163 lines
3.6 KiB
C
163 lines
3.6 KiB
C
/* to sRGB from HSV
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*
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* 9/6/15
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* - from sRGB2HSV.c
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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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#define SIXTH_OF_CHAR (42.5)
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typedef VipsColourCode VipsHSV2sRGB;
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typedef VipsColourCodeClass VipsHSV2sRGBClass;
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G_DEFINE_TYPE( VipsHSV2sRGB, vips_HSV2sRGB, VIPS_TYPE_COLOUR_CODE );
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static void
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vips_HSV2sRGB_line( VipsColour *colour, VipsPel *out, VipsPel **in, int width )
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{
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unsigned char *p = (unsigned char *) in[0];
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unsigned char *q = (unsigned char *) out;
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int i;
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for( i = 0; i < width; i++ ) {
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float c, x, m;
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c = p[2] * p[1] / 255.0;
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x = c * (1 - VIPS_FABS( fmod( p[0] / SIXTH_OF_CHAR, 2 ) - 1 ));
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m = p[2] - c;
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if( p[0] < (int) SIXTH_OF_CHAR ) {
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q[0] = c + m;
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q[1] = x + m;
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q[2] = 0 + m;
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}
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else if( p[0] < (int) (2 * SIXTH_OF_CHAR) ) {
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q[0] = x + m;
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q[1] = c + m;
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q[2] = 0 + m;
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}
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else if( p[0] < (int) (3 * SIXTH_OF_CHAR) ) {
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q[0] = 0 + m;
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q[1] = c + m;
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q[2] = x + m;
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}
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else if( p[0] < (int) (4 * SIXTH_OF_CHAR) ) {
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q[0] = 0 + m;
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q[1] = x + m;
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q[2] = c + m;
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}
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else if( p[0] < (int) (5 * SIXTH_OF_CHAR) ) {
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q[0] = x + m;
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q[1] = 0 + m;
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q[2] = c + m;
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}
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else {
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q[0] = c + m;
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q[1] = 0 + m;
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q[2] = x + m;
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}
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p += 3;
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q += 3;
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}
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}
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static void
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vips_HSV2sRGB_class_init( VipsHSV2sRGBClass *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 = "HSV2sRGB";
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object_class->description = _( "transform HSV to sRGB" );
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colour_class->process_line = vips_HSV2sRGB_line;
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}
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static void
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vips_HSV2sRGB_init( VipsHSV2sRGB *HSV2sRGB )
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{
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VipsColour *colour = VIPS_COLOUR( HSV2sRGB );
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VipsColourCode *code = VIPS_COLOUR_CODE( HSV2sRGB );
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colour->interpretation = VIPS_INTERPRETATION_sRGB;
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colour->format = VIPS_FORMAT_UCHAR;
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colour->bands = 3;
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colour->input_bands = 3;
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code->input_coding = VIPS_CODING_NONE;
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code->input_format = VIPS_FORMAT_UCHAR;
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code->input_interpretation = VIPS_INTERPRETATION_HSV;
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}
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/**
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* vips_HSV2sRGB: (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 HSV to sRGB.
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*
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* HSV is a crude polar coordinate system for RGB images. It is provided for
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* compatibility with other image processing systems. See vips_Lab2LCh() for a
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* much better colour space.
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*
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* See also: vips_sRGB2HSV().
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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_HSV2sRGB( 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( "HSV2sRGB", ap, in, out );
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va_end( ap );
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return( result );
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}
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