extern crate pdfpdf;
use pdfpdf::Pdf;
use pdfpdf::graphicsstate::Color;
fn main() {
let x: Vec<f32> = (0..600).map(|n| n as f32).collect();
let y: Vec<f32> = x.iter()
.map(|x| (-(x - 300.0).powi(2) / 1200.0).exp() * 600.0)
.collect();
Pdf::new()
.add_page(600.0, 600.0)
.set_stroke_color(Color::gray(100))
.draw_line(x.into_iter().zip(y.into_iter()))
.write_to("spectrum.pdf")
.unwrap();
}