Esa Kataja
01227b3382
Page 1 of Engel (Bosse/Partitura) has a boxed VERSE 1 label in the left margin at the same rows as the preceding system's bass lyric line — ink on both sides of the page throughout the band, so no horizontal line separates them. The label belongs to system 2, the lyrics to system 1. A cut is therefore a polyline spanning the page, two points being the ordinary straight case. A slice bounded by a non-straight cut is not rectangular: its image is the region's bounding box with everything outside made transparent, which composites invisibly on the viewer's sheet. Masking paints transparency, never white.
noteman-slicer
Turns a score PDF into the ordered slice images noteman consumes, plus the navigation markers that sit on them.
A slice is one system — one full line of music across all voices, typically 4–12 bars with lyrics intact. noteman displays them as a continuous vertical scroll, so the slicer's job is to cut a printed page into systems, clean them up enough to read on a tablet, and tag them with the score's navigation symbols.
Status: design only. No code yet. The design is settled; see below.
How it works
Open a PDF, and the tool proposes cuts between systems, a skew correction, and a content rectangle. You correct all of it — source quality varies too much for unattended processing, so detection is an accelerator that nothing depends on being right. You mark the header and footer regions discarded, set black and white points until the paper disappears and the notes go solid, place the rehearsal letters and jump markers, fill in the title block, and export.
Out comes one zip: the slices in order, their markers, the original PDF, and the song metadata. That bundle is the only channel to noteman — there's no API between the two tools.
Erasing previous-owner pencil marks, chord letters and breath marks stays in GIMP. That's the irreducible manual part, and GIMP with a stylus is already good at it.
Installation
Not yet installable. When it is:
uv tool install --editable .
That puts a noteman-slicer command on PATH which runs from any directory — no venv to
activate. Dependencies (PyMuPDF, PySide6, OpenCV, numpy) are all wheels; nothing
needs a system package.
Documentation
| CONTEXT.md | Glossary. What a slice, cut, discard, bundle and song scale actually mean here. Start here. |
| docs/spec.md | The specification: pipeline, geometry model, detection, editor, bundle format, and what noteman has to change. |
Deferred work is tracked as issues and milestones on the Gitea repo, not in this tree.
Decisions that were expensive to reach, each with the evidence behind it:
| ADR 0001 | The slicer owns all image processing; the bundle is the only channel to noteman. |
| ADR 0002 | Raster only in release 1 — measured SVG slice sizes and what they showed. |
| ADR 0003 | Lossless WebP beats every lossy option and every alternative format here. |
| ADR 0004 | No unattended mode: detection suggests, a human confirms. |
| ADR 0005 | PyMuPDF for all PDF access, accepting AGPL. |
| ADR 0006 | Systems are found by vertical brackets; row-darkness gaps get it wrong. |