src/common/tonemap.h

/* Copyright (c) 1997 Regents of the University of California */

/* SCCSid "$SunId$ LBL" */

/*
 * Header file for tone mapping functions.
 */
                                /* required non-system header files */
#include        "color.h"


/****    Argument Macros    ****/
                                /* Flags of what to do */
#define TM_F_HCONTR     01              /* human contrast sensitivity */
#define TM_F_MESOPIC    02              /* mesopic color sensitivity */
#define TM_F_LINEAR     04              /* linear brightness mapping */
#define TM_F_ACUITY     010             /* acuity adjustment */
#define TM_F_VEIL       020             /* veiling glare */
#define TM_F_CWEIGHT    040             /* center weighting */
#define TM_F_FOVEAL     0100            /* use foveal sample size */
#define TM_F_BW         0200            /* luminance only */
#define TM_F_NOSTDERR   0400            /* don't report errors to stderr */
                                /* combined modes */
#define TM_F_CAMERA     0
#define TM_F_HUMAN      (TM_F_HCONTR|TM_F_MESOPIC|TM_F_VEIL|\
                                TM_F_ACUITY|TM_F_FOVEAL)
#define TM_F_UNIMPL     (TM_F_CWEIGHT|TM_F_VEIL|TM_F_ACUITY|TM_F_FOVEAL)

                                /* special pointer values */
#define TM_XYZPRIM      (RGBPRIMP)NULL  /* indicate XYZ primaries (Note 1) */
#define TM_NOCHROM      (BYTE *)NULL    /* indicate no chrominance */
#define TM_NOCHROMP     (BYTE **)NULL   /* indicate no chrominances */
#define TM_GETFILE      (FILE *)NULL    /* indicate file must be opened */

/****    Error Return Values    ****/

#define TM_E_OK         0               /* normal return status */
#define TM_E_NOMEM      1               /* out of memory */
#define TM_E_ILLEGAL    2               /* illegal argument value */
#define TM_E_TMINVAL    3               /* no valid tone mapping */
#define TM_E_TMFAIL     4               /* cannot compute tone mapping */
#define TM_E_BADFILE    5               /* cannot open or understand file */
#define TM_E_CODERR1    6               /* code consistency error 1 */
#define TM_E_CODERR2    7               /* code consistency error 2 */


/****    Conversion Constants and Table Sizes    ****/

#define TM_BRTSCALE     128             /* brightness scale factor (integer) */

#define TM_MAXPKG       8               /* maximum number of color formats */


/****    Global Data Types and Structures    ****/

#ifndef MEM_PTR
#define MEM_PTR         void *
#endif

extern char     *tmErrorMessage[];      /* error messages */

typedef short   TMbright;               /* encoded luminance type */

                                /* basic tone mapping data structure */
extern struct tmStruct {
        int             flags;          /* flags of what to do */
        RGBPRIMP        monpri;         /* monitor RGB primaries */
        double          mongam;         /* monitor gamma value (approx.) */
        COLOR           clf;            /* computed luminance coefficients */
        int             cdiv[3];        /* computed color divisors */
        RGBPRIMP        inppri;         /* current input primaries */
        double          inpsf;          /* current input scalefactor */
        COLORMAT        cmat;           /* color conversion matrix */
        TMbright        brmin, brmax;   /* input brightness limits */   
        int             *histo;         /* input histogram */
        unsigned short  *lumap;         /* computed luminance map */
        struct tmStruct *tmprev;        /* previous tone mapping */
        MEM_PTR         pd[TM_MAXPKG];  /* pointers to private data */
}       *tmTop;                 /* current tone mapping stack */

                                /* conversion package functions */
#ifdef  NOPROTO
struct tmPackage {
        MEM_PTR         (*Init)();      /* initialize private data */
        void            (*NewSpace)();  /* new input color space (optional) */
        void            (*Free)();      /* free private data */
};
#else
struct tmPackage {
        MEM_PTR         (*Init)(struct tmStruct *tms);
        int             (*NewSpace)(struct tmStruct *tms);
        void            (*Free)(MEM_PTR pp);
};
#endif
                                /* our list of conversion packages */
extern struct tmPackage *tmPkg[TM_MAXPKG];
extern int      tmNumPkgs;      /* number of registered packages */


