[wxWidgets.git] / src / tiff / libtiff / tif_color.c

/* $Id$ */

/*
 * Copyright (c) 1988-1997 Sam Leffler
 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

/*
 * CIE L*a*b* to CIE XYZ and CIE XYZ to RGB conversion routines are taken
 * from the VIPS library (http://www.vips.ecs.soton.ac.uk) with
 * the permission of John Cupitt, the VIPS author.
 */

/*
 * TIFF Library.
 *
 * Color space conversion routines.
 */

#include "tiffiop.h"
#include <math.h>

/*
 * Convert color value from the CIE L*a*b* 1976 space to CIE XYZ.
 */
void
TIFFCIELabToXYZ(TIFFCIELabToRGB *cielab, uint32 l, int32 a, int32 b,
		float *X, float *Y, float *Z)
{
	float L = (float)l * 100.0F / 255.0F;
	float cby, tmp;

	if( L < 8.856F ) {
		*Y = (L * cielab->Y0) / 903.292F;
		cby = 7.787F * (*Y / cielab->Y0) + 16.0F / 116.0F;
	} else {
		cby = (L + 16.0F) / 116.0F;
		*Y = cielab->Y0 * cby * cby * cby;
	}

	tmp = (float)a / 500.0F + cby;
	if( tmp < 0.2069F )
		*X = cielab->X0 * (tmp - 0.13793F) / 7.787F;
	else    
		*X = cielab->X0 * tmp * tmp * tmp;

	tmp = cby - (float)b / 200.0F;
	if( tmp < 0.2069F )
		*Z = cielab->Z0 * (tmp - 0.13793F) / 7.787F;
	else    
		*Z = cielab->Z0 * tmp * tmp * tmp;
}

#define RINT(R) ((uint32)((R)>0?((R)+0.5):((R)-0.5)))
/*
 * Convert color value from the XYZ space to RGB.
 */
void
TIFFXYZToRGB(TIFFCIELabToRGB *cielab, float X, float Y, float Z,
	     uint32 *r, uint32 *g, uint32 *b)
{
	int i;
	float Yr, Yg, Yb;
	float *matrix = &cielab->display.d_mat[0][0];

	/* Multiply through the matrix to get luminosity values. */
	Yr =  matrix[0] * X + matrix[1] * Y + matrix[2] * Z;
	Yg =  matrix[3] * X + matrix[4] * Y + matrix[5] * Z;
	Yb =  matrix[6] * X + matrix[7] * Y + matrix[8] * Z;

	/* Clip input */
	Yr = TIFFmax(Yr, cielab->display.d_Y0R);
	Yg = TIFFmax(Yg, cielab->display.d_Y0G);
	Yb = TIFFmax(Yb, cielab->display.d_Y0B);

	/* Avoid overflow in case of wrong input values */
	Yr = TIFFmin(Yr, cielab->display.d_YCR);
	Yg = TIFFmin(Yg, cielab->display.d_YCG);
	Yb = TIFFmin(Yb, cielab->display.d_YCB);

	/* Turn luminosity to colour value. */
	i = (int)((Yr - cielab->display.d_Y0R) / cielab->rstep);
	i = TIFFmin(cielab->range, i);
	*r = RINT(cielab->Yr2r[i]);

	i = (int)((Yg - cielab->display.d_Y0G) / cielab->gstep);
	i = TIFFmin(cielab->range, i);
	*g = RINT(cielab->Yg2g[i]);

	i = (int)((Yb - cielab->display.d_Y0B) / cielab->bstep);
	i = TIFFmin(cielab->range, i);
	*b = RINT(cielab->Yb2b[i]);

	/* Clip output. */
	*r = TIFFmin(*r, cielab->display.d_Vrwr);
	*g = TIFFmin(*g, cielab->display.d_Vrwg);
	*b = TIFFmin(*b, cielab->display.d_Vrwb);
}
#undef RINT

/* 
 * Allocate conversion state structures and make look_up tables for
 * the Yr,Yb,Yg <=> r,g,b conversions.
 */
int
TIFFCIELabToRGBInit(TIFFCIELabToRGB* cielab,
		    const TIFFDisplay *display, float *refWhite)
{
	int i;
	double gamma;

	cielab->range = CIELABTORGB_TABLE_RANGE;

