| /* Turn XYZ to Lab colourspace. |
| * |
| * Modifed: |
| * 16/11/94 JC |
| * - uses im_wrapone() |
| * - in-line conversion |
| * 27/1/03 JC |
| * - swapped cbrt() for pow(), more portable |
| * 12/11/04 |
| * - swapped pow() for cbrt() again, pow() is insanely slow on win32 |
| * - added a configure test for cbrt(). |
| * 23/11/04 |
| * - use a large LUT instead, about 5x faster |
| * 23/11/06 |
| * - ahem, build the LUT outside the eval thread |
| * 2/11/09 |
| * - gtkdoc |
| */ |
| |
| /* |
| |
| 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/thread.h> |
| #include <vips/internal.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC*/ |
| |
| #ifndef HAVE_CBRT |
| #define cbrt( X ) pow( (X), 1.0 / 3.0 ) |
| #endif /*!HAVE_CBRT*/ |
| |
| /* Lookup table size. |
| */ |
| #define QUANT_ELEMENTS (100000) |
| |
| float cbrt_table[QUANT_ELEMENTS]; |
| |
| void |
| imb_XYZ2Lab_tables( void ) |
| { |
| static int built_tables = 0; |
| |
| int was_built; |
| int i; |
| |
| g_mutex_lock( im__global_lock ); |
| was_built = built_tables; |
| built_tables = 1; |
| g_mutex_unlock( im__global_lock ); |
| if( was_built ) |
| return; |
| |
| for( i = 0; i < QUANT_ELEMENTS; i++ ) { |
| float Y = (double) i / QUANT_ELEMENTS; |
| |
| if( Y < 0.008856 ) |
| cbrt_table[i] = 7.787 * Y + (16.0 / 116.0); |
| else |
| cbrt_table[i] = cbrt( Y ); |
| } |
| } |
| |
| /* Process a buffer of data. |
| */ |
| void |
| imb_XYZ2Lab( float *p, float *q, int n, im_colour_temperature *temp ) |
| { |
| int x; |
| |
| for( x = 0; x < n; x++ ) { |
| float nX, nY, nZ; |
| int i; |
| float f; |
| float cbx, cby, cbz; |
| |
| nX = QUANT_ELEMENTS * p[0] / temp->X0; |
| nY = QUANT_ELEMENTS * p[1] / temp->Y0; |
| nZ = QUANT_ELEMENTS * p[2] / temp->Z0; |
| p += 3; |
| |
| i = (int) nX; |
| if( i < 0 ) |
| i = 0; |
| if( i > QUANT_ELEMENTS - 2 ) |
| i = QUANT_ELEMENTS - 2; |
| f = nX - i; |
| cbx = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]); |
| |
| i = (int) nY; |
| if( i < 0 ) |
| i = 0; |
| if( i > QUANT_ELEMENTS - 2 ) |
| i = QUANT_ELEMENTS - 2; |
| f = nY - i; |
| cby = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]); |
| |
| i = (int) nZ; |
| if( i < 0 ) |
| i = 0; |
| if( i > QUANT_ELEMENTS - 2 ) |
| i = QUANT_ELEMENTS - 2; |
| f = nZ - i; |
| cbz = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]); |
| |
| q[0] = 116.0 * cby - 16.0; |
| q[1] = 500.0 * (cbx - cby); |
| q[2] = 200.0 * (cby - cbz); |
| q += 3; |
| } |
| } |
| |
| /** |
| * im_XYZ2Lab_temp: |
| * @in: input image |
| * @out: output image |
| * @X0: colour temperature |
| * @Y0: colour temperature |
| * @Z0: colour temperature |
| * |
| * Turn XYZ to Lab. @X0, @y0, @Z0 give the Lab colour temperature. |
| * |
| * Returns: 0 on success, -1 on error. |
| */ |
| int |
| im_XYZ2Lab_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; |
| imb_XYZ2Lab_tables(); |
| |
| return( im__colour_unary( "im_XYZ2Lab", in, out, IM_TYPE_LAB, |
| (im_wrapone_fn) imb_XYZ2Lab, temp, NULL ) ); |
| } |
| |
| /** |
| * im_XYZ2Lab: |
| * @in: input image |
| * @out: output image |
| * |
| * Turn XYZ to D65 Lab. |
| * |
| * Returns: 0 on success, -1 on error. |
| */ |
| int |
| im_XYZ2Lab( IMAGE *in, IMAGE *out ) |
| { |
| return( im_XYZ2Lab_temp( in, out, IM_D65_X0, IM_D65_Y0, IM_D65_Z0 ) ); |
| } |