| 1 | greg | 3.25 | /* RCSid $Id: tonemap.h,v 3.24 2010/07/27 16:13:40 greg Exp $ */ | 
| 2 | greg | 3.1 | /* | 
| 3 |  |  | * Header file for tone mapping functions. | 
| 4 | gwlarson | 3.8 | * | 
| 5 |  |  | * Include after "color.h" | 
| 6 | greg | 3.1 | */ | 
| 7 | schorsch | 3.13 | #ifndef _RAD_TONEMAP_H_ | 
| 8 |  |  | #define _RAD_TONEMAP_H_ | 
| 9 | schorsch | 3.16 |  | 
| 10 | greg | 3.23 | #include        "tiff.h"        /* needed for int32, etc. */ | 
| 11 | schorsch | 3.16 |  | 
| 12 | greg | 3.11 | #ifdef __cplusplus | 
| 13 |  |  | extern "C" { | 
| 14 |  |  | #endif | 
| 15 | greg | 3.15 |  | 
| 16 | greg | 3.1 | /****    Argument Macros    ****/ | 
| 17 | greg | 3.20 | /* flags of what to do */ | 
| 18 | greg | 3.1 | #define TM_F_HCONTR     01              /* human contrast sensitivity */ | 
| 19 |  |  | #define TM_F_MESOPIC    02              /* mesopic color sensitivity */ | 
| 20 |  |  | #define TM_F_LINEAR     04              /* linear brightness mapping */ | 
| 21 |  |  | #define TM_F_ACUITY     010             /* acuity adjustment */ | 
| 22 |  |  | #define TM_F_VEIL       020             /* veiling glare */ | 
| 23 |  |  | #define TM_F_CWEIGHT    040             /* center weighting */ | 
| 24 |  |  | #define TM_F_FOVEAL     0100            /* use foveal sample size */ | 
| 25 |  |  | #define TM_F_BW         0200            /* luminance only */ | 
| 26 | greg | 3.2 | #define TM_F_NOSTDERR   0400            /* don't report errors to stderr */ | 
| 27 | greg | 3.1 | /* combined modes */ | 
| 28 |  |  | #define TM_F_CAMERA     0 | 
| 29 |  |  | #define TM_F_HUMAN      (TM_F_HCONTR|TM_F_MESOPIC|TM_F_VEIL|\ | 
| 30 |  |  | TM_F_ACUITY|TM_F_FOVEAL) | 
| 31 |  |  | #define TM_F_UNIMPL     (TM_F_CWEIGHT|TM_F_VEIL|TM_F_ACUITY|TM_F_FOVEAL) | 
| 32 |  |  |  | 
| 33 |  |  | /* special pointer values */ | 
| 34 |  |  | #define TM_XYZPRIM      (RGBPRIMP)NULL  /* indicate XYZ primaries (Note 1) */ | 
| 35 |  |  | #define TM_NOCHROM      (BYTE *)NULL    /* indicate no chrominance */ | 
| 36 |  |  | #define TM_NOCHROMP     (BYTE **)NULL   /* indicate no chrominances */ | 
| 37 |  |  | #define TM_GETFILE      (FILE *)NULL    /* indicate file must be opened */ | 
| 38 | gwlarson | 3.8 |  | 
| 39 | greg | 3.1 |  | 
| 40 |  |  | /****    Error Return Values    ****/ | 
| 41 |  |  |  | 
| 42 |  |  | #define TM_E_OK         0               /* normal return status */ | 
| 43 |  |  | #define TM_E_NOMEM      1               /* out of memory */ | 
| 44 |  |  | #define TM_E_ILLEGAL    2               /* illegal argument value */ | 
| 45 |  |  | #define TM_E_TMINVAL    3               /* no valid tone mapping */ | 
| 46 |  |  | #define TM_E_TMFAIL     4               /* cannot compute tone mapping */ | 
| 47 |  |  | #define TM_E_BADFILE    5               /* cannot open or understand file */ | 
| 48 | greg | 3.4 | #define TM_E_CODERR1    6               /* code consistency error 1 */ | 
| 49 |  |  | #define TM_E_CODERR2    7               /* code consistency error 2 */ | 
| 50 | greg | 3.1 |  | 
| 51 | greg | 3.4 |  | 
| 52 | greg | 3.1 | /****    Conversion Constants and Table Sizes    ****/ | 
| 53 |  |  |  | 
| 54 | greg | 3.25 | #define TM_BRTSCALE     256             /* brightness scale factor (integer) */ | 
| 55 | greg | 3.1 |  | 
| 56 | gwlarson | 3.10 | #define TM_NOBRT        (-1<<15)        /* bogus brightness value */ | 