	_TIFFmemcpy(&cielab->display, display, sizeof(TIFFDisplay));

	/* Red */
	gamma = 1.0 / cielab->display.d_gammaR ;
	cielab->rstep =
		(cielab->display.d_YCR - cielab->display.d_Y0R)	/ cielab->range;
	for(i = 0; i <= cielab->range; i++) {
		cielab->Yr2r[i] = cielab->display.d_Vrwr
		    * ((float)pow((double)i / cielab->range, gamma));
	}

	/* Green */
	gamma = 1.0 / cielab->display.d_gammaG ;
	cielab->gstep =
	    (cielab->display.d_YCR - cielab->display.d_Y0R) / cielab->range;
	for(i = 0; i <= cielab->range; i++) {
		cielab->Yg2g[i] = cielab->display.d_Vrwg
		    * ((float)pow((double)i / cielab->range, gamma));
	}

	/* Blue */
	gamma = 1.0 / cielab->display.d_gammaB ;
	cielab->bstep =
	    (cielab->display.d_YCR - cielab->display.d_Y0R) / cielab->range;
	for(i = 0; i <= cielab->range; i++) {
		cielab->Yb2b[i] = cielab->display.d_Vrwb
		    * ((float)pow((double)i / cielab->range, gamma));
	}

	/* Init reference white point */
	cielab->X0 = refWhite[0];
	cielab->Y0 = refWhite[1];
	cielab->Z0 = refWhite[2];

	return 0;
}

/* 
 * Convert color value from the YCbCr space to CIE XYZ.
 * The colorspace conversion algorithm comes from the IJG v5a code;
 * see below for more information on how it works.
 */
#define	SHIFT			16
#define	FIX(x)			((int32)((x) * (1L<<SHIFT) + 0.5))
#define	ONE_HALF		((int32)(1<<(SHIFT-1)))
#define	Code2V(c, RB, RW, CR)	((((c)-(int32)(RB))*(float)(CR))/(float)(((RW)-(RB)) ? ((RW)-(RB)) : 1))
#define	CLAMP(f,min,max)	((f)<(min)?(min):(f)>(max)?(max):(f))
#define HICLAMP(f,max)		((f)>(max)?(max):(f))

void
TIFFYCbCrtoRGB(TIFFYCbCrToRGB *ycbcr, uint32 Y, int32 Cb, int32 Cr,
	       uint32 *r, uint32 *g, uint32 *b)
{
	int32 i;

	/* XXX: Only 8-bit YCbCr input supported for now */
	Y = HICLAMP(Y, 255), Cb = CLAMP(Cb, 0, 255), Cr = CLAMP(Cr, 0, 255);

	i = ycbcr->Y_tab[Y] + ycbcr->Cr_r_tab[Cr];
	*r = CLAMP(i, 0, 255);
	i = ycbcr->Y_tab[Y]
	    + (int)((ycbcr->Cb_g_tab[Cb] + ycbcr->Cr_g_tab[Cr]) >> SHIFT);
	*g = CLAMP(i, 0, 255);
	i = ycbcr->Y_tab[Y] + ycbcr->Cb_b_tab[Cb];
	*b = CLAMP(i, 0, 255);
}

/*
 * Initialize the YCbCr->RGB conversion tables.  The conversion
 * is done according to the 6.0 spec:
 *
 *    R = Y + Cr*(2 - 2*LumaRed)
 *    B = Y + Cb*(2 - 2*LumaBlue)
 *    G =   Y
 *        - LumaBlue*Cb*(2-2*LumaBlue)/LumaGreen
 *        - LumaRed*Cr*(2-2*LumaRed)/LumaGreen
 *
 * To avoid floating point arithmetic the fractional constants that
 * come out of the equations are represented as fixed point values
 * in the range 0...2^16.  We also eliminate multiplications by
 * pre-calculating possible values indexed by Cb and Cr (this code
 * assumes conversion is being done for 8-bit samples).
 */
int
TIFFYCbCrToRGBInit(TIFFYCbCrToRGB* ycbcr, float *luma, float *refBlackWhite)
{
    TIFFRGBValue* clamptab;
    int i;
    
