Add a New line button for another fingering row.

Each line keeps its own charts and staff. Save PNG stacks every line. Version 0.2.3.

Co-authored-by: catpersonisme <catpersonisme@gmail.com>

README.md

@@ -7,17 +7,17 @@ The usual way to run it is one Linux AppImage. That file contains the window and
 ## Run the AppImage
 
 ```bash
-chmod +x Recorder-Tab-Converter-0.2.1.AppImage
+chmod +x Recorder-Tab-Converter-0.2.3.AppImage
-./Recorder-Tab-Converter-0.2.1.AppImage
+./Recorder-Tab-Converter-0.2.3.AppImage
 ```
 
 If the file will not start because FUSE is missing:
 
 ```bash
-APPIMAGE_EXTRACT_AND_RUN=1 ./Recorder-Tab-Converter-0.2.1.AppImage
+APPIMAGE_EXTRACT_AND_RUN=1 ./Recorder-Tab-Converter-0.2.3.AppImage
 ```
 
-Open **Empty line**, or start from **Twinkle, opening** or **Ode, held note**. Drag any chart from C5 to D7, or drag **Rest** or **Space**, onto the line. Drag a placed item to move it. Choose a duration under it. Remove takes it off. **Shorter**, **Taller**, **Narrower**, **Wider**, and the corner grip change the line box. **Save PNG** downloads the finished row.
+Open **Empty line**, or start from **Twinkle, opening** or **Ode, held note**. Drag any chart from C5 to D7, or drag **Rest** or **Space**, onto a line. Drag a placed item to move it, including onto another line. **New line** adds a row underneath. Plus and minus change the length. Remove takes an item off. **Shorter**, **Taller**, **Narrower**, **Wider**, and the corner grip change the box. **Save PNG** downloads every line.
 
 ## Build the AppImage
 
@@ -30,7 +30,7 @@ From a checkout, one command:
 That installs Node packages, builds the app, and writes:
 
 ```text
-dist/Recorder-Tab-Converter-0.2.1.AppImage
+dist/Recorder-Tab-Converter-0.2.3.AppImage
 ```
 
 The AppImage is not committed. Keep it under 600MB.
@@ -47,6 +47,6 @@ The dev server listens on [http://127.0.0.1:3847](http://127.0.0.1:3847).
 
 ## Fingerings
 
-Baroque (English) fingerings are the first choice on the [Dolmetsch Online chart for recorders in C](https://dolmetsch.com/textfingeringchart.htm) (Brian Blood). The soprano is treated in concert pitch: it sounds as written, low C is C5, and the chart stops at D7. Double holes 6 and 7, forked F, and the second-octave thumb pinch are included. Alternate fingerings on that chart are not shown.
+Baroque (English) fingerings are the first choice on the [Dolmetsch Online chart for recorders in C](https://dolmetsch.com/textfingeringchart.htm) (Brian Blood). The soprano is labeled in concert pitch: low C is C5, and the chart stops at D7. Double holes 6 and 7, forked F, and the second-octave thumb pinch are included. Alternate fingerings on that chart are not shown.
 
-Each chart is drawn foot-up: holes 7 and 6 at the top, then 5 through 1, then the thumb, with the mouthpiece at the bottom. A filled hole is closed. A treble staff under the holes shows the pitch and the length: notehead, stem, flags, dots, and rests.
+Each chart is drawn foot-up: holes 7 and 6 at the top, then 5 through 1, then the thumb, with the mouthpiece at the bottom. A filled hole is closed. A treble staff under the holes is written one octave below the sounding pitch. Low C, labeled C5, sits on the ledger line below the staff. Sounding C6 is written C5, and sounding C7 is written C6. Length is a notehead, stem, flags, dots, and rests. Labels keep the sounding names.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "recorder-tab-converter",
-  "version": "0.2.1",
+  "version": "0.2.3",
   "private": true,
   "description": "Arrange soprano recorder fingering charts by dragging them onto a line.",
   "main": "electron/main.cjs",

src/components/editor.tsx

@@ -6,20 +6,23 @@ import { DURATION_PRESETS } from "@/lib/duration";
 import { downloadBlob, renderLinePng } from "@/lib/export-png";
 import { CHART_NOTES, fingeringFor } from "@/lib/fingering";
 import {
+  appendLine,
   clampLineBox,
   cloneLine,
   createNote,
   createRest,
   createSpace,
   dropIndexFromPoint,
-  insertNote,
   LINE_EXAMPLES,
-  moveNote,
   neighborDuration,
+  placeOnLine,
+  removeLine,
   removeNote,
   setDuration,
+  transferNote,
   type LineKind,
   type LineNote,
+  type ScoreLine,
 } from "@/lib/line";
 import { chartPixelHeight } from "@/lib/notation";
 import { pngFilename, PNG_CHART_WIDTH } from "@/lib/png-layout";
@@ -33,6 +36,7 @@ type Drag = {
   kind: LineKind;
   pitch: string;
   id: string;
+  lineId: string;
   pointerId: number;
   startX: number;
   startY: number;
@@ -41,17 +45,18 @@ type Drag = {
   armed: boolean;
 };
 
