160 lines
4.1 KiB
C
160 lines
4.1 KiB
C
/* Gamma-correct image with factor gammafactor.
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*
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* Copyright: 1990, N. Dessipris.
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*
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* Written on: 19/07/1990
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* Modified on:
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* 19/6/95 JC
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* - redone as library function
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* 23/3/10
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* - gtkdoc
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* - 16 bit as well
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* 1/8/13
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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 <vips/intl.h>
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#include <vips/vips.h>
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#include "pconversion.h"
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typedef struct _VipsGammacorrect {
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VipsConversion parent_instance;
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VipsImage *in;
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double exponent;
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} VipsGammacorrect;
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typedef VipsConversionClass VipsGammacorrectClass;
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G_DEFINE_TYPE( VipsGammacorrect, vips_gammacorrect, VIPS_TYPE_CONVERSION );
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static int
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vips_gammacorrect_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsConversion *conversion = VIPS_CONVERSION( object );
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VipsGammacorrect *gammacorrect = (VipsGammacorrect *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 5 );
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VipsImage *in = gammacorrect->in;
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double mx1, mx2;
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if( VIPS_OBJECT_CLASS( vips_gammacorrect_parent_class )->
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build( object ) )
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return( -1 );
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if( vips_check_u8or16( class->nickname, in ) ||
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vips_identity( &t[0],
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"ushort", in->BandFmt == VIPS_FORMAT_USHORT,
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NULL ) ||
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vips_pow_const1( t[0], &t[1], gammacorrect->exponent, NULL ) ||
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vips_max( t[0], &mx1, NULL ) ||
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vips_max( t[1], &mx2, NULL ) ||
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vips_linear1( t[1], &t[2], mx1 / mx2, 0, NULL ) ||
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vips_cast( t[2], &t[3], in->BandFmt, NULL ) ||
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vips_maplut( in, &t[4], t[3], NULL ) ||
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vips_image_write( t[4], conversion->out ) )
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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_gammacorrect_class_init( VipsGammacorrectClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
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VipsOperationClass *operation_class = VIPS_OPERATION_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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vobject_class->nickname = "gammacorrect";
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vobject_class->description = _( "gammacorrect a pair of images" );
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vobject_class->build = vips_gammacorrect_build;
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operation_class->flags = VIPS_OPERATION_SEQUENTIAL_UNBUFFERED;
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VIPS_ARG_IMAGE( class, "in", -1,
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_( "in" ),
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_( "Input image" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsGammacorrect, in ) );
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VIPS_ARG_DOUBLE( class, "exponent", 0,
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_( "exponent" ),
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_( "Gamma factor" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsGammacorrect, exponent ),
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0.000001, 1000.0, 2.4 );
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}
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static void
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vips_gammacorrect_init( VipsGammacorrect *gammacorrect )
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{
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gammacorrect->exponent = 2.4;
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}
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/**
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* vips_gammacorrect:
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* @in: input image
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* @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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* @exponent: gamma factor, default 2.4
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*
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* Gamma-correct an 8- or 16-bit unsigned image with a lookup table. The
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* output format is the same as the input format.
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*
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* See also: vips_identity(), vips_pow_const1(), vips_maplut()
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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_gammacorrect( 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( "gammacorrect", ap, in, out );
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va_end( ap );
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return( result );
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}
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