182 lines
4.5 KiB
C
182 lines
4.5 KiB
C
/* Lab2LabQ: quantise FLOAT Lab image into 10 11 11 format
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*
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* 4 bytes per pel: l a b lsbs
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* this is an image wrapper which calls line-wise packing
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* Copyright K.Martinez 3/5/93
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* Modified:
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* 7/6/93 JC
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* - adapted for partial v2
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* 5/5/94 JC
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* - some nint->+0.5, for speed and to ease portability
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* - other nint->rint
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* - now inclues <math.h>!
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* 15/11/94 JC
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* - all nint(), rint() removed for speed
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* - now -128 rather than -127 for a, b
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* - checks input type properly
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* 16/11/94 JC
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* - uses new im_wrap_oneonebuf()
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* 22/5/95 JC
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* - changed L to scale by 10.24, not 10.23
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* 11/7/95 JC
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* - now uses IM_RINT() for rounding
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* 4/9/97 JC
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* - L* = 100.0 now allowed
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* 5/11/00 JC
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* - go int earlier for speed up
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* 20/6/02 JC
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* - oops, were not clipping a/b range correctly
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* 1/11/09
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* - gtkdoc
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* - cleanups
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* 20/9/12
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* - redo 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 "pcolour.h"
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typedef VipsColourCode VipsLab2LabQ;
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typedef VipsColourCodeClass VipsLab2LabQClass;
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G_DEFINE_TYPE( VipsLab2LabQ, vips_Lab2LabQ, VIPS_TYPE_COLOUR_CODE );
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/* @(#) convert float Lab to packed Lab32 format 10 11 11 bits
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* works only on buffers, not IMAGEs
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* Copyright 1993 K.Martinez
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* Modified: 3/5/93, 16/6/93
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*/
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static void
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vips_Lab2LabQ_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
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{
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float * restrict p = (float *) in[0];
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VipsPel * restrict q = out;
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int i;
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for( i = 0; i < width; i++ ) {
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float fval;
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int lsbs;
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int intv;
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/* Scale L up to 10 bits.
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*/
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intv = VIPS_ROUND_UINT( 10.23 * p[0] );
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intv = VIPS_CLIP( 0, intv, 1023 );
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lsbs = (intv & 0x3) << 6; /* 00000011 -> 11000000 */
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q[0] = intv >> 2; /* drop bot 2 bits and store */
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fval = 8.0 * p[1]; /* do a */
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intv = VIPS_RINT( fval );
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intv = VIPS_CLIP( -1024, intv, 1023 );
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lsbs |= (intv & 0x7) << 3; /* 00000111 -> 00111000 */
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q[1] = intv >> 3; /* drop bot 3 bits & store */
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fval = 8.0 * p[2]; /* do b */
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intv = VIPS_RINT( fval );
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intv = VIPS_CLIP( -1024, intv, 1023 );
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lsbs |= (intv & 0x7);
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q[2] = intv >> 3;
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q[3] = lsbs; /* store lsb band */
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p += 3;
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q += 4;
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}
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}
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void
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vips__Lab2LabQ_vec( VipsPel *out, float *in, int width )
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{
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vips_Lab2LabQ_line( NULL, out, (VipsPel **) &in, width );
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}
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static void
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vips_Lab2LabQ_class_init( VipsLab2LabQClass *class )
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{
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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VipsColourClass *colour_class = VIPS_COLOUR_CLASS( class );
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object_class->nickname = "Lab2LabQ";
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object_class->description = _( "transform float Lab to LabQ coding" );
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colour_class->process_line = vips_Lab2LabQ_line;
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}
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static void
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vips_Lab2LabQ_init( VipsLab2LabQ *Lab2LabQ )
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{
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VipsColour *colour = VIPS_COLOUR( Lab2LabQ );
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VipsColourCode *code = VIPS_COLOUR_CODE( Lab2LabQ );
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colour->coding = VIPS_CODING_LABQ;
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colour->interpretation = VIPS_INTERPRETATION_LABQ;
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colour->format = VIPS_FORMAT_UCHAR;
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colour->input_bands = 3;
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colour->bands = 4;
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code->input_coding = VIPS_CODING_NONE;
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code->input_format = VIPS_FORMAT_FLOAT;
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}
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/**
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* vips_Lab2LabQ: (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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* Convert a Lab three-band float image to LabQ (#VIPS_CODING_LABQ).
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*
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* See also: vips_LabQ2Lab().
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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_Lab2LabQ( 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( "Lab2LabQ", ap, in, out );
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va_end( ap );
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return( result );
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}
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