+type DropTarget = { lineId: string; index: number };
+
 export function Editor() {
-  const [notes, setNotes] = useState<LineNote[]>([]);
+  const [lines, setLines] = useState<ScoreLine[]>([{ id: "line-1", notes: [] }]);
   const [title, setTitle] = useState("Empty line");
   const [drag, setDrag] = useState<Drag | null>(null);
-  const [dropIndex, setDropIndex] = useState<number | null>(null);
+  const [dropTarget, setDropTarget] = useState<DropTarget | null>(null);
   const [boxWidth, setBoxWidth] = useState<number | null>(null);
   const [boxHeight, setBoxHeight] = useState(520);
   const [saving, setSaving] = useState(false);
   const [saveError, setSaveError] = useState<string | null>(null);
   const dragRef = useRef<Drag | null>(null);
-  const lineRef = useRef<HTMLDivElement>(null);
   const frameRef = useRef<HTMLDivElement>(null);
   const paletteRef = useRef<HTMLDivElement>(null);
   const exportRef = useRef<HTMLDivElement>(null);
@@ -63,15 +68,23 @@ export function Editor() {
   }
 
   useEffect(() => {
-    function pointIndex(clientX: number, clientY: number) {
+    function pointTarget(clientX: number, clientY: number): DropTarget | null {
-      const line = lineRef.current;
+      const rows = [...document.querySelectorAll<HTMLElement>("[data-line-id]")];
-      if (!line) return -1;
+      let best: (DropTarget & { distance: number }) | null = null;
-      const rect = line.getBoundingClientRect();
+      for (const row of rows) {
-      const centers = [...line.querySelectorAll<HTMLElement>("[data-note-id]")].map((element) => {
+        const lineId = row.dataset.lineId;
-        const box = element.getBoundingClientRect();
+        if (!lineId) continue;
-        return box.left + box.width / 2;
+        const rect = row.getBoundingClientRect();
-      });
+        const centers = [...row.querySelectorAll<HTMLElement>("[data-note-id]")].map((element) => {
-      return dropIndexFromPoint(clientX, clientY, rect, centers);
+          const box = element.getBoundingClientRect();
+          return box.left + box.width / 2;
+        });
+        const index = dropIndexFromPoint(clientX, clientY, rect, centers);
+        if (index < 0) continue;
+        const distance = Math.abs(clientY - (rect.top + rect.bottom) / 2);
+        if (!best || distance < best.distance) best = { lineId, index, distance };
+      }
+      return best ? { lineId: best.lineId, index: best.index } : null;
     }
 
     function onMove(event: PointerEvent) {
@@ -87,28 +100,30 @@ export function Editor() {
           Math.abs(dx) > Math.abs(dy);
         if (touchScroll) {
           updateDrag(null);
-          setDropIndex(null);
+          setDropTarget(null);
           return;
         }
         if (Math.hypot(dx, dy) < 8) return;
       }
       window.getSelection()?.removeAllRanges();
-      if (lineRef.current) {
+      const rows = [...document.querySelectorAll<HTMLElement>("[data-line-id]")];
-        const rect = lineRef.current.getBoundingClientRect();
+      for (const candidate of rows) {
-        if (event.clientX > rect.right - 28) lineRef.current.scrollLeft += 14;
+        const rect = candidate.getBoundingClientRect();
-        if (event.clientX < rect.left + 28) lineRef.current.scrollLeft -= 14;
+        const verticallyNear = event.clientY >= rect.top - 36 && event.clientY <= rect.bottom + 36;
+        if (!verticallyNear) continue;
+        if (event.clientX > rect.right - 28) candidate.scrollLeft += 14;
+        if (event.clientX < rect.left + 28) candidate.scrollLeft -= 14;
       }
       const next = { ...current, x: event.clientX, y: event.clientY, armed: true };
       updateDrag(next);
-      const index = pointIndex(event.clientX, event.clientY);
+      setDropTarget(pointTarget(event.clientX, event.clientY));
-      setDropIndex(index >= 0 ? index : null);
     }
 
