src/common/tonemap.c

#ifndef lint
static const char       RCSid[] = "$Id: tonemap.c,v 3.28 2006/08/09 16:26:54 greg Exp $";
#endif
/*
 * Tone mapping functions.
 * See tonemap.h for detailed function descriptions.
 * Added von Kries white-balance calculations 10/01 (GW).
 *
 * Externals declared in tonemap.h
 */

#include "copyright.h"

#include        <stdio.h>
#include        <math.h>
#include        "tmprivat.h"
#include        "tmerrmsg.h"

#define exp10(x)        exp(M_LN10*(x))

                                        /* our list of conversion packages */
struct tmPackage        *tmPkg[TM_MAXPKG];
int     tmNumPkgs = 0;                  /* number of registered packages */

                                        /* luminance->brightness lookup */
static TMbright         *tmFloat2BrtLUT = NULL;

#define tmCvLumLUfp(pf) tmFloat2BrtLUT[*(int32 *)(pf) >> 15]


TMstruct *
tmInit(                                 /* initialize new tone mapping */
int     flags,
RGBPRIMP        monpri,
double  gamval
)
{
        COLORMAT        cmat;
        TMstruct        *tmnew;
        int     i;
                                                /* allocate structure */
        tmnew = (TMstruct *)malloc(sizeof(TMstruct));
        if (tmnew == NULL)
                return(NULL);

        tmnew->flags = flags & ~TM_F_UNIMPL;
        if (tmnew->flags & TM_F_BW)
                tmnew->flags &= ~TM_F_MESOPIC;
                                                /* set monitor transform */
        if (monpri == NULL || monpri == stdprims || tmnew->flags & TM_F_BW) {
                tmnew->monpri = stdprims;
                tmnew->clf[RED] = rgb2xyzmat[1][0];
                tmnew->clf[GRN] = rgb2xyzmat[1][1];
                tmnew->clf[BLU] = rgb2xyzmat[1][2];
        } else {
                comprgb2xyzmat(cmat, tmnew->monpri=monpri);
                tmnew->clf[RED] = cmat[1][0];
                tmnew->clf[GRN] = cmat[1][1];
                tmnew->clf[BLU] = cmat[1][2];
        }
                                                /* set gamma value */
        if (gamval < MINGAM)
                tmnew->mongam = DEFGAM;
        else
                tmnew->mongam = gamval;
                                                /* set color divisors */
        for (i = 0; i < 3; i++)
                tmnew->cdiv[i] = 256.*pow(tmnew->clf[i], 1./tmnew->mongam);

                                                /* set input transform */
        tmnew->inppri = tmnew->monpri;
        tmnew->cmat[0][0] = tmnew->cmat[1][1] = tmnew->cmat[2][2] =
                        tmnew->inpsf = WHTEFFICACY;
        tmnew->cmat[0][1] = tmnew->cmat[0][2] = tmnew->cmat[1][0] =
        tmnew->cmat[1][2] = tmnew->cmat[2][0] = tmnew->cmat[2][1] = 0.;
        tmnew->inpdat = NULL;
        tmnew->hbrmin = 10; tmnew->hbrmax = -10;
        tmnew->histo = NULL;
        tmnew->mbrmin = 10; tmnew->mbrmax = -10;
        tmnew->lumap = NULL;
                                                /* zero private data */
        for (i = TM_MAXPKG; i--; )
                tmnew->pd[i] = NULL;
        tmnew->lastError = TM_E_OK;
        tmnew->lastFunc = "NoErr";
                                                /* return new TMstruct */
        return(tmnew);
}


int
tmSetSpace(                     /* set input color space for conversions */
TMstruct        *tms,
RGBPRIMP        pri,
double  sf,
MEM_PTR dat
)
{
        static const char funcName[] = "tmSetSpace";
        int     i, j;
                                                /* error check */
        if (tms == NULL)
                returnErr(TM_E_TMINVAL);
        if (sf <= 1e-12)
                returnErr(TM_E_ILLEGAL);
                                                /* check if no change */
        if (pri == tms->inppri && FEQ(sf, tms->inpsf) && dat == tms->inpdat)
                returnOK;
        tms->inppri = pri;                      /* let's set it */
        tms->inpsf = sf;
        tms->inpdat = dat;

        if (tms->flags & TM_F_BW) {             /* color doesn't matter */
                tms->monpri = tms->inppri;              /* eliminate xform */
                if (tms->inppri == TM_XYZPRIM) {
                        tms->clf[CIEX] = tms->clf[CIEZ] = 0.;
                        tms->clf[CIEY] = 1.;
                } else {
                        comprgb2xyzmat(tms->cmat, tms->monpri);
                        tms->clf[RED] = tms->cmat[1][0];
                        tms->clf[GRN] = tms->cmat[1][1];
                        tms->clf[BLU] = tms->cmat[1][2];
                }
                tms->cmat[0][0] = tms->cmat[1][1] = tms->cmat[2][2] =
                                tms->inpsf;
                tms->cmat[0][1] = tms->cmat[0][2] = tms->cmat[1][0] =
                tms->cmat[1][2] = tms->cmat[2][0] = tms->cmat[2][1] = 0.;

        } else if (tms->inppri == TM_XYZPRIM)   /* input is XYZ */
                compxyz2rgbWBmat(tms->cmat, tms->monpri);

        else {                                  /* input is RGB */
                if (tms->inppri != tms->monpri &&
                                PRIMEQ(tms->inppri, tms->monpri))
                        tms->inppri = tms->monpri;      /* no xform */
                comprgb2rgbWBmat(tms->cmat, tms->inppri, tms->monpri);
        }
        for (i = 0; i < 3; i++)
                for (j = 0; j < 3; j++)
                        tms->cmat[i][j] *= tms->inpsf;
                                                /* set color divisors */
        for (i = 0; i < 3; i++)
                if (tms->clf[i] > .001)
                        tms->cdiv[i] =
                                256.*pow(tms->clf[i], 1./tms->mongam);
                else
                        tms->cdiv[i] = 1;
                                                /* notify packages */
        for (i = tmNumPkgs; i--; )
                if (tms->pd[i] != NULL && tmPkg[i]->NewSpace != NULL)
                        (*tmPkg[i]->NewSpace)(tms);
        returnOK;
}


void
tmClearHisto(                           /* clear current histogram */
TMstruct        *tms
)
{
        if (tms == NULL || tms->histo == NULL)
                return;
        free((MEM_PTR)tms->histo);
        tms->histo = NULL;
}


TMbright
tmCvLuminance(                          /* convert a single luminance */
double  lum
)
{
        double  d;

