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/* Copyright (c) 1997 Regents of the University of California */ |
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|
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/* SCCSid "$SunId$ LBL" */ |
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|
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/* |
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* Header file for tone mapping functions. |
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*/ |
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/* required non-system header files */ |
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#include "color.h" |
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|
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/**** Argument Macros ****/ |
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/* Flags of what to do */ |
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#define TM_F_HCONTR 01 /* human contrast sensitivity */ |
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#define TM_F_MESOPIC 02 /* mesopic color sensitivity */ |
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#define TM_F_LINEAR 04 /* linear brightness mapping */ |
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#define TM_F_ACUITY 010 /* acuity adjustment */ |
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#define TM_F_VEIL 020 /* veiling glare */ |
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#define TM_F_CWEIGHT 040 /* center weighting */ |
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#define TM_F_FOVEAL 0100 /* use foveal sample size */ |
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#define TM_F_BW 0200 /* luminance only */ |
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#define TM_F_NOSTDERR 0400 /* don't report errors to stderr */ |
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/* combined modes */ |
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#define TM_F_CAMERA 0 |
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#define TM_F_HUMAN (TM_F_HCONTR|TM_F_MESOPIC|TM_F_VEIL|\ |
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TM_F_ACUITY|TM_F_FOVEAL) |
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#define TM_F_UNIMPL (TM_F_CWEIGHT|TM_F_VEIL|TM_F_ACUITY|TM_F_FOVEAL) |
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|
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/* special pointer values */ |
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#define TM_XYZPRIM (RGBPRIMP)NULL /* indicate XYZ primaries (Note 1) */ |
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#define TM_NOCHROM (BYTE *)NULL /* indicate no chrominance */ |
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#define TM_NOCHROMP (BYTE **)NULL /* indicate no chrominances */ |
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#define TM_GETFILE (FILE *)NULL /* indicate file must be opened */ |
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|
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/**** Error Return Values ****/ |
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|
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#define TM_E_OK 0 /* normal return status */ |
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#define TM_E_NOMEM 1 /* out of memory */ |
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#define TM_E_ILLEGAL 2 /* illegal argument value */ |
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#define TM_E_TMINVAL 3 /* no valid tone mapping */ |
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#define TM_E_TMFAIL 4 /* cannot compute tone mapping */ |
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#define TM_E_BADFILE 5 /* cannot open or understand file */ |
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|
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/**** Conversion Constants and Table Sizes ****/ |
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|
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#define TM_BRTSCALE 128 /* brightness scale factor (integer) */ |
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|
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#define TM_GAMTSZ 1024 /* gamma lookup table size */ |
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|
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/**** Global Data Structures ****/ |
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|
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extern char *tmErrorMessage[]; /* error messages */ |
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|
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typedef short TMbright; /* encoded luminance type */ |
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|
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/* basic tone mapping data structure */ |
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extern struct tmStruct { |
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int flags; /* flags of what to do */ |
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RGBPRIMP monpri; /* monitor RGB primaries */ |
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double mongam; /* monitor gamma value (approx.) */ |
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BYTE gamb[TM_GAMTSZ];/* gamma lookup table from mongam */ |
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COLOR clf; /* computed luminance coefficients */ |
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COLR clfb; /* normalized version of clf */ |
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RGBPRIMP inppri; /* current input primaries */ |
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double inpsf; /* current input scalefactor */ |
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TMbright inpsfb; /* encoded version of inpsf */ |
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COLORMAT cmat; /* color conversion matrix */ |
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TMbright brmin, brmax; /* input brightness limits */ |
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int *histo; /* input histogram */ |
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unsigned short *lumap; /* computed luminance map */ |
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struct tmStruct *tmprev; /* previous tone mapping */ |
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} *tmTop; /* current tone mapping stack */ |
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|
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/**** Useful Macros ****/ |
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|
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#define tmLuminance(li) exp((li)/(double)TM_BRTSCALE) |
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|
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/**** Library Function Calls ****/ |
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|
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#ifdef NOPROTO |
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|
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extern struct tmStruct *tmInit(), *tmPop(), *tmDup(); |
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extern void tmClearHisto(), tmDone(); |
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extern int tmSetSpace(), tmCvColors(), tmCvColrs(); |
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extern int tmAddHisto(), tmComputeMapping(), tmMapPixels(); |
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extern int tmLoadPicture(), tmMapPicture(), tmPull(), tmPush(); |
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|
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#else |
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|
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extern struct tmStruct * |
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tmInit(int flags, RGBPRIMP monpri, double gamval); |
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/* |
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Initialize new tone mapping and push it onto stack. |
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|
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flags - TM_F_* flags indicating what is to be done. |
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monpri - display monitor primaries (Note 1). |
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gamval - display gamma response (can be approximate). |
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|
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returns - new tmTop, or NULL if insufficient memory. |
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*/ |
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|
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extern int |
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tmSetSpace(RGBPRIMP pri, double sf); |
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/* |
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Set color primaries and scale factor for incoming scanlines. |
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|
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pri - RGB color input primaries (Note 1). |
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sf - scale factor to get to luminance in cd/m^2. |