     function onUp(event: PointerEvent) {
       const current = dragRef.current;
       if (!current || event.pointerId !== current.pointerId) return;
-      const index = current.armed ? pointIndex(event.clientX, event.clientY) : -1;
+      const target = current.armed ? pointTarget(event.clientX, event.clientY) : null;
-      if (current.armed && index >= 0) {
+      if (current.armed && target) {
         if (current.source === "palette") {
           const note =
             current.kind === "rest"
@@ -116,14 +131,14 @@ export function Editor() {
               : current.kind === "space"
                 ? createSpace()
                 : createNote(current.pitch);
-          setNotes((existing) => insertNote(existing, index, note));
+          setLines((existing) => placeOnLine(existing, target.lineId, target.index, note));
           setTitle("Your line");
         } else {
-          setNotes((existing) => moveNote(existing, current.id, index));
+          setLines((existing) => transferNote(existing, current.lineId, current.id, target.lineId, target.index));
         }
       }
       updateDrag(null);
-      setDropIndex(null);
+      setDropTarget(null);
     }
 
     function onSelectStart(event: Event) {
@@ -194,7 +209,8 @@ export function Editor() {
   }
 
   async function savePng() {
-    if (!exportRef.current || notes.length === 0) {
+    const filled = lines.some((line) => line.notes.length > 0);
+    if (!exportRef.current || !filled) {
       setSaveError("Add a note, rest, or space before saving a PNG.");
       return;
     }
@@ -218,18 +234,19 @@ export function Editor() {
         <p className="text-sm tracking-[0.16em] text-[#6a4328] uppercase">Soprano in C · Baroque</p>
         <h1 className="font-heading text-4xl leading-tight md:text-5xl">Recorder fingering editor</h1>
         <p className="max-w-2xl text-base leading-7 text-muted-foreground">
-          Drag a chart, a rest, or a space onto the line. Drag a placed item sideways to reorder it.
+          Drag a chart, a rest, or a space onto a line. Drag a placed item sideways to reorder it, or
-          The staff under the holes shows the pitch and the length. Resize the line box, then save the
+          onto another line. New line adds a row underneath. The staff under the holes shows the pitch
-          finished row as a PNG. The foot, with the double holes, stays at the top.
+          and the length. Resize the box, then save every line as a PNG. The foot, with the double holes,
+          stays at the top.
         </p>
       </header>
 
