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Merge PR #850
This commit is contained in:
Brandon Thomas committed
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@@ -55,6 +55,28 @@ const HEADER_MAX: u64 = 4096;
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/// wrote the proxy's pixels (colour matrix and profile are baked into them) and stored tone curve.
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const LOOK_FIELD: &str = "look_version";
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/// The JPEG quality a smart preview's pixels are stored at. The original 92 left the 8×8 DCT's
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/// quantised DC — each block's own mean, luma and chroma — visible as block steps across the frame
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/// and as a small constant colour shift; that is the largest part of what a proxy gets wrong
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/// against the original, and the only part a parameter can reach. 97 shrinks those quantisers to
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/// roughly 1/2.6 of their steps, which is what removes the steps, at about twice the file size
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/// (~1 MB per preview at 2560 px). What is left is the 8-bit sRGB quantisation itself, which only
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/// a lossless proxy format can close. (ICED: the measured change is printed by the fidelity test
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/// below; drop this to 95 for ~1.4× the size and roughly half the gain.)
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const JPEG_QUALITY: u8 = 97;
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/// The header field that records which version of this module's own encoding wrote a proxy's pixels
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/// (the source mapping above and [`JPEG_QUALITY`]). Not to be confused with [`LOOK_FIELD`], which
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/// tracks the camera-look fit that is baked into those pixels.
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const ENC_FIELD: &str = "enc";
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/// The value of [`ENC_FIELD`] this build writes. Bump it whenever [`encode`]'s mapping or JPEG
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/// settings change, so proxies an older build wrote are rebuilt: a missing field reads as 0, which
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/// makes every proxy from before this version stale. Version 2 is the first to record the field at
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/// all (a version 1 proxy is stored at JPEG quality 92, which this build raises to [`JPEG_QUALITY`]).
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/// Crate-visible so the look-marker test pins the marker format to it instead of to a literal.
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pub(crate) const ENCODE_VERSION: u64 = 2;
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/// Encode a source image (and the decoder's camera tone curve, if any) as a smart preview.
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pub fn encode(img: &Rgb32f, tone: Option<&CameraTone>) -> Result<Vec<u8>, String> {
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// scale so all but the brightest 0.05 % fit into 0..1
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@@ -78,13 +100,19 @@ pub fn encode(img: &Rgb32f, tone: Option<&CameraTone>) -> Result<Vec<u8>, String
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let rgba = Rgba8 { width: img.width, height: img.height, data };
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let jpg = lightcraft_codecs::encode_jpeg(
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&lightcraft_codecs::EncodeImage::rgba8(&rgba),
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92,
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JPEG_QUALITY,
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lightcraft_codecs::ChromaSubsampling::S444,
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&Default::default(),
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)
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.map_err(|e| e.to_string())?;
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let mut out = MAGIC.to_vec();
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let mut head = serde_json::json!({"w": img.width, "h": img.height, "scale": scale, LOOK_FIELD: crate::camera_preview::LOOK_VERSION});
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let mut head = serde_json::json!({
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"w": img.width,
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"h": img.height,
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"scale": scale,
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LOOK_FIELD: crate::camera_preview::LOOK_VERSION,
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ENC_FIELD: ENCODE_VERSION,
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});
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if let Some(t) = tone {
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head["tone"] = serde_json::to_value(t).map_err(|e| e.to_string())?;
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}
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@@ -265,10 +293,17 @@ fn header_look_version(head: &serde_json::Value) -> u64 {
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head.get(LOOK_FIELD).and_then(serde_json::Value::as_u64).unwrap_or(0)
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}
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/// Whether the complete proxy at `path` was written by an older camera-look fit than this build's
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/// (so its stored curve, and the colour baked into its pixels, are out of date). A proxy from a
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/// newer build is left alone (rebuilding it here would only undo that build's work), as is one
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/// that can't be read: those are [`is_valid`]'s business.
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/// The encode version a header records: a missing, negative, fractional or otherwise malformed
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/// value counts as 0 (older than any real version), like [`header_look_version`].
