Merge PR #1410

# Conflicts:
#	docs/whats-new.md

docs/parity-checklist.md

@@ -82,7 +82,7 @@ differences and missing bindings are in [ui-parity.md](ui-parity.md#shortcuts).
 | LR-IMP-SIDECAR-SPLIT | Separate XMP sidecar variants | P2 | ⬜ | `cmd:library.xmpPreferences` | sidecar naming option exists (stem/full), no split sidecars |
 | LR-IMP-FORMATS | Supported formats | P0 | 🟡 | `crates/codecs/src/lib.rs`, `crates/raw/src/lib.rs`, `crates/raw/src/jxl.rs` | JPEG, PNG, TIFF (1- to 64-bit integer, 16- to 64-bit float, incl. bilevel and CCITT fax), WebP, JXL, PSD, GIF, BMP (lossy wide-gamut JXL decodes to the right colours: jxl-oxide desaturated XYB rendered to P3/Rec. 2020, worked around in `crates/codecs/src/jxl.rs`); DNG (incl. lossy / Smart Preview DNG and DNG 1.7 JPEG XL tiles/strips: lossless ones decode bit-exactly on synthetic CFA and LinearRaw files, lossy ones are restored to the declared linear primaries without clipping or gamut mapping, checked on one real file with 108 lossy tiles, and any tile that fails to decode makes the file preview-only; DNG 1.7 row/column-interleaved rasters (`RowInterleaveFactor` / `ColumnInterleaveFactor`) are undone before the mosaic is read, so a file from Adobe's converter with a 2×2 interleave no longer decodes as four scaled-down copies in the wrong colours; a dimension the factor does not divide decodes with short trailing fields; verified on 4 real ILCE-6400 JPEG XL DNGs rendering bit-identical to their non-interleaved twins, factors above 2 rest on the plain reading of the tag; a single-chunk JPEG XL preview IFD is offered as the embedded preview; a DNG whose samples pile up at one value well below its stated `WhiteLevel`, as a camera app's 12-bit Bayer DNG that states 4095 and clips at 3567, has those samples raised to the white level on decode, so highlight reconstruction sees the clipped areas instead of white balance tinting them magenta, issue #548, `crates/raw/src/saturation.rs`), CR2 (colour-filter layout from the file's `CR2CFAPattern` tag, issue #85), ARW (pre-2017 bodies: white balance and black level from the encrypted `SR2SubIFD`, issue #148, its `WB_RGGBLevels` being the white balance the camera applied, issue #535; the DSLR-A900's packed 12-bit strip, two pixels per three bytes, read only when the strip is exactly 1.5 bytes per pixel, with its camera-JPEG window centred, checked on one CC0 file (A850 unmeasured); downsized Sony lossless YCbCr 4:2:0 / 4:2:2 tiles decoded to linear RGB, verified on private ILCE-7M4 3:2 & 4:3 examples including 16-bit full-resolution export; Sony DSC-R1 .SR2 decodes, its big-endian 16-bit words read in the order that fits the sample range, checked on the CC0 3221 sample; its crop and white balance live in the SR2SubIFD and are not read yet; ARW6 Compressed / Compressed (HQ) of the ILCE-7RM6 (`crates/raw/src/vendor/arw6.rs`, `crates/raw/src/llvc.rs`; 12-bit codes exact against a black-box oracle on 8 CC0 files, FF over the full frame, APS-C in the interior (LibRaw's own edge rows differ); output through our own companding curve, measured from CC0 lossless / ARW6 pairs; geometry checked against the camera JPEG, `docs/arw6-compression.md`; the ILCE-7M5 writes the same codec, unverified)), NEF (uncompressed, lossless and lossy compressed 12/14-bit, `crates/raw/src/vendor/nefc.rs`), RAF (uncompressed, lossless/lossy compressed Bayer and X-Trans; `crates/raw/src/vendor/rafc.rs`, full sensor verification on 13 bodies, `docs/raf-compression.md`), RW2 / Leica RWL / Panasonic RAW in every raw format (compressed 4 and 6, the prefix-coded strips of format 8 from the GH6 on, packed 2/5/7, the 16-bit words of the 2005–2007 bodies; black levels, in-camera aspect crops and mapped-out defect pixels; 178 CC0 files from 118 bodies checked, `crates/raw/src/vendor/rw2.rs`), PEF, ORF (uncompressed; colour-filter layout from the file's Exif `CFAPattern`; 12.8 bit/px 16-byte blocks of ten 12-bit samples + a zero pad byte, E-300 / E-330 / E-500 verified on CC0 files, E-M5 Mark II / PEN-F high-res files decode smooth but CFA and black unverified), Kodak DCS520C TIFF (a two-component 12-bit lossless JPEG strip, the two components the even and odd columns; the file's `GrayResponseCurve` table linearises the companded samples to 12 bits, black measured per CFA position, white balance from the `KodakIFD`; `RawFormat::KodakDcs`, `crates/raw/src/vendor/kodak.rs`, checked on the one CC0 sample against its IFD0 thumbnail), Hasselblad 3FR and FFF (a TIFF without a DNG version tag that describes its CFA IFD, levels, crop and white balance with DNG's tags; `RawFormat::CfaTiff`, read by `dng::decode_as`, RGGB when the file states no `CFAPattern`): uncompressed (X1D, X1D II, X2D, CFV 100C) and Hasselblad's lossless JPEG with scan selection value 8 (every FFF; H3D, H4D and CFV-50c 3FR), `ljpeg::decode_hasselblad`, its rule measured on 14 CC0 files with the ljpeg-explorer tool, Samsung SRW without compression (NX5, NX10, NX11 and the NX20-generation bodies NX20, NX200, NX210, NX1000 and NX1100 as 12-bit packed samples in either bit order, EX1 and WB2000 as 16-bit words; layout, camera-JPEG framing, levels and white balance from the maker note, `crates/raw/src/vendor/srw.rs`; median ΔE vs the camera JPEG 2.2–7.6 on 11 of the 12 files from 10 bodies checked, 10.7 (5.7 registered)Line truncated
 | LR-IMP-CAMERA-COVERAGE | Camera coverage, verified per model | P0 | 🟡 | `crates/raw/tests/corpus.rs`, `xtask/src/main.rs` | a supported container is not the same as every camera that writes it decoding correctly: ~55 CC0 corpus files plus 6 exact-sensor CR3 cases and 4 pinned EOS R5 Mark II files (plus ~60 NEFs checked by hand and 178 Panasonic / Leica RW2, RWL and RAW files from 118 bodies, checked against each file's own JPEG) against the >1,000 models Lightroom lists; per-model differences still surface (e.g. the CR2 colour-filter layout differed by model until it was read from the file's own tag, issue #85, checked on 35 CR2 bodies; CR2 black levels were read from border columns light already reaches, left of `SensorInfo`'s border, so CR2s rendered dark with crushed shadows (EOS 6D: 2591 instead of 2047), now measured from the masked columns only, checked on 8 corpus bodies; pre-2017 Sony ARWs opened green until their scrambled white balance / black level were read, issue #148, checked on 16 ARWs from 15 Sony bodies; their white balance now comes from the encrypted `SR2SubIFD`'s `WB_RGGBLevels`, the gains the camera applied, which 14 bodies (DSLR-A450 … A700, NEX-3/5/C3, SLT-A33/A35/A55, ILCE-6001, UMC-R10C) had no other source for and which the maker-note estimate read before missed by up to 100 % on preset shots, issue #535, checked against ExifTool on 100 decoded ARWs from 87 Sony bodies; the encrypted SR2 black level is now read from its directory entry (the DSLR-A450/A500/A550/A700 read 354–975 instead of 512), checked on 126 ARWs from 97 Sony bodies, and downsized lossless M/S ARWs use their measured black level 1024 instead of 512, checked on 12 files from 4 bodies, issue #535, and on a fifth, the ILCE-7CM2 (issue #697: 0.5.0 rendered its lossless M file with that 512 pedestal, the darkest half of a dusk scene +11 L* and blue, the lamplight white; its darkest 0.1 % per channel sits at 1017/1020/1024, and with 1024 the render is within +3 L* of the camera JPEG; the body's compressed and uncompressed "M-size" files are Bayer at 4736×3132 with black 512, two public ones in the corpus); pre-2017 Sony bodies shot in the camera's 16:9 mode (ILCE-7SM2, DSLR-A580) now get the 16:9 crop of their camera JPEG instead of the whole 3:2 frame with padding columns, issue #535; Canon PowerShot and EOS M CR2s whose `ColorData` is stored as bytes opened green until the bytes were read as 