       <div className="flex flex-wrap gap-2">
         <Button
           type="button"
-          variant={notes.length === 0 ? "default" : "outline"}
+          variant={lines.length === 1 && lines[0].notes.length === 0 ? "default" : "outline"}
           onClick={() => {
-            setNotes([]);
+            setLines([{ id: "line-1", notes: [] }]);
             setTitle("Empty line");
           }}
         >
@@ -241,7 +258,7 @@ export function Editor() {
             type="button"
             variant="outline"
             onClick={() => {
-              setNotes(cloneLine([...example.notes]));
+              setLines([{ id: "line-1", notes: cloneLine([...example.notes]) }]);
               setTitle(example.title);
             }}
           >
@@ -273,6 +290,7 @@ export function Editor() {
                 kind: "rest",
                 pitch: "",
                 id: "",
+                lineId: "",
                 pointerId: event.pointerId,
                 startX: event.clientX,
                 startY: event.clientY,
@@ -292,6 +310,7 @@ export function Editor() {
                 kind: "space",
                 pitch: "",
                 id: "",
+                lineId: "",
                 pointerId: event.pointerId,
                 startX: event.clientX,
                 startY: event.clientY,
@@ -314,6 +333,7 @@ export function Editor() {
                   kind: "note",
                   pitch,
                   id: "",
+                  lineId: "",
                   pointerId: event.pointerId,
                   startX: event.clientX,
                   startY: event.clientY,
@@ -334,12 +354,20 @@ export function Editor() {
           <div>
             <h2 className="font-heading text-2xl">{title}</h2>
             <p className="text-sm text-muted-foreground">
-              Treble staff, 4/4. Noteheads, stems, flags, and dots show the length. Plus and minus
+              Treble staff written an octave below the sounding pitch, 4/4. Noteheads, stems, flags, and dots show the length. Plus and minus
               change it. A space is empty room you can still drag. The box is {boxHeight}px tall
               {boxWidth ? `, ${boxWidth}px wide` : ""}.
             </p>
           </div>
-          <ScrollButtons target={lineRef} label="line" />
+          <ScrollButtons
+            label="lines"
+            onLeft={() =>
+              document.querySelectorAll<HTMLElement>("[data-line-id]").forEach((row) => row.scrollBy({ left: -180, behavior: "smooth" }))
+            }
+            onRight={() =>
+              document.querySelectorAll<HTMLElement>("[data-line-id]").forEach((row) => row.scrollBy({ left: 180, behavior: "smooth" }))
+            }
+          />
         </div>
         <div className="flex flex-wrap gap-2">
           <Button type="button" variant="outline" size="sm" onClick={() => nudgeBox(0, -48)}>
@@ -357,57 +385,99 @@ export function Editor() {
           <Button type="button" variant="outline" size="sm" onClick={() => setBoxWidth(null)}>
             Fit width
           </Button>
-          <Button type="button" size="sm" onClick={savePng} disabled={notes.length === 0 || saving}>
+          <Button
+            type="button"
+            variant="outline"
+            size="sm"
+            onClick={() => {
+              setLines((existing) => appendLine(existing));
+              setBoxHeight((height) => clampLineBox(400, height + 260, 960).height);
+            }}
+          >
+            New line
+          </Button>
+          <Button type="button" size="sm" onClick={savePng} disabled={lines.every((line) => line.notes.length === 0) || saving}>
             {saving ? "Saving…" : "Save PNG"}
           </Button>
         </div>
         {saveError ? <p className="text-sm text-destructive">{saveError}</p> : null}
         <div ref={frameRef} className="relative max-w-full" style={{ width: boxWidth ?? "100%", height: boxHeight }}>
           <div
-            ref={lineRef}
             data-line
-            className={`h-full overflow-auto rounded-none border-2 bg-card px-3 py-4 select-none ${
+            className={`flex h-full flex-col gap-4 overflow-auto rounded-none border-2 bg-card px-3 py-4 select-none ${
-              dropIndex !== null ? "border-primary" : "border-foreground"
+              dropTarget !== null ? "border-primary" : "border-foreground"
             }`}
           >
-            {notes.length === 0 ? (
+            {lines.map((line, lineIndex) => (
-              <p className="px-2 py-16 text-center text-sm text-muted-foreground">
+              <div key={line.id} className="space-y-2">
-                Drop a fingering, a rest, or a space here. The line is empty.
+                <div className="flex items-center justify-between gap-2">
-              </p>
+                  <p className="text-sm font-medium">Line {lineIndex + 1}</p>
-            ) : (
+                  {lines.length > 1 ? (
-              <div className="flex w-max min-w-full items-end gap-2">
+                    <Button
-                {notes.map((note, index) => (
+                      type="button"
-                  <div key={note.id} className="flex items-end gap-2">
+                      variant="ghost"
-                    {dropIndex === index ? <DropCaret /> : null}
+                      size="xs"
-                    <PlacedItem
+                      aria-label={`Remove line ${lineIndex + 1}`}
-                      note={note}
+                      onClick={() => setLines((existing) => removeLine(existing, line.id))}
-                      dimmed={drag?.source === "line" && drag.armed && drag.id === note.id}
+                    >
-                      onPointerDown={(event) =>
+                      <X />
-                        beginDrag(event, {
+                      Remove line
-                          source: "line",
+                    </Button>
-                          kind: note.kind,
+                  ) : null}
-                          id: note.id,
+                </div>
-                          pitch: note.pitch,
+                <div data-line-id={line.id} className="overflow-x-auto">
-                          pointerId: event.pointerId,
+                  {line.notes.length === 0 ? (
-                          startX: event.clientX,
+                    <p className="px-2 py-10 text-center text-sm text-muted-foreground">
-                          startY: event.clientY,
+                      Drop a fingering, a rest, or a space here. The line is empty.
-                          x: event.clientX,
+                    </p>
-                          y: event.clientY,
+                  ) : (
-                          armed: false,
+                    <div className="flex w-max min-w-full items-end gap-2">
-                        })
+                      {line.notes.map((note, index) => (
-                      }
+                        <div key={note.id} className="flex items-end gap-2">
-                      onDuration={(quarters) => {
+                          {dropTarget?.lineId === line.id && dropTarget.index === index ? <DropCaret /> : null}
-                        const preset = DURATION_PRESETS.find((item) => item.quarters === quarters);
+                          <PlacedItem
-                        if (!preset) return;
+                            note={note}
-                        setNotes((existing) => setDuration(existing, note.id, preset));
+                            dimmed={drag?.source === "line" && drag.armed && drag.id === note.id}
-                      }}
+                            onPointerDown={(event) =>
-                      onRemove={() => setNotes((existing) => removeNote(existing, note.id))}
+                              beginDrag(event, {
-                    />
+                                source: "line",
-                  </div>
+                                kind: note.kind,
-                ))}
+                                id: note.id,
-                {dropIndex === notes.length ? <DropCaret /> : null}
+                                lineId: line.id,
+                                pitch: note.pitch,
+                                pointerId: event.pointerId,
+                                startX: event.clientX,
+                                startY: event.clientY,
+                                x: event.clientX,
+                                y: event.clientY,
+                                armed: false,
+                              })
+                            }
+                            onDuration={(quarters) => {
+                              const preset = DURATION_PRESETS.find((item) => item.quarters === quarters);
+                              if (!preset) return;
+                              setLines((existing) =>
+                                existing.map((row) =>
+                                  row.id === line.id ? { ...row, notes: setDuration(row.notes, note.id, preset) } : row,
+                                ),
+                              );
+                            }}
+                            onRemove={() =>
+                              setLines((existing) =>
+                                existing.map((row) =>
+                                  row.id === line.id ? { ...row, notes: removeNote(row.notes, note.id) } : row,
+                                ),
+                              )
+                            }
+                          />
+                        </div>
+                      ))}
+                      {dropTarget?.lineId === line.id && dropTarget.index === line.notes.length ? <DropCaret /> : null}
+                    </div>
+                  )}
+                </div>
               </div>
-            )}
+            ))}
           </div>
           <div
             role="slider"
@@ -457,24 +527,28 @@ export function Editor() {
       ) : null}
 