#define LumaRed	    luma[0]
#define LumaGreen   luma[1]
#define LumaBlue    luma[2]

    clamptab = (TIFFRGBValue*)(
	(uint8*) ycbcr+TIFFroundup_32(sizeof (TIFFYCbCrToRGB), sizeof (long)));  
    _TIFFmemset(clamptab, 0, 256);		/* v < 0 => 0 */
    ycbcr->clamptab = (clamptab += 256);
    for (i = 0; i < 256; i++)
	clamptab[i] = (TIFFRGBValue) i;
    _TIFFmemset(clamptab+256, 255, 2*256);	/* v > 255 => 255 */
    ycbcr->Cr_r_tab = (int*) (clamptab + 3*256);
    ycbcr->Cb_b_tab = ycbcr->Cr_r_tab + 256;
    ycbcr->Cr_g_tab = (int32*) (ycbcr->Cb_b_tab + 256);
    ycbcr->Cb_g_tab = ycbcr->Cr_g_tab + 256;
    ycbcr->Y_tab = ycbcr->Cb_g_tab + 256;

    { float f1 = 2-2*LumaRed;		int32 D1 = FIX(f1);
      float f2 = LumaRed*f1/LumaGreen;	int32 D2 = -FIX(f2);
      float f3 = 2-2*LumaBlue;		int32 D3 = FIX(f3);
      float f4 = LumaBlue*f3/LumaGreen;	int32 D4 = -FIX(f4);
      int x;

#undef LumaBlue
#undef LumaGreen
#undef LumaRed
      
      /*
       * i is the actual input pixel value in the range 0..255
       * Cb and Cr values are in the range -128..127 (actually
       * they are in a range defined by the ReferenceBlackWhite
       * tag) so there is some range shifting to do here when
       * constructing tables indexed by the raw pixel data.
       */
      for (i = 0, x = -128; i < 256; i++, x++) {
	    int32 Cr = (int32)Code2V(x, refBlackWhite[4] - 128.0F,
			    refBlackWhite[5] - 128.0F, 127);
	    int32 Cb = (int32)Code2V(x, refBlackWhite[2] - 128.0F,
			    refBlackWhite[3] - 128.0F, 127);

	    ycbcr->Cr_r_tab[i] = (int32)((D1*Cr + ONE_HALF)>>SHIFT);
	    ycbcr->Cb_b_tab[i] = (int32)((D3*Cb + ONE_HALF)>>SHIFT);
	    ycbcr->Cr_g_tab[i] = D2*Cr;
	    ycbcr->Cb_g_tab[i] = D4*Cb + ONE_HALF;
	    ycbcr->Y_tab[i] =
		    (int32)Code2V(x + 128, refBlackWhite[0], refBlackWhite[1], 255);
      }
    }

    return 0;
}
#undef	HICLAMP
#undef	CLAMP
#undef	Code2V
#undef	SHIFT
#undef	ONE_HALF
#undef	FIX