#ifdef isfinite
        if (!isfinite(lum) || lum <= TM_NOLUM)
#else
        if (lum <= TM_NOLUM)
#endif
                return(TM_NOBRT);
        d = TM_BRTSCALE*log(lum);
        if (d > 0.)
                return((TMbright)(d+.5));
        return((TMbright)(d-.5));
}


int
tmCvLums(                               /* convert luminances using lookup */
TMbright        *ls,
float           *scan,
int             len
)
{
        if (tmFloat2BrtLUT == NULL) {   /* initialize lookup table */
                int32   i;
                tmFloat2BrtLUT = (TMbright *)malloc(sizeof(TMbright)*0x10000);
                if (tmFloat2BrtLUT == NULL)
                        return(TM_E_NOMEM);
                for (i = 0; i < 0x10000; i++) {
                        int32   l = (i<<1 | 1) << 14;
#ifndef isfinite
                        if ((l & 0x7f800000) == 0x7f800000)
                                tmFloat2BrtLUT[i] = TM_NOBRT;
                        else
#endif
                        tmFloat2BrtLUT[i] = tmCvLuminance(*(float *)&l);
                }
        }
        if (len <= 0)
                return(TM_E_OK);
        if ((ls == NULL) | (scan == NULL))
                return(TM_E_ILLEGAL);
        while (len--) {
                if (*scan <= TM_NOLUM) {
                        *ls++ = TM_NOBRT;
                        ++scan;
                        continue;
                }
                *ls++ = tmCvLumLUfp(scan++);
        }
        return(TM_E_OK);
}


int
tmCvGrays(                              /* convert float gray values */
TMstruct        *tms,
TMbright        *ls,
float           *scan,
int             len
)
{
        static const char funcName[] = "tmCvGrays";
        int     i;

        if (tms == NULL)
                returnErr(TM_E_TMINVAL);
        if ((ls == NULL) | (scan == NULL) | (len < 0))
                returnErr(TM_E_ILLEGAL);
        if (tmFloat2BrtLUT == NULL)                     /* initialize */
                tmCvLums(NULL, NULL, 0);
        for (i = len; i--; ) {
                float   lum = tms->inpsf * scan[i];
                if (lum <= TM_NOLUM)
                        ls[i] = TM_NOBRT;
                else
                        ls[i] = tmCvLumLUfp(&lum);
        }
        returnOK;
}


int
tmCvColors(                             /* convert float colors */
TMstruct        *tms,
TMbright        *ls,
BYTE    *cs,
COLOR   *scan,
int     len
)
{
        static const char funcName[] = "tmCvColors";
        static BYTE     gamtab[1024];
        static double   curgam = .0;
        COLOR   cmon;
        float   lum, slum, d;
        int     i;

        if (tms == NULL)
                returnErr(TM_E_TMINVAL);
        if ((ls == NULL) | (scan == NULL) | (len < 0))
                returnErr(TM_E_ILLEGAL);
        if (tmFloat2BrtLUT == NULL)                     /* initialize */
                tmCvLums(NULL, NULL, 0);
        if (cs != TM_NOCHROM && fabs(tms->mongam - curgam) > .02) {
                curgam = tms->mongam;                   /* (re)build table */
                for (i = 1024; i--; )
                        gamtab[i] = (int)(256.*pow((i+.5)/1024., 1./curgam));
        }
        for (i = len; i--; ) {
                if (tmNeedMatrix(tms)) {                /* get monitor RGB */
                        colortrans(cmon, tms->cmat, scan[i]);
                } else {
                        cmon[RED] = tms->inpsf*scan[i][RED];
                        cmon[GRN] = tms->inpsf*scan[i][GRN];
                        cmon[BLU] = tms->inpsf*scan[i][BLU];
                }
#ifdef isfinite
                if (!isfinite(cmon[RED]) || cmon[RED] < .0f) cmon[RED] = .0f;
                if (!isfinite(cmon[GRN]) || cmon[GRN] < .0f) cmon[GRN] = .0f;
                if (!isfinite(cmon[BLU]) || cmon[BLU] < .0f) cmon[BLU] = .0f;
#else
                if (cmon[RED] < .0f) cmon[RED] = .0f;
                if (cmon[GRN] < .0f) cmon[GRN] = .0f;
                if (cmon[BLU] < .0f) cmon[BLU] = .0f;
#endif
                                                        /* world luminance */
                lum =   tms->clf[RED]*cmon[RED] +
                        tms->clf[GRN]*cmon[GRN] +
                        tms->clf[BLU]*cmon[BLU] ;
                if (lum <= TM_NOLUM) {                  /* convert brightness */
                        lum = cmon[RED] = cmon[GRN] = cmon[BLU] = TM_NOLUM;
                        ls[i] = TM_NOBRT;
                } else
                        ls[i] = tmCvLumLUfp(&lum);
                if (cs == TM_NOCHROM)                   /* no color? */
                        continue;
                if (tms->flags & TM_F_MESOPIC && lum < LMESUPPER) {
                        slum = scotlum(cmon);           /* mesopic adj. */
                        if (lum < LMESLOWER) {
                                cmon[RED] = cmon[GRN] = cmon[BLU] = slum;
                        } else {
                                d = (lum - LMESLOWER)/(LMESUPPER - LMESLOWER);
                                if (tms->flags & TM_F_BW)
                                        cmon[RED] = cmon[GRN] =
                                                        cmon[BLU] = d*lum;
                                else
                                        scalecolor(cmon, d);
                                d = (1.f-d)*slum;
                                cmon[RED] += d;
                                cmon[GRN] += d;
                                cmon[BLU] += d;
                        }
                } else if (tms->flags & TM_F_BW) {
                        cmon[RED] = cmon[GRN] = cmon[BLU] = lum;
                }
                d = tms->clf[RED]*cmon[RED]/lum;
                cs[3*i  ] = d>=.999f ? 255 : gamtab[(int)(1024.f*d)];
                d = tms->clf[GRN]*cmon[GRN]/lum;
                cs[3*i+1] = d>=.999f ? 255 : gamtab[(int)(1024.f*d)];
                d = tms->clf[BLU]*cmon[BLU]/lum;
                cs[3*i+2] = d>=.999f ? 255 : gamtab[(int)(1024.f*d)];
        }
        returnOK;
}


int
tmAddHisto(                             /* add values to histogram */
TMstruct        *tms,
TMbright        *ls,
int     len,
int     wt
)
{
        static const char funcName[] = "tmAddHisto";
        int     oldorig=0, oldlen, horig, hlen;
        int     i, j;

        if (tms == NULL)
                returnErr(TM_E_TMINVAL);
        if (len < 0)
                returnErr(TM_E_ILLEGAL);
        if (len == 0)
                returnOK;
                                                /* first, grow limits */
        if (tms->histo == NULL) {
                for (i = len; i-- && ls[i] < MINBRT; )
                        ;
                if (i < 0)
                        returnOK;
                tms->hbrmin = tms->hbrmax = ls[i];
                oldlen = 0;
        } else {
                oldorig = (tms->hbrmin-MINBRT)/HISTEP;
                oldlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - oldorig;
        }
        for (i = len; i--; ) {
                if ((j = ls[i]) < MINBRT)
                        continue;
                if (j < tms->hbrmin)
                        tms->hbrmin = j;
                else if (j > tms->hbrmax)
                        tms->hbrmax = j;
        }
        horig = (tms->hbrmin-MINBRT)/HISTEP;
        hlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - horig;
        if (hlen > oldlen) {                    /* (re)allocate histogram */
                int     *newhist = (int *)calloc(hlen, sizeof(int));
                if (newhist == NULL)
                        returnErr(TM_E_NOMEM);
                if (oldlen) {                   /* copy and free old */
                        for (i = oldlen, j = i+oldorig-horig; i; )
                                newhist[--j] = tms->histo[--i];
                        free((MEM_PTR)tms->histo);
                }
                tms->histo = newhist;
        }
        if (wt == 0)
                returnOK;
        for (i = len; i--; )                    /* add in new counts */
                if (ls[i] >= MINBRT)
                        tms->histo[ (ls[i]-MINBRT)/HISTEP - horig ] += wt;
        returnOK;
}


