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diff --git a/tiff/man/TIFFcolor.3tiff b/tiff/man/TIFFcolor.3tiff deleted file mode 100644 index a3faf79..0000000 --- a/tiff/man/TIFFcolor.3tiff +++ /dev/null @@ -1,268 +0,0 @@ -.\" $Id: TIFFcolor.3tiff,v 1.3 2006/03/23 14:54:02 dron Exp $ -.\" -.\" Copyright (c) 2003, Andrey Kiselev <dron@ak4719.spb.edu> -.\" -.\" 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. -.\" -.if n .po 0 -.TH COLOR 3TIFF "December 21, 2003" "libtiff" -.SH NAME -TIFFYCbCrToRGBInit, TIFFYCbCrtoRGB, TIFFCIELabToRGBInit, TIFFCIELabToXYZ, -TIFFXYZToRGB \- color conversion routines. -.SH SYNOPSIS -.B "#include <tiffio.h>" -.sp -.BI "int TIFFYCbCrToRGBInit(TIFFYCbCrToRGB *" ycbcr ", float *" luma ", float *"refBlackWhite" );" -.br -.BI "void TIFFYCbCrtoRGB(TIFFYCbCrToRGB *" ycbcr ", uint32 " Y ", int32 " Cb ", int32 " Cr ", uint32 *" R ", uint32 *" G ", uint32 *" B " );" -.sp -.BI "int TIFFCIELabToRGBInit(TIFFCIELabToRGB *" cielab ", TIFFDisplay *" display ", float *" refWhite ");" -.br -.BI "void TIFFCIELabToXYZ(TIFFCIELabToRGB *" cielab ", uint32 " L ", int32 " a ", int32 " b ", float *" X ", float *" Y ", float *" Z ");" -.br -.BI "void TIFFXYZToRGB(TIFFCIELabToRGB *" cielab ", float " X ", float " Y ", float " Z" , uint32 *" R ", uint32 *" G ", uint32 *" B ");" -.SH DESCRIPTION -TIFF supports several color spaces for images stored in that format. There is -usually a problem of application to handle the data properly and convert -between different colorspaces for displaying and printing purposes. To -simplify this task libtiff implements several color conversion routines -itself. In particular, these routines used in -.B TIFFRGBAImage(3TIFF) -interface. -.PP -.B TIFFYCbCrToRGBInit() -used to initialize -.I YCbCr -to -.I RGB -conversion state. Allocating and freeing of the -.I ycbcr -structure belongs to programmer. -.I TIFFYCbCrToRGB -defined in -.B tiffio.h -as -.PP -.RS -.nf -typedef struct { /* YCbCr->RGB support */ - TIFFRGBValue* clamptab; /* range clamping table */ - int* Cr_r_tab; - int* Cb_b_tab; - int32* Cr_g_tab; - int32* Cb_g_tab; - int32* Y_tab; -} TIFFYCbCrToRGB; -.fi -.RE -.PP -.I luma -is a float array of three values representing proportions of the red, green -and blue in luminance, Y (see section 21 of the TIFF 6.0 specification, where -the YCbCr images discussed). -.I TIFFTAG_YCBCRCOEFFICIENTS -holds that values in TIFF file. -.I refBlackWhite -is a float array of 6 values which specifies a pair of headroom and footroom -image data values (codes) for each image component (see section 20 of the -TIFF 6.0 specification where the colorinmetry fields discussed). -.I TIFFTAG_REFERENCEBLACKWHITE -is responsible for storing these values in TIFF file. Following code snippet -should helps to understand the the technique: -.PP -.RS -.nf -float *luma, *refBlackWhite; -uint16 hs, vs; - -/* Initialize structures */ -ycbcr = (TIFFYCbCrToRGB*) - _TIFFmalloc(TIFFroundup(sizeof(TIFFYCbCrToRGB), sizeof(long)) - + 4*256*sizeof(TIFFRGBValue) - + 2*256*sizeof(int) - + 3*256*sizeof(int32)); -if (ycbcr == NULL) { - TIFFError("YCbCr->RGB", - "No space for YCbCr->RGB conversion state"); - exit(0); -} - -TIFFGetFieldDefaulted(tif, TIFFTAG_YCBCRCOEFFICIENTS, &luma); -TIFFGetFieldDefaulted(tif, TIFFTAG_REFERENCEBLACKWHITE, &refBlackWhite); -if (TIFFYCbCrToRGBInit(ycbcr, luma, refBlackWhite) < 0) - exit(0); - -/* Start conversion */ -uint32 r, g, b; -uint32 Y; -int32 Cb, Cr; - -for each pixel in image - TIFFYCbCrtoRGB(img->ycbcr, Y, Cb, Cr, &r, &g, &b); - -/* Free