agg 0.1.0

High-quality 2D graphics engine based on Anti-grain Geometry
Documentation 
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//! Writing of PPM (Portable Pixmap Format) files
//!
//! See <https://en.wikipedia.org/wiki/Netpbm_format#PPM_example>
//!
use std::fs;
use std::fs::File;
use std::path::Path;
use std::io::prelude::*;

/// Compare two PPM files, panic'ing on a difference
pub fn compare_ppm<P: AsRef<Path>>(f1: P, f2: P) {
    let d1 = fs::read(f1).expect("Unable to read file");
    let d2 = fs::read(f2).expect("Unable to read file");
    for (i,(v1,v2)) in d1.iter().zip(d2.iter()).enumerate() {
        if v1 != v2 {
            eprintln!("{}: {} {}", i, v1, v2);
            assert_eq!(v1,v2);
        }
    }
}
/// Write a PPM file
///
/// P6 - Binary Portable Pixmap (0-255 RGB data)
///
/// PPM uses 24 bits per pixel: 8 for red, 8 for green, 8 for blue.
///
/// Width and Height are specified, then the maximum value for any color
///
/// Then the data in row-major order (C-format)
///
pub fn write_ppm<P: AsRef<Path>>(buf: &[u8], width: usize, height: usize, filename: P) -> Result<(),std::io::Error> {
    let mut fd = File::create(filename)?;
    write!(fd, "P6 {} {} 255 ", width, height)?;
    fd.write_all(buf)?;
    Ok(())
}