| 57 | greg | 3.11 | #define TM_NOLUM        (1e-17)         /* ridiculously small luminance */ | 
| 58 | gwlarson | 3.10 |  | 
| 59 | greg | 3.4 | #define TM_MAXPKG       8               /* maximum number of color formats */ | 
| 60 | greg | 3.1 |  | 
| 61 |  |  |  | 
| 62 | greg | 3.4 | /****    Global Data Types and Structures    ****/ | 
| 63 |  |  |  | 
| 64 |  |  | #ifndef MEM_PTR | 
| 65 |  |  | #define MEM_PTR         void * | 
| 66 |  |  | #endif | 
| 67 |  |  |  | 
| 68 | greg | 3.1 | extern char     *tmErrorMessage[];      /* error messages */ | 
| 69 |  |  |  | 
| 70 |  |  | typedef short   TMbright;               /* encoded luminance type */ | 
| 71 |  |  |  | 
| 72 |  |  | /* basic tone mapping data structure */ | 
| 73 | greg | 3.20 | typedef struct { | 
| 74 | greg | 3.1 | int             flags;          /* flags of what to do */ | 
| 75 |  |  | RGBPRIMP        monpri;         /* monitor RGB primaries */ | 
| 76 |  |  | double          mongam;         /* monitor gamma value (approx.) */ | 
| 77 |  |  | COLOR           clf;            /* computed luminance coefficients */ | 
| 78 | greg | 3.4 | int             cdiv[3];        /* computed color divisors */ | 
| 79 | greg | 3.1 | RGBPRIMP        inppri;         /* current input primaries */ | 
| 80 |  |  | double          inpsf;          /* current input scalefactor */ | 
| 81 | greg | 3.19 | MEM_PTR         inpdat;         /* current input client data */ | 
| 82 | greg | 3.1 | COLORMAT        cmat;           /* color conversion matrix */ | 
| 83 | gregl | 3.7 | TMbright        hbrmin, hbrmax; /* histogram brightness limits */ | 
| 84 | greg | 3.1 | int             *histo;         /* input histogram */ | 
| 85 | gregl | 3.7 | TMbright        mbrmin, mbrmax; /* mapped brightness limits */ | 
| 86 | greg | 3.1 | unsigned short  *lumap;         /* computed luminance map */ | 
| 87 | greg | 3.4 | MEM_PTR         pd[TM_MAXPKG];  /* pointers to private data */ | 
| 88 | greg | 3.18 | int             lastError;      /* last error incurred */ | 
| 89 |  |  | const char      *lastFunc;      /* error-generating function name */ | 
| 90 | greg | 3.17 | } TMstruct; | 
| 91 | greg | 3.4 |  | 
| 92 |  |  | /* conversion package functions */ | 
| 93 |  |  | struct tmPackage { | 
| 94 | greg | 3.17 | MEM_PTR         (*Init)(TMstruct *tms); | 
| 95 |  |  | void            (*NewSpace)(TMstruct *tms); | 
| 96 | greg | 3.4 | void            (*Free)(MEM_PTR pp); | 
| 97 |  |  | }; | 
| 98 |  |  | /* our list of conversion packages */ | 
| 99 |  |  | extern struct tmPackage *tmPkg[TM_MAXPKG]; | 
| 100 |  |  | extern int      tmNumPkgs;      /* number of registered packages */ | 
| 101 |  |  |  | 
| 102 |  |  |  | 
| 103 | greg | 3.1 | /****    Useful Macros    ****/ | 
| 104 |  |  |  | 
| 105 | greg | 3.4 | /* compute luminance from encoded value */ | 
| 106 | greg | 3.11 | #define tmLuminance(li) exp((li)*(1./TM_BRTSCALE)) | 
| 107 | greg | 3.1 |  | 
| 108 | greg | 3.4 | /* does tone mapping need color matrix? */ | 
| 109 |  |  | #define tmNeedMatrix(t) ((t)->monpri != (t)->inppri) | 
| 110 |  |  |  | 
| 111 |  |  | /* register a conversion package */ | 
| 112 |  |  | #define tmRegPkg(pf)    ( tmNumPkgs >= TM_MAXPKG ? -1 : \ | 
| 113 |  |  | (tmPkg[tmNumPkgs] = (pf), tmNumPkgs++) ) | 
| 114 |  |  |  | 