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returns - 0 on success, TM_E_* code on failure. |
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*/ |
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|
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extern void |
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tmClearHisto(void); |
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/* |
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Clear histogram for current tone mapping. |
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*/ |
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|
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extern int |
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tmCvColors(TMbright *ls, BYTE *cs, COLOR *scan, int len); |
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/* |
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Convert RGB/XYZ float scanline to encoded luminance and chrominance. |
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|
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ls - returned encoded luminance values. |
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cs - returned encoded chrominance values (Note 2). |
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scan - input scanline. |
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len - scanline length. |
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returns - 0 on success, TM_E_* on error. |
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*/ |
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|
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extern int |
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tmCvColrs(TMbright *ls, BYTE *cs, COLR *scan, int len); |
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/* |
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Convert RGBE/XYZE scanline to encoded luminance and chrominance. |
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|
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ls - returned encoded luminance values. |
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cs - returned encoded chrominance values (Note 2). |
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scan - input scanline. |
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len - scanline length. |
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returns - 0 on success, TM_E_* on error. |
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*/ |
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|
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extern int |
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tmAddHisto(TMbright *ls, int len, int wt); |
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/* |
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Add brightness values to current histogram. |
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ls - encoded luminance values. |
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len - number of luminance values. |
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wt - integer weight to use for each value (usually 1 or -1). |
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|
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returns - 0 on success, TM_E_* on error. |
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*/ |
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|
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extern int |
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tmComputeMapping(double gamval, double Lddyn, double Ldmax); |
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/* |
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Compute tone mapping function. |
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|
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gamval - display gamma response (0. for default). |
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Lddyn - the display's dynamic range (0. for default). |
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Ldmax - maximum display luminance in cd/m^2 (0. for default). |
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returns - 0 on success, TM_E_* on failure. |
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*/ |
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|
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extern int |
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tmMapPixels(BYTE *ps, TMbright *ls, BYTE *cs, int len); |
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/* |
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Apply tone mapping function to pixel values. |
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|
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ps - returned pixel values (Note 2). |
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ls - encoded luminance values. |
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cs - encoded chrominance values (Note 2). |
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len - number of pixels. |
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returns - 0 on success, TM_E_* on failure. |
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*/ |
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|
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extern int |
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tmLoadPicture(TMbright **lpp, BYTE **cpp, int *xp, int *yp, |
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char *fname, FILE *fp); |
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/* |
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Load Radiance picture and convert to tone mapping representation. |
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Calls tmSetSpace() to calibrate input color space. |
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|
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lpp - returned array of encoded luminances, English ordering. |
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cpp - returned array of encoded chrominances (Note 2). |
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xp, yp - returned picture dimensions. |
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fname - picture file name. |
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fp - pointer to open file (Note 3). |
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returns - 0 on success, TM_E_* on failure. |
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*/ |
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|
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extern int |
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tmMapPicture(BYTE **psp, int *xp, int *yp, int flags, |
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RGBPRIMP monpri, double gamval, double Lddyn, double Ldmax, |
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char *fname, FILE *fp); |
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/* |
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Load and apply tone mapping to Radiance picture. |
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Stack is restored to its original state upon return. |
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If fp is TM_GETFILE and (flags&TM_F_UNIMPL)!=0, tmMapPicture() |
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calls pcond to perform the actual conversion, which takes |
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longer but gives access to all the TM_F_* features. |
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|
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psp - returned array of tone mapped pixels, English ordering. |
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xp, yp - returned picture dimensions. |
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flags - TM_F_* flags indicating what is to be done. |
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monpri - display monitor primaries (Note 1). |
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gamval - display gamma response. |
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Lddyn - the display's dynamic range (0. for default). |
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Ldmax - maximum display luminance in cd/m^2 (0. for default). |
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fname - picture file name. |
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fp - pointer to open file (Note 3). |
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returns - 0 on success, TM_E_* on failure. |
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*/ |
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extern struct tmStruct * |
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tmPop(void); |
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/* |
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Pops current tone mapping from stack. |
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|
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returns - pointer to tone mapping structure, or NULL if none. |
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*/ |
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|
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extern int |
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tmPull(struct tmStruct *tms); |
