389 lines
8.6 KiB
C
389 lines
8.6 KiB
C
/* Convert colours in various ways.
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*
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* Written: January 1990
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* Modified .. innumerable times
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* Code by: DS, JC, J-Ph.L.
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* 18/7/93 JC
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* - final tidies before v7 release
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* - ANSIfied
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* - code for samples removed
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* 5/5/94 JC
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* - nint() -> rint() to make ANSI easier
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* 14/3/96 JC
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* - new display characterisation
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* - speed-up to im_col_XYZ2rgb() and im_col_rgb2XYZ()
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* 4/3/98 JC
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* - new display profile for ultra2
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* - new sRGB profile
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* 17/8/98 JC
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* - error_exit() removed, now clips
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* 26/11/03 Andrey Kiselev
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* - tiny clean-up for calcul_tables()
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* - some reformatting
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* 23/7/07
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* - tiny cleanup for make_hI() prevents cond jump on ui in valgrind
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* 14/3/08
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* - more tiny cond jump valgrind fixes
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* 23/10/09
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* - gtkdoc comments
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <math.h>
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#include <vips/vips.h>
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#include <vips/internal.h>
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/**
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* im_col_pythagoras:
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* @L1: Input coordinate 1
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* @a1: Input coordinate 1
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* @b1: Input coordinate 1
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* @L2: Input coordinate 2
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* @a2: Input coordinate 2
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* @b2: Input coordinate 2
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*
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* Pythagorean distance between two points in colour space. Lab/XYZ/UCS etc.
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*/
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float
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im_col_pythagoras( float L1, float a1, float b1, float L2, float a2, float b2 )
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{
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float dL = L1 - L2;
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float da = a1 - a2;
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float db = b1 - b2;
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return( sqrt( dL*dL + da*da + db*db ) );
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}
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/* Functions to convert from Lab to uniform colour space and back.
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*/
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/**
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* im_col_dECMC:
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* @L1: Input coordinate 1
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* @a1: Input coordinate 1
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* @b1: Input coordinate 1
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* @L2: Input coordinate 2
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* @a2: Input coordinate 2
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* @b2: Input coordinate 2
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*
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* CMC colour difference from a pair of Lab values.
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*
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* Returns: CMC(1:1) colour difference
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*/
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float
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im_col_dECMC( float L1, float a1, float b1,
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float L2, float a2, float b2 )
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{
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float h1, C1;
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float h2, C2;
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float Lucs1, Cucs1, hucs1;
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float Lucs2, Cucs2, hucs2;
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float aucs1, bucs1;
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float aucs2, bucs2;
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/* Turn to LCh.
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*/
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im_col_ab2Ch( a1, b1, &C1, &h1 );
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im_col_ab2Ch( a2, b2, &C2, &h2 );
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/* Turn to LCh in CMC space.
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*/
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Lucs1 = im_col_L2Lucs( L1 );
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Cucs1 = im_col_C2Cucs( C1 );
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hucs1 = im_col_Ch2hucs( C1, h1 );
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Lucs2 = im_col_L2Lucs( L2 );
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Cucs2 = im_col_C2Cucs( C2 );
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hucs2 = im_col_Ch2hucs( C2, h2 );
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/* Turn to Lab in CMC space.
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*/
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im_col_Ch2ab( Cucs1, hucs1, &aucs1, &bucs1 );
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im_col_Ch2ab( Cucs2, hucs2, &aucs2, &bucs2 );
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/* Find difference.
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*/
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return( im_col_pythagoras( Lucs1, aucs1, bucs1, Lucs2, aucs2, bucs2 ) );
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}
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/**
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* im_col_dE00:
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* @L1: Input coordinate 1
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* @a1: Input coordinate 1
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* @b1: Input coordinate 1
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* @L2: Input coordinate 2
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* @a2: Input coordinate 2
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* @b2: Input coordinate 2
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*
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* CIEDE2000, from:
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*
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* Luo, Cui, Rigg, "The Development of the CIE 2000 Colour-Difference
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* Formula: CIEDE2000", COLOR research and application, pp 340
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*
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* Returns: CIE dE2000 colour difference.
