Unix standard form by argc and argv. Return the information in the options as *cmdlineP. If command line is internally inconsistent (invalid options, etc.), issue error message to stderr and abort program. Note that the strings we return are stored in the storage that was passed to us as the argv array. We also trash *argv. -----------------------------------------------------------------------------*/ optEntry *option_def = malloc( 100*sizeof( optEntry ) ); /* Instructions to optParseOptions3 on how to parse our options. */ optStruct3 opt; unsigned int bpercentSpec, wpercentSpec; unsigned int brightmax; unsigned int option_def_index; option_def_index = 0; /* incremented by OPTENT3 */ OPTENT3(0, "bpercent", OPT_FLOAT, &cmdlineP->bpercent, &bpercentSpec, 0); OPTENT3(0, "wpercent", OPT_FLOAT, &cmdlineP->wpercent, &wpercentSpec, 0); OPTENT3(0, "bvalue", OPT_UINT, &cmdlineP->bvalue, &cmdlineP->bvalueSpec, 0); OPTENT3(0, "wvalue", OPT_UINT, &cmdlineP->wvalue, &cmdlineP->wvalueSpec, 0); OPTENT3(0, "keephues", OPT_FLAG, NULL, &cmdlineP->keephues, 0); OPTENT3(0, "brightmax", OPT_FLAG, NULL, &brightmax, 0); opt.opt_table = option_def; opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */ opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */ optParseOptions3( &argc, argv, opt, sizeof(opt), 0 ); /* Uses and sets argc, argv, and some of *cmdline_p and others. */ if(wpercentSpec && cmdlineP->wvalueSpec) pm_error("You may specify only one of -wpercent and -wvalue"); if(bpercentSpec && cmdlineP->bvalueSpec) pm_error("You may specify only one of -bpercent and -bvalue"); if (!wpercentSpec) cmdlineP->wpercent = 1.0; if (!bpercentSpec) cmdlineP->bpercent = 2.0; if (cmdlineP->wpercent < 0.0) pm_error("You specified a negative value for wpercent: %f", cmdlineP->wpercent); if (cmdlineP->bpercent < 0.0) pm_error("You specified a negative value for bpercent: %f", cmdlineP->bpercent); if (cmdlineP->wpercent > 100.0) pm_error("You specified a per centage > 100 for wpercent: %f", cmdlineP->wpercent); if (cmdlineP->bpercent > 100.0) pm_error("You specified a per centage > 100 for bpercent: %f", cmdlineP->bpercent); cmdlineP->brightMethod = brightmax > 0 ? BRIGHT_MAX : BRIGHT_LUMIN; if (argc-1 > 1) pm_error("Program takes at most one argument: the input file " "specification. " "You specified %d arguments.", argc-1); if (argc-1 < 1) cmdlineP->inputFilespec = "-"; else cmdlineP->inputFilespec = argv[1]; } static void buildHistogram(FILE * const ifp, int const cols, int const rows, xelval const maxval, int const format, unsigned int hist[], enum brightMethod const brightMethod) { /*---------------------------------------------------------------------------- Build the histogram of brightness values for the image that is in file 'ifp', which is positioned just after the header (at the raster). The histogram is the array hist[] such that hist[x] is the number of xels in the image that have brightness x. That brightness is either the intensity of most intense component of the xel or it is the luminosity of the xel, depending on 'brightMethod'. In either case, it is based on the same maxval as the image, which is 'maxval'. The image is 'cols' columns wide by 'rows' rows high. Leave the file positioned arbitrarily. -----------------------------------------------------------------------------*/ int row; xel * xelrow; xelrow = pnm_allocrow(cols); { unsigned int i; for (i = 0; i <= maxval; ++i) hist[i] = 0; } for (row = 0; row < rows; ++row) { int col; pnm_readpnmrow(ifp, xelrow, cols, maxval, format); for (col = 0; col < cols; ++col) { xelval brightness; xel const p = xelrow[col]; if (PNM_FORMAT_TYPE(format) == PPM_TYPE) { if (brightMethod == BRIGHT_MAX) brightness = MAX(PPM_GETR(p), MAX(PPM_GETR(p), PPM_GETB(p))); else brightness = PPM_LUMIN(p); } else brightness = PNM_GET1(p); ++hist[brightness]; } } pnm_freerow(xelrow); } static void computeBottomPercentile(unsigned int hist[], unsigned int const highest, unsigned int const total, float const percent, unsigned int * const percentileP) { /*---------------------------------------------------------------------------- Compute the lowest index of hist[] such that the sum of the hist[] values with that index and lower represent at least 'percent' per cent of 'n' (which is assumed to be the sum of all the values in hist[], given to us to save us the time of computing it). -----------------------------------------------------------------------------*/ unsigned int cutoff = total * percent / 100.0; unsigned int count; unsigned int percentile; percentile = 0; /* initial value */ count = hist[0]; /* initial value */ while (count < cutoff) { if (percentile == highest) pm_error("Internal error: computeBottomPercentile() received" "a 'total' value greater than the sum of the hist[]" "values"); ++percentile; count += hist[percentile]; } *percentileP = percentile; } static void computeTopPercentile(unsigned int hist[], unsigned int const highest, unsigned int const total, float const percent, unsigned int * const percentileP) { /*---------------------------------------------------------------------------- Compute the highest index of hist[] such that the sum of the hist[] values with that index and higher represent 'percent' per cent