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/*
* This file is part of Siril, an astronomy image processor.
* Copyright (C) 2005-2011 Francois Meyer (dulle at free.fr)
* Copyright (C) 2012-2019 team free-astro (see more in AUTHORS file)
* Reference site is https://free-astro.org/index.php/Siril
*
* Siril is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Siril 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Siril. If not, see <http://www.gnu.org/licenses/>.
*/
#include "filters.h"
#include <math.h>
/* A common narrow-band filter list. */
narrow_filter narrow_band_filters[] = {
/* narrow band filters */
{ "H-alpha", 656.28 },
{ "H-beta", 486.1 },
{ "O III", 500.7 },
{ "S II", 671.7 },
{ "N II", 658.35 }
};
int get_nb_narrow_filters() {
return sizeof(narrow_band_filters) / sizeof(narrow_filter);
}
/*
* TODO: Add common broad band filters with their number
* example list: http://www.myastroshop.com.au/guides/filters.asp
*/
broad_filter broad_band_filters[] = {
/* broad band filters */
{ "#1 (red)", "#ff0000" },
{ "#2 (blue)", "#0000ff" },
};
/** Taken from Earl F. Glynn's web page:
* http://www.efg2.com/Lab/ScienceAndEngineering/Spectra.htm
* http://www.physics.sfasu.edu/astro/color/spectra.html
*
* Fills the rgb struct passed as arg with RGB values corresponding to the
* wavelength.
*
* I couldn't find why gamma is 0.8 anywhere. */
static double Gamma = 0.80;
void wavelength_to_RGB(double wavelength, GdkRGBA *rgb){
double factor;
double Red,Green,Blue;
if((wavelength >= 380) && (wavelength<440)){
Red = -(wavelength - 440) / (440 - 380);
Green = 0.0;
Blue = 1.0;
}else if((wavelength >= 440) && (wavelength<490)){
Red = 0.0;
Green = (wavelength - 440) / (490 - 440);
Blue = 1.0;
}else if((wavelength >= 490) && (wavelength<510)){
Red = 0.0;
Green = 1.0;
Blue = -(wavelength - 510) / (510 - 490);
}else if((wavelength >= 510) && (wavelength<580)){
Red = (wavelength - 510) / (580 - 510);
Green = 1.0;
Blue = 0.0;
}else if((wavelength >= 580) && (wavelength<645)){
Red = 1.0;
Green = -(wavelength - 645) / (645 - 580);
Blue = 0.0;
}else if((wavelength >= 645) && (wavelength<781)){
Red = 1.0;
Green = 0.0;
Blue = 0.0;
}else{
Red = 0.0;
Green = 0.0;
Blue = 0.0;
};
// Let the intensity fall off near the vision limits
if((wavelength >= 380) && (wavelength<420)){
factor = 0.3 + 0.7*(wavelength - 380) / (420 - 380);
}else if((wavelength >= 420) && (wavelength<701)){
factor = 1.0;
}else if((wavelength >= 701) && (wavelength<781)){
factor = 0.3 + 0.7*(780 - wavelength) / (780 - 700);
}else{
factor = 0.0;
};
// Don't want 0^x = 1 for x <> 0
rgb->red = Red==0.0 ? 0 : pow(Red * factor, Gamma);
rgb->green = Green==0.0 ? 0 : pow(Green * factor, Gamma);
rgb->blue = Blue==0.0 ? 0 : pow(Blue * factor, Gamma);
rgb->alpha = 1.0;
}
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