16-bit words, 25 files from 25 bodies checked; private Z 8 crop verified; the Nikon D4, which records no CropArea, gets its image area and white level measured on 148 NEFs against the camera JPEG (optical-black stripes and magenta clipped highlights gone); the D7100, whose data holds picture beyond the camera's frame, develops at Lightroom's frame (the camera JPEG's size) in full frame and 1.3x crop, so Lightroom crops line up (#1248).; CR2 white levels came from masked rows holding samples at 16383, so on the EOS 50D, 60D, 450D (Rebel XSi), 500D (Rebel T1i), 550D (Rebel T2i), 1200D (Rebel T5) and 100D (Rebel SL1) clipped highlights sat at 81–98% of the range and were not treated as clipped, now taken from the active area only, issue #1272). Compressed RAF sensor arrays verified on 13 Fujifilm bodies (`docs/raf-compression.md`). ILCE-7RM6 ARW6 12-bit codes verified on 8 CC0 files (FF and APS-C, both compression modes). Sony ILCE-7CR (61 MP): lossless compressed L and M and compressed ARW2 samples of one scene in the corpus (black level, default crop, as-shot gains, lossless vs compressed mosaic agreement, fitted camera look), and all nine public codings (also uncompressed, small and APS-C crop) decode and fit. Grow the CC0 corpus per model and test each sample decodes with plausible colour. Nikon CropArea and untagged-preview colour-space regression tests; the Nikon D4, which records no CropArea, gets its image area and white level measured on 148 NEFs against the camera JPEG (optical-black stripes and magenta clipped highlights gone). Pentax PEFs without area tags (KP, KF, K-3 Mark III, K-70, K-1, K-1 Mark II, K-S1, K-S2, 645Z) no longer keep their masked border: black, empty and saturated lines are trimmed against the maker-note BlackPoint, issue #1271, measured on 38 CC0 PEFs from 30 bodies.; Canon PowerShot and EOS M CR2s whose `ColorData` is stored as bytes opened green until the bytes were read as 16-bit words, 25 files from 25 bodies checked). Compressed RAF sensor arrays verified on 13 Fujifilm bodies (`docs/raf-compression.md`). ILCE-7RM6 ARW6 12-bit codes verified on 8 CC0 files (FF and APS-C, both compression modes). Sony ILCE-7CR (61 MP): lossless compressed L and M and compressed ARW2 samples of one scene in the corpus (black level, default crop, as-shot gains, lossless vs compressed mosaic agreement, fitted camera look), and all nine public codings (also uncompressed, small and APS-C crop) decode and fit. Grow the CC0 corpus per model and test each sample decodes with plausible colour. Nikon CropArea andLine truncated
-| LR-IMP-PREVIEW-READ | Preview reads the header, not the raw | P0 | ✅ | `crates/raw/src/preview.rs` (`bounded_preview`, `embedded_preview_from_range`), `crates/engine/src/files.rs` (`preview_window`), `docs/raw-preview-reads.md`, `crates/engine/src/files.rs` (`preview_window`, `planned_preview`), `crates/raw/src/sparse.rs` (`preview_plan`) | a grid thumbnail and a loupe preview of an unedited raw show the camera's embedded JPEG, which sits near the start of the file (a 24 MP Fuji RAF keeps its 5.6 MB JPEG in a 56 MB file), so the preview loader reads the header and that JPEG instead of the whole file: 56.5 MB → 5.9 MB and ~10 s → 0.96 s measured on one real RAF over a GVFS/SMB Wi-Fi share (byte-identical preview pixels; `LIGHTCRAFT_PROFILE=1` reports the bytes); the RAF pointer is read from its fixed header fields, a CR3's boxes and a TIFF raw whose preview tag sits past the prefix are read through `lightcraft_raw::sparse::preview_plan`, which names the ranges `embedded_preview` reads and nothing else; a cached render as stand-in, an edited photo and a raw without an embedded JPEG still render; the formats it cannot describe (CRW/MRW/X3F are found by scanning, NEF/ORF/PEF probe from samples) keep the whole-file path, and a lying pointer, a short read or a file that changes underneath us falls back to it rather than losing the preview. An unedited raw's **grid thumbnail is that camera JPEG itself**, so no sensor decode is scheduled behind it (`Session::embedded_thumb_is_final`, `grid::skips_the_real_render`): drawing a 512 px thumbnail used to decode the whole raw — 45 s a photo at 1.2 MB/s, 8.3 GB for a 149-raw folder — and the queue it built delayed the render the user was waiting for |
