asonix/blurhash-update
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A couple simplifications

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This commit is contained in:
asonix 2024-02-18 01:13:28 -06:00
parent a07038a61d
commit d55e17ec78
3 changed files with 76 additions and 46 deletions
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15
benches/benchy.rs
View file

@ -45,13 +45,14 @@ pub fn criterion_benchmark(c: &mut Criterion) {
let bytes = rgba.as_bytes();
b.iter(|| {
let mut encoder = blurhash_update::encoder(
Components { x: 4, y: 3 },
ImageBounds { width, height },
)
.unwrap();
encoder.update(bytes);
let _bhash = black_box(encoder.finalize());
let _bhash = black_box(
blurhash_update::encode(
Components { x: 4, y: 3 },
ImageBounds { width, height },
bytes,
)
.unwrap(),
);
});
});
}

101
src/lib.rs
View file

@ -3,7 +3,7 @@ mod srgb_lookup;
use std::f32::consts::PI;
use srgb_lookup::SRGB_LOOKUP;
use srgb_lookup::srgb_to_linear;
pub struct Components {
pub x: u32,
@ -38,12 +38,21 @@ pub struct Encoder {
bounds: ImageBounds,
}
pub fn encoder(components: Components, bounds: ImageBounds) -> Result<Encoder, ComponentError> {
Encoder::new(components, bounds)
pub fn encode(
components: Components,
bounds: ImageBounds,
rgba8_image: &[u8],
) -> Result<String, ComponentError> {
let mut encoder = Encoder::new(components, bounds)?;
encoder.update(rgba8_image);
Ok(encoder.finalize())
}
impl Encoder {
fn new(Components { x, y }: Components, bounds: ImageBounds) -> Result<Self, ComponentError> {
pub fn new(
Components { x, y }: Components,
bounds: ImageBounds,
) -> Result<Self, ComponentError> {
if !(1..=9).contains(&x) || !(1..=9).contains(&y) {
return Err(ComponentError);
}
@ -60,27 +69,27 @@ impl Encoder {
})
}
pub fn update(&mut self, buf: &[u8]) {
pub fn update(&mut self, rgba8_image: &[u8]) {
const BYTES_PER_PIXEL: usize = 4;
// get offset in terms of already-processed bytes
let offset = self.index % BYTES_PER_PIXEL;
// get offset in terms of remaining bytes on head of buf
// get offset in terms of remaining bytes on head of rgba8_image
let offset = (BYTES_PER_PIXEL - offset) % BYTES_PER_PIXEL;
for (ComponentState { basis, .. }, [_, g, b]) in self.factors.iter_mut() {
for (byte, value) in buf[..offset].iter().zip(
[&mut *b, &mut *g][0..offset.saturating_sub(2)]
for (byte, value) in rgba8_image[..offset].iter().zip(
[&mut *b, &mut *g][..offset.saturating_sub(BYTES_PER_PIXEL - 2)]
.iter_mut()
.rev(),
) {
**value += *basis * SRGB_LOOKUP[*byte as usize]
**value += *basis * srgb_to_linear(*byte);
}
}
let pixels = ((self.index + offset) / BYTES_PER_PIXEL) as u32;
let mut chunks = buf[offset..].chunks_exact(BYTES_PER_PIXEL);
let mut chunks = rgba8_image[offset..].chunks_exact(BYTES_PER_PIXEL);
for (i, chunk) in (&mut chunks).enumerate() {
let px = pixels + i as u32;
@ -97,14 +106,14 @@ impl Encoder {
self.bounds.height as _,
);
*r += basis * SRGB_LOOKUP[chunk[0] as usize];
*g += basis * SRGB_LOOKUP[chunk[1] as usize];
*b += basis * SRGB_LOOKUP[chunk[2] as usize];
*r += basis * srgb_to_linear(chunk[0]);
*g += basis * srgb_to_linear(chunk[1]);
*b += basis * srgb_to_linear(chunk[2]);
}
}
if !chunks.remainder().is_empty() {
let px = pixels + (buf[offset..].len() / BYTES_PER_PIXEL) as u32;
let px = pixels + (rgba8_image[offset..].len() / BYTES_PER_PIXEL) as u32;