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fn header_encode_version(head: &serde_json::Value) -> u64 {
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head.get(ENC_FIELD).and_then(serde_json::Value::as_u64).unwrap_or(0)
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}
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/// Whether the complete proxy at `path` is out of date for this build: written by an older
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/// camera-look fit than this build's (so its stored curve, and the colour baked into its pixels, are
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/// out of date), or by an older encoding of its own pixels ([`ENCODE_VERSION`], i.e. a lower JPEG
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/// quality). A proxy from a newer build is left alone (rebuilding it here would only undo that
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/// build's work), as is one that can't be read: those are [`is_valid`]'s business.
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pub fn is_stale(path: &Path) -> bool {
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use std::io::Read;
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if !is_valid(path) {
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@@ -283,15 +318,18 @@ pub fn is_stale(path: &Path) -> bool {
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let Some(nl) = rest.iter().position(|b| *b == b'\n') else { return false };
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rest.get(..nl)
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.and_then(|h| serde_json::from_slice::<serde_json::Value>(h).ok())
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.is_some_and(|h| header_look_version(&h) < u64::from(crate::camera_preview::LOOK_VERSION))
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.is_some_and(|h| header_look_version(&h) < u64::from(crate::camera_preview::LOOK_VERSION) || header_encode_version(&h) < ENCODE_VERSION)
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}
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/// The marker file in a smart previews folder: the `LOOK_VERSION` its proxies were last checked
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/// at ([`look_checked`]).
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/// The marker file in a smart previews folder: the camera-look fit version and encode version its
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/// proxies were last checked at ([`look_checked`]).
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const LOOK_MARKER: &str = "look-version";
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/// Whether the smart previews folder `dir` has been checked for stale proxies at this build's
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/// camera-look fit version (or a newer one). A missing or unreadable marker counts as not.
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/// Whether the smart previews folder `dir` has been checked for out-of-date proxies at this build's
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/// camera-look fit version and encode version (or newer ones). A missing or unreadable marker counts
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/// as not, and so does one written before the encode version was recorded — it only says the look
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/// was checked, so this build scans the folder once more and rebuilds the proxies [`is_stale`]
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/// finds.
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pub fn look_checked(dir: &Path) -> bool {
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use std::io::Read;
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let Ok(f) = std::fs::File::open(dir.join(LOOK_MARKER)) else { return false };
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@@ -299,14 +337,20 @@ pub fn look_checked(dir: &Path) -> bool {
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if f.take(64).read_to_string(&mut text).is_err() {
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return false;
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}
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text.trim().parse::<u64>().is_ok_and(|v| v >= u64::from(crate::camera_preview::LOOK_VERSION))
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let mut versions = text.split_whitespace();
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let (Some(look), Some(enc)) = (versions.next(), versions.next()) else { return false };
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match (look.parse::<u64>(), enc.parse::<u64>()) {
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(Ok(look), Ok(enc)) => look >= u64::from(crate::camera_preview::LOOK_VERSION) && enc >= ENCODE_VERSION,
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_ => false,
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}
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}
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/// Record that the proxies in `dir` were checked at this build's camera-look fit version.
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/// Record that the proxies in `dir` were checked at this build's camera-look fit version and encode
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/// version.
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pub fn mark_look_checked(dir: &Path) -> Result<(), String> {
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let path = dir.join(LOOK_MARKER);
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lightcraft_catalog::safe_file::write_atomic(&path, format!("{}\n", crate::camera_preview::LOOK_VERSION).as_bytes())
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.map_err(|e| format!("{}: {e}", path.display()))
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let text = format!("{} {}\n", crate::camera_preview::LOOK_VERSION, ENCODE_VERSION);
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lightcraft_catalog::safe_file::write_atomic(&path, text.as_bytes()).map_err(|e| format!("{}: {e}", path.display()))
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}
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/// Load the proxy at `path`.