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*/
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float
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im_col_dE00( float L1, float a1, float b1,
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float L2, float a2, float b2 )
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{
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/* Code if you want XYZ params and the colour temp used in the reference
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float
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im_col_dE00( float X1, float Y1, float Z1,
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float X2, float Y2, float Z2 )
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{
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const double X0 = 94.811;
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const double Y0 = 100.0;
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const double Z0 = 107.304;
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#define f(I) ((I) > 0.008856 ? \
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cbrt( (I), 1.0 / 3.0 ) : 7.7871 * (I) + (16.0 / 116.0))
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double nX1 = f( X1 / X0 );
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double nY1 = f( Y1 / Y0 );
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double nZ1 = f( Z1 / Z0 );
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double L1 = 116 * nY1 - 16;
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double a1 = 500 * (nX1 - nY1);
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double b1 = 200 * (nY1 - nZ1);
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double nX2 = f( X2 / X0 );
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double nY2 = f( Y2 / Y0 );
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double nZ2 = f( Z2 / Z0 );
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double L2 = 116 * nY2 - 16;
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double a2 = 500 * (nX2 - nY2);
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double b2 = 200 * (nY2 - nZ2);
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*/
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/* Chroma and mean chroma (C bar)
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*/
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double C1 = sqrt( a1 * a1 + b1 * b1 );
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double C2 = sqrt( a2 * a2 + b2 * b2 );
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double Cb = (C1 + C2) / 2;
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/* G
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*/
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double Cb7 = Cb * Cb * Cb * Cb * Cb * Cb * Cb;
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double G = 0.5 * (1 - sqrt( Cb7 / (Cb7 + pow( 25, 7 )) ));
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/* L', a', b', C', h'
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*/
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double L1d = L1;
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double a1d = (1 + G) * a1;
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double b1d = b1;
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double C1d = sqrt( a1d * a1d + b1d * b1d );
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double h1d = im_col_ab2h( a1d, b1d );
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double L2d = L2;
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double a2d = (1 + G) * a2;
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double b2d = b2;
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double C2d = sqrt( a2d * a2d + b2d * b2d );
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double h2d = im_col_ab2h( a2d, b2d );
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/* L' bar, C' bar, h' bar
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*/
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double Ldb = (L1d + L2d) / 2;
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double Cdb = (C1d + C2d) / 2;
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double hdb = fabs( h1d - h2d ) < 180 ?
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(h1d + h2d) / 2 :
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fabs( h1d + h2d - 360 ) / 2;
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/* dtheta, RC
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*/
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double hdbd = (hdb - 275) / 25;
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double dtheta = 30 * exp( -(hdbd * hdbd) );
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double Cdb7 = Cdb * Cdb * Cdb * Cdb * Cdb * Cdb * Cdb;
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double RC = 2 * sqrt( Cdb7 / (Cdb7 + pow( 25, 7 )) );
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/* RT, T.
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*/
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double RT = -sin( IM_RAD( 2 * dtheta ) ) * RC;
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double T = 1 -
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0.17 * cos( IM_RAD( hdb - 30 ) ) +
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0.24 * cos( IM_RAD( 2 * hdb ) ) +
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0.32 * cos( IM_RAD( 3 * hdb + 6 ) ) -
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0.20 * cos( IM_RAD( 4 * hdb - 63 ) );
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/* SL, SC, SH
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*/
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double Ldb50 = Ldb - 50;
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double SL = 1 + (0.015 * Ldb50 * Ldb50) / sqrt( 20 + Ldb50 * Ldb50);
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double SC = 1 + 0.045 * Cdb;
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double SH = 1 + 0.015 * Cdb * T;
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/* hue difference ... careful!
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*/
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double dhd = fabs( h1d - h2d ) < 180 ?
