283 lines
6.2 KiB
C
283 lines
6.2 KiB
C
/* Turn XYZ to Lab colourspace.
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*
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* Modifed:
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* 16/11/94 JC
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* - uses im_wrapone()
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* - in-line conversion
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* 27/1/03 JC
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* - swapped cbrt() for pow(), more portable
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* 12/11/04
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* - swapped pow() for cbrt() again, pow() is insanely slow on win32
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* - added a configure test for cbrt().
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* 23/11/04
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* - use a large LUT instead, about 5x faster
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* 23/11/06
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* - ahem, build the LUT outside the eval thread
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* 2/11/09
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* - gtkdoc
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* 3/8/11
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* - fix a race in the table build
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* 19/9/12
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* - redone as a class
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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., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 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 <glib/gi18n-lib.h>
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#include <stdio.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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#include "pcolour.h"
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#ifndef HAVE_CBRT
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#define cbrt( X ) pow( (X), 1.0 / 3.0 )
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#endif /*!HAVE_CBRT*/
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/* Lookup table size.
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*/
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#define QUANT_ELEMENTS (100000)
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static float cbrt_table[QUANT_ELEMENTS];
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typedef struct _VipsXYZ2Lab {
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VipsColourTransform parent_instance;
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/* The colour temperature -- default to D65.
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*/
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VipsArea *temp;
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/* Broken out as xyz.
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*/
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double X0;
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double Y0;
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double Z0;
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} VipsXYZ2Lab;
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typedef VipsColourTransformClass VipsXYZ2LabClass;
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G_DEFINE_TYPE( VipsXYZ2Lab, vips_XYZ2Lab, VIPS_TYPE_COLOUR_TRANSFORM );
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static void *
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table_init( void *client )
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{
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int i;
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for( i = 0; i < QUANT_ELEMENTS; i++ ) {
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float Y = (double) i / QUANT_ELEMENTS;
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if( Y < 0.008856 )
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cbrt_table[i] = 7.787 * Y + (16.0 / 116.0);
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else
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cbrt_table[i] = cbrt( Y );
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}
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return( NULL );
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}
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static void
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vips_col_XYZ2Lab_helper( VipsXYZ2Lab *XYZ2Lab,
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float X, float Y, float Z, float *L, float *a, float *b )
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{
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static GOnce once = G_ONCE_INIT;
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VIPS_ONCE( &once, table_init, NULL );
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float nX, nY, nZ;
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int i;
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float f;
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float cbx, cby, cbz;
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nX = QUANT_ELEMENTS * X / XYZ2Lab->X0;
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nY = QUANT_ELEMENTS * Y / XYZ2Lab->Y0;
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nZ = QUANT_ELEMENTS * Z / XYZ2Lab->Z0;
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/* CLIP is much faster than FCLIP, and we want an int result.
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*/
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i = VIPS_CLIP( 0, (int) nX, QUANT_ELEMENTS - 2 );
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f = nX - i;
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cbx = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
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i = VIPS_CLIP( 0, (int) nY, QUANT_ELEMENTS - 2 );
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f = nY - i;
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cby = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
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i = VIPS_CLIP( 0, (int) nZ, QUANT_ELEMENTS - 2 );
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f = nZ - i;
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cbz = cbrt_table[i] + f * (cbrt_table[i + 1] - cbrt_table[i]);
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*L = 116.0 * cby - 16.0;
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*a = 500.0 * (cbx - cby);
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*b = 200.0 * (cby - cbz);
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}
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/* Process a buffer of data.
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*/
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static void
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vips_XYZ2Lab_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
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{
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VipsXYZ2Lab *XYZ2Lab = (VipsXYZ2Lab *) colour;
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float *p = (float *) in[0];
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float *q = (float *) out;
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int x;
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for( x = 0; x < width; x++ ) {
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float X, Y, Z;
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float L, a, b;
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X = p[0];
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Y = p[1];
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Z = p[2];
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p += 3;
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vips_col_XYZ2Lab_helper( XYZ2Lab, X, Y, Z, &L, &a, &b );
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q[0] = L;
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q[1] = a;
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q[2] = b;
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q += 3;
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}
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}
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/**
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* vips_col_XYZ2Lab:
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* @X: Input CIE XYZ colour
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* @Y: Input CIE XYZ colour
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* @Z: Input CIE XYZ colour
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* @L: (out): Return CIE Lab value
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* @a: (out): Return CIE Lab value
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* @b: (out): Return CIE Lab value
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*
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* Calculate XYZ from Lab, D65.
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*
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* See also: vips_XYZ2Lab().
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*/
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void
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vips_col_XYZ2Lab( float X, float Y, float Z, float *L, float *a, float *b )
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{
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VipsXYZ2Lab XYZ2Lab;
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XYZ2Lab.X0 = VIPS_D65_X0;
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XYZ2Lab.Y0 = VIPS_D65_Y0;
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XYZ2Lab.Z0 = VIPS_D65_Z0;
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vips_col_XYZ2Lab_helper( &XYZ2Lab, X, Y, Z, L, a, b );
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}
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static int
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vips_XYZ2Lab_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsXYZ2Lab *XYZ2Lab = (VipsXYZ2Lab *) object;
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if( XYZ2Lab->temp ) {
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if( vips_check_vector_length( class->nickname,
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XYZ2Lab->temp->n, 3 ) )
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return( -1 );
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XYZ2Lab->X0 = ((double *) XYZ2Lab->temp->data)[0];
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XYZ2Lab->Y0 = ((double *) XYZ2Lab->temp->data)[1];
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XYZ2Lab->Z0 = ((double *) XYZ2Lab->temp->data)[2];
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}
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if( VIPS_OBJECT_CLASS( vips_XYZ2Lab_parent_class )->build( object ) )
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return( -1 );
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return( 0 );
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}
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static void
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vips_XYZ2Lab_class_init( VipsXYZ2LabClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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object_class->nickname = "XYZ2Lab";
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object_class->description = _( "transform XYZ to Lab" );
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object_class->build = vips_XYZ2Lab_build;
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colour_class->process_line = vips_XYZ2Lab_line;
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VIPS_ARG_BOXED( class, "temp", 110,
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_( "Temperature" ),
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_( "Colour temperature" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsXYZ2Lab, temp ),
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VIPS_TYPE_ARRAY_DOUBLE );
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}
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static void
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vips_XYZ2Lab_init( VipsXYZ2Lab *XYZ2Lab )
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{
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VipsColour *colour = VIPS_COLOUR( XYZ2Lab );
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XYZ2Lab->X0 = VIPS_D65_X0;
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XYZ2Lab->Y0 = VIPS_D65_Y0;
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XYZ2Lab->Z0 = VIPS_D65_Z0;
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colour->interpretation = VIPS_INTERPRETATION_LAB;
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}
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/**
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* vips_XYZ2Lab: (method)
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* @in: input image
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* @out: (out): output image
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* * @temp: #VipsArrayDouble, colour temperature
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*
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* Turn XYZ to Lab, optionally specifying the colour temperature. @temp
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* defaults to D65.
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*
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* Returns: 0 on success, -1 on error.
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*/
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int
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vips_XYZ2Lab( 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( "XYZ2Lab", ap, in, out );
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va_end( ap );
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return( result );
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}
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