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@@ -451,4 +495,186 @@ mod tests {
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assert!(mean < 0.02, "mean encoded error {mean}");
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assert!(decode(b"nope").is_err());
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}
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/// A smooth, deterministic stand-in for a photo: a bright, near-neutral "sky" crossing over into
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/// a saturated colour field, every value inside 0..1 so the proxy's 0.05 % highlight clip never
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/// enters what is measured. Built from a rendered demo scene so the dimensions and the flat
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/// row-major layout are the real ones.
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fn smooth_scene(w: usize, h: usize) -> Rgb32f {
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let mut img = lightcraft_scenes::demo_library()[0].render(w, h);
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let (w, h) = (img.width.max(1), img.height.max(1));
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for (i, px) in img.data.iter_mut().enumerate() {
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let u = (i % w) as f32 / (w - 1).max(1) as f32;
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let v = (i / w) as f32 / (h - 1).max(1) as f32;
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let t = (v * v * (3.0 - 2.0 * v)).clamp(0.0, 1.0); // smoothstep: a fade, not a step
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let sky = [0.10 + 0.70 * v, 0.14 + 0.72 * v, 0.30 + 0.62 * v];
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let field = [0.86 - 0.26 * u, 0.18 + 0.62 * u, 0.12 + 0.30 * (1.0 - u)];
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*px = std::array::from_fn(|k| (sky[k] * (1.0 - t) + field[k] * t).clamp(0.0, 1.0));
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}
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img
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}
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/// CIE L*a*b* (D65) of a scene-linear colour: the perceptual yardstick a proxy is held to. The
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/// input is clamped into 0..1, the only range a proxy ever stores.
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fn lab(c: [f32; 3]) -> [f64; 3] {
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let (r, g, b) = (c[0].clamp(0.0, 1.0) as f64, c[1].clamp(0.0, 1.0) as f64, c[2].clamp(0.0, 1.0) as f64);
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let (x, y, z) = (
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(0.4124 * r + 0.3576 * g + 0.1805 * b) / 0.95047,
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0.2126 * r + 0.7152 * g + 0.0722 * b,
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(0.0193 * r + 0.1192 * g + 0.9505 * b) / 1.08883,
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);
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let f = |t: f64| if t > 216.0 / 24389.0 { t.cbrt() } else { (841.0 / 108.0) * t + 4.0 / 29.0 };
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let (fx, fy, fz) = (f(x), f(y), f(z));
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[116.0 * fy - 16.0, 500.0 * (fx - fy), 200.0 * (fy - fz)]
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}
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/// The mean CIE76 ΔE between two same-sized scene-linear images: monotone in CIEDE2000 for a
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/// low-contrast, near-neutral difference like a proxy's, and enough to rank two encoders.
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fn mean_delta_e(a: &Rgb32f, b: &Rgb32f) -> f64 {
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let n = a.data.len().min(b.data.len());
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if n == 0 {
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return 0.0;
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}
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(0..n)
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.map(|i| {
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let (p, q) = (lab(a.data[i]), lab(b.data[i]));
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((p[0] - q[0]).powi(2) + (p[1] - q[1]).powi(2) + (p[2] - q[2]).powi(2)).sqrt()
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})
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.sum::<f64>()
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/ n as f64
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}
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/// A deliberately frozen copy of the pixel mapping and container this module used before the
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/// quality raise: the 99.95 % highlight scale, the sRGB 8-bit mapping, JPEG quality 92, and the
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/// version-1 header (width, height, scale and camera-look fit — no encode version). A copy on
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/// purpose: it must not follow `encode` as that changes, so the fidelity test measures what the
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/// quality raise bought instead of trusting a written-down number.