let px_x = px % self.bounds.width;
let px_y = px / self.bounds.width;
@ -119,12 +128,12 @@ impl Encoder {
);
for (byte, value) in chunks.remainder().iter().zip([&mut *r, &mut *g, &mut *b]) {
*value += *basis * SRGB_LOOKUP[*byte as usize]
*value += *basis * srgb_to_linear(*byte);
}
}
}
self.index += buf.len();
self.index += rgba8_image.len();
}
pub fn finalize(mut self) -> String {
@ -146,21 +155,15 @@ impl Encoder {
let size_flag = self.components.x - 1 + (self.components.y - 1) * 9;
base83::encode(size_flag, 1, &mut blurhash);
let maximum_value = if !ac.is_empty() {
let maximum = ac.iter().fold(0.0_f32, |maximum, (_, [r, g, b])| {
maximum.max(r.abs()).max(g.abs()).max(b.abs())
});
let maximum = ac.iter().fold(0.0_f32, |maximum, (_, [r, g, b])| {
maximum.max(r.abs()).max(g.abs()).max(b.abs())
});
let quantized_maximum = (maximum * 166. - 0.5).floor().max(0.) as u32;
let quantized_maximum = (maximum * 166. - 0.5).floor().max(0.) as u32;
base83::encode(quantized_maximum, 1, &mut blurhash);
base83::encode(quantized_maximum, 1, &mut blurhash);
(quantized_maximum + 1) as f32 / 166.
} else {
base83::encode(0, 1, &mut blurhash);
1.
};
let maximum_value = (quantized_maximum + 1) as f32 / 166.;
base83::encode(encode_dc(dc), 4, &mut blurhash);
@ -238,19 +241,43 @@ mod tests {
let width = 4;
let height = 4;
let mut encoder = super::encoder(
let b1 = super::encode(
crate::Components { x: 4, y: 3 },
crate::ImageBounds { width, height },
&input,
)
.unwrap();
encoder.update(&input);
let b1 = encoder.finalize();
let b2 = blurhash::encode(4, 3, width, height, &input).unwrap();
assert_eq!(b1, b2);
}
#[test]
fn one_component() {
let inputs = [
"data/19dd1c444d1c7939.png",
"data/f73d2ee39133d871.jpg",
"data/shenzi.png",
];
for input in inputs {
let img = image::open(input).unwrap();
let (width, height) = img.dimensions();
let b1 = super::encode(
crate::Components { x: 1, y: 1 },
crate::ImageBounds { width, height },
img.to_rgba8().as_bytes(),
)
.unwrap();
let b2 = blurhash::encode(1, 1, width, height, img.to_rgba8().as_bytes()).unwrap();
assert_eq!(b1, b2);
}
}
#[test]
fn matches_blurhash() {
let inputs = [
@ -263,13 +290,12 @@ mod tests {
let img = image::open(input).unwrap();
let (width, height) = img.dimensions();
let mut encoder = super::encoder(
let b1 = super::encode(
crate::Components { x: 4, y: 3 },
crate::ImageBounds { width, height },
img.to_rgba8().as_bytes(),
)
.unwrap();
encoder.update(img.to_rgba8().as_bytes());
let b1 = encoder.finalize();
let b2 = blurhash::encode(4, 3, width, height, img.to_rgba8().as_bytes()).unwrap();
@ -291,16 +317,15 @@ mod tests {
let rgba8_img = img.to_rgba8();
let bytes = rgba8_img.as_bytes();
let mut encoder = super::encoder(
let b1 = super::encode(
crate::Components { x: 4, y: 3 },
crate::ImageBounds { width, height },
bytes,
)
.unwrap();
encoder.update(bytes);
let b1 = encoder.finalize();
for chunk_count in 2..20 {
encoder = super::encoder(
let mut encoder = super::Encoder::new(
crate::Components { x: 4, y: 3 },
crate::ImageBounds { width, height },
)

6
src/srgb_lookup.rs
View file

@ -1,4 +1,4 @@
pub(crate) static SRGB_LOOKUP: [f32; 256] = [
static SRGB_LOOKUP: [f32; 256] = [
0.0,
0.000303527,
0.000607054,
@ -256,3 +256,7 @@ pub(crate) static SRGB_LOOKUP: [f32; 256] = [
0.9911022,
1.0,
];
pub(crate) fn srgb_to_linear(value: u8) -> f32 {
SRGB_LOOKUP[value as usize]
}