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.
        Memory for the luminance and chroma arrays is allocated using
        malloc(3), and should be freed with free(3) when no longer needed.
        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.
        Memory for the final pixel array is allocated using malloc(3),
        and should be freed with free(3) when it is no longer needed.

        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 tmComputeMapping() 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:	3.5
Committed:	Mon Apr 21 15:23:42 1997 UTC (27 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.4:	+5 -1 lines
Log Message:	small comment changes
#	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	3.5	Memory for the luminance and chroma arrays is allocated using
226			malloc(3), and should be freed with free(3) when no longer needed.
227	greg	3.3	Calls tmSetSpace() to calibrate input color space.
228	greg	3.1
229			lpp - returned array of encoded luminances, English ordering.
230			cpp - returned array of encoded chrominances (Note 2).
231			xp, yp - returned picture dimensions.
232			fname - picture file name.
233			fp - pointer to open file (Note 3).
234
235			returns - 0 on success, TM_E_* on failure.
236			*/
237
238			extern int
239			tmMapPicture(BYTE *psp, int xp, int *yp, int flags,
240			RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax,
241			char fname, FILE fp);
242			/*
243			Load and apply tone mapping to Radiance picture.
244			Stack is restored to its original state upon return.
245			If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture()
246			calls pcond to perform the actual conversion, which takes
247			longer but gives access to all the TM_F_* features.
248	greg	3.5	Memory for the final pixel array is allocated using malloc(3),
249			and should be freed with free(3) when it is no longer needed.
250	greg	3.1
251			psp - returned array of tone mapped pixels, English ordering.
252			xp, yp - returned picture dimensions.
253			flags - TM_F_* flags indicating what is to be done.
254			monpri - display monitor primaries (Note 1).
255			gamval - display gamma response.
256			Lddyn - the display's dynamic range (0. for default).
257			Ldmax - maximum display luminance in cd/m^2 (0. for default).
258			fname - picture file name.
259			fp - pointer to open file (Note 3).
260
261			returns - 0 on success, TM_E_* on failure.
262			*/
263
264			extern struct tmStruct *
265			tmPop(void);
266			/*
267			Pops current tone mapping from stack.
268
269			returns - pointer to tone mapping structure, or NULL if none.
270			*/
271
272			extern int
273			tmPull(struct tmStruct *tms);
274			/*
275			Pull tone mapping from anywhere in stack.
276
277			tms - tone mapping structure to find.
278
279			returns - 1 if found in stack, 0 otherwise.
280			*/
281
282			extern int
283			tmPush(struct tmStruct *tms);
284			/*
285			Make tone mapping active by (pulling it and) pushing it to the top.
286
287			tms - initialized tone mapping structure.
288
289			returns - 0 on success, TM_E_* if tms is invalid.
290			*/
291
292	greg	3.3	extern struct tmStruct *
293			tmDup(void);
294			/*
295			Duplicate the current tone mapping into a new structure on the stack.
296
297			returns - pointer to new top, or NULL on error.
298			*/
299
300	greg	3.1	extern void
301			tmDone(struct tmStruct *tms);
302			/*
303			Free data associated with the given tone mapping structure.
304			Calls tmPull() first to remove it from the stack if present.
305			The calls tmDone(tmPop()), tmDone(tmTop) and tmDone(NULL)
306			all have the same effect, which is to remove and free
307			the current tone mapping.
308
309			tms - tone mapping structure to free.
310			*/
311
312			#endif
313	greg	3.4
314
315	greg	3.1	/** Notes **/
316			/*
317			General:
318
319			The usual sequence after calling tmInit() is to convert some
320			pixel values to chroma and luminance encodings, which can
321			be passed to tmAddHisto() to put into the tone mapping histogram.
322			This histogram is then used along with the display parameters
323	greg	3.5	by tmComputeMapping() to compute the luminance mapping function.
324	greg	3.1	(Colors are tone-mapped as they are converted if TM_F_MESOPIC
325			is set.) The encoded chroma and luminance values may then be
326			passed to tmMapPixels() to apply the computed tone mapping in
327			a second pass.
328
329			Especially for RGBE colors in the same color space as the
330			target display, the conversion to chroma and luminance values
331			is fast enough that it may be recomputed on the second pass
332			if memory is at a premium. (Since the chroma values are only
333			used during final mapping, setting the cs parameter to TM_NOCHROM
334			on the first pass will save time.) Another memory saving option
335			if third and subsequent passes are not needed is to use the
336	greg	3.3	same array to store the mapped pixels as used to store
337	greg	3.1	the encoded chroma values. This way, only two extra bytes
338			for storing encoded luminances are required per pixel. This
339			is the method employed by tmMapPicture(), for example.
340			*/
341			/*
342			Note 1:
343
344			All RGBPRIMP values should be pointers to static structures.
345			I.e., the same pointer should be used for the same primaries,
346			and those primaries should not change from one call to the next.
347			This is because the routines use the pointer value to identify
348			computed conversion matrices, so the matrices do not have to be
349			rebuilt each time. If you are using the standard primaries,
350			use the standard primary pointer, stdprims.
351
352			To indicate a set of input primaries are actually CIE XYZ,
353			the TM_XYZPRIM macro may be passed. If the input primaries
354			are unknown, it is wisest to pass tmTop->monpri to tmSetSpace().
355			By default, the input primaries equal the monitor primaries
356			and the scalefactor is set to WHTEFFICACY in tmInit().
357			*/
358			/*
359			Note 2:
360
361			Chrominance is optional in most of these routines, whether
362			TM_F_BW is set or not. Passing a value of TM_NOCHROM (or
363			TM_NOCHROMP for picture reading) indicates that returned
364			color values are not desired.
365
366			If TM_NOCHROM is passed to a mapping routine expecting chroma
367			input, it will do without it and return luminance channel
368			rather than RGB pixel values. Otherwise, the array for
369			returned pixel values may be the same array used to pass
370			encoded chrominances if no other mappings are desired.
371			*/
372			/*
373			Note 3:
374
375			Picture files may either be opened by the calling routine or by
376			the library function. If opened by the calling routine, the
377			pointer to the stream is passed, which may be a pipe or other
378			non-seekable input as it is only read once. It must be
379			positioned at the beginning when the function is called, and it
380			will be positioned at the end on return. It will not be closed.
381			If the passed stream pointer is TM_GETFILE, then the library
382			function will open the file, read its contents and close it
383			before returning, whether or not an error was encountered.
384			*/