| 115 |  |  | /* get the specific package's data */ | 
| 116 |  |  | #define tmPkgData(t,i)  ((t)->pd[i]!=NULL ? (t)->pd[i] : (*tmPkg[i]->Init)(t)) | 
| 117 |  |  |  | 
| 118 |  |  |  | 
| 119 | greg | 3.1 | /****    Library Function Calls    ****/ | 
| 120 |  |  |  | 
| 121 | greg | 3.21 | extern TMbright | 
| 122 |  |  | tmCvLuminance(double lum); | 
| 123 |  |  | /* | 
| 124 |  |  | Convert a single luminance value to an encoded brightness value. | 
| 125 |  |  | */ | 
| 126 | greg | 3.1 |  | 
| 127 | greg | 3.22 | extern int | 
| 128 |  |  | tmCvLums(TMbright *ls, float *scan, int len); | 
| 129 |  |  | /* | 
| 130 |  |  | Convert luminance values to encoded brightness values using lookup. | 
| 131 |  |  |  | 
| 132 |  |  | ls      -       returned encoded luminance values. | 
| 133 |  |  | scan    -       input scanline. | 
| 134 |  |  | len     -       scanline length. | 
| 135 |  |  |  | 
| 136 |  |  | returns -       0 on success, TM_E_* on error. | 
| 137 |  |  | */ | 
| 138 |  |  |  | 
| 139 | greg | 3.17 | extern TMstruct * | 
| 140 | greg | 3.1 | tmInit(int flags, RGBPRIMP monpri, double gamval); | 
| 141 |  |  | /* | 
| 142 | greg | 3.17 | Allocate and initialize new tone mapping. | 
| 143 | greg | 3.1 |  | 
| 144 |  |  | flags   -       TM_F_* flags indicating what is to be done. | 
| 145 |  |  | monpri  -       display monitor primaries (Note 1). | 
| 146 |  |  | gamval  -       display gamma response (can be approximate). | 
| 147 |  |  |  | 
| 148 | greg | 3.17 | returns -       new tone-mapping pointer, or NULL if no memory. | 
| 149 | greg | 3.1 | */ | 
| 150 |  |  |  | 
| 151 |  |  | extern int | 
| 152 | greg | 3.19 | tmSetSpace(TMstruct *tms, RGBPRIMP pri, double sf, MEM_PTR dat); | 
| 153 | greg | 3.1 | /* | 
| 154 |  |  | Set color primaries and scale factor for incoming scanlines. | 
| 155 |  |  |  | 
| 156 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 157 | greg | 3.1 | pri     -       RGB color input primaries (Note 1). | 
| 158 |  |  | sf      -       scale factor to get to luminance in cd/m^2. | 
| 159 | greg | 3.19 | dat     -       application-specific data (NULL if not needed) | 
| 160 | greg | 3.1 |  | 
| 161 |  |  | returns -       0 on success, TM_E_* code on failure. | 
| 162 |  |  | */ | 
| 163 |  |  |  | 
| 164 |  |  | extern void | 
| 165 | greg | 3.17 | tmClearHisto(TMstruct *tms); | 
| 166 | greg | 3.1 | /* | 
| 167 |  |  | Clear histogram for current tone mapping. | 
| 168 | greg | 3.17 |  | 
| 169 |  |  | tms     -       tone mapping structure pointer. | 
| 170 | greg | 3.1 | */ | 
| 171 |  |  |  | 
| 172 |  |  | extern int | 
| 173 | greg | 3.17 | tmAddHisto(TMstruct *tms, TMbright *ls, int len, int wt); | 
| 174 | greg | 3.1 | /* | 
| 175 |  |  | Add brightness values to current histogram. | 
| 176 |  |  |  | 
| 177 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 178 | greg | 3.1 | ls      -       encoded luminance values. | 
| 179 |  |  | len     -       number of luminance values. | 
| 180 |  |  | wt      -       integer weight to use for each value (usually 1 or -1). | 
| 181 |  |  |  | 
| 182 |  |  | returns -       0 on success, TM_E_* on error. | 
| 183 |  |  | */ | 
| 184 |  |  |  | 
| 185 |  |  | extern int | 
| 186 | greg | 3.17 | tmFixedMapping(TMstruct *tms, double expmult, double gamval); | 
| 187 | greg | 3.11 | /* | 
