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Diffstat (limited to 'vendor/image/src/codecs/hdr/encoder.rs')
| -rw-r--r-- | vendor/image/src/codecs/hdr/encoder.rs | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/vendor/image/src/codecs/hdr/encoder.rs b/vendor/image/src/codecs/hdr/encoder.rs new file mode 100644 index 0000000..c3a176d --- /dev/null +++ b/vendor/image/src/codecs/hdr/encoder.rs @@ -0,0 +1,433 @@ +use crate::codecs::hdr::{rgbe8, Rgbe8Pixel, SIGNATURE}; +use crate::color::Rgb; +use crate::error::ImageResult; +use std::cmp::Ordering; +use std::io::{Result, Write}; + +/// Radiance HDR encoder +pub struct HdrEncoder<W: Write> { + w: W, +} + +impl<W: Write> HdrEncoder<W> { + /// Creates encoder + pub fn new(w: W) -> HdrEncoder<W> { + HdrEncoder { w } + } + + /// Encodes the image ```data``` + /// that has dimensions ```width``` and ```height``` + pub fn encode(mut self, data: &[Rgb<f32>], width: usize, height: usize) -> ImageResult<()> { + assert!(data.len() >= width * height); + let w = &mut self.w; + w.write_all(SIGNATURE)?; + w.write_all(b"\n")?; + w.write_all(b"# Rust HDR encoder\n")?; + w.write_all(b"FORMAT=32-bit_rle_rgbe\n\n")?; + w.write_all(format!("-Y {} +X {}\n", height, width).as_bytes())?; + + if !(8..=32_768).contains(&width) { + for &pix in data { + write_rgbe8(w, to_rgbe8(pix))?; + } + } else { + // new RLE marker contains scanline width + let marker = rgbe8(2, 2, (width / 256) as u8, (width % 256) as u8); + // buffers for encoded pixels + let mut bufr = vec![0; width]; + let mut bufg = vec![0; width]; + let mut bufb = vec![0; width]; + let mut bufe = vec![0; width]; + let mut rle_buf = vec![0; width]; + for scanline in data.chunks(width) { + for ((((r, g), b), e), &pix) in bufr + .iter_mut() + .zip(bufg.iter_mut()) + .zip(bufb.iter_mut()) + .zip(bufe.iter_mut()) + .zip(scanline.iter()) + { + let cp = to_rgbe8(pix); + *r = cp.c[0]; + *g = cp.c[1]; + *b = cp.c[2]; + *e = cp.e; + } + write_rgbe8(w, marker)?; // New RLE encoding marker + rle_buf.clear(); + rle_compress(&bufr[..], &mut rle_buf); + w.write_all(&rle_buf[..])?; + rle_buf.clear(); + rle_compress(&bufg[..], &mut rle_buf); + w.write_all(&rle_buf[..])?; + rle_buf.clear(); + rle_compress(&bufb[..], &mut rle_buf); + w.write_all(&rle_buf[..])?; + rle_buf.clear(); + rle_compress(&bufe[..], &mut rle_buf); + w.write_all(&rle_buf[..])?; + } + } + Ok(()) + } +} + +#[derive(Debug, PartialEq, Eq)] +enum RunOrNot { + Run(u8, usize), + Norun(usize, usize), +} +use self::RunOrNot::{Norun, Run}; + +const RUN_MAX_LEN: usize = 127; +const NORUN_MAX_LEN: usize = 128; + +struct RunIterator<'a> { + data: &'a [u8], + curidx: usize, +} + +impl<'a> RunIterator<'a> { + fn new(data: &'a [u8]) -> RunIterator<'a> { + RunIterator { data, curidx: 0 } + } +} + +impl<'a> Iterator for RunIterator<'a> { + type Item = RunOrNot; + + fn next(&mut self) -> Option<Self::Item> { + if self.curidx == self.data.len() { + None + } else { + let cv = self.data[self.curidx]; + let crun = self.data[self.curidx..] + .iter() + .take_while(|&&v| v == cv) + .take(RUN_MAX_LEN) + .count(); + let ret = if crun > 2 { + Run(cv, crun) + } else { + Norun(self.curidx, crun) + }; + self.curidx += crun; + Some(ret) + } + } +} + +struct NorunCombineIterator<'a> { + runiter: RunIterator<'a>, + prev: Option<RunOrNot>, +} + +impl<'a> NorunCombineIterator<'a> { + fn new(data: &'a [u8]) -> NorunCombineIterator<'a> { + NorunCombineIterator { + runiter: RunIterator::new(data), + prev: None, + } + } +} + +// Combines sequential noruns produced by RunIterator +impl<'a> Iterator for NorunCombineIterator<'a> { + type Item = RunOrNot; + fn next(&mut self) -> Option<Self::Item> { + loop { + match self.prev.take() { + Some(Run(c, len)) => { + // Just return stored run + return Some(Run(c, len)); + } + Some(Norun(idx, len)) => { + // Let's see if we need to continue norun + match self.runiter.next() { + Some(Norun(_, len1)) => { + // norun continues + let clen = len + len1; // combined length + match clen.cmp(&NORUN_MAX_LEN) { + Ordering::Equal => return