src/common/tonemap.h

/* RCSid $Id$ */
/*
 * Header file for tone mapping functions.
 *
 * Include after "color.h"
 */

#include "copyright.h"

#ifdef __cplusplus
extern "C" {
#endif

/****    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_NOBRT        (-1<<15)        /* bogus brightness value */
#define TM_NOLUM        (1e-17)         /* ridiculously small luminance */

#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 */
extern int      tmLastError;            /* last error incurred by library */
extern char     *tmLastFunction;        /* error-generating function name */

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        hbrmin, hbrmax; /* histogram brightness limits */       
        int             *histo;         /* input histogram */
        TMbright        mbrmin, mbrmax; /* mapped brightness limits */
        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);
        void            (*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)*(1./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 int      tmSetSpace(), tmPull(), tmPush();
extern void     tmClearHisto(), tmDone();
extern int      tmAddHisto();
extern int      tmFixedMapping(), tmComputeMapping(), tmMapPixels();
extern int      tmCvColors(), tmCvGrays(), tmCvColrs();
extern int      tmLoadPicture(), tmMapPicture();

#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
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
tmFixedMapping(double expmult, double gamval);
/*
        Assign a fixed, linear tone-mapping using the given multiplier,
        which is the ratio of maximum output to uncalibrated input.
        This mapping will be used in subsequent calls to tmMapPixels()
        until a new tone mapping is computed.
        Only the min. and max. values are used from the histogram.
        
        expmult -       the fixed exposure multiplier to use.
        gamval  -       display gamma response (0. for default).
        returns -       0 on success, TM_E_* on error.
*/

extern int
tmComputeMapping(double gamval, double Lddyn, double Ldmax);
/*
        Compute tone mapping function from the current histogram.
        This mapping will be used in subsequent calls to tmMapPixels()
        until a new tone mapping is computed.
        I.e., calls to tmAddHisto() have no immediate effect.

        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 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.
*/

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
tmCvGrays(TMbright *ls, float *scan, int len);
/*
        Convert gray float scanline to encoded luminance.

        ls      -       returned encoded luminance values.
        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
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, picture 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, picture 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.
*/