       <div ref={exportRef} className="pointer-events-none absolute h-px w-px overflow-hidden" aria-hidden>
-        {notes.map((note) => (
+        {lines.map((line) => (
-          <div
+          <div key={line.id} data-export-line={line.id}>
-            key={note.id}
+            {line.notes.map((note) => (
-            data-export-slot
+              <div
-            data-kind={note.kind}
+                key={note.id}
-            data-quarters={note.quarters}
+                data-export-slot
-            data-duration={note.label}
+                data-kind={note.kind}
-            data-pitch={note.pitch}
+                data-quarters={note.quarters}
-          >
+                data-duration={note.label}
-            {note.kind === "note" ? (
+                data-pitch={note.pitch}
-              <FingeringDiagram
+              >
-                fingering={fingeringFor(note.pitch, "baroque")}
+                {note.kind === "note" ? (
-                pitch={note.pitch}
+                  <FingeringDiagram
-                quarters={note.quarters}
+                    fingering={fingeringFor(note.pitch, "baroque")}
-                width={PNG_CHART_WIDTH}
+                    pitch={note.pitch}
-              />
+                    quarters={note.quarters}
-            ) : null}
+                    width={PNG_CHART_WIDTH}
-            {note.kind === "rest" ? <RestMark quarters={note.quarters} width={PNG_CHART_WIDTH} /> : null}
+                  />
+                ) : null}
+                {note.kind === "rest" ? <RestMark quarters={note.quarters} width={PNG_CHART_WIDTH} /> : null}
+              </div>
+            ))}
           </div>
         ))}
       </div>
@@ -597,9 +671,13 @@ function DropCaret() {
 function ScrollButtons({
   target,
   label,
+  onLeft,
+  onRight,
 }: {
-  target: RefObject<HTMLDivElement | null>;
+  target?: RefObject<HTMLDivElement | null>;
   label: string;
+  onLeft?: () => void;
+  onRight?: () => void;
 }) {
   return (
     <div className="flex shrink-0 gap-1">
@@ -608,7 +686,7 @@ function ScrollButtons({
         variant="outline"
         size="icon-sm"
         aria-label={`Scroll ${label} left`}
-        onClick={() => target.current?.scrollBy({ left: -180, behavior: "smooth" })}
+        onClick={() => onLeft?.() ?? target?.current?.scrollBy({ left: -180, behavior: "smooth" })}
       >
         <ChevronLeft />
       </Button>
@@ -617,7 +695,7 @@ function ScrollButtons({
         variant="outline"
         size="icon-sm"
         aria-label={`Scroll ${label} right`}
-        onClick={() => target.current?.scrollBy({ left: 180, behavior: "smooth" })}
+        onClick={() => onRight?.() ?? target?.current?.scrollBy({ left: 180, behavior: "smooth" })}
       >
         <ChevronRight />
       </Button>

src/components/fingering-diagram.tsx

@@ -83,7 +83,7 @@ export function FingeringDiagram({
 
   const [h1, h2, h3, h4, h5, h6a, h6b, h7a, h7b] = fingering.holes;
   const value = noteValue(quarters);
-  const label = `${pitch}, ${durationLabel(quarters)} on the treble staff. Foot at the top, mouthpiece at the bottom. ${fingeringProse(fingering)}. ${fingeringMarks(fingering).join(", ")}`;
+  const label = `${pitch}, written one octave lower, ${durationLabel(quarters)} on the treble staff. Foot at the top, mouthpiece at the bottom. ${fingeringProse(fingering)}. ${fingeringMarks(fingering).join(", ")}`;
 
   return (
     <svg

src/lib/export-png.ts

@@ -1,4 +1,4 @@
-import { pngItemFromNote, pngLayout, type PngItem } from "@/lib/png-layout";
+import { pngItemFromNote, pngStackLayout, type PngItem } from "@/lib/png-layout";
 
 const INK = "#1a1a1a";
 const PAPER = "#fbf6ee";
@@ -23,8 +23,8 @@ function loadSvg(svg: SVGElement): Promise<HTMLImageElement> {
   });
 }
 