+| LR-IMP-PREVIEW-READ | Preview reads the header, not the raw | P0 | ✅ | `crates/raw/src/preview.rs` (`bounded_preview`, `embedded_preview_from_range`, `embedded_preview_covering`), `crates/engine/src/files.rs` (`preview_window`), `docs/raw-preview-reads.md`, `crates/engine/src/files.rs` (`preview_window`, `planned_preview`), `crates/raw/src/sparse.rs` (`preview_plan`) | a grid thumbnail and a loupe preview of an unedited raw show the camera's embedded JPEG, which sits near the start of the file (a 24 MP Fuji RAF keeps its 5.6 MB JPEG in a 56 MB file), so the preview loader reads the header and that JPEG instead of the whole file: 56.5 MB → 5.9 MB and ~10 s → 0.96 s measured on one real RAF over a GVFS/SMB Wi-Fi share (byte-identical preview pixels; `LIGHTCRAFT_PROFILE=1` reports the bytes); the RAF pointer is read from its fixed header fields, a CR3's boxes and a TIFF raw whose preview tag sits past the prefix are read through `lightcraft_raw::sparse::preview_plan`, which names the ranges `embedded_preview` reads and nothing else; a cached render as stand-in, an edited photo and a raw without an embedded JPEG still render; the formats it cannot describe (CRW/MRW/X3F are found by scanning, NEF/ORF/PEF probe from samples) keep the whole-file path, and a lying pointer, a short read or a file that changes underneath us falls back to it rather than losing the preview. An unedited raw's **grid thumbnail is that camera JPEG itself**, so no sensor decode is scheduled behind it (`Session::embedded_thumb_is_final`, `grid::skips_the_real_render`): drawing a 512 px thumbnail used to decode the whole raw — 45 s a photo at 1.2 MB/s, 8.3 GB for a 149-raw folder — and the queue it built delayed the render the user was waiting for. Stand-ins and grid thumbnails decode the smallest embedded JPEG that covers the requested size and is a copy of the largest (aspect ratio within 1 %, same component count), not always the largest, on the whole-file and the plan route alike: an A7R VI's 1616 × 1080 JPEG (0.3 MB) instead of its 9984 × 6656 one (5.6 MB), and mid-sized NEF / RW2 JPEGs |
 | LR-IMP-CULL-AT-IMPORT | Culling analysis at import | P2 | 🟡 | `cmd:photo.analyze` | run Assisted Culling on the imported photos (they're selected after an import); not automatic |
 | LR-IMP-MOVE | Move on import [Classic] | P1 | ✅ | `cmd:library.import` (`mode` move), `crates/engine/src/import_move.rs`, `crates/engine/src/tests_import_move.rs`, `crates/ui-egui/src/import.rs` | Transfer ▸ Move with Copy's destination, folders (day / month / one folder / custom template), rename template and example destination; XMP sidecars (both namings) move along; each source is removed only after its destination is written (hard link on the same volume, else copied, synced and compared byte for byte) and its catalog record is saved; failed, duplicate, unchecked files keep their sources, taken names get -1, -2…, never overwritten; files already in the destination/library are added in place; sources that can't be removed (read-only card) are kept and reported (`kept`). Undo removes the photos from the library but leaves the moved files at the destination. No Copy as DNG while moving |
 | LR-IMP-DNG-CONVERT | Convert to DNG on import [Classic] | P2 | ✅ | `cmd:library.import` (`dng`), `crates/ui-egui/src/import.rs` | copy imports: Raw files ▸ Copy as DNG (lossless; the card is untouched); the raw copy is removed only once its DNG is verified and on disk (issue #106) |