| 188 |  |  | Assign a fixed, linear tone-mapping using the given multiplier, | 
| 189 |  |  | which is the ratio of maximum output to uncalibrated input. | 
| 190 |  |  | This mapping will be used in subsequent calls to tmMapPixels() | 
| 191 |  |  | until a new tone mapping is computed. | 
| 192 |  |  | Only the min. and max. values are used from the histogram. | 
| 193 |  |  |  | 
| 194 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 195 | greg | 3.11 | expmult -       the fixed exposure multiplier to use. | 
| 196 |  |  | gamval  -       display gamma response (0. for default). | 
| 197 | greg | 3.18 |  | 
| 198 | greg | 3.11 | returns -       0 on success, TM_E_* on error. | 
| 199 |  |  | */ | 
| 200 |  |  |  | 
| 201 |  |  | extern int | 
| 202 | greg | 3.17 | tmComputeMapping(TMstruct *tms, double gamval, double Lddyn, double Ldmax); | 
| 203 | greg | 3.1 | /* | 
| 204 | greg | 3.11 | Compute tone mapping function from the current histogram. | 
| 205 |  |  | This mapping will be used in subsequent calls to tmMapPixels() | 
| 206 |  |  | until a new tone mapping is computed. | 
| 207 |  |  | I.e., calls to tmAddHisto() have no immediate effect. | 
| 208 | greg | 3.1 |  | 
| 209 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 210 | greg | 3.1 | gamval  -       display gamma response (0. for default). | 
| 211 |  |  | Lddyn   -       the display's dynamic range (0. for default). | 
| 212 |  |  | Ldmax   -       maximum display luminance in cd/m^2 (0. for default). | 
| 213 |  |  |  | 
| 214 |  |  | returns -       0 on success, TM_E_* on failure. | 
| 215 |  |  | */ | 
| 216 |  |  |  | 
| 217 |  |  | extern int | 
| 218 | greg | 3.17 | tmMapPixels(TMstruct *tms, BYTE *ps, TMbright *ls, BYTE *cs, int len); | 
| 219 | greg | 3.1 | /* | 
| 220 |  |  | Apply tone mapping function to pixel values. | 
| 221 |  |  |  | 
| 222 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 223 | greg | 3.1 | ps      -       returned pixel values (Note 2). | 
| 224 |  |  | ls      -       encoded luminance values. | 
| 225 |  |  | cs      -       encoded chrominance values (Note 2). | 
| 226 |  |  | len     -       number of pixels. | 
| 227 |  |  |  | 
| 228 |  |  | returns -       0 on success, TM_E_* on failure. | 
| 229 |  |  | */ | 
| 230 |  |  |  | 
| 231 | greg | 3.17 | extern TMstruct * | 
| 232 |  |  | tmDup(TMstruct *orig); | 
| 233 | greg | 3.3 | /* | 
| 234 | greg | 3.17 | Duplicate the given tone mapping into a new struct. | 
| 235 | greg | 3.3 |  | 
| 236 | greg | 3.17 | orig    -       tone mapping structure to duplicate. | 
| 237 | greg | 3.18 |  | 
| 238 | greg | 3.17 | returns -       pointer to new struct, or NULL on error. | 
| 239 | greg | 3.3 | */ | 
| 240 |  |  |  | 
| 241 | greg | 3.1 | extern void | 
| 242 | greg | 3.17 | tmDone(TMstruct *tms); | 
| 243 | greg | 3.1 | /* | 
| 244 |  |  | Free data associated with the given tone mapping structure. | 
| 245 |  |  |  | 
| 246 |  |  | tms     -       tone mapping structure to free. | 
| 247 |  |  | */ | 
| 248 |  |  |  | 
| 249 | greg | 3.11 | extern int | 
| 250 | greg | 3.22 | tmCvGrays(TMstruct *tms, TMbright *ls, float *scan, int len); | 
| 251 | greg | 3.11 | /* | 
| 252 | greg | 3.22 | Convert gray float scanline to encoded luminance. | 
| 253 | greg | 3.11 |  | 
| 254 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 255 | greg | 3.11 | ls      -       returned encoded luminance values. | 