-export async function renderLinePng(exportRoot: HTMLElement, title: string): Promise<Blob> {
+async function readRow(line: HTMLElement): Promise<{ items: PngItem[]; images: Array<HTMLImageElement | null> } | null> {
-  const slots = [...exportRoot.querySelectorAll<HTMLElement>("[data-export-slot]")];
+  const slots = [...line.querySelectorAll<HTMLElement>(":scope > [data-export-slot]")];
   const items: PngItem[] = [];
   const images: Array<HTMLImageElement | null> = [];
   for (const slot of slots) {
@@ -41,9 +41,24 @@ export async function renderLinePng(exportRoot: HTMLElement, title: string): Pro
     const svg = slot.querySelector("svg");
     images.push(svg ? await loadSvg(svg) : null);
   }
-  if (items.length === 0) throw new Error("Add a note, rest, or space before saving a PNG.");
+  if (items.length === 0) return null;
+  return { items, images };
+}
 
-  const layout = pngLayout(items, title);
+export async function renderLinePng(exportRoot: HTMLElement, title: string): Promise<Blob> {
+  const lineNodes = [...exportRoot.querySelectorAll<HTMLElement>("[data-export-line]")];
+  const sources = lineNodes.length > 0 ? lineNodes : [exportRoot];
+  const rows: Array<{ items: PngItem[]; images: Array<HTMLImageElement | null> }> = [];
+  for (const line of sources) {
+    const row = await readRow(line);
+    if (row) rows.push(row);
+  }
+  if (rows.length === 0) throw new Error("Add a note, rest, or space before saving a PNG.");
+
+  const layout = pngStackLayout(
+    rows.map((row) => row.items),
+    title,
+  );
   const scale = 2;
   const canvas = document.createElement("canvas");
   canvas.width = Math.ceil(layout.width * scale);
@@ -60,26 +75,30 @@ export async function renderLinePng(exportRoot: HTMLElement, title: string): Pro
   ctx.font = "600 22px Georgia, serif";
   ctx.fillText(title, layout.pad, layout.pad + 40);
 
-  const glyphTop = layout.pad + 56;
+  let glyphTop = layout.pad + 56;
-  let x = layout.pad;
+  rows.forEach((row, rowIndex) => {
-  items.forEach((item, index) => {
+    const laid = layout.rows[rowIndex];
-    const slotWidth = layout.slots[index]?.width ?? item.glyphWidth;
+    let x = layout.pad;
-    if (item.kind === "space") {
+    row.items.forEach((item, index) => {
-      ctx.save();
+      const slotWidth = laid?.slots[index]?.width ?? item.glyphWidth;
-      ctx.strokeStyle = SPACE_STROKE;
+      if (item.kind === "space") {
-      ctx.setLineDash([4, 4]);
+        ctx.save();
-      ctx.strokeRect(x + 6, glyphTop + 8, Math.max(8, item.glyphWidth - 12), layout.glyphHeight - 16);
+        ctx.strokeStyle = SPACE_STROKE;
-      ctx.restore();
+        ctx.setLineDash([4, 4]);
-    } else if (images[index]) {
+        ctx.strokeRect(x + 6, glyphTop + 8, Math.max(8, item.glyphWidth - 12), laid.glyphHeight - 16);
-      ctx.drawImage(images[index], x, glyphTop, item.glyphWidth, item.glyphHeight);
+        ctx.restore();
-    }
+      } else if (row.images[index]) {
-    const center = x + item.glyphWidth / 2;
+        ctx.drawImage(row.images[index], x, glyphTop, item.glyphWidth, item.glyphHeight);
-    ctx.textAlign = "center";
+      }
-    ctx.fillStyle = INK;
+      const center = x + item.glyphWidth / 2;
-    ctx.font = "600 13px sans-serif";
+      ctx.textAlign = "center";
-    ctx.fillText(item.caption, center, glyphTop + layout.glyphHeight + 18);
+      ctx.fillStyle = INK;
-    ctx.textAlign = "start";
+      ctx.font = "600 13px sans-serif";
-    x += slotWidth + layout.gap;
+      ctx.fillText(item.caption, center, glyphTop + laid.glyphHeight + 18);
+      ctx.textAlign = "start";
+      x += slotWidth + laid.gap;
+    });
+    glyphTop += laid.glyphHeight + 28 + layout.rowGap;
   });
 
   const blob = await new Promise<Blob | null>((resolve) => canvas.toBlob(resolve, "image/png"));

src/lib/line.ts

@@ -86,6 +86,52 @@ export function cloneLine(notes: LineNote[]): LineNote[] {
   return notes.map((note) => ({ ...note, id: newId("n") }));
 }
 