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fn encode_at_q92(img: &Rgb32f) -> Vec<u8> {
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let mut lum: Vec<f32> = img.data.iter().map(|c| c[0].max(c[1]).max(c[2])).filter(|v| v.is_finite()).collect();
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let scale = if lum.is_empty() {
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1.0
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} else {
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let k = ((lum.len() as f64) * 0.9995) as usize;
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let k = k.min(lum.len() - 1);
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let (_, v, _) = lum.select_nth_unstable_by(k, f32::total_cmp);
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v.max(1.0)
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};
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let data: Vec<[u8; 4]> = img
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.data
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.iter()
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.map(|c| {
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let e = |v: f32| (linear_to_srgb((v / scale).clamp(0.0, 1.0)) * 255.0).round() as u8;
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[e(c[0]), e(c[1]), e(c[2]), 255]
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})
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.collect();
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let rgba = Rgba8 { width: img.width, height: img.height, data };
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let jpg = lightcraft_codecs::encode_jpeg(
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&lightcraft_codecs::EncodeImage::rgba8(&rgba),
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92,
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lightcraft_codecs::ChromaSubsampling::S444,
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&Default::default(),
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)
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.unwrap();
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// the version-1 container the decoder needs: magic, header, JPEG — and no `enc` field
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let mut out = MAGIC.to_vec();
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let head = serde_json::json!({"w": img.width, "h": img.height, "scale": scale, LOOK_FIELD: crate::camera_preview::LOOK_VERSION});
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out.extend_from_slice(head.to_string().as_bytes());
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out.push(b'\n');
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out.extend_from_slice(&jpg);
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out
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}
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/// The mean CIE76 ΔE between two same-sized scene-linear images, each reduced first to one
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/// sample per 8×8 block — the block's mean colour. JPEG stores a block's DC coefficient, its
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/// mean, and rebuilds the whole block from it, so a proxy differs from the original by a
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/// constant per block: the "8×8 block pattern" a preview shows. Averaging a block's 64 pixels
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/// keeps that constant while shrinking the 8-bit sRGB rounding the two encoders share
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/// eightfold, which is what a per-pixel ΔE drowns in.
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fn mean_block_delta_e(a: &Rgb32f, b: &Rgb32f) -> f64 {
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let w = a.width.min(b.width).max(1);
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let h = a.height.min(b.height).max(1);
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let (mut sum, mut n) = (0.0f64, 0usize);
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for by in (0..h).step_by(8) {
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for bx in (0..w).step_by(8) {
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let (mut sa, mut sb, mut count) = ([0.0f64; 3], [0.0f64; 3], 0u32);
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for y in by..(by + 8).min(h) {
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for x in bx..(bx + 8).min(w) {
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if let (Some(ca), Some(cb)) = (a.data.get(y * a.width + x), b.data.get(y * b.width + x)) {
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for k in 0..3 {
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sa[k] += f64::from(ca[k]);
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sb[k] += f64::from(cb[k]);
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}
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count += 1;
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}
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}
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}
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let d = f64::from(count.max(1));
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let (pa, pb) = (
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lab([(sa[0] / d) as f32, (sa[1] / d) as f32, (sa[2] / d) as f32]),
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lab([(sb[0] / d) as f32, (sb[1] / d) as f32, (sb[2] / d) as f32]),
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);
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sum += ((pa[0] - pb[0]).powi(2) + (pa[1] - pb[1]).powi(2) + (pa[2] - pb[2]).powi(2)).sqrt();
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n += 1;
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}
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}
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sum / n.max(1) as f64
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}
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/// for [`a_smooth_proxy_keeps_the_scene_closer_than_the_old_quality`] to pass. The shared 8-bit
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/// sRGB quantization floor both encoders share caps the achievable ratio at 0.632 on this scene,
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/// a no-op encoder scores 1.000, and this is their geometric midpoint: it fails the moment the
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/// quality raise is reverted and never trips on the honest result (measured 0.683).