/****    Useful Macros    ****/

                                /* compute luminance from encoded value */
#define tmLuminance(li) exp((li)/(double)TM_BRTSCALE)

                                /* does tone mapping need color matrix? */
#define tmNeedMatrix(t) ((t)->monpri != (t)->inppri)

                                /* register a conversion package */
#define tmRegPkg(pf)    ( tmNumPkgs >= TM_MAXPKG ? -1 : \
                                (tmPkg[tmNumPkgs] = (pf), tmNumPkgs++) )

                                /* get the specific package's data */
#define tmPkgData(t,i)  ((t)->pd[i]!=NULL ? (t)->pd[i] : (*tmPkg[i]->Init)(t))


/****    Library Function Calls    ****/

#ifdef  NOPROTO

extern struct tmStruct  *tmInit(), *tmPop(), *tmDup();
extern void     tmClearHisto(), tmDone();
extern int      tmSetSpace(), tmCvColors(), tmCvColrs();
extern int      tmAddHisto(), tmComputeMapping(), tmMapPixels();
extern int      tmLoadPicture(), tmMapPicture(), tmPull(), tmPush();

#else

extern struct tmStruct *
tmInit(int flags, RGBPRIMP monpri, double gamval);
/*
        Initialize new tone mapping and push it onto stack.

        flags   -       TM_F_* flags indicating what is to be done.
        monpri  -       display monitor primaries (Note 1).
        gamval  -       display gamma response (can be approximate).

        returns -       new tmTop, or NULL if insufficient memory.
*/

extern int
tmSetSpace(RGBPRIMP pri, double sf);
/*
        Set color primaries and scale factor for incoming scanlines.

        pri     -       RGB color input primaries (Note 1).
        sf      -       scale factor to get to luminance in cd/m^2.

        returns -       0 on success, TM_E_* code on failure.
*/

extern void
tmClearHisto(void);
/*
        Clear histogram for current tone mapping.
*/

extern int
tmCvColors(TMbright *ls, BYTE *cs, COLOR *scan, int len);
/*
        Convert RGB/XYZ float scanline to encoded luminance and chrominance.

        ls      -       returned encoded luminance values.
        cs      -       returned encoded chrominance values (Note 2).
        scan    -       input scanline.
        len     -       scanline length.

        returns -       0 on success, TM_E_* on error.
*/

extern int
tmCvColrs(TMbright *ls, BYTE *cs, COLR *scan, int len);
/*
        Convert RGBE/XYZE scanline to encoded luminance and chrominance.

        ls      -       returned encoded luminance values.
        cs      -       returned encoded chrominance values (Note 2).
        scan    -       input scanline.
        len     -       scanline length.

        returns -       0 on success, TM_E_* on error.
*/

extern int
tmAddHisto(TMbright *ls, int len, int wt);
/*
        Add brightness values to current histogram.

        ls      -       encoded luminance values.
        len     -       number of luminance values.
        wt      -       integer weight to use for each value (usually 1 or -1).

        returns -       0 on success, TM_E_* on error.
*/

extern int
tmComputeMapping(double gamval, double Lddyn, double Ldmax);
/*
        Compute tone mapping function.

        gamval  -       display gamma response (0. for default).
        Lddyn   -       the display's dynamic range (0. for default).
        Ldmax   -       maximum display luminance in cd/m^2 (0. for default).

        returns -       0 on success, TM_E_* on failure.
*/

extern int
tmMapPixels(BYTE *ps, TMbright *ls, BYTE *cs, int len);
/*
        Apply tone mapping function to pixel values.

        ps      -       returned pixel values (Note 2).
        ls      -       encoded luminance values.
        cs      -       encoded chrominance values (Note 2).
        len     -       number of pixels.

        returns -       0 on success, TM_E_* on failure.
*/

extern int
tmLoadPicture(TMbright **lpp, BYTE **cpp, int *xp, int *yp,
                char *fname, FILE *fp);
/*
        Load Radiance picture and convert to tone mapping representation.
        Calls tmSetSpace() to calibrate input color space.