#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.
*/

#ifdef __cplusplus
}
#endif
Revision:	3.12
Committed:	Tue Feb 25 02:47:22 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R5
Changes since 3.11:	+2 -57 lines
Log Message:	Replaced inline copyright notice with #include "copyright.h"
#	User	Rev	Content
1	greg	3.12	/* RCSid $Id$ */
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
8	greg	3.12	#include "copyright.h"
9	greg	3.11
10			#ifdef __cplusplus
11			extern "C" {
12			#endif
13	greg	3.4
14	greg	3.1	/** Argument Macros **/
15			/* Flags of what to do */
16			#define TM_F_HCONTR 01 /* human contrast sensitivity */
17			#define TM_F_MESOPIC 02 /* mesopic color sensitivity */
18			#define TM_F_LINEAR 04 /* linear brightness mapping */
19			#define TM_F_ACUITY 010 /* acuity adjustment */
20			#define TM_F_VEIL 020 /* veiling glare */
21			#define TM_F_CWEIGHT 040 /* center weighting */
22			#define TM_F_FOVEAL 0100 /* use foveal sample size */
23			#define TM_F_BW 0200 /* luminance only */
24	greg	3.2	#define TM_F_NOSTDERR 0400 /* don't report errors to stderr */
25	greg	3.1	/* combined modes */
26			#define TM_F_CAMERA 0
27			#define TM_F_HUMAN (TM_F_HCONTR\|TM_F_MESOPIC\|TM_F_VEIL\|\
28			TM_F_ACUITY\|TM_F_FOVEAL)
29			#define TM_F_UNIMPL (TM_F_CWEIGHT\|TM_F_VEIL\|TM_F_ACUITY\|TM_F_FOVEAL)
30
31			/* special pointer values */
32			#define TM_XYZPRIM (RGBPRIMP)NULL /* indicate XYZ primaries (Note 1) */
33			#define TM_NOCHROM (BYTE )NULL / indicate no chrominance */
34			#define TM_NOCHROMP (BYTE *)NULL / indicate no chrominances */
35			#define TM_GETFILE (FILE )NULL / indicate file must be opened */
36	gwlarson	3.8
37	greg	3.1
38			/** Error Return Values **/
39
40			#define TM_E_OK 0 /* normal return status */
41			#define TM_E_NOMEM 1 /* out of memory */
42			#define TM_E_ILLEGAL 2 /* illegal argument value */
43			#define TM_E_TMINVAL 3 /* no valid tone mapping */
44			#define TM_E_TMFAIL 4 /* cannot compute tone mapping */
45			#define TM_E_BADFILE 5 /* cannot open or understand file */
46	greg	3.4	#define TM_E_CODERR1 6 /* code consistency error 1 */
47			#define TM_E_CODERR2 7 /* code consistency error 2 */
48	greg	3.1
49	greg	3.4
50	greg	3.1	/** Conversion Constants and Table Sizes **/
51
52			#define TM_BRTSCALE 128 /* brightness scale factor (integer) */
53
54	gwlarson	3.10	#define TM_NOBRT (-1<<15) /* bogus brightness value */
55	greg	3.11	#define TM_NOLUM (1e-17) /* ridiculously small luminance */
56	gwlarson	3.10
57	greg	3.4	#define TM_MAXPKG 8 /* maximum number of color formats */
58	greg	3.1
59
60	greg	3.4	/** Global Data Types and Structures **/
61
62			#ifndef MEM_PTR
63			#define MEM_PTR void *
64			#endif
65
66	greg	3.1	extern char tmErrorMessage[]; / error messages */
67	gregl	3.6	extern int tmLastError; /* last error incurred by library */
68			extern char tmLastFunction; / error-generating function name */
69	greg	3.1
70			typedef short TMbright; /* encoded luminance type */
71
72			/* basic tone mapping data structure */
73			extern struct tmStruct {
74			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			COLORMAT cmat; /* color conversion matrix */
82	gregl	3.7	TMbright hbrmin, hbrmax; /* histogram brightness limits */
83	greg	3.1	int histo; / input histogram */
84	gregl	3.7	TMbright mbrmin, mbrmax; /* mapped brightness limits */
85	greg	3.1	unsigned short lumap; / computed luminance map */
86			struct tmStruct tmprev; / previous tone mapping */
87	greg	3.4	MEM_PTR pd[TM_MAXPKG]; /* pointers to private data */
88	greg	3.1	} tmTop; / current tone mapping stack */
89	greg	3.4
90			/* conversion package functions */
91			#ifdef NOPROTO
92			struct tmPackage {
93			MEM_PTR (Init)(); / initialize private data */
94			void (NewSpace)(); / new input color space (optional) */
95			void (Free)(); / free private data */
96			};
97			#else
98			struct tmPackage {
99			MEM_PTR (Init)(struct tmStruct tms);
100	greg	3.11	void (NewSpace)(struct tmStruct tms);
101	greg	3.4	void (*Free)(MEM_PTR pp);
102			};
103			#endif
104			/* our list of conversion packages */
105			extern struct tmPackage *tmPkg[TM_MAXPKG];
106			extern int tmNumPkgs; /* number of registered packages */
107
108
109	greg	3.1	/** Useful Macros **/
110
111	greg	3.4	/* compute luminance from encoded value */
112	greg	3.11	#define tmLuminance(li) exp((li)*(1./TM_BRTSCALE))
113	greg	3.1
114	greg	3.4	/* does tone mapping need color matrix? */
115			#define tmNeedMatrix(t) ((t)->monpri != (t)->inppri)
116
117			/* register a conversion package */
118			#define tmRegPkg(pf) ( tmNumPkgs >= TM_MAXPKG ? -1 : \
119			(tmPkg[tmNumPkgs] = (pf), tmNumPkgs++) )
120
121			/* get the specific package's data */
122			#define tmPkgData(t,i) ((t)->pd[i]!=NULL ? (t)->pd[i] : (*tmPkg[i]->Init)(t))
123
124
125	greg	3.1	/** Library Function Calls **/
126
127	greg	3.4	#ifdef NOPROTO
128	greg	3.1
129	greg	3.3	extern struct tmStruct tmInit(), tmPop(), *tmDup();
130	greg	3.11	extern int tmSetSpace(), tmPull(), tmPush();
131	greg	3.1	extern void tmClearHisto(), tmDone();
132	greg	3.11	extern int tmAddHisto();
133			extern int tmFixedMapping(), tmComputeMapping(), tmMapPixels();
134			extern int tmCvColors(), tmCvGrays(), tmCvColrs();