static double
htcontrs(               /* human threshold contrast sensitivity, dL(La) */
double  La
)
{
        double  l10La, l10dL;
                                /* formula taken from Ferwerda et al. [SG96] */
        if (La < 1.148e-4)
                return(1.38e-3);
        l10La = log10(La);
        if (l10La < -1.44)              /* rod response regime */
                l10dL = pow(.405*l10La + 1.6, 2.18) - 2.86;
        else if (l10La < -.0184)
                l10dL = l10La - .395;
        else if (l10La < 1.9)           /* cone response regime */
                l10dL = pow(.249*l10La + .65, 2.7) - .72;
        else
                l10dL = l10La - 1.255;

        return(exp10(l10dL));
}


static int
tmNewMap(                       /* allocate new tone-mapping array */
TMstruct        *tms
)
{
        if (tms->lumap != NULL && (tms->mbrmax - tms->mbrmin) !=
                                        (tms->hbrmax - tms->hbrmin)) {
                free((MEM_PTR)tms->lumap);
                tms->lumap = NULL;
        }
        tms->mbrmin = tms->hbrmin;
        tms->mbrmax = tms->hbrmax;
        if (tms->mbrmin > tms->mbrmax)
                return 0;
        if (tms->lumap == NULL)
                tms->lumap = (unsigned short *)malloc(sizeof(unsigned short)*
                                        (tms->mbrmax-tms->mbrmin+1));
        return(tms->lumap != NULL);
}


int
tmFixedMapping(                 /* compute fixed, linear tone-mapping */
TMstruct        *tms,
double  expmult,
double  gamval
)
{
        static const char funcName[] = "tmFixedMapping";
        double          d;
        int     i;
        
        if (!tmNewMap(tms))
                returnErr(TM_E_NOMEM);
        if (expmult <= .0)
                expmult = 1.;
        if (gamval < MINGAM)
                gamval = tms->mongam;
        d = log(expmult/tms->inpsf);
        for (i = tms->mbrmax-tms->mbrmin+1; i--; ) {
                double  val = 256. * exp(
                        ( d + (tms->mbrmin+i)*(1./TM_BRTSCALE) )
                        / gamval);
                tms->lumap[i] = val >= (double)0xffff ? 0xffff : (int)val;
        }
        returnOK;
}


int
tmComputeMapping(                       /* compute histogram tone-mapping */
TMstruct        *tms,
double  gamval,
double  Lddyn,
double  Ldmax
)
{
        static const char funcName[] = "tmComputeMapping";
        int     *histo;
        float   *cumf;
        int     brt0, histlen, threshold, ceiling, trimmings;
        double  logLddyn, Ldmin, Ldavg, Lwavg, Tr, Lw, Ld;
        int32   histot;
        double  sum;
        double  d;
        int     i, j;

        if (tms == NULL || tms->histo == NULL)
                returnErr(TM_E_TMINVAL);
                                        /* check arguments */
        if (Lddyn < MINLDDYN) Lddyn = DEFLDDYN;
        if (Ldmax < MINLDMAX) Ldmax = DEFLDMAX;
        if (gamval < MINGAM) gamval = tms->mongam;
                                        /* compute handy values */
        Ldmin = Ldmax/Lddyn;
        logLddyn = log(Lddyn);
        Ldavg = sqrt(Ldmax*Ldmin);
        i = (tms->hbrmin-MINBRT)/HISTEP;
        brt0 = MINBRT + HISTEP/2 + i*HISTEP;
        histlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - i;
                                        /* histogram total and mean */
        histot = 0; sum = 0;
        j = brt0 + histlen*HISTEP;
        for (i = histlen; i--; ) {
                histot += tms->histo[i];
                sum += (j -= HISTEP) * tms->histo[i];
        }
        threshold = histot*0.005 + .5;
        if (!histot)
                returnErr(TM_E_TMFAIL);
        Lwavg = tmLuminance( (double)sum / histot );
                                        /* use linear tone mapping? */
        if (tms->flags & TM_F_LINEAR || threshold < 4)
                goto linearmap;
                                        /* allocate space for mapping */
        if (!tmNewMap(tms))
                returnErr(TM_E_NOMEM);
                                        /* clamp histogram */
        histo = (int *)malloc(histlen*sizeof(int));
        cumf = (float *)malloc((histlen+2)*sizeof(float));
        if ((histo == NULL) | (cumf == NULL))
                returnErr(TM_E_NOMEM);
        cumf[histlen+1] = 1.;           /* guard for assignment code */
        for (i = histlen; i--; )        /* make malleable copy */
                histo[i] = tms->histo[i];
        do {                            /* iterate to solution */
                sum = 0;                /* cumulative probability */
                for (i = 0; i < histlen; i++) {
                        cumf[i] = (double)sum/histot;
                        sum += histo[i];
                }
                cumf[histlen] = 1.;
                Tr = histot * (double)(tms->hbrmax - tms->hbrmin) /
                        ((double)histlen*TM_BRTSCALE) / logLddyn;
                ceiling = Tr + 1.;
                trimmings = 0;          /* clip to envelope */
                for (i = histlen; i--; ) {
                        if (tms->flags & TM_F_HCONTR) {
                                Lw = tmLuminance(brt0 + i*HISTEP);
                                Ld = Ldmin * exp( logLddyn *
                                        .5*(cumf[i]+cumf[i+1]) );
                                ceiling = Tr * (htcontrs(Ld) * Lw) /
                                        (htcontrs(Lw) * Ld) + 1.;
                        }
                        if (histo[i] > ceiling) {
                                trimmings += histo[i] - ceiling;
                                histo[i] = ceiling;
                        }
                }
                                        /* check if we're out of data */
                if ((histot -= trimmings) <= threshold) {
                        free((MEM_PTR)histo);
                        free((MEM_PTR)cumf);
                        goto linearmap;
                }
        } while (trimmings > threshold);
                                        /* assign tone-mapping */
        for (i = tms->mbrmax-tms->mbrmin+1; i--; ) {
                j = d = (double)i/(tms->mbrmax-tms->mbrmin)*histlen;
                d -= (double)j;
                Ld = Ldmin*exp(logLddyn*((1.-d)*cumf[j]+d*cumf[j+1]));
                d = (Ld - Ldmin)/(Ldmax - Ldmin);
                tms->lumap[i] = 256.*pow(d, 1./gamval);
        }
        free((MEM_PTR)histo);           /* clean up and return */
        free((MEM_PTR)cumf);
        returnOK;
linearmap:                              /* linear tone-mapping */
        if (tms->flags & TM_F_HCONTR)
                d = htcontrs(Ldavg) / htcontrs(Lwavg);
        else
                d = Ldavg / Lwavg;
        return(tmFixedMapping(tms, tms->inpsf*d/Ldmax, gamval));
}


int
tmMapPixels(                    /* apply tone-mapping to pixel(s) */
TMstruct        *tms,
BYTE    *ps,
TMbright        *ls,
BYTE    *cs,
int     len
)
{
        static const char funcName[] = "tmMapPixels";
        int32   li, pv;

        if (tms == NULL || tms->lumap == NULL)
                returnErr(TM_E_TMINVAL);
        if ((ps == NULL) | (ls == NULL) | (len < 0))
                returnErr(TM_E_ILLEGAL);
        while (len--) {
                if ((li = *ls++) < tms->mbrmin) {
                        li = 0;
                } else {
                        if (li > tms->mbrmax)
                                li = tms->mbrmax;
                        li = tms->lumap[li - tms->mbrmin];
                }
                if (cs == TM_NOCHROM)
                        *ps++ = li>255 ? 255 : li;
                else {
                        pv = *cs++ * li / tms->cdiv[RED];
                        *ps++ = pv>255 ? 255 : pv;
                        pv = *cs++ * li / tms->cdiv[GRN];
                        *ps++ = pv>255 ? 255 : pv;
                        pv = *cs++ * li / tms->cdiv[BLU];
                        *ps++ = pv>255 ? 255 : pv;
                }
        }
        returnOK;
}