        lpp     -       returned array of encoded luminances, English ordering.
        cpp     -       returned array of encoded chrominances (Note 2).
        xp, yp  -       returned picture dimensions.
        fname   -       picture file name.
        fp      -       pointer to open file (Note 3).

        returns -       0 on success, TM_E_* on failure.
*/

extern int
tmMapPicture(BYTE **psp, int *xp, int *yp, int flags,
                RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax,
                char *fname, FILE *fp);
/*
        Load and apply tone mapping to Radiance picture.
        Stack is restored to its original state upon return.
        If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture()
        calls pcond to perform the actual conversion, which takes
        longer but gives access to all the TM_F_* features.

        psp     -       returned array of tone mapped pixels, English ordering.
        xp, yp  -       returned picture dimensions.
        flags   -       TM_F_* flags indicating what is to be done.
        monpri  -       display monitor primaries (Note 1).
        gamval  -       display gamma response.
        Lddyn   -       the display's dynamic range (0. for default).
        Ldmax   -       maximum display luminance in cd/m^2 (0. for default).
        fname   -       picture file name.
        fp      -       pointer to open file (Note 3).

        returns -       0 on success, TM_E_* on failure.
*/

extern struct tmStruct *
tmPop(void);
/*
        Pops current tone mapping from stack.

        returns -       pointer to tone mapping structure, or NULL if none.
*/

extern int
tmPull(struct tmStruct *tms);
/*
        Pull tone mapping from anywhere in stack.

        tms     -       tone mapping structure to find.

        returns -       1 if found in stack, 0 otherwise.
*/

extern int
tmPush(struct tmStruct *tms);
/*
        Make tone mapping active by (pulling it and) pushing it to the top.

        tms     -       initialized tone mapping structure.

        returns -       0 on success, TM_E_* if tms is invalid.
*/

extern struct tmStruct *
tmDup(void);
/*
        Duplicate the current tone mapping into a new structure on the stack.

        returns -       pointer to new top, or NULL on error.
*/

extern void
tmDone(struct tmStruct *tms);
/*
        Free data associated with the given tone mapping structure.
        Calls tmPull() first to remove it from the stack if present.
        The calls tmDone(tmPop()), tmDone(tmTop) and tmDone(NULL)
        all have the same effect, which is to remove and free
        the current tone mapping.

        tms     -       tone mapping structure to free.
*/

#endif


/****    Notes    ****/
/*
        General:

        The usual sequence after calling tmInit() is to convert some
        pixel values to chroma and luminance encodings, which can
        be passed to tmAddHisto() to put into the tone mapping histogram.
        This histogram is then used along with the display parameters
        by tmComputMapping() to compute the luminance mapping function.
        (Colors are tone-mapped as they are converted if TM_F_MESOPIC
        is set.)  The encoded chroma and luminance values may then be
        passed to tmMapPixels() to apply the computed tone mapping in
        a second pass.

        Especially for RGBE colors in the same color space as the
        target display, the conversion to chroma and luminance values
        is fast enough that it may be recomputed on the second pass
        if memory is at a premium.  (Since the chroma values are only
        used during final mapping, setting the cs parameter to TM_NOCHROM
        on the first pass will save time.)  Another memory saving option
        if third and subsequent passes are not needed is to use the
        same array to store the mapped pixels as used to store
        the encoded chroma values.  This way, only two extra bytes
        for storing encoded luminances are required per pixel.  This
        is the method employed by tmMapPicture(), for example.
*/
/*
        Note 1:

        All RGBPRIMP values should be pointers to static structures.
        I.e., the same pointer should be used for the same primaries,
        and those primaries should not change from one call to the next.
        This is because the routines use the pointer value to identify
        computed conversion matrices, so the matrices do not have to be
        rebuilt each time.  If you are using the standard primaries,
        use the standard primary pointer, stdprims.