Some(Norun(idx, clen)), + Ordering::Greater => { + // combined norun exceeds maximum length. store extra part of norun + self.prev = + Some(Norun(idx + NORUN_MAX_LEN, clen - NORUN_MAX_LEN)); + // then return maximal norun + return Some(Norun(idx, NORUN_MAX_LEN)); + } + Ordering::Less => { + // len + len1 < NORUN_MAX_LEN + self.prev = Some(Norun(idx, len + len1)); + // combine and continue loop + } + } + } + Some(Run(c, len1)) => { + // Run encountered. Store it + self.prev = Some(Run(c, len1)); + return Some(Norun(idx, len)); // and return combined norun + } + None => { + // End of sequence + return Some(Norun(idx, len)); // return combined norun + } + } + } // End match self.prev.take() == Some(NoRun()) + None => { + // No norun to combine + match self.runiter.next() { + Some(Norun(idx, len)) => { + self.prev = Some(Norun(idx, len)); + // store for combine and continue the loop + } + Some(Run(c, len)) => { + // Some run. Just return it + return Some(Run(c, len)); + } + None => { + // That's all, folks + return None; + } + } + } // End match self.prev.take() == None + } // End match + } // End loop + } +} + +// Appends RLE compressed ```data``` to ```rle``` +fn rle_compress(data: &[u8], rle: &mut Vec<u8>) { + rle.clear(); + if data.is_empty() { + rle.push(0); // Technically correct. It means read next 0 bytes. + return; + } + // Task: split data into chunks of repeating (max 127) and non-repeating bytes (max 128) + // Prepend non-repeating chunk with its length + // Replace repeating byte with (run length + 128) and the byte + for rnr in NorunCombineIterator::new(data) { + match rnr { + Run(c, len) => { + assert!(len <= 127); + rle.push(128u8 + len as u8); + rle.push(c); + } + Norun(idx, len) => { + assert!(len <= 128); + rle.push(len as u8); + rle.extend_from_slice(&data[idx..idx + len]); + } + } + } +} + +fn write_rgbe8<W: Write>(w: &mut W, v: Rgbe8Pixel) -> Result<()> { + w.write_all(&[v.c[0], v.c[1], v.c[2], v.e]) +} + +/// Converts ```Rgb<f32>``` into ```Rgbe8Pixel``` +pub fn to_rgbe8(pix: Rgb<f32>) -> Rgbe8Pixel { + let pix = pix.0; + let mx = f32::max(pix[0], f32::max(pix[1], pix[2])); + if mx <= 0.0 { + Rgbe8Pixel { c: [0, 0, 0], e: 0 } + } else { + // let (frac, exp) = mx.frexp(); // unstable yet + let exp = mx.log2().floor() as i32 + 1; + let mul = f32::powi(2.0, exp); + let mut conv = [0u8; 3]; + for (cv, &sv) in conv.iter_mut().zip(pix.iter()) { + *cv = f32::trunc(sv / mul * 256.0) as u8; + } + Rgbe8Pixel { + c: conv, + e: (exp + 128) as u8, + } + } +} + +#[test] +fn to_rgbe8_test() { + use crate::codecs::hdr::rgbe8; + let test_cases = vec![rgbe8(0, 0, 0, 0), rgbe8(1, 1, 128, 128)]; + for &pix in &test_cases { + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + } + for mc in 128..255 { + // TODO: use inclusive range when stable + let pix = rgbe8(mc, mc, mc, 100); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + let pix = rgbe8(mc, 0, mc, 130); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + let pix = rgbe8(0, 0, mc, 140); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + let pix = rgbe8(1, 0, mc, 150); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + let pix = rgbe8(1, mc, 10, 128); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + for c in 0..255 { + // Radiance HDR seems to be pre IEEE 754. + // exponent can be -128 (represented as 0u8), so some colors cannot be represented in normalized f32 + // Let's exclude exponent value of -128 (0u8) from testing + let pix = rgbe8(1, mc, c, if c == 0 { 1 } else { c }); + assert_eq!(pix, to_rgbe8(pix.to_hdr())); + } + } + fn relative_dist(a: Rgb<f32>, b: Rgb<f32>) -> f32 { + // maximal difference divided by maximal value + let max_diff = + a.0.iter() + .zip(b.0.iter()) + .fold(0.0, |diff, (&a, &b)| f32::max(diff, (a - b).abs())); + let max_val = + a.0.iter() + .chain(b.0.iter()) + .fold(0.0, |maxv, &a| f32::max(maxv, a)); + if max_val == 0.0 { + 0.0 + } else { + max_diff / max_val + } + } + let test_values = vec![ + 0.000_001, 0.000_02, 0.000_3, 0.004, 0.05, 0.6, 7.0, 80.0, 900.0, 1_000.0, 20_000.0, + 300_000.0, + ]; + for &r in &test_values { + for &g in &test_values { + for &b in &test_values { + let c1 = Rgb([r, g, b]); + let c2 = to_rgbe8(c1).to_hdr(); + let rel_dist = relative_dist(c1, c2); + // Maximal value is normalized to the range 128..256, thus we have 1/128 precision + assert!