70 lines
1.7 KiB
Rust
70 lines
1.7 KiB
Rust
//! Portable Pixel Map format images.
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use crate::{err::*, fixed::FixedLong, image::*};
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use std::io;
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/// Writes a PPM file from an image.
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///
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/// # Errors
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///
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/// Errors if `out` cannot be written to.
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pub fn write_ppm(out: &mut impl io::Write, im: &impl Image) -> ResultS<()>
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{
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write!(out, "P3\n{} {}\n{}\n", im.w(), im.h(), u16::max_value())?;
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for y in 0..im.h() {
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for x in 0..im.w() {
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let cr = im.index(x, y);
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write!(out, "{} {} {} ", cr.r(), cr.g(), cr.b())?;
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}
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out.write_all(b"\n")?;
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}
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Ok(())
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}
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/// Reads a PPM file into an image.
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pub fn read_ppm(inp: &[u8]) -> ResultS<Image16>
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{
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let mut it = inp.split(|&n| n == b'\n' || n == b'\r' || n == b' ');
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if ok!(it.next(), "no magic number")? != b"P3" {
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bail!("not P3 format");
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}
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let mut get_num = move || -> ResultS<u16> {
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let st = loop {
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match ok!(it.next(), "no more strings")? {
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b"" => {}
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st => break st
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}
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};
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let st = unsafe {std::str::from_utf8_unchecked(st)};
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let nu = u16::from_str_radix(st, 10)?;
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Ok(nu)
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};
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let width = get_num()?;
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let height = get_num()?;
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let depth = i64::from(get_num()?);
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let mut im = Image16::new(usize::from(width), usize::from(height));
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for _ in 0..height * width {
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let r = FixedLong::from_int(get_num()?.into());
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let g = FixedLong::from_int(get_num()?.into());
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let b = FixedLong::from_int(get_num()?.into());
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let r = (r / depth * 0xFFFF).integ() as u16;
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let g = (g / depth * 0xFFFF).integ() as u16;
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let b = (b / depth * 0xFFFF).integ() as u16;
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im.cr.push(Color16::new(r, g, b));
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}
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Ok(im)
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}
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// EOF
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