| /* Lab to XYZ. |
| * |
| * Modified: |
| * 15/11/94 JC |
| * - ANSIfied |
| * - sets Type of output |
| * - better error messages |
| * 16/11/94 JC |
| * - partialed |
| * - in-line conversion |
| * 8/2/95 JC |
| * - new im_wrapone function |
| * 2/11/09 |
| * - gtkdoc |
| * - cleanups |
| */ |
| |
| /* |
| |
| This file is part of VIPS. |
| |
| VIPS is free software; you can redistribute it and/or modify |
| it under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| */ |
| |
| /* |
| |
| These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk |
| |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif /*HAVE_CONFIG_H*/ |
| #include <vips/intl.h> |
| |
| #include <stdio.h> |
| #include <math.h> |
| |
| #include <vips/vips.h> |
| #include <vips/internal.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| /* Process a buffer of data. |
| */ |
| void |
| imb_Lab2XYZ( float *p, float *q, int n, im_colour_temperature *temp ) |
| { |
| int x; |
| |
| for( x = 0; x < n; x++ ) { |
| float L, a, b; |
| float X, Y, Z; |
| double cby, tmp; |
| |
| L = p[0]; |
| a = p[1]; |
| b = p[2]; |
| p += 3; |
| |
| if( L < 8.0 ) { |
| Y = (L * temp->Y0) / 903.3; |
| cby = 7.787 * (Y / temp->Y0) + 16.0 / 116.0; |
| } |
| else { |
| cby = (L + 16.0) / 116.0; |
| Y = temp->Y0 * cby * cby * cby; |
| } |
| |
| tmp = a / 500.0 + cby; |
| if( tmp < 0.2069 ) |
| X = temp->X0 * (tmp - 0.13793) / 7.787; |
| else |
| X = temp->X0 * tmp * tmp * tmp; |
| |
| tmp = cby - b / 200.0; |
| if( tmp < 0.2069 ) |
| Z = temp->Z0 * (tmp - 0.13793) / 7.787; |
| else |
| Z = temp->Z0 * tmp * tmp * tmp; |
| |
| /* Write. |
| */ |
| q[0] = X; |
| q[1] = Y; |
| q[2] = Z; |
| q += 3; |
| } |
| } |
| |
| /** |
| * im_Lab2XYZ_temp: |
| * @in: input image |
| * @out: output image |
| * @X0: colour temperature |
| * @Y0: colour temperature |
| * @Z0: colour temperature |
| * |
| * Turn Lab to XYZ. @X0, @y0, @Z0 give the Lab colour temperature. |
| * |
| * Returns: 0 on success, -1 on error. |
| */ |
| int |
| im_Lab2XYZ_temp( IMAGE *in, IMAGE *out, double X0, double Y0, double Z0 ) |
| { |
| im_colour_temperature *temp; |
| |
| if( !(temp = IM_NEW( out, im_colour_temperature )) ) |
| return( -1 ); |
| temp->X0 = X0; |
| temp->Y0 = Y0; |
| temp->Z0 = Z0; |
| |
| return( im__colour_unary( "im_Lab2XYZ_temp", in, out, IM_TYPE_XYZ, |
| (im_wrapone_fn) imb_Lab2XYZ, temp, NULL ) ); |
| } |
| |
| /** |
| * im_Lab2XYZ: |
| * @in: input image |
| * @out: output image |
| * |
| * Turn D65 Lab to XYZ. |
| * |
| * Returns: 0 on success, -1 on error. |
| */ |
| int |
| im_Lab2XYZ( IMAGE *in, IMAGE *out ) |
| { |
| return( im_Lab2XYZ_temp( in, out, IM_D65_X0, IM_D65_Y0, IM_D65_Z0 ) ); |
| } |