From 11cb75681b1b13813dae6d60214ca6904c5a0d36 Mon Sep 17 00:00:00 2001
From: Andrey Kiselev <dron@ak4719.spb.edu>
Date: Sat, 6 Dec 2003 15:55:41 +0000
Subject: [PATCH] Read WhitePoint tag from the file and properly use it for CIE
 Lab->RGB transform.

---
 libtiff/tif_aux.c      | 25 +++++++++++++++----------
 libtiff/tif_getimage.c | 13 +++++++++----
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/libtiff/tif_aux.c b/libtiff/tif_aux.c
index 81d51011..79d0b198 100644
--- a/libtiff/tif_aux.c
+++ b/libtiff/tif_aux.c
@@ -1,4 +1,4 @@
-/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_aux.c,v 1.5 2003-07-08 15:51:57 warmerda Exp $ */
+/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_aux.c,v 1.6 2003-12-06 15:55:41 dron Exp $ */
 
 /*
  * Copyright (c) 1991-1997 Sam Leffler
@@ -31,8 +31,6 @@
  */
 #include "tiffiop.h"
 #include "tif_predict.h"
-
-#ifdef COLORIMETRY_SUPPORT
 #include <math.h>
 
 static void
@@ -66,7 +64,6 @@ TIFFDefaultRefBlackWhite(TIFFDirectory* td)
 	    td->td_refblackwhite[2*i+1] = (float)((1L<<td->td_bitspersample)-1L);
 	}
 }
-#endif
 
 /*
  * Like TIFFGetField, but return any default
@@ -123,7 +120,6 @@ TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
 			*va_arg(ap, uint16*) = (uint16) sp->predictor;
 			return (1);
                 }
-#ifdef CMYK_SUPPORT
 	case TIFFTAG_DOTRANGE:
 		*va_arg(ap, uint16 *) = 0;
 		*va_arg(ap, uint16 *) = (1<<td->td_bitspersample)-1;
@@ -134,7 +130,6 @@ TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
 	case TIFFTAG_NUMBEROFINKS:
 		*va_arg(ap, uint16 *) = td->td_ninks;
 		return (1);
-#endif
 	case TIFFTAG_EXTRASAMPLES:
 		*va_arg(ap, uint16 *) = td->td_extrasamples;
 		*va_arg(ap, uint16 **) = td->td_sampleinfo;
@@ -156,7 +151,6 @@ TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
 	case TIFFTAG_IMAGEDEPTH:
 		*va_arg(ap, uint32 *) = td->td_imagedepth;
 		return (1);
-#ifdef YCBCR_SUPPORT
 	case TIFFTAG_YCBCRCOEFFICIENTS:
 		if (!td->td_ycbcrcoeffs) {
 			td->td_ycbcrcoeffs = (float *)
@@ -175,8 +169,20 @@ TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
 	case TIFFTAG_YCBCRPOSITIONING:
 		*va_arg(ap, uint16 *) = td->td_ycbcrpositioning;
 		return (1);
-#endif
-#ifdef COLORIMETRY_SUPPORT
+	case TIFFTAG_WHITEPOINT:
+		if (!td->td_whitepoint) {
+			td->td_whitepoint = (float *)
+				_TIFFmalloc(2 * sizeof (float));
+			/* TIFF 6.0 specification says that it is no default
+			   value for the WhitePoint, but AdobePhotoshop TIFF
+			   Technical Note tells that it should be CIE D50. */
+			td->td_whitepoint[0] =
+				D50_X0 / (D50_X0 + D50_Y0 + D50_Z0);
+			td->td_whitepoint[1] =
+				D50_Y0 / (D50_X0 + D50_Y0 + D50_Z0);
+		}
+		*va_arg(ap, float **) = td->td_whitepoint;
+		return (1);
 	case TIFFTAG_TRANSFERFUNCTION:
 		if (!td->td_transferfunction[0])
 			TIFFDefaultTransferFunction(td);
@@ -191,7 +197,6 @@ TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
 			TIFFDefaultRefBlackWhite(td);
 		*va_arg(ap, float **) = td->td_refblackwhite;
 		return (1);
-#endif
 	}
 	return (0);
 }
diff --git a/libtiff/tif_getimage.c b/libtiff/tif_getimage.c
index 4ccded4b..0fdcbbc4 100644
--- a/libtiff/tif_getimage.c
+++ b/libtiff/tif_getimage.c
@@ -1,4 +1,4 @@
-/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_getimage.c,v 1.32 2003-12-04 10:31:54 dron Exp $ */
+/* $Header: /cvs/maptools/cvsroot/libtiff/libtiff/tif_getimage.c,v 1.33 2003-12-06 15:55:41 dron Exp $ */
 
 /*
  * Copyright (c) 1991-1997 Sam Leffler
@@ -2050,6 +2050,8 @@ initCIELabConversion(TIFFRGBAImage* img)
 {
 	static char module[] = "initCIELabConversion";
 
+	float *coeffs, X0, Y0, Z0;
+
 	if (!img->cielab) {
 		img->cielab = (TIFFCIELabToRGB *)
 			_TIFFmalloc(sizeof(TIFFCIELabToRGB));
@@ -2059,9 +2061,12 @@ initCIELabConversion(TIFFRGBAImage* img)
 			return NULL;
 		}
 	}
-	
-	if (TIFFCIELabToRGBInit(img->cielab, &display_sRGB,
-				D50_X0, D50_Y0, D50_Z0) < 0) {
+
+	TIFFGetFieldDefaulted(img->tif, TIFFTAG_WHITEPOINT, &coeffs);
+	Y0 = 100.0;
+	X0 = coeffs[0] / coeffs[1] * Y0;
+	Z0 = (1.0 - coeffs[0] - coeffs[1]) / coeffs[1] * Y0;
+	if (TIFFCIELabToRGBInit(img->cielab, &display_sRGB, X0, Y0, Z0) < 0) {
 		TIFFError(module,
 		    "Failed to initialize CIE L*a*b*->RGB conversion state.");
 		_TIFFfree(img->cielab);