+++ /dev/null
-/* $Id: tif_color.c,v 1.1 2005/06/17 13:54:52 vp153 Exp $ */
-
-/*
- * 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 );
-
- /* Turn luminosity to colour value. */
- i = TIFFmin(cielab->range,
- (int)((Yr - cielab->display.d_Y0R) / cielab->rstep));
- *r = RINT(cielab->Yr2r[i]);
-
- i = TIFFmin(cielab->range,
- (int)((Yg - cielab->display.d_Y0G) / cielab->gstep));
- *g = RINT(cielab->Yg2g[i]);
-
- i = TIFFmin(cielab->range,
- (int)((Yb - cielab->display.d_Y0B) / cielab->bstep));
- *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,
- 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))
-
-void
-TIFFYCbCrtoRGB(TIFFYCbCrToRGB *ycbcr, uint32 Y, int32 Cb, int32 Cr,
- uint32 *r, uint32 *g, uint32 *b)
-{
- /* XXX: Only 8-bit YCbCr input supported for now */
- Y = CLAMP(Y, 0, 255), Cb = CLAMP(Cb, 0, 255), Cr = CLAMP(Cr, 0, 255);
-
- *r = ycbcr->clamptab[ycbcr->Y_tab[Y] + ycbcr->Cr_r_tab[Cr]];
- *g = ycbcr->clamptab[ycbcr->Y_tab[Y]
- + (int)((ycbcr->Cb_g_tab[Cb] + ycbcr->Cr_g_tab[Cr]) >> SHIFT)];
- *b = ycbcr->clamptab[ycbcr->Y_tab[Y] + ycbcr->Cb_b_tab[Cb]];
-}
-
-/*
- * 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*)(
- (tidata_t) ycbcr+TIFFroundup(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 CLAMP
-#undef Code2V
-#undef SHIFT
-#undef ONE_HALF
-#undef FIX
-
-/* vim: set ts=8 sts=8 sw=8 noet: */
projects / opencv / blobdiff