| 256 |  |  | scan    -       input scanline. | 
| 257 |  |  | len     -       scanline length. | 
| 258 |  |  |  | 
| 259 |  |  | returns -       0 on success, TM_E_* on error. | 
| 260 |  |  | */ | 
| 261 |  |  |  | 
| 262 |  |  | extern int | 
| 263 | greg | 3.22 | tmCvColors(TMstruct *tms, TMbright *ls, BYTE *cs, COLOR *scan, int len); | 
| 264 | greg | 3.11 | /* | 
| 265 | greg | 3.22 | Convert RGB/XYZ float scanline to encoded luminance and chrominance. | 
| 266 | greg | 3.11 |  | 
| 267 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 268 | greg | 3.11 | ls      -       returned encoded luminance values. | 
| 269 | greg | 3.22 | cs      -       returned encoded chrominance values (Note 2). | 
| 270 | greg | 3.11 | scan    -       input scanline. | 
| 271 |  |  | len     -       scanline length. | 
| 272 |  |  |  | 
| 273 |  |  | returns -       0 on success, TM_E_* on error. | 
| 274 |  |  | */ | 
| 275 |  |  |  | 
| 276 |  |  | extern int | 
| 277 | greg | 3.17 | tmCvColrs(TMstruct *tms, TMbright *ls, BYTE *cs, COLR *scan, int len); | 
| 278 | greg | 3.11 | /* | 
| 279 |  |  | Convert RGBE/XYZE scanline to encoded luminance and chrominance. | 
| 280 |  |  |  | 
| 281 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 282 | greg | 3.11 | ls      -       returned encoded luminance values. | 
| 283 |  |  | cs      -       returned encoded chrominance values (Note 2). | 
| 284 |  |  | scan    -       input scanline. | 
| 285 |  |  | len     -       scanline length. | 
| 286 |  |  |  | 
| 287 |  |  | returns -       0 on success, TM_E_* on error. | 
| 288 |  |  | */ | 
| 289 |  |  |  | 
| 290 |  |  | extern int | 
| 291 | greg | 3.17 | tmLoadPicture(TMstruct *tms, TMbright **lpp, BYTE **cpp, int *xp, int *yp, | 
| 292 | greg | 3.11 | char *fname, FILE *fp); | 
| 293 |  |  | /* | 
| 294 |  |  | Load Radiance picture and convert to tone mapping representation. | 
| 295 |  |  | Memory for the luminance and chroma arrays is allocated using | 
| 296 |  |  | malloc(3), and should be freed with free(3) when no longer needed. | 
| 297 |  |  | Calls tmSetSpace() to calibrate input color space. | 
| 298 |  |  |  | 
| 299 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 300 | greg | 3.11 | lpp     -       returned array of encoded luminances, picture ordering. | 
| 301 |  |  | cpp     -       returned array of encoded chrominances (Note 2). | 
| 302 |  |  | xp, yp  -       returned picture dimensions. | 
| 303 |  |  | fname   -       picture file name. | 
| 304 |  |  | fp      -       pointer to open file (Note 3). | 
| 305 |  |  |  | 
| 306 |  |  | returns -       0 on success, TM_E_* on failure. | 
| 307 |  |  | */ | 
| 308 |  |  |  | 
| 309 |  |  | extern int | 
| 310 |  |  | tmMapPicture(BYTE **psp, int *xp, int *yp, int flags, | 
| 311 |  |  | RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax, | 
| 312 |  |  | char *fname, FILE *fp); | 
| 313 |  |  | /* | 
| 314 |  |  | Load and apply tone mapping to Radiance picture. | 
| 315 |  |  | If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture() | 
| 316 |  |  | calls pcond to perform the actual conversion, which takes | 
| 317 |  |  | longer but gives access to all the TM_F_* features. | 
| 318 |  |  | Memory for the final pixel array is allocated using malloc(3), | 