docs/raw-preview-reads.md

@@ -111,17 +111,36 @@ Measured on the real folder: idle for a minute, the app read 12 previews (**26.9
 **zero** raws for thumbnails, against 638 MB of whole-file reads for the same 12 photos before. The
 render queue stayed empty.
 
+## The smallest JPEG that covers the box
+
+Many TIFF-based raws keep more than one embedded JPEG. A Sony A7R VI ARW holds a 1616 × 1080 one
+(0.3 MB) beside the 9984 × 6656 one (5.6 MB), and Nikon NEF and Panasonic RW2 files have mid-sized
+copies too. The loupe stand-in and the grid thumbnail (`embedded_preview_srgb`) decode the smallest
+JPEG whose long edge is at least the size asked for (`lightcraft_raw::embedded_preview_covering`).
+They take the largest one when no other JPEG is big enough. The plan route picks the same way
+(`preview_window` takes the size asked for), so a raw read through the plan gets the JPEG the whole
+file would give. A smaller JPEG only counts as a copy of the picture when its aspect ratio is within
+1 % of the largest one's and it has the same number of colour components. That rules out letterboxed
+thumbnails of another shape and the grey masks an iPhone ProRAW DNG keeps at the picture's shape.
+Sources for editing (an unsupported raw's JPEG, `load_embedded_preview`) and the camera-look fit still
+use the largest JPEG, so their geometry and colour do not depend on the size level.
+
 ## Tests
 
 - `crates/raw/src/preview.rs`: the header-only range matches `embedded_preview` byte for byte; a
   clamped prefix, a padded extent, a late pointer, a lying pointer and a non-JPEG window are all
-  covered.
+  covered. `a_stand_in_takes_the_smallest_covering_jpeg_of_the_same_shape` covers the picker: a
+  smaller JPEG that covers the box is taken, the largest when none does, and a thumbnail of another
+  shape or a grey mask never is.
 - `crates/engine/src/files.rs`: on a synthetic RAF with a 200 KB tail, the quick path and the
   whole-file path produce identical pixels, and the read stays under half the file. On a synthetic
   TIFF/DNG whose preview only its tags locate — the plan path — the same identity holds and the CFA
   strip is not read; the same structure without the tag that makes it a raw declines instead of
   guessing, and the caller keeps reading it whole. So do a file whose own orientation or Adobe RGB
   colour space only the whole-file path can show, while one that states sRGB stays on the fast path.
+  A synthetic DNG with a full-size and a half-size JPEG gets, on the plan path, the half-size one for
+  a box it covers and the full-size one otherwise, with the same pixels as the whole-file path
+  (`preview_loading_plans_the_smallest_covering_jpeg`).
 - `crates/raw/tests/sparse_corpus.rs`: `preview_plan` is asked for **every** corpus file, not only
   the ones whose header plan is `Ready`, and the preview it yields must equal the whole file's with
   the skipped bytes `0` and `0xFF`. The test prints what each format reads.

docs/whats-new.md

@@ -22,6 +22,11 @@
 - With Dehaze on, panning a photo zoomed to 1:1 or moving a slider while zoomed no longer samples the whole
   original again to find the haze colour. On a 64 MP raw (Sony A7R VI) that took ~0.2 s of CPU per pan and per
   slider step; a slider step now takes ~5 ms on the GPU.
+### Thumbnails of raw files appear sooner
+- Grid thumbnails and the first picture in the loupe of an unedited raw now come from the smallest JPEG the camera
+  stored that is big enough, not always from the largest one. On a Sony A7R VI file a 512 px thumbnail decodes
+  0.3 MB of JPEG instead of 5.6 MB and is ready several times sooner; Nikon and Panasonic raws with a mid-sized
+  JPEG get faster too.
 ## 2026-10-12
 
 ### Canon CR2 highlights