        To indicate a set of input primaries are actually CIE XYZ,
        the TM_XYZPRIM macro may be passed.  If the input primaries
        are unknown, it is wisest to pass tmTop->monpri to tmSetSpace().
        By default, the input primaries equal the monitor primaries
        and the scalefactor is set to WHTEFFICACY in tmInit().
*/
/*
        Note 2:

        Chrominance is optional in most of these routines, whether
        TM_F_BW is set or not.  Passing a value of TM_NOCHROM (or
        TM_NOCHROMP for picture reading) indicates that returned
        color values are not desired.
        
        If TM_NOCHROM is passed to a mapping routine expecting chroma
        input, it will do without it and return luminance channel
        rather than RGB pixel values.  Otherwise, the array for
        returned pixel values may be the same array used to pass
        encoded chrominances if no other mappings are desired.
*/
/*
        Note 3:

        Picture files may either be opened by the calling routine or by
        the library function.  If opened by the calling routine, the
        pointer to the stream is passed, which may be a pipe or other
        non-seekable input as it is only read once.  It must be
        positioned at the beginning when the function is called, and it
        will be positioned at the end on return.  It will not be closed.
        If the passed stream pointer is TM_GETFILE, then the library
        function will open the file, read its contents and close it
        before returning, whether or not an error was encountered.
*/
Revision:	3.4
Committed:	Fri Apr 18 13:59:48 1997 UTC (27 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.3:	+48 -8 lines
Log Message:	added notion of conversion packages with private data
#	User	Rev	Content
1	greg	3.1	/* Copyright (c) 1997 Regents of the University of California */
2
3			/* SCCSid "$SunId$ LBL" */
4
5			/*
6			* Header file for tone mapping functions.
7			*/
8			/* required non-system header files */
9			#include "color.h"
10
11	greg	3.4
12	greg	3.1	/** Argument Macros **/
13			/* Flags of what to do */
14			#define TM_F_HCONTR 01 /* human contrast sensitivity */
15			#define TM_F_MESOPIC 02 /* mesopic color sensitivity */
16			#define TM_F_LINEAR 04 /* linear brightness mapping */
17			#define TM_F_ACUITY 010 /* acuity adjustment */
18			#define TM_F_VEIL 020 /* veiling glare */
19			#define TM_F_CWEIGHT 040 /* center weighting */
20			#define TM_F_FOVEAL 0100 /* use foveal sample size */
21			#define TM_F_BW 0200 /* luminance only */
22	greg	3.2	#define TM_F_NOSTDERR 0400 /* don't report errors to stderr */
23	greg	3.1	/* combined modes */
24			#define TM_F_CAMERA 0
25			#define TM_F_HUMAN (TM_F_HCONTR\|TM_F_MESOPIC\|TM_F_VEIL\|\
26			TM_F_ACUITY\|TM_F_FOVEAL)
27			#define TM_F_UNIMPL (TM_F_CWEIGHT\|TM_F_VEIL\|TM_F_ACUITY\|TM_F_FOVEAL)
28
29			/* special pointer values */
30			#define TM_XYZPRIM (RGBPRIMP)NULL /* indicate XYZ primaries (Note 1) */
31			#define TM_NOCHROM (BYTE )NULL / indicate no chrominance */
32			#define TM_NOCHROMP (BYTE *)NULL / indicate no chrominances */
33			#define TM_GETFILE (FILE )NULL / indicate file must be opened */
34
35			/** Error Return Values **/
36
37			#define TM_E_OK 0 /* normal return status */
38			#define TM_E_NOMEM 1 /* out of memory */
39			#define TM_E_ILLEGAL 2 /* illegal argument value */
40			#define TM_E_TMINVAL 3 /* no valid tone mapping */
41			#define TM_E_TMFAIL 4 /* cannot compute tone mapping */
42			#define TM_E_BADFILE 5 /* cannot open or understand file */
43	greg	3.4	#define TM_E_CODERR1 6 /* code consistency error 1 */
44			#define TM_E_CODERR2 7 /* code consistency error 2 */
45	greg	3.1
46	greg	3.4
47	greg	3.1	/** Conversion Constants and Table Sizes **/
48
49			#define TM_BRTSCALE 128 /* brightness scale factor (integer) */
50
51	greg	3.4	#define TM_MAXPKG 8 /* maximum number of color formats */