| 319 |  |  | and should be freed with free(3) when it is no longer needed. | 
| 320 |  |  |  | 
| 321 |  |  | psp     -       returned array of tone mapped pixels, picture ordering. | 
| 322 |  |  | xp, yp  -       returned picture dimensions. | 
| 323 |  |  | flags   -       TM_F_* flags indicating what is to be done. | 
| 324 |  |  | monpri  -       display monitor primaries (Note 1). | 
| 325 |  |  | gamval  -       display gamma response. | 
| 326 |  |  | Lddyn   -       the display's dynamic range (0. for default). | 
| 327 |  |  | Ldmax   -       maximum display luminance in cd/m^2 (0. for default). | 
| 328 |  |  | fname   -       picture file name. | 
| 329 |  |  | fp      -       pointer to open file (Note 3). | 
| 330 |  |  |  | 
| 331 |  |  | returns -       0 on success, TM_E_* on failure. | 
| 332 |  |  | */ | 
| 333 |  |  |  | 
| 334 | greg | 3.15 | extern int | 
| 335 | greg | 3.17 | tmCvRGB48(TMstruct *tms, TMbright *ls, BYTE *cs, uint16 (*scan)[3], | 
| 336 |  |  | int len, double gv); | 
| 337 | greg | 3.15 | /* | 
| 338 |  |  | Convert 48-bit RGB scanline to encoded luminance and chrominance. | 
| 339 |  |  |  | 
| 340 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 341 | greg | 3.15 | ls      -       returned encoded luminance values. | 
| 342 |  |  | cs      -       returned encoded chrominance values (Note 2). | 
| 343 |  |  | scan    -       input scanline. | 
| 344 |  |  | len     -       scanline length. | 
| 345 |  |  | gv      -       input gamma value. | 
| 346 |  |  |  | 
| 347 |  |  | returns -       0 on success, TM_E_* on error. | 
| 348 |  |  | */ | 
| 349 |  |  |  | 
| 350 |  |  | extern int | 
| 351 | greg | 3.17 | tmCvGray16(TMstruct *tms, TMbright *ls, uint16 *scan, int len, double gv); | 
| 352 | greg | 3.15 | /* | 
| 353 |  |  | Convert 16-bit gray scanline to encoded luminance. | 
| 354 |  |  |  | 
| 355 | greg | 3.17 | tms     -       tone mapping structure pointer. | 
| 356 | greg | 3.15 | ls      -       returned encoded luminance values. | 
| 357 |  |  | scan    -       input scanline. | 
| 358 |  |  | len     -       scanline length. | 
| 359 |  |  | gv      -       input gamma value. | 
| 360 | greg | 3.4 |  | 
| 361 | greg | 3.15 | returns -       0 on success, TM_E_* on error. | 
| 362 |  |  | */ | 
| 363 | greg | 3.4 |  | 
| 364 | greg | 3.1 | /****    Notes    ****/ | 
| 365 |  |  | /* | 
| 366 |  |  | General: | 
| 367 |  |  |  | 
| 368 |  |  | The usual sequence after calling tmInit() is to convert some | 
| 369 |  |  | pixel values to chroma and luminance encodings, which can | 
| 370 |  |  | be passed to tmAddHisto() to put into the tone mapping histogram. | 
| 371 |  |  | This histogram is then used along with the display parameters | 
| 372 | greg | 3.5 | by tmComputeMapping() to compute the luminance mapping function. | 
| 373 | greg | 3.1 | (Colors are tone-mapped as they are converted if TM_F_MESOPIC | 
| 374 |  |  | is set.)  The encoded chroma and luminance values may then be | 
| 375 |  |  | passed to tmMapPixels() to apply the computed tone mapping in | 
| 376 |  |  | a second pass. | 
| 377 |  |  |  | 
| 378 |  |  | Especially for RGBE colors in the same color space as the | 
| 379 |  |  | target display, the conversion to chroma and luminance values | 
| 380 |  |  | is fast enough that it may be recomputed on the second pass | 