TMstruct *
tmDup(                          /* duplicate top tone mapping */
TMstruct        *tms
)
{
        int     len;
        int     i;
        TMstruct        *tmnew;

        if (tms == NULL)                /* anything to duplicate? */
                return(NULL);
        tmnew = (TMstruct *)malloc(sizeof(TMstruct));
        if (tmnew == NULL)
                return(NULL);
        *tmnew = *tms;          /* copy everything */
        if (tmnew->histo != NULL) {     /* duplicate histogram */
                len = (tmnew->hbrmax-MINBRT)/HISTEP + 1 -
                                (tmnew->hbrmin-MINBRT)/HISTEP;
                tmnew->histo = (int *)malloc(len*sizeof(int));
                if (tmnew->histo != NULL)
                        for (i = len; i--; )
                                tmnew->histo[i] = tms->histo[i];
        }
        if (tmnew->lumap != NULL) {     /* duplicate luminance mapping */
                len = tmnew->mbrmax-tmnew->mbrmin+1;
                tmnew->lumap = (unsigned short *)malloc(
                                                len*sizeof(unsigned short) );
                if (tmnew->lumap != NULL)
                        for (i = len; i--; )
                                tmnew->lumap[i] = tms->lumap[i];
        }
                                        /* clear package data */
        for (i = tmNumPkgs; i--; )
                tmnew->pd[i] = NULL;
                                        /* return copy */
        return(tmnew);
}


void
tmDone(tms)                     /* done with tone mapping -- destroy it */
TMstruct        *tms;
{
        int     i;
                                        /* NULL arg. is equiv. to tms */
        if (tms == NULL)
                return;
                                        /* free tables */
        if (tms->histo != NULL)
                free((MEM_PTR)tms->histo);
        if (tms->lumap != NULL)
                free((MEM_PTR)tms->lumap);
                                        /* free private data */
        for (i = tmNumPkgs; i--; )
                if (tms->pd[i] != NULL)
                        (*tmPkg[i]->Free)(tms->pd[i]);
        free((MEM_PTR)tms);             /* free basic structure */
}

/******************** Shared but Private library routines *********************/

BYTE    tmMesofact[BMESUPPER-BMESLOWER];

void
tmMkMesofact()                          /* build mesopic lookup factor table */
{
        int     i;

        if (tmMesofact[BMESUPPER-BMESLOWER-1])
                return;

        for (i = BMESLOWER; i < BMESUPPER; i++)
                tmMesofact[i-BMESLOWER] = 256. *
                                (tmLuminance(i) - LMESLOWER) /
                                (LMESUPPER - LMESLOWER);
}