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const PROXY_BLOCK_GAIN: f64 = 0.8;
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#[test]
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fn a_smooth_proxy_keeps_the_scene_closer_than_the_old_quality() {
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let img = smooth_scene(256, 160);
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let ours = decode(&encode(&img, None).unwrap()).unwrap().0;
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let before = decode(&encode_at_q92(&img)).unwrap().0;
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let block = (mean_block_delta_e(&img, &ours), mean_block_delta_e(&img, &before));
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let pixel = (mean_delta_e(&img, &ours), mean_delta_e(&img, &before));
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println!(
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"smooth-scene proxy round-trip: block-mean ΔE76 {:.3} at q{JPEG_QUALITY} vs {:.3} at q92 \
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(per-pixel {:.3} vs {:.3})",
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block.0, block.1, pixel.0, pixel.1
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);
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assert!(block.1 > 0.0, "the old encoder must measure something to compare against");
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assert!(
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block.0 <= PROXY_BLOCK_GAIN * block.1,
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"q{JPEG_QUALITY} leaves a block-mean ΔE of {:.3}, not the ≤{:.3} the quality raise should buy over q92's {:.3} \
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(the 8-bit sRGB floor caps the achievable ratio at ~0.63 on this scene)",
|
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block.0,
|
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PROXY_BLOCK_GAIN * block.1,
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block.1
|
||||
);
|
||||
}
|
||||
|
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#[test]
|
||||
fn a_proxy_from_an_older_encode_is_stale() {
|
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let dir = temp("encode-version");
|
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let img = lightcraft_scenes::demo_library()[0].render(64, 40);
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let bytes = encode(&img, None).unwrap();
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let path = dir.join("p.lcsp");
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std::fs::write(&path, &bytes).unwrap();
|
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assert!(!is_stale(&path), "this build's own proxy is up to date");
|
||||
// one written before the encode version was recorded is not
|
||||
let nl = MAGIC.len() + bytes[MAGIC.len()..].iter().position(|b| *b == b'\n').unwrap();
|
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let head: serde_json::Value = serde_json::from_slice(&bytes[MAGIC.len()..nl]).unwrap();
|
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assert_eq!(head[ENC_FIELD].as_u64(), Some(ENCODE_VERSION));
|
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let mut older = head.as_object().cloned().unwrap_or_default();
|
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older.remove(ENC_FIELD);
|
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let mut old = MAGIC.to_vec();
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old.extend_from_slice(serde_json::Value::Object(older).to_string().as_bytes());
|
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old.extend_from_slice(&bytes[nl..]);
|
||||
std::fs::write(&path, &old).unwrap();
|
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assert!(is_valid(&path), "losing the field keeps the file readable");
|
||||
assert!(is_stale(&path), "an older encoding is rebuilt");
|
||||
// the marker records both versions, and one from before the encode version forces a scan
|
||||
assert!(!look_checked(&dir));
|
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mark_look_checked(&dir).unwrap();
|
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assert!(look_checked(&dir));
|
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std::fs::write(dir.join(LOOK_MARKER), "99\n").unwrap();
|
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assert!(!look_checked(&dir), "a look-only marker is not enough to skip the rebuild");
|
||||
let _ = std::fs::remove_dir_all(&dir);
|
||||
}
|
||||
}
|
||||
@@ -1438,14 +1438,20 @@ fn smart_preview_look_marker_is_read_safely() {
|
||||
let dir = temp_dir("smartlook-marker");
|
||||
assert!(!crate::smart::look_checked(&dir), "no marker");
|
||||
let cur = crate::camera_preview::LOOK_VERSION;
|
||||
let enc = crate::smart::ENCODE_VERSION;
|
||||
for (text, checked) in [
|
||||
(String::new(), false),
|
||||
("banana".into(), false),
|
||||
("-1".into(), false),
|
||||
(format!("{}", cur.saturating_sub(1)), false),
|
||||
("9".repeat(200), false),
|
||||
(format!("{cur}\n"), true),
|
||||
(format!(" {}\n", cur + 1), true),
|
||||
// Written before the encode version was recorded: only says the look was checked, so the
|
||||
// folder is scanned once more and the old-encoding proxies are rebuilt.
|
||||
(format!("{cur}\n"), false),
|
||||
(format!("{cur} {}\n", enc.saturating_sub(1)), false),
|
||||
(format!("{cur} banana\n"), false),
|
||||
(format!("{cur} {enc}\n"), true),
|
||||
(format!(" {} {}\n", cur + 1, enc + 1), true),
|
||||
] {
|
||||
std::fs::write(dir.join("look-version"), &text).unwrap();
|
||||
assert_eq!(crate::smart::look_checked(&dir), checked, "{text:?}");
|
||||
|
||||
Reference in new issue
Block a user