| 381 |  |  | if memory is at a premium.  (Since the chroma values are only | 
| 382 |  |  | used during final mapping, setting the cs parameter to TM_NOCHROM | 
| 383 |  |  | on the first pass will save time.)  Another memory saving option | 
| 384 |  |  | if third and subsequent passes are not needed is to use the | 
| 385 | greg | 3.3 | same array to store the mapped pixels as used to store | 
| 386 | greg | 3.1 | the encoded chroma values.  This way, only two extra bytes | 
| 387 |  |  | for storing encoded luminances are required per pixel.  This | 
| 388 |  |  | is the method employed by tmMapPicture(), for example. | 
| 389 |  |  | */ | 
| 390 |  |  | /* | 
| 391 |  |  | Note 1: | 
| 392 |  |  |  | 
| 393 |  |  | All RGBPRIMP values should be pointers to static structures. | 
| 394 |  |  | I.e., the same pointer should be used for the same primaries, | 
| 395 |  |  | and those primaries should not change from one call to the next. | 
| 396 |  |  | This is because the routines use the pointer value to identify | 
| 397 |  |  | computed conversion matrices, so the matrices do not have to be | 
| 398 |  |  | rebuilt each time.  If you are using the standard primaries, | 
| 399 |  |  | use the standard primary pointer, stdprims. | 
| 400 |  |  |  | 
| 401 |  |  | To indicate a set of input primaries are actually CIE XYZ, | 
| 402 |  |  | the TM_XYZPRIM macro may be passed.  If the input primaries | 
| 403 |  |  | are unknown, it is wisest to pass tmTop->monpri to tmSetSpace(). | 
| 404 |  |  | By default, the input primaries equal the monitor primaries | 
| 405 |  |  | and the scalefactor is set to WHTEFFICACY in tmInit(). | 
| 406 |  |  | */ | 
| 407 |  |  | /* | 
| 408 |  |  | Note 2: | 
| 409 |  |  |  | 
| 410 |  |  | Chrominance is optional in most of these routines, whether | 
| 411 |  |  | TM_F_BW is set or not.  Passing a value of TM_NOCHROM (or | 
| 412 |  |  | TM_NOCHROMP for picture reading) indicates that returned | 
| 413 |  |  | color values are not desired. | 
| 414 |  |  |  | 
| 415 |  |  | If TM_NOCHROM is passed to a mapping routine expecting chroma | 
| 416 |  |  | input, it will do without it and return luminance channel | 
| 417 |  |  | rather than RGB pixel values.  Otherwise, the array for | 
| 418 |  |  | returned pixel values may be the same array used to pass | 
| 419 |  |  | encoded chrominances if no other mappings are desired. | 
| 420 |  |  | */ | 
| 421 |  |  | /* | 
| 422 |  |  | Note 3: | 
| 423 |  |  |  | 
| 424 |  |  | Picture files may either be opened by the calling routine or by | 
| 425 |  |  | the library function.  If opened by the calling routine, the | 
| 426 |  |  | pointer to the stream is passed, which may be a pipe or other | 
| 427 |  |  | non-seekable input as it is only read once.  It must be | 
| 428 |  |  | positioned at the beginning when the function is called, and it | 
| 429 |  |  | will be positioned at the end on return.  It will not be closed. | 
| 430 |  |  | If the passed stream pointer is TM_GETFILE, then the library | 
| 431 |  |  | function will open the file, read its contents and close it | 
| 432 |  |  | before returning, whether or not an error was encountered. | 
| 433 |  |  | */ | 
| 434 | greg | 3.11 |  | 
| 435 |  |  | #ifdef __cplusplus | 
| 436 |  |  | } | 
| 437 |  |  | #endif | 
| 438 | schorsch | 3.13 | #endif /* _RAD_TONEMAP_H_ */ | 
| 439 |  |  |  |