52	greg	3.1
53
54	greg	3.4	/** Global Data Types and Structures **/
55
56			#ifndef MEM_PTR
57			#define MEM_PTR void *
58			#endif
59
60	greg	3.1	extern char tmErrorMessage[]; / error messages */
61
62			typedef short TMbright; /* encoded luminance type */
63
64			/* basic tone mapping data structure */
65			extern struct tmStruct {
66			int flags; /* flags of what to do */
67			RGBPRIMP monpri; /* monitor RGB primaries */
68			double mongam; /* monitor gamma value (approx.) */
69			COLOR clf; /* computed luminance coefficients */
70	greg	3.4	int cdiv[3]; /* computed color divisors */
71	greg	3.1	RGBPRIMP inppri; /* current input primaries */
72			double inpsf; /* current input scalefactor */
73			COLORMAT cmat; /* color conversion matrix */
74			TMbright brmin, brmax; /* input brightness limits */
75			int histo; / input histogram */
76			unsigned short lumap; / computed luminance map */
77			struct tmStruct tmprev; / previous tone mapping */
78	greg	3.4	MEM_PTR pd[TM_MAXPKG]; /* pointers to private data */
79	greg	3.1	} tmTop; / current tone mapping stack */
80	greg	3.4
81			/* conversion package functions */
82			#ifdef NOPROTO
83			struct tmPackage {
84			MEM_PTR (Init)(); / initialize private data */
85			void (NewSpace)(); / new input color space (optional) */
86			void (Free)(); / free private data */
87			};
88			#else
89			struct tmPackage {
90			MEM_PTR (Init)(struct tmStruct tms);
91			int (NewSpace)(struct tmStruct tms);
92			void (*Free)(MEM_PTR pp);
93			};
94			#endif
95			/* our list of conversion packages */
96			extern struct tmPackage *tmPkg[TM_MAXPKG];
97			extern int tmNumPkgs; /* number of registered packages */
98
99
100	greg	3.1	/** Useful Macros **/
101
102	greg	3.4	/* compute luminance from encoded value */
103	greg	3.1	#define tmLuminance(li) exp((li)/(double)TM_BRTSCALE)
104
105	greg	3.4	/* does tone mapping need color matrix? */
106			#define tmNeedMatrix(t) ((t)->monpri != (t)->inppri)
107
108			/* register a conversion package */
109			#define tmRegPkg(pf) ( tmNumPkgs >= TM_MAXPKG ? -1 : \
110			(tmPkg[tmNumPkgs] = (pf), tmNumPkgs++) )
111
112			/* get the specific package's data */
113			#define tmPkgData(t,i) ((t)->pd[i]!=NULL ? (t)->pd[i] : (*tmPkg[i]->Init)(t))
114
115
116	greg	3.1	/** Library Function Calls **/
117
118	greg	3.4	#ifdef NOPROTO
119	greg	3.1
120	greg	3.3	extern struct tmStruct tmInit(), tmPop(), *tmDup();
121	greg	3.1	extern void tmClearHisto(), tmDone();
122			extern int tmSetSpace(), tmCvColors(), tmCvColrs();
123			extern int tmAddHisto(), tmComputeMapping(), tmMapPixels();
124			extern int tmLoadPicture(), tmMapPicture(), tmPull(), tmPush();
125
126			#else
127
128			extern struct tmStruct *
129			tmInit(int flags, RGBPRIMP monpri, double gamval);
130			/*
131			Initialize new tone mapping and push it onto stack.
132
133			flags - TM_F_* flags indicating what is to be done.
134			monpri - display monitor primaries (Note 1).
135			gamval - display gamma response (can be approximate).
136
137			returns - new tmTop, or NULL if insufficient memory.
138			*/
139
140			extern int
141			tmSetSpace(RGBPRIMP pri, double sf);
142			/*
143			Set color primaries and scale factor for incoming scanlines.
144
145			pri - RGB color input primaries (Note 1).
146			sf - scale factor to get to luminance in cd/m^2.
147
148			returns - 0 on success, TM_E_* code on failure.
149			*/
150
151			extern void
152			tmClearHisto(void);
153			/*
154			Clear histogram for current tone mapping.
155			*/
156
157			extern int
158			tmCvColors(TMbright ls, BYTE cs, COLOR *scan, int len);
159			/*
160			Convert RGB/XYZ float scanline to encoded luminance and chrominance.
161
162			ls - returned encoded luminance values.
163			cs - returned encoded chrominance values (Note 2).
164			scan - input scanline.
165			len - scanline length.
166
167			returns - 0 on success, TM_E_* on error.
168			*/
169
170			extern int
