Scanned scores are black ink on white paper stored as 8-bit greyscale or
RGB, which costs several times what the same page costs as a bilevel
image. Across an 11-song corpus this is 27.6 MB to 7.7 MB; Engel's
bundle goes from 5997 KB to 2092 KB with byte-identical slices, since
only the archived copy changes.
Three approaches were measured and discarded first, which is worth
recording because two of them are the obvious ones. Converting RGB to
greyscale and re-encoding makes these files 20-86% LARGER: the source
JPEGs are already near 0.7 bits per pixel, so re-encoding adds
generation loss and spends more bits than the original did, and dropping
chroma recovers nothing because JPEG already subsamples it. Lossless
structural optimisation gains 0.1%, because images are 99% of every file
and there are no duplicates. Downsampling works but 300 DPI is print
resolution, and the PDF exists to be printed.
Two failure modes were found by looking at output rather than at byte
counts, and both are now refused:
- A scan at ~115 DPI came back with broken staff lines. Guarded on
resolution as the image is *placed on the page*, so a tiled scan with
126 small images still qualifies where a pixel count would reject it.
- Cover artwork was flattened to grey. Guarded on chroma: artwork
measures 44% off-grey against 3% for sensor tint on a greyscale scan.
The first threshold of 2% was a false positive that cost 685 KB on one
song for nothing; 10% sits in the gap with room either side.
Exposed as a button rather than a checkbox. It reports what it skipped
and why, and shows a before/after crop, because the failure it can
produce is obvious at a glance and invisible in a size figure. Off by
default: this is lossy on the copy kept for printing.
The bundle is documented as a standalone format rather than as a note
between two programs: producers and consumers are generic, the marker
vocabulary is defined musically rather than by what a viewer does with
it, and image properties are stated as guarantees with the reasoning
where it is not obvious. Anything that reads scores can implement it
without knowing this tool exists.
Taking that view changed the substance in three places. Marker types now
carry their musical meaning rather than a UI mapping. The rule against
re-importing became a statement about identity - indices mean something
only within one bundle, so two bundles of a piece are independent
documents. And forward-compatibility rules were added, which a protocol
needs and a handover note did not: ignore unknown fields and marker
types, refuse an unknown version.
Tempo is now an integer, beats per minute, exported as a JSON number and
omitted when blank; the editor accepts digits only. A figure can drive a
metronome or a click track where a verbal marking cannot, and readers do
not agree on what Andante means. This needs the consumer's column
changed from free-form text, which the format document flags.
Every figure in the document comes from a real export.
Re-engraving is a rescue path for the handful of systems a scan cannot
deliver, so the window is an editing surface rather than an automation
project. Three full-width rows - the scanned system, the render, the
form - because a system is wide and short and the job is comparing one
against the other bar by bar. The render is shown scaled to the scan's
staff height, which is what export does anyway, so it previews the real
thing.
A form rather than a text box. Key and time are slice-level, clef,
notes and lyrics per voice: every staff in a system carries the same key
signature, and Kaipaava proves it across five-staff and two-staff
systems alike. Notes and lyrics stay raw LilyPond, so slurs, dynamics,
tuplets and the laissezVibrer/repeatTie idiom for ties crossing into the
next slice all work untouched.
Notes are entered in \relative mode, referenced to the middle of each
clef's staff, so a part needs no octave marks at all in the common case.
The time signature is used for spacing and bar checks but not printed:
the printed score repeats the key at every system and the time only at
the first, so a re-engraved middle slice showing one would stand out.
Seeded from what can be known reliably. Voice count comes from counting
staves in the slice; key, time and clefs are inherited from the song,
because the slices being re-engraved are the illegible ones and reading
a key signature off them is exactly the measurement that fails. After
the first replacement in a song only the notes need typing.
Staff counting needed two corrections against the corpus: compare gaps
against line spacing rather than staff height, since adjacent staves can
sit closer together than one staff is tall; and require five lines in a
group, since Engel's 'uh______' lyric extenders are long horizontal runs
too and each counted as a staff. Kaipaava now reads 2,2,2,2,5 on page 1,
Ketun 6, Engel 4.
Also in this change:
- Title is required for export, every other metadata field optional,
enforced in bundle.write so the CLI and the editor both get it. Tempo
added; noteman already has a free-form column for it.
- The panel is a splitter rather than a fixed width, sections collapse
under bold grey disclosure headers, and it scrolls.
- A re-engraved slice is washed amber with an ENGRAVED badge, and
markers get badges too. Thin coloured text was invisible against a
scan.
Closes#31Closes#32Closes#33Closes#34
Markers are stored per (page, slot), parallel to the discard flags, so
adding or removing a cut keeps them aligned with their slices. On a
split they stay with the upper half: a marker sits on a printed symbol
and nothing can say which side that symbol landed on, so predictable
beats clever.
Jump targets are chosen by clicking the slice rather than from the
thumbnail strip the plan called for. Less code, and it reads the score
instead of a list of thumbnails - which is what you want when hunting
for the Coda sign. Any page; PageUp/PageDown while picking.
Export resolves (page, slot) to the bundle's array index, the only
cross-reference the format has. A jump whose target was discarded or
re-cut away is dropped rather than exported dangling, since noteman
would have nothing to resolve it to.
tests/test_markers.py covers the enum size - that is the coupling
between two repos - along with cut-edit alignment, index resolution,
the dangling-target drop, and round-trips through both the project file
and a real bundle.
Closes#28Closes#29Closes#30
Opening an exported song starts a fresh session from detection instead
of resuming: cuts, discards and metadata do not carry over, so a re-cut
never inherits decisions that have already shipped. --resume overrides
it on edit, export and project.
This reverses what was agreed in planning and written into docs/spec.md
and CONTEXT.md, which promised resume-across-sessions and re-export.
Both are corrected. The cost is deliberate and worth stating: changing
the width cap or adding the SVG renderer later now means re-cutting each
song by hand rather than regenerating every bundle from its project
file.
Export records the flag in bundle.write, so no caller can forget it.
Also removed --refit and the Auto-fit buttons, which were added without
being asked for and whose only purpose - migrating projects made before
the content rectangle was proposed - disappears once exported projects
start fresh. Reset now restores detection's proposal rather than the
whole page: clearing to full width would undo the thing the rectangle
exists for, so one button covers it.
open_project() replaces four copies of load-or-detect across the CLI
and the editor.
Project state plus PDF in, finished slice images out. Slices are cut as
polygons rather than row ranges, so a stepped cut yields a slice with a
transparent notch instead of one that covers its neighbour.
Masking paints white, which the ink-to-alpha step turns into full
transparency — the same outcome the spec asks for, one step earlier.
Scale normalises every slice to the median staff height before fitting
the song to 1920px, so a rescanned page sits at the same note size as
its neighbours. The cap only ever shrinks: a song narrower than 1920
stays narrower.
Alpha quantisation rounds to 16 values spanning 0-255 inclusive.
Flooring, as first written, capped full ink at 240 and left every note
6% transparent — caught by decoding an exported slice rather than by
reading the code.
Ketun joululaulu exports 24 slices at a uniform 1489px, under the cap
and correctly not upscaled from its 200 DPI source; Feliz Navidad 20;
Elaman nalka 18.
Closes#21Closes#22Closes#23Closes#24Closes#25Closes#27
Esa Kataja