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/* |
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Pull tone mapping from anywhere in stack. |
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tms - tone mapping structure to find. |
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returns - 1 if found in stack, 0 otherwise. |
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*/ |
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extern int |
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tmPush(struct tmStruct *tms); |
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/* |
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Make tone mapping active by (pulling it and) pushing it to the top. |
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tms - initialized tone mapping structure. |
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returns - 0 on success, TM_E_* if tms is invalid. |
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*/ |
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extern struct tmStruct * |
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tmDup(void); |
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/* |
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Duplicate the current tone mapping into a new structure on the stack. |
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returns - pointer to new top, or NULL on error. |
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*/ |
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extern void |
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tmDone(struct tmStruct *tms); |
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/* |
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Free data associated with the given tone mapping structure. |
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Calls tmPull() first to remove it from the stack if present. |
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The calls tmDone(tmPop()), tmDone(tmTop) and tmDone(NULL) |
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all have the same effect, which is to remove and free |
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the current tone mapping. |
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|
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tms - tone mapping structure to free. |
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*/ |
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|
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#endif |
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|
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/**** Notes ****/ |
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/* |
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General: |
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|
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The usual sequence after calling tmInit() is to convert some |
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pixel values to chroma and luminance encodings, which can |
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be passed to tmAddHisto() to put into the tone mapping histogram. |
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This histogram is then used along with the display parameters |
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by tmComputMapping() to compute the luminance mapping function. |
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(Colors are tone-mapped as they are converted if TM_F_MESOPIC |
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is set.) The encoded chroma and luminance values may then be |
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passed to tmMapPixels() to apply the computed tone mapping in |
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a second pass. |
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|
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Especially for RGBE colors in the same color space as the |
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target display, the conversion to chroma and luminance values |
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is fast enough that it may be recomputed on the second pass |
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if memory is at a premium. (Since the chroma values are only |
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used during final mapping, setting the cs parameter to TM_NOCHROM |
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on the first pass will save time.) Another memory saving option |
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if third and subsequent passes are not needed is to use the |
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same array to store the mapped pixels as used to store |
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the encoded chroma values. This way, only two extra bytes |
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for storing encoded luminances are required per pixel. This |
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is the method employed by tmMapPicture(), for example. |
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*/ |
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/* |
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Note 1: |
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|
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All RGBPRIMP values should be pointers to static structures. |
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I.e., the same pointer should be used for the same primaries, |
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and those primaries should not change from one call to the next. |
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This is because the routines use the pointer value to identify |
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computed conversion matrices, so the matrices do not have to be |
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rebuilt each time. If you are using the standard primaries, |
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use the standard primary pointer, stdprims. |
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|
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To indicate a set of input primaries are actually CIE XYZ, |
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the TM_XYZPRIM macro may be passed. If the input primaries |
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are unknown, it is wisest to pass tmTop->monpri to tmSetSpace(). |
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By default, the input primaries equal the monitor primaries |
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and the scalefactor is set to WHTEFFICACY in tmInit(). |
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*/ |
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/* |
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Note 2: |
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|
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Chrominance is optional in most of these routines, whether |
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TM_F_BW is set or not. Passing a value of TM_NOCHROM (or |
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TM_NOCHROMP for picture reading) indicates that returned |
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color values are not desired. |
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|
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If TM_NOCHROM is passed to a mapping routine expecting chroma |
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input, it will do without it and return luminance channel |
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rather than RGB pixel values. Otherwise, the array for |
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returned pixel values may be the same array used to pass |
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encoded chrominances if no other mappings are desired. |
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*/ |
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/* |
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Note 3: |
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|
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Picture files may either be opened by the calling routine or by |
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the library function. If opened by the calling routine, the |
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pointer to the stream is passed, which may be a pipe or other |
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non-seekable input as it is only read once. It must be |
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positioned at the beginning when the function is called, and it |
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will be positioned at the end on return. It will not be closed. |
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If the passed stream pointer is TM_GETFILE, then the library |
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function will open the file, read its contents and close it |
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before returning, whether or not an error was encountered. |
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*/ |