171			tmCvColrs(TMbright ls, BYTE cs, COLR *scan, int len);
172			/*
173			Convert RGBE/XYZE scanline to encoded luminance and chrominance.
174
175			ls - returned encoded luminance values.
176			cs - returned encoded chrominance values (Note 2).
177			scan - input scanline.
178			len - scanline length.
179
180			returns - 0 on success, TM_E_* on error.
181			*/
182
183			extern int
184			tmAddHisto(TMbright *ls, int len, int wt);
185			/*
186			Add brightness values to current histogram.
187
188			ls - encoded luminance values.
189			len - number of luminance values.
190			wt - integer weight to use for each value (usually 1 or -1).
191
192			returns - 0 on success, TM_E_* on error.
193			*/
194
195			extern int
196			tmComputeMapping(double gamval, double Lddyn, double Ldmax);
197			/*
198			Compute tone mapping function.
199
200			gamval - display gamma response (0. for default).
201			Lddyn - the display's dynamic range (0. for default).
202			Ldmax - maximum display luminance in cd/m^2 (0. for default).
203
204			returns - 0 on success, TM_E_* on failure.
205			*/
206
207			extern int
208			tmMapPixels(BYTE ps, TMbright ls, BYTE *cs, int len);
209			/*
210			Apply tone mapping function to pixel values.
211
212			ps - returned pixel values (Note 2).
213			ls - encoded luminance values.
214			cs - encoded chrominance values (Note 2).
215			len - number of pixels.
216
217			returns - 0 on success, TM_E_* on failure.
218			*/
219
220			extern int
221			tmLoadPicture(TMbright lpp, BYTE cpp, int xp, int yp,
222			char fname, FILE fp);
223			/*
224			Load Radiance picture and convert to tone mapping representation.
225	greg	3.3	Calls tmSetSpace() to calibrate input color space.
226	greg	3.1
227			lpp - returned array of encoded luminances, English ordering.
228			cpp - returned array of encoded chrominances (Note 2).
229			xp, yp - returned picture dimensions.
230			fname - picture file name.
231			fp - pointer to open file (Note 3).
232
233			returns - 0 on success, TM_E_* on failure.
234			*/
235
236			extern int
237			tmMapPicture(BYTE *psp, int xp, int *yp, int flags,
238			RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax,
239			char fname, FILE fp);
240			/*
241			Load and apply tone mapping to Radiance picture.
242			Stack is restored to its original state upon return.
243			If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture()
244			calls pcond to perform the actual conversion, which takes
245			longer but gives access to all the TM_F_* features.
246
247			psp - returned array of tone mapped pixels, English ordering.
248			xp, yp - returned picture dimensions.
249			flags - TM_F_* flags indicating what is to be done.
250			monpri - display monitor primaries (Note 1).
251			gamval - display gamma response.
252			Lddyn - the display's dynamic range (0. for default).
253			Ldmax - maximum display luminance in cd/m^2 (0. for default).
254			fname - picture file name.
255			fp - pointer to open file (Note 3).
256
257			returns - 0 on success, TM_E_* on failure.
258			*/
259
260			extern struct tmStruct *
261			tmPop(void);
262			/*
263			Pops current tone mapping from stack.
264
265			returns - pointer to tone mapping structure, or NULL if none.
266			*/
267
268			extern int
269			tmPull(struct tmStruct *tms);
270			/*
271			Pull tone mapping from anywhere in stack.
272
273			tms - tone mapping structure to find.
274
275			returns - 1 if found in stack, 0 otherwise.
276			*/
277
278			extern int
279			tmPush(struct tmStruct *tms);
280			/*
281			Make tone mapping active by (pulling it and) pushing it to the top.
282
283			tms - initialized tone mapping structure.
284
285			returns - 0 on success, TM_E_* if tms is invalid.
286			*/
287
288	greg	3.3	extern struct tmStruct *
289			tmDup(void);
290			/*
291			Duplicate the current tone mapping into a new structure on the stack.
292
293			returns - pointer to new top, or NULL on error.