int
tmErrorReturn(                          /* error return (with message) */
const char      *func,
TMstruct        *tms,
int     err
)
{
        if (tms != NULL) {
                tms->lastFunc = func;
                tms->lastError = err;
                if (tms->flags & TM_F_NOSTDERR)
                        return(err);
        }
        fputs(func, stderr);
        fputs(": ", stderr);
        fputs(tmErrorMessage[err], stderr);
        fputs("!\n", stderr);
        return(err);
}
Revision:	3.29
Committed:	Wed May 23 21:38:50 2007 UTC (18 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.28:	+5 -5 lines
Log Message:	Made tone-mapping function more robust for degenerate images
#	User	Rev	Content
1	greg	3.1	#ifndef lint
2	greg	3.29	static const char RCSid[] = "$Id: tonemap.c,v 3.28 2006/08/09 16:26:54 greg Exp $";
3	greg	3.1	#endif
4			/*
5			* Tone mapping functions.
6			* See tonemap.h for detailed function descriptions.
7	greg	3.9	* Added von Kries white-balance calculations 10/01 (GW).
8			*
9			* Externals declared in tonemap.h
10			*/
11
12	greg	3.10	#include "copyright.h"
13	greg	3.1
14			#include <stdio.h>
15			#include <math.h>
16			#include "tmprivat.h"
17			#include "tmerrmsg.h"
18
19			#define exp10(x) exp(M_LN10*(x))
20
21	greg	3.4	/* our list of conversion packages */
22			struct tmPackage *tmPkg[TM_MAXPKG];
23			int tmNumPkgs = 0; /* number of registered packages */
24	greg	3.1
25	greg	3.23	/* luminance->brightness lookup */
26	greg	3.24	static TMbright *tmFloat2BrtLUT = NULL;
27	greg	3.23
28			#define tmCvLumLUfp(pf) tmFloat2BrtLUT[(int32 )(pf) >> 15]
29
30	gregl	3.5
31	greg	3.16	TMstruct *
32			tmInit( /* initialize new tone mapping */
33			int flags,
34			RGBPRIMP monpri,
35			double gamval
36			)
37	greg	3.1	{
38			COLORMAT cmat;
39	greg	3.16	TMstruct *tmnew;
40			int i;
41	greg	3.1	/* allocate structure */
42	greg	3.16	tmnew = (TMstruct *)malloc(sizeof(TMstruct));
43	greg	3.1	if (tmnew == NULL)
44			return(NULL);
45
46			tmnew->flags = flags & ~TM_F_UNIMPL;
47	greg	3.15	if (tmnew->flags & TM_F_BW)
48			tmnew->flags &= ~TM_F_MESOPIC;
49	greg	3.1	/* set monitor transform */
50			if (monpri == NULL \|\| monpri == stdprims \|\| tmnew->flags & TM_F_BW) {
51			tmnew->monpri = stdprims;
52			tmnew->clf[RED] = rgb2xyzmat[1][0];
53			tmnew->clf[GRN] = rgb2xyzmat[1][1];
54			tmnew->clf[BLU] = rgb2xyzmat[1][2];
55			} else {
56	greg	3.26	comprgb2xyzmat(cmat, tmnew->monpri=monpri);
57	greg	3.1	tmnew->clf[RED] = cmat[1][0];
58			tmnew->clf[GRN] = cmat[1][1];
59			tmnew->clf[BLU] = cmat[1][2];
60			}
61			/* set gamma value */
62			if (gamval < MINGAM)
63			tmnew->mongam = DEFGAM;
64			else
65			tmnew->mongam = gamval;
66	greg	3.4	/* set color divisors */
67			for (i = 0; i < 3; i++)
68			tmnew->cdiv[i] = 256.*pow(tmnew->clf[i], 1./tmnew->mongam);
69
70	greg	3.1	/* set input transform */
71			tmnew->inppri = tmnew->monpri;
72			tmnew->cmat[0][0] = tmnew->cmat[1][1] = tmnew->cmat[2][2] =
73			tmnew->inpsf = WHTEFFICACY;
74			tmnew->cmat[0][1] = tmnew->cmat[0][2] = tmnew->cmat[1][0] =
75			tmnew->cmat[1][2] = tmnew->cmat[2][0] = tmnew->cmat[2][1] = 0.;
76	greg	3.18	tmnew->inpdat = NULL;
77	greg	3.9	tmnew->hbrmin = 10; tmnew->hbrmax = -10;
78	greg	3.1	tmnew->histo = NULL;
79	greg	3.9	tmnew->mbrmin = 10; tmnew->mbrmax = -10;
80	greg	3.1	tmnew->lumap = NULL;
81	greg	3.4	/* zero private data */
82			for (i = TM_MAXPKG; i--; )
83			tmnew->pd[i] = NULL;
84	greg	3.17	tmnew->lastError = TM_E_OK;
85			tmnew->lastFunc = "NoErr";
86	greg	3.16	/* return new TMstruct */
87			return(tmnew);
88	greg	3.1	}
89
90
91			int
92	greg	3.16	tmSetSpace( /* set input color space for conversions */
93			TMstruct *tms,
94			RGBPRIMP pri,
95	greg	3.18	double sf,
96			MEM_PTR dat
97	greg	3.16	)
98	greg	3.1	{
99	greg	3.17	static const char funcName[] = "tmSetSpace";
100	greg	3.16	int i, j;
101	greg	3.1	/* error check */
102	greg	3.16	if (tms == NULL)
103	greg	3.1	returnErr(TM_E_TMINVAL);
104			if (sf <= 1e-12)
105			returnErr(TM_E_ILLEGAL);
106			/* check if no change */
107	greg	3.18	if (pri == tms->inppri && FEQ(sf, tms->inpsf) && dat == tms->inpdat)
108	greg	3.1	returnOK;
109	greg	3.16	tms->inppri = pri; /* let's set it */
110			tms->inpsf = sf;
111	greg	3.18	tms->inpdat = dat;
112	greg	3.1
113	greg	3.16	if (tms->flags & TM_F_BW) { /* color doesn't matter */
114			tms->monpri = tms->inppri; /* eliminate xform */
115			if (tms->inppri == TM_XYZPRIM) {
116			tms->clf[CIEX] = tms->clf[CIEZ] = 0.;
117			tms->clf[CIEY] = 1.;
118	greg	3.1	} else {
119	greg	3.26	comprgb2xyzmat(tms->cmat, tms->monpri);
120	greg	3.16	tms->clf[RED] = tms->cmat[1][0];
121			tms->clf[GRN] = tms->cmat[1][1];
122			tms->clf[BLU] = tms->cmat[1][2];
123			}
124			tms->cmat[0][0] = tms->cmat[1][1] = tms->cmat[2][2] =
125			tms->inpsf;
126			tms->cmat[0][1] = tms->cmat[0][2] = tms->cmat[1][0] =
127			tms->cmat[1][2] = tms->cmat[2][0] = tms->cmat[2][1] = 0.;
128	greg	3.1
129	greg	3.16	} else if (tms->inppri == TM_XYZPRIM) /* input is XYZ */
130			compxyz2rgbWBmat(tms->cmat, tms->monpri);
131	greg	3.1
132			else { /* input is RGB */
133	greg	3.16	if (tms->inppri != tms->monpri &&
134			PRIMEQ(tms->inppri, tms->monpri))
135			tms->inppri = tms->monpri; /* no xform */
136			comprgb2rgbWBmat(tms->cmat, tms->inppri, tms->monpri);
137	greg	3.1	}
138			for (i = 0; i < 3; i++)
139			for (j = 0; j < 3; j++)
140	greg	3.16	tms->cmat[i][j] *= tms->inpsf;
141	greg	3.4	/* set color divisors */
142			for (i = 0; i < 3; i++)
143	greg	3.16	if (tms->clf[i] > .001)
144			tms->cdiv[i] =
145			256.*pow(tms->clf[i], 1./tms->mongam);
146	greg	3.4	else
147	greg	3.16	tms->cdiv[i] = 1;
148	greg	3.4	/* notify packages */
149			for (i = tmNumPkgs; i--; )
150	greg	3.16	if (tms->pd[i] != NULL && tmPkg[i]->NewSpace != NULL)
