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use std::fs::File;
use std::io::Write;
const IMG_WIDTH: usize = 256;
const IMG_HEIGHT: usize = 256;
#[derive(Debug, Copy, Clone)]
struct Pixel {
r: u8,
g: u8,
b: u8,
}
impl Default for Pixel {
fn default() -> Self {
Pixel { r:0, g:0, b:0 }
}
}
struct View<'a> {
data: &'a[[Pixel; IMG_WIDTH]; IMG_HEIGHT],
viewer: fn(&[[Pixel; IMG_WIDTH]; IMG_HEIGHT]) -> Result<String, std::io::Error>,
}
impl<'a> View<'a> {
fn display(&self) {
let result = (self.viewer)(self.data);
match result {
Ok(success_msg) => {
println!("{}", success_msg);
},
Err(error_msg) => {
eprintln!("{}", error_msg);
}
}
}
}
fn ppm_exporter(data: &[[Pixel; IMG_WIDTH]; IMG_HEIGHT]) -> Result<String, std::io::Error> {
let file_name = "output.ppm";
let mut file = File::create(file_name)?;
// header
let mut txt_data = String::from("P3\n");
txt_data.push_str(format!("{} {}\n255\n", IMG_WIDTH, IMG_HEIGHT).as_str());
// data point
data.iter().for_each(|row| {
row.iter().for_each(|&pixel| {
txt_data.push_str(&format!("{} {} {}\n", pixel.r, pixel.g, pixel.b));
})
});
file.write_all(txt_data.as_bytes())?;
Ok(format!("Output rendered to file {}", file_name))
}
fn main() {
let mut data = [[Pixel::default(); IMG_WIDTH]; IMG_HEIGHT];
(0..IMG_HEIGHT).for_each(|j| {
(0..IMG_WIDTH).for_each(|i| {
let r = i as f32 / IMG_WIDTH as f32;
let g = j as f32 / IMG_HEIGHT as f32;
let b = 0.0f32;
let ir = (255.999 * r) as u8;
let ig = (255.999 * g) as u8;
let ib = (255.999 * b) as u8;
data[i][j] = Pixel { r: ir, g: ig, b: ib};
})
});
let view = View {
data: &data,
viewer: ppm_exporter,
};
view.display();
}
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