dr-export gains write_linear_dng — LinearRaw, DNG 1.4, u16 samples at
the sensor's scale, the body's matrices with their illuminants, the
as-shot neutral, the EXIF block an export writes — streamed strip by
strip through a closure so the composite is never held (FR-MRG-11). The
tiff crate's directory is a map, so PhotometricInterpretation is written
over what new_image set, which is the trick the S15.1 spike thought it
had to hand-roll around. The test reads the file back through rawler.
dr-decode's RawImage carries samples_per_pixel (a linear DNG is 3), the
body's profile with its calibrations mapped back to EXIF illuminant
codes, and the cleaned make and model. The GPU uploads a three-sample
image as it is, normalised by black and white like a photosite, through
a full f16 conversion — subnormals kept, because a 14-bit LSB sits at
f16's smallest normal and rounding it to zero would crush exactly the
shadows the file was written to keep.
`cargo fmt --check` is a required step and had drifted across 45 files. Most of
it arrived this week: several operations were written in parallel worktrees and
merged by hand, and a hand-merge resolves conflicts without ever running the
formatter over the result.
No behaviour changes — this is `cargo fmt --all` and nothing else, kept as its
own commit so the next reader can skip it wholesale rather than search it for
one that matters.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Colour came from whichever matrix rawler happened to key `D65`, the second
one was discarded, and the rendering was left linear. That is the dcraw
default, and FR-DEV-3e names it as the reason people abandon a converter in
the first hour: correct in the abstract, flat and poor on skin in practice.
The decoder now builds a camera profile.
- `ColorMatrix1/2` and `CalibrationIlluminant1/2`. rawler surfaces these as
an illuminant-keyed map — for DNGs from the tags, and for native formats
from its own camera database — so a Canon CR2 arrives with a tungsten
matrix and a daylight matrix exactly as an Adobe DNG of the same frame
would. Dual-illuminant support is therefore not a DNG feature here.
- `ForwardMatrix1/2`, read straight from the root IFD, because rawler parses
them and never surfaces them. Where a file carries both, they replace the
inverted colour matrix: the same relationship measured in the direction
rendering actually wants, rather than an inversion that amplifies the
measurement error exactly where skin lives.
- `AsShotNeutral`, used to estimate what the scene was lit by and to
interpolate between the two calibrations in mireds. The estimate is
circular — the temperature needs a matrix and the matrix needs the
temperature — so it is a fixed point, three rounds, as Adobe's SDK does it.
Bodies calibrated at neither D65 nor A stopped rendering uncalibrated as a
side effect: a Phase One IQ3 carries D55 and D75 and used to get no matrix
at all.
And a base curve, applied per channel in camera RGB between the last
adjustment and the conversion out of camera space — a toe, a steep midtone
and a shoulder, which is the difference between a photograph and a scan of
one. It is not an edit: no slider, nothing in the sidecar, because it
belongs to the body rather than to anything anyone decided, and a sidecar is
shared between bodies. It is not a develop node either, and `ops/README.md`
now records why. It evaluates on the tone curve's own spline rather than a
second copy, so a profile author placing a control point and a photographer
dragging one mean the same thing by it.
The curves are data. `core/dr-decode/profiles/base_curves.yaml` ships inside
the binary as a floor and is superseded by any copy on disk carrying a
higher `version:`, so a body can be added and distributed without a release
— and, under the GPL, contributed. The comparison runs both ways: a stale
pack cannot hold an upgraded binary back at last year's rendering.
Canon EOS 6D and R6, Nikon Z 6 and D750, Sony A7 III and Fujifilm X-T3 ship
with their own curves. Every other body gets a conservative default, which
is much closer to right than the identity is for any of them. A JPEG gets
none — it has already been rendered once, by the camera.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
dtourolle