151			(*tmPkg[i]->NewSpace)(tms);
152	greg	3.1	returnOK;
153			}
154
155
156			void
157	greg	3.23	tmClearHisto( /* clear current histogram */
158	greg	3.16	TMstruct *tms
159			)
160	greg	3.1	{
161	greg	3.16	if (tms == NULL \|\| tms->histo == NULL)
162	greg	3.1	return;
163	greg	3.16	free((MEM_PTR)tms->histo);
164			tms->histo = NULL;
165	greg	3.1	}
166
167
168	greg	3.23	TMbright
169			tmCvLuminance( /* convert a single luminance */
170			double lum
171			)
172			{
173			double d;
174
175			#ifdef isfinite
176			if (!isfinite(lum) \|\| lum <= TM_NOLUM)
177			#else
178			if (lum <= TM_NOLUM)
179			#endif
180			return(TM_NOBRT);
181			d = TM_BRTSCALE*log(lum);
182			if (d > 0.)
183			return((TMbright)(d+.5));
184			return((TMbright)(d-.5));
185			}
186
187
188			int
189			tmCvLums( /* convert luminances using lookup */
190			TMbright *ls,
191			float *scan,
192			int len
193			)
194			{
195			if (tmFloat2BrtLUT == NULL) { /* initialize lookup table */
196			int32 i;
197			tmFloat2BrtLUT = (TMbright )malloc(sizeof(TMbright)0x10000);
198			if (tmFloat2BrtLUT == NULL)
199			return(TM_E_NOMEM);
200			for (i = 0; i < 0x10000; i++) {
201			int32 l = (i<<1 \| 1) << 14;
202			#ifndef isfinite
203			if ((l & 0x7f800000) == 0x7f800000)
204			tmFloat2BrtLUT[i] = TM_NOBRT;
205			else
206			#endif
207			tmFloat2BrtLUT[i] = tmCvLuminance((float )&l);
208			}
209			}
210			if (len <= 0)
211			return(TM_E_OK);
212			if ((ls == NULL) \| (scan == NULL))
213			return(TM_E_ILLEGAL);
214			while (len--) {
215			if (*scan <= TM_NOLUM) {
216			*ls++ = TM_NOBRT;
217			++scan;
218			continue;
219			}
220			*ls++ = tmCvLumLUfp(scan++);
221			}
222			return(TM_E_OK);
223			}
224
225
226			int
227			tmCvGrays( /* convert float gray values */
228			TMstruct *tms,
229			TMbright *ls,
230			float *scan,
231			int len
232			)
233			{
234			static const char funcName[] = "tmCvGrays";
235			int i;
236
237			if (tms == NULL)
238			returnErr(TM_E_TMINVAL);
239			if ((ls == NULL) \| (scan == NULL) \| (len < 0))
240			returnErr(TM_E_ILLEGAL);
241	greg	3.24	if (tmFloat2BrtLUT == NULL) /* initialize */
242			tmCvLums(NULL, NULL, 0);
243	greg	3.23	for (i = len; i--; ) {
244			float lum = tms->inpsf * scan[i];
245			if (lum <= TM_NOLUM)
246			ls[i] = TM_NOBRT;
247			else
248			ls[i] = tmCvLumLUfp(&lum);
249			}
250			returnOK;
251			}
252
253
254	greg	3.1	int
255	greg	3.16	tmCvColors( /* convert float colors */
256			TMstruct *tms,
257			TMbright *ls,
258			BYTE *cs,
259			COLOR *scan,
260			int len
261			)
262	greg	3.1	{
263	greg	3.17	static const char funcName[] = "tmCvColors";
264	greg	3.20	static BYTE gamtab[1024];
265			static double curgam = .0;
266	greg	3.1	COLOR cmon;
267	greg	3.23	float lum, slum, d;
268	greg	3.16	int i;
269	greg	3.1
270	greg	3.16	if (tms == NULL)
271	greg	3.1	returnErr(TM_E_TMINVAL);
272	schorsch	3.13	if ((ls == NULL) \| (scan == NULL) \| (len < 0))
273	greg	3.1	returnErr(TM_E_ILLEGAL);
274	greg	3.24	if (tmFloat2BrtLUT == NULL) /* initialize */
275			tmCvLums(NULL, NULL, 0);
276	greg	3.21	if (cs != TM_NOCHROM && fabs(tms->mongam - curgam) > .02) {
277	greg	3.20	curgam = tms->mongam; /* (re)build table */
278			for (i = 1024; i--; )
279			gamtab[i] = (int)(256.*pow((i+.5)/1024., 1./curgam));
280			}
281	greg	3.1	for (i = len; i--; ) {
282	greg	3.16	if (tmNeedMatrix(tms)) { /* get monitor RGB */
283			colortrans(cmon, tms->cmat, scan[i]);
284	greg	3.15	} else {
285	greg	3.16	cmon[RED] = tms->inpsf*scan[i][RED];
286			cmon[GRN] = tms->inpsf*scan[i][GRN];
287			cmon[BLU] = tms->inpsf*scan[i][BLU];
288	greg	3.1	}
289	greg	3.23	#ifdef isfinite
290			if (!isfinite(cmon[RED]) \|\| cmon[RED] < .0f) cmon[RED] = .0f;
291			if (!isfinite(cmon[GRN]) \|\| cmon[GRN] < .0f) cmon[GRN] = .0f;
292			if (!isfinite(cmon[BLU]) \|\| cmon[BLU] < .0f) cmon[BLU] = .0f;
293			#else
294			if (cmon[RED] < .0f) cmon[RED] = .0f;
295			if (cmon[GRN] < .0f) cmon[GRN] = .0f;
296			if (cmon[BLU] < .0f) cmon[BLU] = .0f;
297	greg	3.22	#endif
298	greg	3.1	/* world luminance */
299	greg	3.16	lum = tms->clf[RED]*cmon[RED] +
300			tms->clf[GRN]*cmon[GRN] +
301			tms->clf[BLU]*cmon[BLU] ;
302	greg	3.25	if (lum <= TM_NOLUM) { /* convert brightness */
303			lum = cmon[RED] = cmon[GRN] = cmon[BLU] = TM_NOLUM;
304	greg	3.23	ls[i] = TM_NOBRT;
305	greg	3.25	} else
306	greg	3.23	ls[i] = tmCvLumLUfp(&lum);
307	greg	3.1	if (cs == TM_NOCHROM) /* no color? */
308			continue;
309	greg	3.16	if (tms->flags & TM_F_MESOPIC && lum < LMESUPPER) {
310	greg	3.1	slum = scotlum(cmon); /* mesopic adj. */
311	greg	3.25	if (lum < LMESLOWER) {
312	greg	3.1	cmon[RED] = cmon[GRN] = cmon[BLU] = slum;
313	greg	3.25	} else {
314	greg	3.1	d = (lum - LMESLOWER)/(LMESUPPER - LMESLOWER);
315	greg	3.16	if (tms->flags & TM_F_BW)
316	greg	3.1	cmon[RED] = cmon[GRN] =
317			cmon[BLU] = d*lum;
318			else
319			scalecolor(cmon, d);
320	greg	3.23	d = (1.f-d)*slum;
321	greg	3.1	cmon[RED] += d;
322			cmon[GRN] += d;
323			cmon[BLU] += d;
324			}
325	greg	3.16	} else if (tms->flags & TM_F_BW) {
326	greg	3.1	cmon[RED] = cmon[GRN] = cmon[BLU] = lum;
327			}
328	greg	3.16	d = tms->clf[RED]*cmon[RED]/lum;
329	greg	3.23	cs[3i ] = d>=.999f ? 255 : gamtab[(int)(1024.fd)];
330	greg	3.16	d = tms->clf[GRN]*cmon[GRN]/lum;
331	greg	3.23	cs[3i+1] = d>=.999f ? 255 : gamtab[(int)(1024.fd)];
332	greg	3.16	d = tms->clf[BLU]*cmon[BLU]/lum;
333	greg	3.23	cs[3i+2] = d>=.999f ? 255 : gamtab[(int)(1024.fd)];
334	greg	3.1	}
335			returnOK;
336			}
337
338
339	greg	3.9	int
340	greg	3.16	tmAddHisto( /* add values to histogram */
341			TMstruct *tms,
342			TMbright *ls,
343			int len,
344			int wt
345			)
346	greg	3.1	{
347	greg	3.17	static const char funcName[] = "tmAddHisto";
348	greg	3.9	int oldorig=0, oldlen, horig, hlen;