/* vim: set ts=8 sts=8 sw=8 noet: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 8
 * fill-column: 78
 * End:
 */
Commit	Line	Data
8414a40c VZ	1	/* $Id$ */
	2
	3	/*
	4	* Copyright (c) 1988-1997 Sam Leffler
	5	* Copyright (c) 1991-1997 Silicon Graphics, Inc.
	6	*
	7	* Permission to use, copy, modify, distribute, and sell this software and
	8	* its documentation for any purpose is hereby granted without fee, provided
	9	* that (i) the above copyright notices and this permission notice appear in
	10	* all copies of the software and related documentation, and (ii) the names of
	11	* Sam Leffler and Silicon Graphics may not be used in any advertising or
	12	* publicity relating to the software without the specific, prior written
	13	* permission of Sam Leffler and Silicon Graphics.
	14	*
	15	* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	16	* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	17	* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	18	*
	19	* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	20	* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	21	* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	22	* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	23	* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	24	* OF THIS SOFTWARE.
	25	*/
	26
	27	/*
	28	* CIE Lab* to CIE XYZ and CIE XYZ to RGB conversion routines are taken
	29	* from the VIPS library (http://www.vips.ecs.soton.ac.uk) with
	30	* the permission of John Cupitt, the VIPS author.
	31	*/
	32
	33	/*
	34	* TIFF Library.
	35	*
	36	* Color space conversion routines.
	37	*/
	38
	39	#include "tiffiop.h"
	40	#include <math.h>
	41
	42	/*
	43	* Convert color value from the CIE Lab* 1976 space to CIE XYZ.
	44	*/
	45	void
	46	TIFFCIELabToXYZ(TIFFCIELabToRGB *cielab, uint32 l, int32 a, int32 b,
	47	float X, float Y, float *Z)
	48	{
	49	float L = (float)l * 100.0F / 255.0F;
	50	float cby, tmp;
	51
	52	if( L < 8.856F ) {
	53	Y = (L cielab->Y0) / 903.292F;
	54	cby = 7.787F * (*Y / cielab->Y0) + 16.0F / 116.0F;
	55	} else {
	56	cby = (L + 16.0F) / 116.0F;
	57	Y = cielab->Y0 cby * cby * cby;
	58	}
	59
	60	tmp = (float)a / 500.0F + cby;
	61	if( tmp < 0.2069F )
	62	X = cielab->X0 (tmp - 0.13793F) / 7.787F;
	63	else
	64	X = cielab->X0 tmp * tmp * tmp;
65
66	tmp = cby - (float)b / 200.0F;
67	if( tmp < 0.2069F )
68	Z = cielab->Z0 (tmp - 0.13793F) / 7.787F;
69	else
70	Z = cielab->Z0 tmp * tmp * tmp;
71	}
72
73	#define RINT(R) ((uint32)((R)>0?((R)+0.5):((R)-0.5)))
74	/*
75	* Convert color value from the XYZ space to RGB.
76	*/
77	void
78	TIFFXYZToRGB(TIFFCIELabToRGB *cielab, float X, float Y, float Z,
79	uint32 r, uint32 g, uint32 *b)
80	{
81	int i;
82	float Yr, Yg, Yb;
83	float *matrix = &cielab->display.d_mat[0][0];
84
85	/* Multiply through the matrix to get luminosity values. */
86	Yr = matrix[0] * X + matrix[1] * Y + matrix[2] * Z;
87	Yg = matrix[3] * X + matrix[4] * Y + matrix[5] * Z;
88	Yb = matrix[6] * X + matrix[7] * Y + matrix[8] * Z;
89
90	/* Clip input */
91	Yr = TIFFmax(Yr, cielab->display.d_Y0R);
92	Yg = TIFFmax(Yg, cielab->display.d_Y0G);
93	Yb = TIFFmax(Yb, cielab->display.d_Y0B);
94
95	/* Avoid overflow in case of wrong input values */