294			*/
295
296	greg	3.1	extern void
297			tmDone(struct tmStruct *tms);
298			/*
299			Free data associated with the given tone mapping structure.
300			Calls tmPull() first to remove it from the stack if present.
301			The calls tmDone(tmPop()), tmDone(tmTop) and tmDone(NULL)
302			all have the same effect, which is to remove and free
303			the current tone mapping.
304
305			tms - tone mapping structure to free.
306			*/
307
308			#endif
309	greg	3.4
310
311	greg	3.1	/** Notes **/
312			/*
313			General:
314
315			The usual sequence after calling tmInit() is to convert some
316			pixel values to chroma and luminance encodings, which can
317			be passed to tmAddHisto() to put into the tone mapping histogram.
318			This histogram is then used along with the display parameters
319			by tmComputMapping() to compute the luminance mapping function.
320			(Colors are tone-mapped as they are converted if TM_F_MESOPIC
321			is set.) The encoded chroma and luminance values may then be
322			passed to tmMapPixels() to apply the computed tone mapping in
323			a second pass.
324
325			Especially for RGBE colors in the same color space as the
326			target display, the conversion to chroma and luminance values
327			is fast enough that it may be recomputed on the second pass
328			if memory is at a premium. (Since the chroma values are only
329			used during final mapping, setting the cs parameter to TM_NOCHROM
330			on the first pass will save time.) Another memory saving option
331			if third and subsequent passes are not needed is to use the
332	greg	3.3	same array to store the mapped pixels as used to store
333	greg	3.1	the encoded chroma values. This way, only two extra bytes
334			for storing encoded luminances are required per pixel. This
335			is the method employed by tmMapPicture(), for example.
336			*/
337			/*
338			Note 1:
339
340			All RGBPRIMP values should be pointers to static structures.
341			I.e., the same pointer should be used for the same primaries,
342			and those primaries should not change from one call to the next.
343			This is because the routines use the pointer value to identify
344			computed conversion matrices, so the matrices do not have to be
345			rebuilt each time. If you are using the standard primaries,
346			use the standard primary pointer, stdprims.
347
348			To indicate a set of input primaries are actually CIE XYZ,
349			the TM_XYZPRIM macro may be passed. If the input primaries
350			are unknown, it is wisest to pass tmTop->monpri to tmSetSpace().
351			By default, the input primaries equal the monitor primaries
352			and the scalefactor is set to WHTEFFICACY in tmInit().
353			*/
354			/*
355			Note 2:
356
357			Chrominance is optional in most of these routines, whether
358			TM_F_BW is set or not. Passing a value of TM_NOCHROM (or
359			TM_NOCHROMP for picture reading) indicates that returned
360			color values are not desired.
361
362			If TM_NOCHROM is passed to a mapping routine expecting chroma
363			input, it will do without it and return luminance channel
364			rather than RGB pixel values. Otherwise, the array for
365			returned pixel values may be the same array used to pass
366			encoded chrominances if no other mappings are desired.
367			*/
368			/*
369			Note 3:
370
371			Picture files may either be opened by the calling routine or by
372			the library function. If opened by the calling routine, the
373			pointer to the stream is passed, which may be a pipe or other
374			non-seekable input as it is only read once. It must be
375			positioned at the beginning when the function is called, and it
376			will be positioned at the end on return. It will not be closed.
377			If the passed stream pointer is TM_GETFILE, then the library
378			function will open the file, read its contents and close it
379			before returning, whether or not an error was encountered.
380			*/