135			extern int tmLoadPicture(), tmMapPicture();
136	greg	3.1
137			#else
138
139			extern struct tmStruct *
140			tmInit(int flags, RGBPRIMP monpri, double gamval);
141			/*
142			Initialize new tone mapping and push it onto stack.
143
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			returns - new tmTop, or NULL if insufficient memory.
149			*/
150
151			extern int
152			tmSetSpace(RGBPRIMP pri, double sf);
153			/*
154			Set color primaries and scale factor for incoming scanlines.
155
156			pri - RGB color input primaries (Note 1).
157			sf - scale factor to get to luminance in cd/m^2.
158
159			returns - 0 on success, TM_E_* code on failure.
160			*/
161
162			extern void
163			tmClearHisto(void);
164			/*
165			Clear histogram for current tone mapping.
166			*/
167
168			extern int
169			tmAddHisto(TMbright *ls, int len, int wt);
170			/*
171			Add brightness values to current histogram.
172
173			ls - encoded luminance values.
174			len - number of luminance values.
175			wt - integer weight to use for each value (usually 1 or -1).
176
177			returns - 0 on success, TM_E_* on error.
178			*/
179
180			extern int
181	greg	3.11	tmFixedMapping(double expmult, double gamval);
182			/*
183			Assign a fixed, linear tone-mapping using the given multiplier,
184			which is the ratio of maximum output to uncalibrated input.
185			This mapping will be used in subsequent calls to tmMapPixels()
186			until a new tone mapping is computed.
187			Only the min. and max. values are used from the histogram.
188
189			expmult - the fixed exposure multiplier to use.
190			gamval - display gamma response (0. for default).
191			returns - 0 on success, TM_E_* on error.
192			*/
193
194			extern int
195	greg	3.1	tmComputeMapping(double gamval, double Lddyn, double Ldmax);
196			/*
197	greg	3.11	Compute tone mapping function from the current histogram.
198			This mapping will be used in subsequent calls to tmMapPixels()
199			until a new tone mapping is computed.
200			I.e., calls to tmAddHisto() have no immediate effect.
201	greg	3.1
202			gamval - display gamma response (0. for default).
203			Lddyn - the display's dynamic range (0. for default).
204			Ldmax - maximum display luminance in cd/m^2 (0. for default).
205
206			returns - 0 on success, TM_E_* on failure.
207			*/
208
209			extern int
210			tmMapPixels(BYTE ps, TMbright ls, BYTE *cs, int len);
211			/*
212			Apply tone mapping function to pixel values.
213
214			ps - returned pixel values (Note 2).
215			ls - encoded luminance values.
216			cs - encoded chrominance values (Note 2).
217			len - number of pixels.
218
219			returns - 0 on success, TM_E_* on failure.
220			*/
221
222			extern struct tmStruct *
223			tmPop(void);
224			/*
225			Pops current tone mapping from stack.
226
227			returns - pointer to tone mapping structure, or NULL if none.
228			*/
229
230			extern int
231			tmPull(struct tmStruct *tms);
232			/*
233			Pull tone mapping from anywhere in stack.
234
235			tms - tone mapping structure to find.
236
237			returns - 1 if found in stack, 0 otherwise.
238			*/
239
240			extern int
241			tmPush(struct tmStruct *tms);
242			/*
243			Make tone mapping active by (pulling it and) pushing it to the top.
244
245			tms - initialized tone mapping structure.
246
247			returns - 0 on success, TM_E_* if tms is invalid.
248			*/
249
250	greg	3.3	extern struct tmStruct *
251			tmDup(void);
252			/*
253			Duplicate the current tone mapping into a new structure on the stack.
254
255			returns - pointer to new top, or NULL on error.
256			*/
257
258	greg	3.1	extern void
259			tmDone(struct tmStruct *tms);
260			/*
261			Free data associated with the given tone mapping structure.
262			Calls tmPull() first to remove it from the stack if present.
263			The calls tmDone(tmPop()), tmDone(tmTop) and tmDone(NULL)
264			all have the same effect, which is to remove and free
265			the current tone mapping.
266
267			tms - tone mapping structure to free.
268			*/
269
270	greg	3.11	extern int
271			tmCvColors(TMbright ls, BYTE cs, COLOR *scan, int len);
272			/*
273			Convert RGB/XYZ float scanline to encoded luminance and chrominance.
274
275			ls - returned encoded luminance values.
276			cs - returned encoded chrominance values (Note 2).
277			scan - input scanline.
278			len - scanline length.
279
280			returns - 0 on success, TM_E_* on error.
281			*/
282
283			extern int
284			tmCvGrays(TMbright ls, float scan, int len);
285			/*
286			Convert gray float scanline to encoded luminance.
287
288			ls - returned encoded luminance values.
289			scan - input scanline.
290			len - scanline length.
291
292			returns - 0 on success, TM_E_* on error.
293			*/
294
295			extern int
296			tmCvColrs(TMbright ls, BYTE cs, COLR *scan, int len);
297			/*
298			Convert RGBE/XYZE scanline to encoded luminance and chrominance.
299
300			ls - returned encoded luminance values.
301			cs - returned encoded chrominance values (Note 2).
302			scan - input scanline.
303			len - scanline length.
304
305			returns - 0 on success, TM_E_* on error.
306			*/
307
308			extern int
309			tmLoadPicture(TMbright lpp, BYTE cpp, int xp, int yp,
310			char fname, FILE fp);
311			/*
312			Load Radiance picture and convert to tone mapping representation.