of 'n' (which is assumed to be the sum of all the values in hist[], given to us to save us the time of computing it). -----------------------------------------------------------------------------*/ unsigned int cutoff = total * percent / 100.0; unsigned int count; unsigned int percentile; percentile = highest; /* initial value */ count = hist[highest]; while (count < cutoff) { --percentile; count += hist[percentile]; } *percentileP = percentile; } static void computeEndValues(FILE * const ifp, int const cols, int const rows, xelval const maxval, int const format, struct cmdlineInfo const cmdline, xelval * const bvalueP, xelval * const wvalueP) { /*---------------------------------------------------------------------------- Figure out what original values will be translated to full white and full black -- thus defining to what all the other values get translated. This may involve looking at the image. The image is in the file 'ifp', which is positioned just past the header (at the raster). Leave it positioned arbitrarily. -----------------------------------------------------------------------------*/ unsigned int * hist; /* malloc'ed */ MALLOCARRAY(hist, PNM_OVERALLMAXVAL+1); if (hist == NULL) pm_error("Unable to allocate storage for intensity histogram."); else { buildHistogram(ifp, cols, rows, maxval, format, hist, BRIGHT_LUMIN); if (cmdline.bvalueSpec) *bvalueP = cmdline.bvalue; else computeBottomPercentile(hist, maxval, cols*rows, cmdline.bpercent, bvalueP); if (cmdline.wvalueSpec) *wvalueP = cmdline.wvalue; else computeTopPercentile(hist, maxval, cols*rows, cmdline.wpercent, wvalueP); free(hist); } } static void computeTransferFunction(xelval const bvalue, xelval const wvalue, xelval const maxval, xelval newIntensity[]) { /*---------------------------------------------------------------------------- Compute the transfer function, i.e. the array newIntensity[] such that newIntensity[x] is the intensity of the xel that should replace a xel with intensity x. Define function only for values 0..maxval. -----------------------------------------------------------------------------*/ xelval i; /* Map the lowest intensities to zero */ if (bvalue > 0) for (i = 0; i <= bvalue-1; ++i) newIntensity[i] = 0; { /* Map the middle intensities to 0..maxval */ unsigned int const range = wvalue - bvalue; unsigned int val; /* The following for loop is a hand optimization of this one: for (i = bvalue; i <= wvalue; ++i) newIntensity[i] = (i-bvalue)*maxval/range); (with proper rounding) */ for (i = bvalue, val = maxval/2; i <= wvalue; ++i, val += maxval) newIntensity[i] = MIN(val / range, maxval); } /* Map the highest intensities to maxval */ for (i = wvalue+1; i <= maxval; ++i) newIntensity[i] = maxval; } static void writeRowNormalized(xel * const xelrow, int const cols, xelval const maxval, int const format, bool const keephues, xelval const newIntensity[], xel * const rowbuf) { /*---------------------------------------------------------------------------- Write to Standard Output a normalized version of the xel row 'xelrow'. Normalize it via the transfer function newIntensity[]. Use 'rowbuf' as a work buffer. It is at least 'cols' columns wide. -----------------------------------------------------------------------------*/ xel * const outrow = rowbuf; unsigned int col; for (col = 0; col < cols; ++col) { xel const p = xelrow[col]; if (PPM_FORMAT_TYPE(format) == PPM_TYPE) { if (keephues) { xelval const oldIntensity = PPM_LUMIN(p); float const scaler = (float)newIntensity[oldIntensity]/oldIntensity; xelval const r = MIN((int)(PPM_GETR(p)*scaler+0.5), maxval); xelval const g = MIN((int)(PPM_GETG(p)*scaler+0.5), maxval); xelval const b = MIN((int)(PPM_GETB(p)*scaler+0.5), maxval); PNM_ASSIGN(outrow[col], r, g, b); } else PNM_ASSIGN(outrow[col], newIntensity[PPM_GETR(p)], newIntensity[PPM_GETG(p)], newIntensity[PPM_GETB(p)]); } else PNM_ASSIGN1(outrow[col], newIntensity[PNM_GET1(p)]); } pnm_writepnmrow(stdout, outrow, cols, maxval, format, 0); } int main(int argc, char *argv[]) { struct cmdlineInfo cmdline; FILE *ifp; pm_filepos imagePos; xelval maxval; int rows, cols, format; xelval bvalue, wvalue; pnm_init(&argc, argv); parseCommandLine(argc, argv, &cmdline); ifp = pm_openr_seekable(cmdline.inputFilespec); /* Rescale so that bvalue maps to 0, wvalue maps to maxval. */ pnm_readpnminit(ifp, &cols, &rows, &maxval, &format); pm_tell2(ifp, &imagePos, sizeof(imagePos)); computeEndValues(ifp, cols, rows, maxval, format, cmdline, &bvalue, &wvalue); if (wvalue < bvalue) pm_error("The colors which become black would overlap the " "colors which become white."); else { xelval newIntensity[PNM_OVERALLMAXVAL+1]; int row; xel * xelrow; xel * rowbuf; xelrow = pnm_allocrow(cols); pm_message("remapping %d..%d to %d..%d", bvalue, wvalue, 0, maxval); computeTransferFunction(bvalue, wvalue, maxval, newIntensity); pm_seek2(ifp, &imagePos, sizeof(imagePos)); pnm_writepnminit(stdout, cols, rows, maxval, format, 0); rowbuf = pnm_allocrow(cols); for (row = 0; row < rows; ++row) { pnm_readpnmrow(ifp, xelrow, cols, maxval, format); writeRowNormalized(xelrow, cols, maxval, format, cmdline.keephues, newIntensity, rowbuf); } pnm_freerow(rowbuf); pnm_freerow(xelrow); } pm_close(ifp); exit(0); }