349	greg	3.16	int i, j;
350	greg	3.1
351	greg	3.16	if (tms == NULL)
352	greg	3.1	returnErr(TM_E_TMINVAL);
353	gwlarson	3.8	if (len < 0)
354			returnErr(TM_E_ILLEGAL);
355			if (len == 0)
356			returnOK;
357	greg	3.1	/* first, grow limits */
358	greg	3.16	if (tms->histo == NULL) {
359	greg	3.1	for (i = len; i-- && ls[i] < MINBRT; )
360			;
361			if (i < 0)
362			returnOK;
363	greg	3.16	tms->hbrmin = tms->hbrmax = ls[i];
364	greg	3.1	oldlen = 0;
365			} else {
366	greg	3.16	oldorig = (tms->hbrmin-MINBRT)/HISTEP;
367			oldlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - oldorig;
368	greg	3.1	}
369			for (i = len; i--; ) {
370			if ((j = ls[i]) < MINBRT)
371			continue;
372	greg	3.16	if (j < tms->hbrmin)
373			tms->hbrmin = j;
374			else if (j > tms->hbrmax)
375			tms->hbrmax = j;
376	greg	3.1	}
377	greg	3.16	horig = (tms->hbrmin-MINBRT)/HISTEP;
378			hlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - horig;
379	greg	3.1	if (hlen > oldlen) { /* (re)allocate histogram */
380	greg	3.16	int newhist = (int )calloc(hlen, sizeof(int));
381	greg	3.1	if (newhist == NULL)
382			returnErr(TM_E_NOMEM);
383			if (oldlen) { /* copy and free old */
384	greg	3.2	for (i = oldlen, j = i+oldorig-horig; i; )
385	greg	3.16	newhist[--j] = tms->histo[--i];
386			free((MEM_PTR)tms->histo);
387	greg	3.1	}
388	greg	3.16	tms->histo = newhist;
389	greg	3.1	}
390			if (wt == 0)
391			returnOK;
392			for (i = len; i--; ) /* add in new counts */
393			if (ls[i] >= MINBRT)
394	greg	3.16	tms->histo[ (ls[i]-MINBRT)/HISTEP - horig ] += wt;
395	greg	3.1	returnOK;
396			}
397
398
399			static double
400	greg	3.16	htcontrs( /* human threshold contrast sensitivity, dL(La) */
401			double La
402			)
403	greg	3.1	{
404			double l10La, l10dL;
405			/* formula taken from Ferwerda et al. [SG96] */
406			if (La < 1.148e-4)
407			return(1.38e-3);
408			l10La = log10(La);
409			if (l10La < -1.44) /* rod response regime */
410			l10dL = pow(.405*l10La + 1.6, 2.18) - 2.86;
411			else if (l10La < -.0184)
412			l10dL = l10La - .395;
413			else if (l10La < 1.9) /* cone response regime */
414			l10dL = pow(.249*l10La + .65, 2.7) - .72;
415			else
416			l10dL = l10La - 1.255;
417
418			return(exp10(l10dL));
419			}
420
421
422	greg	3.9	static int
423	greg	3.16	tmNewMap( /* allocate new tone-mapping array */
424			TMstruct *tms
425			)
426	greg	3.9	{
427	greg	3.16	if (tms->lumap != NULL && (tms->mbrmax - tms->mbrmin) !=
428			(tms->hbrmax - tms->hbrmin)) {
429			free((MEM_PTR)tms->lumap);
430			tms->lumap = NULL;
431			}
432			tms->mbrmin = tms->hbrmin;
433			tms->mbrmax = tms->hbrmax;
434			if (tms->mbrmin > tms->mbrmax)
435	greg	3.9	return 0;
436	greg	3.16	if (tms->lumap == NULL)
437			tms->lumap = (unsigned short )malloc(sizeof(unsigned short)
438			(tms->mbrmax-tms->mbrmin+1));
439			return(tms->lumap != NULL);
440	greg	3.9	}
441
442
443			int
444	greg	3.16	tmFixedMapping( /* compute fixed, linear tone-mapping */
445			TMstruct *tms,
446			double expmult,
447			double gamval
448			)
449	greg	3.9	{
450	greg	3.17	static const char funcName[] = "tmFixedMapping";
451	greg	3.9	double d;
452	greg	3.16	int i;
453	greg	3.9
454	greg	3.16	if (!tmNewMap(tms))
455	greg	3.9	returnErr(TM_E_NOMEM);
456			if (expmult <= .0)
457			expmult = 1.;
458			if (gamval < MINGAM)
459	greg	3.16	gamval = tms->mongam;
460			d = log(expmult/tms->inpsf);
461	greg	3.28	for (i = tms->mbrmax-tms->mbrmin+1; i--; ) {
462			double val = 256. * exp(
463	greg	3.16	( d + (tms->mbrmin+i)*(1./TM_BRTSCALE) )
464	greg	3.28	/ gamval);
465			tms->lumap[i] = val >= (double)0xffff ? 0xffff : (int)val;
466			}
467	greg	3.9	returnOK;
468			}
469
470
471	greg	3.1	int
472	greg	3.16	tmComputeMapping( /* compute histogram tone-mapping */
473			TMstruct *tms,
474			double gamval,
475			double Lddyn,
476			double Ldmax
477			)
478	greg	3.1	{
479	greg	3.17	static const char funcName[] = "tmComputeMapping";
480	greg	3.1	int *histo;
481			float *cumf;
482	greg	3.9	int brt0, histlen, threshold, ceiling, trimmings;
483	greg	3.1	double logLddyn, Ldmin, Ldavg, Lwavg, Tr, Lw, Ld;
484	greg	3.11	int32 histot;
485	greg	3.9	double sum;
486	greg	3.16	double d;
487			int i, j;
488	greg	3.1
489	greg	3.16	if (tms == NULL \|\| tms->histo == NULL)
490	greg	3.1	returnErr(TM_E_TMINVAL);
491			/* check arguments */
492			if (Lddyn < MINLDDYN) Lddyn = DEFLDDYN;
493			if (Ldmax < MINLDMAX) Ldmax = DEFLDMAX;
494	greg	3.16	if (gamval < MINGAM) gamval = tms->mongam;
495	greg	3.1	/* compute handy values */
496			Ldmin = Ldmax/Lddyn;
497			logLddyn = log(Lddyn);
498			Ldavg = sqrt(Ldmax*Ldmin);
499	greg	3.16	i = (tms->hbrmin-MINBRT)/HISTEP;
500	greg	3.1	brt0 = MINBRT + HISTEP/2 + i*HISTEP;
501	greg	3.16	histlen = (tms->hbrmax-MINBRT)/HISTEP + 1 - i;
502	greg	3.1	/* histogram total and mean */
503			histot = 0; sum = 0;
504			j = brt0 + histlen*HISTEP;
505			for (i = histlen; i--; ) {
506	greg	3.16	histot += tms->histo[i];
507			sum += (j -= HISTEP) * tms->histo[i];
508	greg	3.1	}
509	greg	3.14	threshold = histot*0.005 + .5;
510	greg	3.29	if (!histot)
511	greg	3.1	returnErr(TM_E_TMFAIL);
512			Lwavg = tmLuminance( (double)sum / histot );
513	greg	3.29	/* use linear tone mapping? */
514			if (tms->flags & TM_F_LINEAR \|\| threshold < 4)
515			goto linearmap;
516	greg	3.9	/* allocate space for mapping */
517	greg	3.16	if (!tmNewMap(tms))
518	greg	3.9	returnErr(TM_E_NOMEM);
519			/* clamp histogram */
520			histo = (int )malloc(histlensizeof(int));
521			cumf = (float )malloc((histlen+2)sizeof(float));
522	schorsch	3.13	if ((histo == NULL) \| (cumf == NULL))
523	greg	3.9	returnErr(TM_E_NOMEM);
524			cumf[histlen+1] = 1.; /* guard for assignment code */
525			for (i = histlen; i--; ) /* make malleable copy */
526	greg	3.16	histo[i] = tms->histo[i];