313			Memory for the luminance and chroma arrays is allocated using
314			malloc(3), and should be freed with free(3) when no longer needed.
315			Calls tmSetSpace() to calibrate input color space.
316
317			lpp - returned array of encoded luminances, picture ordering.
318			cpp - returned array of encoded chrominances (Note 2).
319			xp, yp - returned picture dimensions.
320			fname - picture file name.
321			fp - pointer to open file (Note 3).
322
323			returns - 0 on success, TM_E_* on failure.
324			*/
325
326			extern int
327			tmMapPicture(BYTE *psp, int xp, int *yp, int flags,
328			RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax,
329			char fname, FILE fp);
330			/*
331			Load and apply tone mapping to Radiance picture.
332			Stack is restored to its original state upon return.
333			If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture()
334			calls pcond to perform the actual conversion, which takes
335			longer but gives access to all the TM_F_* features.
336			Memory for the final pixel array is allocated using malloc(3),
337			and should be freed with free(3) when it is no longer needed.
338
339			psp - returned array of tone mapped pixels, picture ordering.
340			xp, yp - returned picture dimensions.
341			flags - TM_F_* flags indicating what is to be done.
342			monpri - display monitor primaries (Note 1).
343			gamval - display gamma response.
344			Lddyn - the display's dynamic range (0. for default).
345			Ldmax - maximum display luminance in cd/m^2 (0. for default).
346			fname - picture file name.
347			fp - pointer to open file (Note 3).
348
349			returns - 0 on success, TM_E_* on failure.
350			*/
351
352	greg	3.1	#endif
353	greg	3.4
354
355	greg	3.1	/** Notes **/
356			/*
357			General:
358
359			The usual sequence after calling tmInit() is to convert some
360			pixel values to chroma and luminance encodings, which can
361			be passed to tmAddHisto() to put into the tone mapping histogram.
362			This histogram is then used along with the display parameters
363	greg	3.5	by tmComputeMapping() to compute the luminance mapping function.
364	greg	3.1	(Colors are tone-mapped as they are converted if TM_F_MESOPIC
365			is set.) The encoded chroma and luminance values may then be
366			passed to tmMapPixels() to apply the computed tone mapping in
367			a second pass.
368
369			Especially for RGBE colors in the same color space as the
370			target display, the conversion to chroma and luminance values
371			is fast enough that it may be recomputed on the second pass
372			if memory is at a premium. (Since the chroma values are only
373			used during final mapping, setting the cs parameter to TM_NOCHROM
374			on the first pass will save time.) Another memory saving option
375			if third and subsequent passes are not needed is to use the
376	greg	3.3	same array to store the mapped pixels as used to store
377	greg	3.1	the encoded chroma values. This way, only two extra bytes
378			for storing encoded luminances are required per pixel. This
379			is the method employed by tmMapPicture(), for example.
380			*/
381			/*
382			Note 1:
383
384			All RGBPRIMP values should be pointers to static structures.
385			I.e., the same pointer should be used for the same primaries,
386			and those primaries should not change from one call to the next.
387			This is because the routines use the pointer value to identify
388			computed conversion matrices, so the matrices do not have to be
389			rebuilt each time. If you are using the standard primaries,
390			use the standard primary pointer, stdprims.
391
392			To indicate a set of input primaries are actually CIE XYZ,
393			the TM_XYZPRIM macro may be passed. If the input primaries
394			are unknown, it is wisest to pass tmTop->monpri to tmSetSpace().
395			By default, the input primaries equal the monitor primaries
396			and the scalefactor is set to WHTEFFICACY in tmInit().
397			*/
398			/*
399			Note 2:
400
401			Chrominance is optional in most of these routines, whether
402			TM_F_BW is set or not. Passing a value of TM_NOCHROM (or
403			TM_NOCHROMP for picture reading) indicates that returned
404			color values are not desired.
405
406			If TM_NOCHROM is passed to a mapping routine expecting chroma
407			input, it will do without it and return luminance channel
408			rather than RGB pixel values. Otherwise, the array for
409			returned pixel values may be the same array used to pass
410			encoded chrominances if no other mappings are desired.
411			*/
412			/*
413			Note 3:
414
415			Picture files may either be opened by the calling routine or by
416			the library function. If opened by the calling routine, the
417			pointer to the stream is passed, which may be a pipe or other
418			non-seekable input as it is only read once. It must be
419			positioned at the beginning when the function is called, and it
420			will be positioned at the end on return. It will not be closed.
421			If the passed stream pointer is TM_GETFILE, then the library
422			function will open the file, read its contents and close it
423			before returning, whether or not an error was encountered.
424			*/
425	greg	3.11
426			#ifdef __cplusplus
427			}
428			#endif