use strict;
use Svg;

sub MakeGrad {
	my ($grad,$a) = @_;
	my ($lo,$hi) = ($$a[0][0], $$a[$#$a][0]);
	for my $stop (@$a) {
		$grad->stop(offset => int(($$stop[0]-$lo)/($hi-$lo)*100+0.5) . '%', 'stop-color' => $$stop[1]);
	}
}

# cone fundamentals in steps of 5nm from 390nm to 710nm, normalized to max=1000
my @lfund = (0,1,2,5,9,13,18,23,28,34,40,45,50,55,65,81,99,119,140,164,192,233,289,360,444,536,629,705,771,826,881,919,940,966,981,994,1000,992,969,956,928,886,834,775,706,631,554,480,401,328,266,213,165,125,93,69,50,36,25,18,12,8,6,4,3);
my @mfund = (0,1,2,5,9,15,22,30,39,52,65,76,87,98,116,145,176,205,236,268,304,357,428,516,616,719,817,886,936,969,995,997,977,957,918,873,814,740,653,573,493,411,334,265,205,156,117,86,62,44,31,22,15,11,7,5,3,2,2,1,1,1,0,0,0);
my @sfund = (10,24,57,122,233,381,544,674,803,904,991,992,955,860,787,738,646,516,390,290,212,161,123,89,61,43,29,19,13,8,5,3,2,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);

my @colorgradient1 = ([390,'#000001'],[400,'#010002'],[410,'#020007'],[420,'#060013'],[440,'#170039'],[450,'#1D004E'],[455,'#1D005B'],[460,'#18006B'],[465,'#000879'],[470,'#002061'],[480,'#00334D'],[490,'#004245'],[500,'#005446'],[520,'#007C4F'],[530,'#00884D'],[535,'#008C48'],[545,'#00912F'],[550,'#159300'],[555,'#409000'],[570,'#7E8000'],[585,'#A56400'],[595,'#B44A00'],[605,'#BA2700'],[610,'#B90C00'],[615,'#B00016'],[620,'#A4001F'],[630,'#8B0021'],[640,'#72001D'],[670,'#310009'],[680,'#220005'],[700,'#0D0001'],[710,'#070001']);
my @colorgradient2 = ([390,'#8E8D8F'],[400,'#8E8D93'],[410,'#908B9C'],[420,'#9587B6'],[430,'#9C7FDA'],[440,'#9C7DE8'],[450,'#9780E9'],[460,'#8F86E5'],[470,'#8390D5'],[490,'#68A6AA'],[500,'#55B29C'],[510,'#30C292'],[520,'#00D189'],[530,'#33D985'],[540,'#5FDB82'],[555,'#96D681'],[570,'#C5C783'],[585,'#EAB186'],[595,'#FAA088'],[605,'#FF918A'],[615,'#FA888B'],[625,'#EB848C'],[655,'#B1898D'],[670,'#9D8C8D'],[690,'#928D8E'],[710,'#8F8D8E']);

my ($bgcolor,$legendcolor,$tracecolor,$spectrum) = (qw(white black white), \@colorgradient1);
#my ($bgcolor,$legendcolor,$tracecolor,$spectrum) = (qw(black white black), \@colorgradient2);
my $graph_width = 480;
my $graph_height = 300;
my $spectrum_top_padding = 10;
my $graph_ofs_x = 40;
my $graph_ofs_y = 20;
my $image_width = $graph_ofs_x + $graph_width + 20;
my $image_height = $graph_ofs_y + $graph_height + 60;

my $svg = new Svg(width => $image_width, height => $image_height, fill => 'none');
MakeGrad($svg->defs()->linearGradient(id => 'spectrum'), $spectrum);

$svg->rect(width => $image_width, height => $image_height, fill => $bgcolor);

my $graph = $svg->group(stroke => $tracecolor, 'stroke-width' => 3, 'stroke-linecap' => 'square');
$graph->translate($graph_ofs_x, $graph_ofs_y);
$graph->rect(x => 0, y => 0, width => $graph_width, height => $graph_height, stroke => 'none', fill => 'url(#spectrum)');
for my $a (\@lfund,\@mfund,\@sfund) {
	$graph->path(d => MakePath(Interpolate([0..$#$a], $a, 4), $graph_width / $#$a, ($graph_height-$spectrum_top_padding)/-1000, 0, $graph_height, 0.25));
}
$graph->line(x1 => 0, y1 => $graph_height, x2 => $graph_width, y2 => $graph_height, stroke => $bgcolor);

my $text = $svg->group('font-family' => 'Nimbus Roman No9 L, Times, serif', 'font-size' => 20, 'text-anchor' => 'middle', stroke => 'none', fill => $legendcolor);
my $ticks = do { my $w = $graph_width+19; my $h = $graph_height+19; "M30.5,10.5l$w,0l0,${h}l-$w,0l0,-$h" };
for (my $i = 390; $i <= 710; $i += 10) {
	my $h = $i % 50 ? 3 : 6;
	my $x = $graph_ofs_x + 0.5 + $graph_width * ($i-390)/(710-390);
	my $y2 = $graph_ofs_y + $graph_height + 9.5 - $h;
	$ticks .= "M$x,10.5l0,${h}M$x,${y2}l0,$h";
	if ($i % 50 == 0) {
		$text->text(x => $x, y => $graph_ofs_y + $graph_height + 30)->add($i);
	}
}
$text->text(x => $graph_ofs_x + $graph_width * 0.5, y => $graph_ofs_y + $graph_height + 50)->add('Wavelength (nm)');
$text->text()->rotate(-90)->translate(20, $graph_ofs_y + $graph_height/2)->add('Normalized cone response (linear energy)');
my $sml_text = $text->group(fill => $tracecolor);
$sml_text->text(x => 145, y => 50)->add('S');
$sml_text->text(x => 230, y => 50)->add('M');
$sml_text->text(x => 355, y => 50)->add('L');
$svg->path(stroke => $legendcolor, 'stroke-width' => 1, d => $ticks);

$svg->write('Cone-fundamentals-with-srgb-spectrum.svg');