+export type ScoreLine = {
+  id: string;
+  notes: LineNote[];
+};
+
+export function appendLine(lines: ScoreLine[], id = newId("line")): ScoreLine[] {
+  return [...lines, { id, notes: [] }];
+}
+
+/** Leave the last line in place. An empty score still has one row. */
+export function removeLine(lines: ScoreLine[], id: string): ScoreLine[] {
+  if (lines.length <= 1) return lines;
+  const next = lines.filter((line) => line.id !== id);
+  return next.length > 0 ? next : lines;
+}
+
+function mapLine(lines: ScoreLine[], id: string, update: (notes: LineNote[]) => LineNote[]): ScoreLine[] {
+  return lines.map((line) => (line.id === id ? { ...line, notes: update(line.notes) } : line));
+}
+
+export function placeOnLine(lines: ScoreLine[], lineId: string, index: number, note: LineNote): ScoreLine[] {
+  return mapLine(lines, lineId, (notes) => insertNote(notes, index, note));
+}
+
+/**
+ * Move a note onto a line. When it stays on the same line, `toIndex` counts the moving note.
+ * When it changes lines, `toIndex` is the slot in the destination.
+ */
+export function transferNote(
+  lines: ScoreLine[],
+  fromLineId: string,
+  noteId: string,
+  toLineId: string,
+  toIndex: number,
+): ScoreLine[] {
+  const source = lines.find((line) => line.id === fromLineId);
+  const note = source?.notes.find((item) => item.id === noteId);
+  if (!source || !note) return lines;
+  if (fromLineId === toLineId) return mapLine(lines, fromLineId, (notes) => moveNote(notes, noteId, toIndex));
+  return lines.map((line) => {
+    if (line.id === fromLineId) return { ...line, notes: removeNote(line.notes, noteId) };
+    if (line.id === toLineId) return { ...line, notes: insertNote(line.notes, toIndex, note) };
+    return line;
+  });
+}
+
 /** -1 when the pointer is outside the line. Otherwise the insertion slot from left to right. */
 export function dropIndexFromPoint(
   pointerX: number,

src/lib/notation.ts

@@ -8,13 +8,15 @@ const RECORDER_VB_H = 188;
 export const STAFF_SPACE = 4.6;
 const STEP = STAFF_SPACE / 2;
 
-const TOP_INDEX = 20;
+/** Highest written note is sounding D7, drawn as D6. */
-const LOW_STEM_STEPS = 7;
+const TOP_INDEX = 13;
-const PAD_TOP = 4;
+/** Lowest written note is sounding C5, drawn as C4 on the ledger line below. */
-const PAD_BOTTOM = 8;
+const LOW_INDEX = -2;
+const PAD_TOP = 6;
+const PAD_BOTTOM = 14;
 
 const ABOVE = TOP_INDEX * STEP;
-const BELOW = LOW_STEM_STEPS * STEP - 5 * STEP + PAD_BOTTOM;
+const BELOW = -LOW_INDEX * STEP + PAD_BOTTOM;
 
 export const BOTTOM_LINE_Y = RECORDER_VB_H + 3 + PAD_TOP + ABOVE;
 export const CHART_VB_H = Math.ceil(BOTTOM_LINE_Y + BELOW);
@@ -31,7 +33,10 @@ const LETTERS = ["C", "D", "E", "F", "G", "A", "B"] as const;
 
 export type Accidental = "sharp" | "flat";
 
-/** Treble staff. Index 0 is the bottom line, E4. C5, the recorder's low C, is 5. */
+/**
+ * Treble staff, written one octave below sounding pitch.
+ * Index 0 is the bottom line, E4. Sounding C5 is written C4, index -2.
+ */
 export function staffPlacement(pitch: string): { index: number; accidental: Accidental | null } | null {
   const match = /^([A-Ga-g])(#|b|♯|♭)?(-?\d+)$/.exec(pitch.trim());
   if (!match) return null;
@@ -41,7 +46,7 @@ export function staffPlacement(pitch: string): { index: number; accidental: Acci
     mark === "#" || mark === "♯" ? "sharp" : mark === "b" || mark === "♭" ? "flat" : null;
   const octave = Number(match[3]);
   if (!Number.isInteger(octave)) return null;
-  const diatonic = (octave - 4) * 7 + LETTERS.indexOf(letter as (typeof LETTERS)[number]);
+  const diatonic = (octave - 1 - 4) * 7 + LETTERS.indexOf(letter as (typeof LETTERS)[number]);
   return { index: diatonic - 2, accidental };
 }
 

src/lib/png-layout.ts

@@ -35,6 +35,17 @@ export function pngSlotWidth(item: PngItem): number {
   return Math.max(item.glyphWidth, text, 48);
 }
 