96	Yr = TIFFmin(Yr, cielab->display.d_YCR);
97	Yg = TIFFmin(Yg, cielab->display.d_YCG);
98	Yb = TIFFmin(Yb, cielab->display.d_YCB);
99
100	/* Turn luminosity to colour value. */
101	i = (int)((Yr - cielab->display.d_Y0R) / cielab->rstep);
102	i = TIFFmin(cielab->range, i);
103	*r = RINT(cielab->Yr2r[i]);
104
105	i = (int)((Yg - cielab->display.d_Y0G) / cielab->gstep);
106	i = TIFFmin(cielab->range, i);
107	*g = RINT(cielab->Yg2g[i]);
108
109	i = (int)((Yb - cielab->display.d_Y0B) / cielab->bstep);
110	i = TIFFmin(cielab->range, i);
111	*b = RINT(cielab->Yb2b[i]);
112
113	/* Clip output. */
114	r = TIFFmin(r, cielab->display.d_Vrwr);
115	g = TIFFmin(g, cielab->display.d_Vrwg);
116	b = TIFFmin(b, cielab->display.d_Vrwb);
117	}
118	#undef RINT
119
120	/*
121	* Allocate conversion state structures and make look_up tables for
122	* the Yr,Yb,Yg <=> r,g,b conversions.
123	*/
124	int
125	TIFFCIELabToRGBInit(TIFFCIELabToRGB* cielab,
80ed523f	126	const TIFFDisplay display, float refWhite)
8414a40c VZ	127	{
	128	int i;
	129	double gamma;
	130
	131	cielab->range = CIELABTORGB_TABLE_RANGE;
	132
	133	_TIFFmemcpy(&cielab->display, display, sizeof(TIFFDisplay));
	134
	135	/* Red */
	136	gamma = 1.0 / cielab->display.d_gammaR ;
	137	cielab->rstep =
	138	(cielab->display.d_YCR - cielab->display.d_Y0R) / cielab->range;
	139	for(i = 0; i <= cielab->range; i++) {
	140	cielab->Yr2r[i] = cielab->display.d_Vrwr
	141	* ((float)pow((double)i / cielab->range, gamma));
	142	}
	143
	144	/* Green */
	145	gamma = 1.0 / cielab->display.d_gammaG ;
	146	cielab->gstep =
	147	(cielab->display.d_YCR - cielab->display.d_Y0R) / cielab->range;
	148	for(i = 0; i <= cielab->range; i++) {
	149	cielab->Yg2g[i] = cielab->display.d_Vrwg
	150	* ((float)pow((double)i / cielab->range, gamma));
	151	}
	152
	153	/* Blue */
	154	gamma = 1.0 / cielab->display.d_gammaB ;
	155	cielab->bstep =
	156	(cielab->display.d_YCR - cielab->display.d_Y0R) / cielab->range;
	157	for(i = 0; i <= cielab->range; i++) {
	158	cielab->Yb2b[i] = cielab->display.d_Vrwb
	159	* ((float)pow((double)i / cielab->range, gamma));
	160	}
	161
	162	/* Init reference white point */
	163	cielab->X0 = refWhite[0];
	164	cielab->Y0 = refWhite[1];
	165	cielab->Z0 = refWhite[2];
	166
	167	return 0;
	168	}
	169
	170	/*
	171	* Convert color value from the YCbCr space to CIE XYZ.
	172	* The colorspace conversion algorithm comes from the IJG v5a code;
	173	* see below for more information on how it works.
	174	*/
	175	#define SHIFT 16
	176	#define FIX(x) ((int32)((x) * (1L<<SHIFT) + 0.5))
	177	#define ONE_HALF ((int32)(1<<(SHIFT-1)))
	178	#define Code2V(c, RB, RW, CR) ((((c)-(int32)(RB))*(float)(CR))/(float)(((RW)-(RB)) ? ((RW)-(RB)) : 1))
	179	#define CLAMP(f,min,max) ((f)<(min)?(min):(f)>(max)?(max):(f))
	180	#define HICLAMP(f,max) ((f)>(max)?(max):(f))
	181
	182	void
	183	TIFFYCbCrtoRGB(TIFFYCbCrToRGB *ycbcr, uint32 Y, int32 Cb, int32 Cr,
	184	uint32 r, uint32 g, uint32 *b)
	185	{
80ed523f VZ	186	int32 i;
80ed523f VZ	187
8414a40c VZ	188	/* XXX: Only 8-bit YCbCr input supported for now */
	189	Y = HICLAMP(Y, 255), Cb = CLAMP(Cb, 0, 255), Cr = CLAMP(Cr, 0, 255);
	190
80ed523f VZ	191	i = ycbcr->Y_tab[Y] + ycbcr->Cr_r_tab[Cr];
	192	*r = CLAMP(i, 0, 255);