state structure */ -_TIFFfree(ycbcr); -.fi -.RE -.PP - -.PP -.B TIFFCIELabToRGBInit() -initializes the -.I CIE L*a*b* 1976 -to -.I RGB -conversion state. -.B TIFFCIELabToRGB -defined as -.PP -.RS -.nf -#define CIELABTORGB_TABLE_RANGE 1500 - -typedef struct { /* CIE Lab 1976->RGB support */ - int range; /* Size of conversion table */ - float rstep, gstep, bstep; - float X0, Y0, Z0; /* Reference white point */ - TIFFDisplay display; - float Yr2r[CIELABTORGB_TABLE_RANGE + 1]; /* Conversion of Yr to r */ - float Yg2g[CIELABTORGB_TABLE_RANGE + 1]; /* Conversion of Yg to g */ - float Yb2b[CIELABTORGB_TABLE_RANGE + 1]; /* Conversion of Yb to b */ -} TIFFCIELabToRGB; -.fi -.RE -.PP -.I display -is a display device description, declared as -.PP -.RS -.nf -typedef struct { - float d_mat[3][3]; /* XYZ -> luminance matrix */ - float d_YCR; /* Light o/p for reference white */ - float d_YCG; - float d_YCB; - uint32 d_Vrwr; /* Pixel values for ref. white */ - uint32 d_Vrwg; - uint32 d_Vrwb; - float d_Y0R; /* Residual light for black pixel */ - float d_Y0G; - float d_Y0B; - float d_gammaR; /* Gamma values for the three guns */ - float d_gammaG; - float d_gammaB; -} TIFFDisplay; -.fi -.RE -.PP -For example, the one can use sRGB device, which has the following parameters: -.PP -.RS -.nf -TIFFDisplay display_sRGB = { - { /* XYZ -> luminance matrix */ - { 3.2410F, -1.5374F, -0.4986F }, - { -0.9692F, 1.8760F, 0.0416F }, - { 0.0556F, -0.2040F, 1.0570F } - }, - 100.0F, 100.0F, 100.0F, /* Light o/p for reference white */ - 255, 255, 255, /* Pixel values for ref. white */ - 1.0F, 1.0F, 1.0F, /* Residual light o/p for black pixel */ - 2.4F, 2.4F, 2.4F, /* Gamma values for the three guns */ -}; -.fi -.RE -.PP -.I refWhite -is a color temperature of the reference white. The -.I TIFFTAG_WHITEPOINT -contains the chromaticity of the white point of the image from where the -reference white can be calculated using following formulae: -.PP -.RS -refWhite_Y = 100.0 -.br -refWhite_X = whitePoint_x / whitePoint_y * refWhite_Y -.br -refWhite_Z = (1.0 - whitePoint_x - whitePoint_y) / whitePoint_y * refWhite_X -.br -.RE -.PP -The conversion itself performed in two steps: at the first one we will convert -.I CIE L*a*b* 1976 -to -.I CIE XYZ -using -.B TIFFCIELabToXYZ() -routine, and at the second step we will convert -.I CIE XYZ -to -.I RGB -using -.B TIFFXYZToRGB(). -Look at the code sample below: -.PP -.RS -.nf -float *whitePoint; -float refWhite[3]; - -/* Initialize structures */ -img->cielab = (TIFFCIELabToRGB *) - _TIFFmalloc(sizeof(TIFFCIELabToRGB)); -if (!cielab) { - TIFFError("CIE L*a*b*->RGB", - "No space for CIE L*a*b*->RGB conversion state."); - exit(0); -} - -TIFFGetFieldDefaulted(tif, TIFFTAG_WHITEPOINT, &whitePoint); -refWhite[1] = 100.0F; -refWhite[0] = whitePoint[0] / whitePoint[1] * refWhite[1]; -refWhite[2] = (1.0F - whitePoint[0] - whitePoint[1]) - / whitePoint[1] * refWhite[1]; -if (TIFFCIELabToRGBInit(cielab, &display_sRGB, refWhite) < 0) { - TIFFError("CIE L*a*b*->RGB", - "Failed to initialize CIE L*a*b*->RGB conversion state."); - _TIFFfree(cielab); - exit(0); -} - -/* Now we can start to convert */ -uint32 r, g, b; -uint32 L; -int32 a, b; -float X, Y, Z; - -for each pixel in image - TIFFCIELabToXYZ(cielab, L, a, b, &X, &Y, &Z); - TIFFXYZToRGB(cielab, X, Y, Z, &r, &g, &b); - -/* Don't forget to free the state structure */ -_TIFFfree(cielab); -.fi -.RE -.PP -.SH "SEE ALSO" -.BR TIFFRGBAImage (3TIFF) -.BR libtiff (3TIFF), -.PP -Libtiff library home page: -.BR http://www.remotesensing.org/libtiff/ |