527	greg	3.9	do { /* iterate to solution */
528			sum = 0; /* cumulative probability */
529			for (i = 0; i < histlen; i++) {
530			cumf[i] = (double)sum/histot;
531			sum += histo[i];
532			}
533			cumf[histlen] = 1.;
534	greg	3.16	Tr = histot * (double)(tms->hbrmax - tms->hbrmin) /
535	greg	3.9	((double)histlen*TM_BRTSCALE) / logLddyn;
536			ceiling = Tr + 1.;
537			trimmings = 0; /* clip to envelope */
538			for (i = histlen; i--; ) {
539	greg	3.16	if (tms->flags & TM_F_HCONTR) {
540	greg	3.9	Lw = tmLuminance(brt0 + i*HISTEP);
541			Ld = Ldmin * exp( logLddyn *
542			.5*(cumf[i]+cumf[i+1]) );
543			ceiling = Tr * (htcontrs(Ld) * Lw) /
544			(htcontrs(Lw) * Ld) + 1.;
545	greg	3.2	}
546	greg	3.9	if (histo[i] > ceiling) {
547			trimmings += histo[i] - ceiling;
548			histo[i] = ceiling;
549	greg	3.1	}
550			}
551	greg	3.9	/* check if we're out of data */
552			if ((histot -= trimmings) <= threshold) {
553			free((MEM_PTR)histo);
554			free((MEM_PTR)cumf);
555			goto linearmap;
556			}
557			} while (trimmings > threshold);
558			/* assign tone-mapping */
559	greg	3.16	for (i = tms->mbrmax-tms->mbrmin+1; i--; ) {
560			j = d = (double)i/(tms->mbrmax-tms->mbrmin)*histlen;
561	greg	3.9	d -= (double)j;
562			Ld = Ldminexp(logLddyn((1.-d)cumf[j]+dcumf[j+1]));
563			d = (Ld - Ldmin)/(Ldmax - Ldmin);
564	greg	3.16	tms->lumap[i] = 256.*pow(d, 1./gamval);
565	greg	3.1	}
566	greg	3.9	free((MEM_PTR)histo); /* clean up and return */
567			free((MEM_PTR)cumf);
568	greg	3.1	returnOK;
569	greg	3.9	linearmap: /* linear tone-mapping */
570	greg	3.16	if (tms->flags & TM_F_HCONTR)
571	greg	3.9	d = htcontrs(Ldavg) / htcontrs(Lwavg);
572			else
573			d = Ldavg / Lwavg;
574	greg	3.16	return(tmFixedMapping(tms, tms->inpsf*d/Ldmax, gamval));
575	greg	3.1	}
576
577
578			int
579	greg	3.16	tmMapPixels( /* apply tone-mapping to pixel(s) */
580			TMstruct *tms,
581			BYTE *ps,
582			TMbright *ls,
583			BYTE *cs,
584			int len
585			)
586	greg	3.1	{
587	greg	3.17	static const char funcName[] = "tmMapPixels";
588	greg	3.16	int32 li, pv;
589	greg	3.1
590	greg	3.16	if (tms == NULL \|\| tms->lumap == NULL)
591	greg	3.1	returnErr(TM_E_TMINVAL);
592	schorsch	3.13	if ((ps == NULL) \| (ls == NULL) \| (len < 0))
593	greg	3.1	returnErr(TM_E_ILLEGAL);
594			while (len--) {
595	greg	3.16	if ((li = *ls++) < tms->mbrmin) {
596	greg	3.9	li = 0;
597			} else {
598	greg	3.16	if (li > tms->mbrmax)
599			li = tms->mbrmax;
600			li = tms->lumap[li - tms->mbrmin];
601	greg	3.9	}
602	greg	3.1	if (cs == TM_NOCHROM)
603			*ps++ = li>255 ? 255 : li;
604			else {
605	greg	3.16	pv = cs++ li / tms->cdiv[RED];
606	greg	3.1	*ps++ = pv>255 ? 255 : pv;
607	greg	3.16	pv = cs++ li / tms->cdiv[GRN];
608	greg	3.1	*ps++ = pv>255 ? 255 : pv;
609	greg	3.16	pv = cs++ li / tms->cdiv[BLU];
610	greg	3.1	*ps++ = pv>255 ? 255 : pv;
611			}
612			}
613			returnOK;
614			}
615
616
617
618
619	greg	3.16	TMstruct *
620			tmDup( /* duplicate top tone mapping */
621			TMstruct *tms
622			)
623	greg	3.3	{
624			int len;
625	greg	3.16	int i;
626			TMstruct *tmnew;
627	greg	3.3
628	greg	3.16	if (tms == NULL) /* anything to duplicate? */
629	greg	3.3	return(NULL);
630	greg	3.16	tmnew = (TMstruct *)malloc(sizeof(TMstruct));
631	greg	3.3	if (tmnew == NULL)
632			return(NULL);
633	greg	3.16	tmnew = tms; /* copy everything */
634	greg	3.3	if (tmnew->histo != NULL) { /* duplicate histogram */
635	gregl	3.6	len = (tmnew->hbrmax-MINBRT)/HISTEP + 1 -
636			(tmnew->hbrmin-MINBRT)/HISTEP;
637	greg	3.3	tmnew->histo = (int )malloc(lensizeof(int));
638			if (tmnew->histo != NULL)
639			for (i = len; i--; )
640	greg	3.16	tmnew->histo[i] = tms->histo[i];
641	greg	3.3	}
642			if (tmnew->lumap != NULL) { /* duplicate luminance mapping */
643	gregl	3.6	len = tmnew->mbrmax-tmnew->mbrmin+1;
644	greg	3.3	tmnew->lumap = (unsigned short *)malloc(
645			len*sizeof(unsigned short) );
646			if (tmnew->lumap != NULL)
647			for (i = len; i--; )
648	greg	3.16	tmnew->lumap[i] = tms->lumap[i];
649	greg	3.3	}
650	greg	3.4	/* clear package data */
651			for (i = tmNumPkgs; i--; )
652			tmnew->pd[i] = NULL;
653	greg	3.16	/* return copy */
654			return(tmnew);
655	greg	3.1	}
656
657
658			void
659			tmDone(tms) /* done with tone mapping -- destroy it */
660	greg	3.16	TMstruct *tms;
661	greg	3.1	{
662	greg	3.16	int i;
663			/* NULL arg. is equiv. to tms */
664			if (tms == NULL)
665	greg	3.1	return;
666			/* free tables */
667			if (tms->histo != NULL)
668	greg	3.4	free((MEM_PTR)tms->histo);
669	greg	3.1	if (tms->lumap != NULL)
670	greg	3.4	free((MEM_PTR)tms->lumap);
671			/* free private data */
672			for (i = tmNumPkgs; i--; )
673			if (tms->pd[i] != NULL)
674			(*tmPkg[i]->Free)(tms->pd[i]);
675			free((MEM_PTR)tms); /* free basic structure */
676	greg	3.9	}
677
678			/****************** Shared but Private library routines *******************/
679
680			BYTE tmMesofact[BMESUPPER-BMESLOWER];
681
682			void
683			tmMkMesofact() /* build mesopic lookup factor table */
684			{
685	greg	3.16	int i;
686	greg	3.9
687			if (tmMesofact[BMESUPPER-BMESLOWER-1])
688			return;
689
690			for (i = BMESLOWER; i < BMESUPPER; i++)
691			tmMesofact[i-BMESLOWER] = 256. *
692			(tmLuminance(i) - LMESLOWER) /
693			(LMESUPPER - LMESLOWER);
694			}
695
696
697			int
698	greg	3.16	tmErrorReturn( /* error return (with message) */
699	greg	3.17	const char *func,
700	greg	3.16	TMstruct *tms,
701			int err
702			)
703	greg	3.9	{
704	greg	3.17	if (tms != NULL) {
705			tms->lastFunc = func;
706			tms->lastError = err;
707			if (tms->flags & TM_F_NOSTDERR)
708			return(err);
709			}
710	greg	3.9	fputs(func, stderr);
711			fputs(": ", stderr);
712			fputs(tmErrorMessage[err], stderr);
713			fputs("!\n", stderr);
714			return(err);
715	greg	3.1	}