	193	i = ycbcr->Y_tab[Y]
	194	+ (int)((ycbcr->Cb_g_tab[Cb] + ycbcr->Cr_g_tab[Cr]) >> SHIFT);
	195	*g = CLAMP(i, 0, 255);
	196	i = ycbcr->Y_tab[Y] + ycbcr->Cb_b_tab[Cb];
	197	*b = CLAMP(i, 0, 255);
8414a40c VZ	198	}
	199
	200	/*
	201	* Initialize the YCbCr->RGB conversion tables. The conversion
	202	* is done according to the 6.0 spec:
	203	*
	204	* R = Y + Cr(2 - 2LumaRed)
	205	* B = Y + Cb(2 - 2LumaBlue)
	206	* G = Y
	207	* - LumaBlueCb(2-2*LumaBlue)/LumaGreen
	208	* - LumaRedCr(2-2*LumaRed)/LumaGreen
	209	*
	210	* To avoid floating point arithmetic the fractional constants that
	211	* come out of the equations are represented as fixed point values
	212	* in the range 0...2^16. We also eliminate multiplications by
	213	* pre-calculating possible values indexed by Cb and Cr (this code
	214	* assumes conversion is being done for 8-bit samples).
	215	*/
	216	int
	217	TIFFYCbCrToRGBInit(TIFFYCbCrToRGB* ycbcr, float luma, float refBlackWhite)
	218	{
	219	TIFFRGBValue* clamptab;
	220	int i;
	221
	222	#define LumaRed luma[0]
	223	#define LumaGreen luma[1]
	224	#define LumaBlue luma[2]
	225
	226	clamptab = (TIFFRGBValue*)(
80ed523f	227	(uint8*) ycbcr+TIFFroundup_32(sizeof (TIFFYCbCrToRGB), sizeof (long)));
8414a40c VZ	228	_TIFFmemset(clamptab, 0, 256); /* v < 0 => 0 */
	229	ycbcr->clamptab = (clamptab += 256);
	230	for (i = 0; i < 256; i++)
	231	clamptab[i] = (TIFFRGBValue) i;
	232	_TIFFmemset(clamptab+256, 255, 2256); / v > 255 => 255 */
	233	ycbcr->Cr_r_tab = (int) (clamptab + 3256);
	234	ycbcr->Cb_b_tab = ycbcr->Cr_r_tab + 256;
	235	ycbcr->Cr_g_tab = (int32*) (ycbcr->Cb_b_tab + 256);
	236	ycbcr->Cb_g_tab = ycbcr->Cr_g_tab + 256;
	237	ycbcr->Y_tab = ycbcr->Cb_g_tab + 256;
	238
	239	{ float f1 = 2-2*LumaRed; int32 D1 = FIX(f1);
	240	float f2 = LumaRed*f1/LumaGreen; int32 D2 = -FIX(f2);
	241	float f3 = 2-2*LumaBlue; int32 D3 = FIX(f3);
	242	float f4 = LumaBlue*f3/LumaGreen; int32 D4 = -FIX(f4);
	243	int x;
	244
	245	#undef LumaBlue
	246	#undef LumaGreen
	247	#undef LumaRed
	248
	249	/*
	250	* i is the actual input pixel value in the range 0..255
	251	* Cb and Cr values are in the range -128..127 (actually
	252	* they are in a range defined by the ReferenceBlackWhite
	253	* tag) so there is some range shifting to do here when
	254	* constructing tables indexed by the raw pixel data.
	255	*/
	256	for (i = 0, x = -128; i < 256; i++, x++) {
	257	int32 Cr = (int32)Code2V(x, refBlackWhite[4] - 128.0F,
	258	refBlackWhite[5] - 128.0F, 127);
	259	int32 Cb = (int32)Code2V(x, refBlackWhite[2] - 128.0F,
	260	refBlackWhite[3] - 128.0F, 127);
	261
	262	ycbcr->Cr_r_tab[i] = (int32)((D1*Cr + ONE_HALF)>>SHIFT);
	263	ycbcr->Cb_b_tab[i] = (int32)((D3*Cb + ONE_HALF)>>SHIFT);
	264	ycbcr->Cr_g_tab[i] = D2*Cr;
	265	ycbcr->Cb_g_tab[i] = D4*Cb + ONE_HALF;
	266	ycbcr->Y_tab[i] =
	267	(int32)Code2V(x + 128, refBlackWhite[0], refBlackWhite[1], 255);
	268	}
	269	}
	270
	271	return 0;
	272	}
	273	#undef HICLAMP
	274	#undef CLAMP
	275	#undef Code2V
	276	#undef SHIFT
	277	#undef ONE_HALF
	278	#undef FIX
	279
	280	/* vim: set ts=8 sts=8 sw=8 noet: */
80ed523f VZ	281	/*
	282	* Local Variables:
	283	* mode: c
	284	* c-basic-offset: 8
	285	* fill-column: 78
	286	* End:
	287	*/