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h1d - h2d :
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360 - (h1d - h2d);
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/* dLd, dCd dHd
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*/
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double dLd = L1d - L2d;
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double dCd = C1d - C2d;
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double dHd = 2 * sqrt( C1d * C2d ) * sin( IM_RAD( dhd / 2 ) );
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/* Parametric factors for viewing parameters.
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*/
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const double kL = 1.0;
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const double kC = 1.0;
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const double kH = 1.0;
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/* Normalised terms.
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*/
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double nL = dLd / (kL * SL);
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double nC = dCd / (kC * SC);
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double nH = dHd / (kH * SH);
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/* dE00!!
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*/
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double dE00 = sqrt( nL * nL + nC * nC + nH * nH + RT * nC * nH );
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/*
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printf( "X1 = %g, Y1 = %g, Z1 = %g\n", X1, Y1, Z1 );
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printf( "X2 = %g, Y2 = %g, Z2 = %g\n", X2, Y2, Z2 );
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printf( "L1 = %g, a1 = %g, b1 = %g\n", L1, a1, b1 );
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printf( "L2 = %g, a2 = %g, b2 = %g\n", L2, a2, b2 );
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printf( "L1d = %g, a1d = %g, b1d = %g, C1d = %g, h1d = %g\n",
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L1d, a1d, b1d, C1d, h1d );
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printf( "L2d = %g, a2d = %g, b2d = %g, C2d = %g, h2d = %g\n",
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L2d, a2d, b2d, C2d, h2d );
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printf( "G = %g, T = %g, SL = %g, SC = %g, SH = %g, RT = %g\n",
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G, T, SL, SC, SH, RT );
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printf( "dE00 = %g\n", dE00 );
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*/
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return( dE00 );
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}
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/* Quick hack wrappers for common colour functions in the new style.
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*/
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int
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vips_LabQ2disp( VipsImage *in, VipsImage **out,
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struct im_col_display *disp, ... )
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{
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va_list ap;
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int result;
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va_start( ap, disp );
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result = vips_call_split( "im_LabQ2disp", ap, in, out, disp );
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va_end( ap );
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return( result );
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}
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int
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vips_argb2rgba( VipsImage *in, VipsImage **out, ... )
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{
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va_list ap;
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int result;
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va_start( ap, out );
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result = vips_call_split( "im_argb2rgba", ap, in, out );
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va_end( ap );
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return( result );
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}
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int
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vips_Yxy2Lab( VipsImage *in, VipsImage **out, ... )
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{
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va_list ap;
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int result;
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va_start( ap, out );
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result = vips_call_split( "im_Yxy2Lab", ap, in, out );
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va_end( ap );
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return( result );
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}
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int
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vips_UCS2XYZ( VipsImage *in, VipsImage **out, ... )
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{
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va_list ap;
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int result;
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va_start( ap, out );
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result = vips_call_split( "im_UCS2XYZ", ap, in, out );
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va_end( ap );
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return( result );
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}
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int
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vips_XYZ2disp( VipsImage *in, VipsImage **out,
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struct im_col_display *disp, ... )
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{
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va_list ap;
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int result;
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va_start( ap, disp );
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result = vips_call_split( "im_XYZ2disp", ap, in, out, disp );
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va_end( ap );
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return( result );
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}
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int
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im__colour_unary( const char *domain,
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IMAGE *in, IMAGE *out, VipsType type,
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im_wrapone_fn buffer_fn, void *a, void *b )
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{
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IMAGE *t[1];
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if( im_check_uncoded( domain, in ) ||
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im_check_bands( domain, in, 3 ) ||
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im_open_local_array( out, t, 1, domain, "p" ) ||
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im_clip2fmt( in, t[0], IM_BANDFMT_FLOAT ) )
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return( -1 );
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if( im_cp_desc( out, t[0] ) )
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return( -1 );
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out->Type = type;
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if( im_wrapone( t[0], out,
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(im_wrapone_fn) buffer_fn, a, b ) )
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return( -1 );
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return( 0 );
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}
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