( + rel_dist <= 1.0 / 128.0, + "Relative distance ({}) exceeds 1/128 for {:?} and {:?}", + rel_dist, + c1, + c2 + ); + } + } + } +} + +#[test] +fn runiterator_test() { + let data = []; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), None); + let data = [5]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Norun(0, 1))); + assert_eq!(run_iter.next(), None); + let data = [1, 1]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Norun(0, 2))); + assert_eq!(run_iter.next(), None); + let data = [0, 0, 0]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Run(0u8, 3))); + assert_eq!(run_iter.next(), None); + let data = [0, 0, 1, 1]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Norun(0, 2))); + assert_eq!(run_iter.next(), Some(Norun(2, 2))); + assert_eq!(run_iter.next(), None); + let data = [0, 0, 0, 1, 1]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Run(0u8, 3))); + assert_eq!(run_iter.next(), Some(Norun(3, 2))); + assert_eq!(run_iter.next(), None); + let data = [1, 2, 2, 2]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Norun(0, 1))); + assert_eq!(run_iter.next(), Some(Run(2u8, 3))); + assert_eq!(run_iter.next(), None); + let data = [1, 1, 2, 2, 2]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Norun(0, 2))); + assert_eq!(run_iter.next(), Some(Run(2u8, 3))); + assert_eq!(run_iter.next(), None); + let data = [2; 128]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Run(2u8, 127))); + assert_eq!(run_iter.next(), Some(Norun(127, 1))); + assert_eq!(run_iter.next(), None); + let data = [2; 129]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Run(2u8, 127))); + assert_eq!(run_iter.next(), Some(Norun(127, 2))); + assert_eq!(run_iter.next(), None); + let data = [2; 130]; + let mut run_iter = RunIterator::new(&data[..]); + assert_eq!(run_iter.next(), Some(Run(2u8, 127))); + assert_eq!(run_iter.next(), Some(Run(2u8, 3))); + assert_eq!(run_iter.next(), None); +} + +#[test] +fn noruncombine_test() { + fn a<T>(mut v: Vec<T>, mut other: Vec<T>) -> Vec<T> { + v.append(&mut other); + v + } + + let v = vec![]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), None); + + let v = vec![1]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Norun(0, 1))); + assert_eq!(rsi.next(), None); + + let v = vec![2, 2]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Norun(0, 2))); + assert_eq!(rsi.next(), None); + + let v = vec![3, 3, 3]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Run(3, 3))); + assert_eq!(rsi.next(), None); + + let v = vec![4, 4, 3, 3, 3]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Norun(0, 2))); + assert_eq!(rsi.next(), Some(Run(3, 3))); + assert_eq!(rsi.next(), None); + + let v = vec![40; 400]; + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Run(40, 127))); + assert_eq!(rsi.next(), Some(Run(40, 127))); + assert_eq!(rsi.next(), Some(Run(40, 127))); + assert_eq!(rsi.next(), Some(Run(40, 19))); + assert_eq!(rsi.next(), None); + + let v = a(a(vec![5; 3], vec![6; 129]), vec![7, 3, 7, 10, 255]); + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Run(5, 3))); + assert_eq!(rsi.next(), Some(Run(6, 127))); + assert_eq!(rsi.next(), Some(Norun(130, 7))); + assert_eq!(rsi.next(), None); + + let v = a(a(vec![5; 2], vec![6; 129]), vec![7, 3, 7, 7, 255]); + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Norun(0, 2))); + assert_eq!(rsi.next(), Some(Run(6, 127))); + assert_eq!(rsi.next(), Some(Norun(129, 7))); + assert_eq!(rsi.next(), None); + + let v: Vec<_> = ::std::iter::repeat(()) + .flat_map(|_| (0..2)) + .take(257) + .collect(); + let mut rsi = NorunCombineIterator::new(&v[..]); + assert_eq!(rsi.next(), Some(Norun(0, 128))); + assert_eq!(rsi.next(), Some(Norun(128, 128))); + assert_eq!(rsi.next(), Some(Norun(256, 1))); + assert_eq!(rsi.next(), None); +} |