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Encode runs of 1 as index (+ "reference" feature)

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This commit is contained in:
Ivan Smirnov 2022-01-03 15:56:03 +03:00
parent ab92cf64b6
commit 465a5b86a1
2 changed files with 21 additions and 5 deletions
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4
Cargo.toml
View file

@ -15,6 +15,10 @@ exclude = [
"assets/*",
]
[features]
default = []
reference = [] # follows reference encoder implementation precisely, but may be slightly slower
[dependencies]
bytemuck = "1.7"

22
src/encode.rs
View file

@ -8,7 +8,7 @@ use crate::pixel::{Pixel, SupportedChannels};
use crate::types::{Channels, ColorSpace};
use crate::utils::{unlikely, BytesMut, GenericWriter, Writer};
#[allow(clippy::cast_possible_truncation)]
#[allow(clippy::cast_possible_truncation, unused_assignments)]
fn qoi_encode_impl<W: Writer, const N: usize>(mut buf: W, data: &[u8]) -> Result<usize>
where
Pixel<N>: SupportedChannels,
@ -17,6 +17,7 @@ where
let mut index = [Pixel::new(); 256];
let mut px_prev = Pixel::new().with_a(0xff);
let mut hash_prev = Pixel::<N>::new().with_a(0xff).hash_index();
let mut run = 0_u8;
let mut px = Pixel::<N>::new().with_a(0xff);
@ -32,14 +33,25 @@ where
}
} else {
if run != 0 {
buf = buf.write_one(QOI_OP_RUN | (run - 1))?;
#[cfg(not(feature = "reference"))]
{
buf = buf.write_one(if run == 1 {
QOI_OP_INDEX | (hash_prev as u8)
} else {
QOI_OP_RUN | (run - 1)
})?;
}
#[cfg(feature = "reference")]
{
buf = buf.write_one(QOI_OP_RUN | (run - 1))?;
}
run = 0;
}
let index_pos = px.hash_index();
let index_px = &mut index[index_pos as usize];
hash_prev = px.hash_index();
let index_px = &mut index[hash_prev as usize];
let px_rgba = px.as_rgba(0xff);
if *index_px == px_rgba {
buf = buf.write_one(QOI_OP_INDEX | index_pos)?;
buf = buf.write_one(QOI_OP_INDEX | hash_prev)?;
} else {
*index_px = px_rgba;
buf = px.encode_into(px_prev, buf)?;