+export const PNG_ROW_GAP = 36;
+
+/** One header, then every fingering line stacked underneath. */
+export function pngStackLayout(rows: PngItem[][], title: string) {
+  const laid = rows.map((items) => pngLayout(items, title));
+  const width = Math.max(1, ...laid.map((row) => row.width));
+  const blocks = laid.reduce((sum, row) => sum + row.glyphHeight + 28, 0);
+  const height = PAD + 44 + blocks + PNG_ROW_GAP * Math.max(0, laid.length - 1) + PAD;
+  return { width, height, rows: laid, pad: PAD, rowGap: PNG_ROW_GAP };
+}
+
 export function pngLayout(items: PngItem[], title: string) {
   const slots = items.map((item) => ({ item, width: pngSlotWidth(item) }));
   const content =

tests/converter.test.ts

@@ -10,10 +10,13 @@ import {
   dropIndexFromPoint,
   insertNote,
   LINE_EXAMPLES,
+  appendLine,
   moveNote,
   neighborDuration,
+  removeLine,
   removeNote,
   setDuration,
+  transferNote,
 } from "@/lib/line";
 import {
   ledgerIndexes,
@@ -23,7 +26,7 @@ import {
   stemDown,
 } from "@/lib/notation";
 import { parsePitch } from "@/lib/pitch";
-import { pngFilename, pngItemFromNote, pngLayout } from "@/lib/png-layout";
+import { pngFilename, pngItemFromNote, pngLayout, pngStackLayout } from "@/lib/png-layout";
 import { extraBeatArrows } from "@/lib/score";
 
 const BAROQUE: Record<string, string> = {
@@ -167,6 +170,29 @@ describe("fingering line", () => {
     expect(pngFilename("   ")).toBe("line.png");
   });
 
+  it("appends a line and can move a note onto it", () => {
+    const top = { id: "a", notes: [createNote("C5", quarter, "c"), createNote("E5", quarter, "e")] };
+    const next = appendLine([top], "b");
+    expect(next.map((line) => line.id)).toEqual(["a", "b"]);
+    expect(next[1].notes).toEqual([]);
+    expect(next[0].notes.map((note) => note.pitch)).toEqual(["C5", "E5"]);
+    const moved = transferNote(next, "a", "e", "b", 0);
+    expect(moved[0].notes.map((note) => note.pitch)).toEqual(["C5"]);
+    expect(moved[1].notes.map((note) => note.pitch)).toEqual(["E5"]);
+    expect(removeLine(moved, "b").map((line) => line.id)).toEqual(["a"]);
+    expect(removeLine([{ id: "a", notes: [] }], "a")).toHaveLength(1);
+  });
+
+  it("stacks every fingering line in the PNG", () => {
+    const top = [pngItemFromNote(createNote("C5", quarter, "c"))];
+    const bottom = [pngItemFromNote(createNote("G5", quarter, "g"))];
+    const one = pngStackLayout([top], "Your line");
+    const two = pngStackLayout([top, bottom], "Your line");
+    expect(two.rows).toHaveLength(2);
+    expect(two.height).toBeGreaterThan(one.height);
+    expect(pngLayout(top, "Your line").glyphHeight).toBe(one.rows[0].glyphHeight);
+  });
+
   it("steps duration without skipping a preset", () => {
     expect(neighborDuration(1, 1)?.quarters).toBe(1.5);
     expect(neighborDuration(1, -1)?.quarters).toBe(0.75);
@@ -176,17 +202,18 @@ describe("fingering line", () => {
 });
 
 describe("treble staff", () => {
-  it("puts low C in the third space and high D on a ledger line", () => {
+  it("writes each sounding pitch one octave lower", () => {
-    expect(staffPlacement("C5")).toEqual({ index: 5, accidental: null });
+    expect(staffPlacement("C5")).toEqual({ index: -2, accidental: null });
-    expect(staffPlacement("C#5")).toEqual({ index: 5, accidental: "sharp" });
+    expect(staffPlacement("C#5")).toEqual({ index: -2, accidental: "sharp" });
-    expect(staffPlacement("Eb5")).toEqual({ index: 7, accidental: "flat" });
+    expect(staffPlacement("Eb5")).toEqual({ index: 0, accidental: "flat" });
-    expect(staffPlacement("G5")).toEqual({ index: 9, accidental: null });
+    expect(staffPlacement("C6")).toEqual({ index: 5, accidental: null });
-    expect(staffPlacement("A5")).toEqual({ index: 10, accidental: null });
+    expect(staffPlacement("C7")).toEqual({ index: 12, accidental: null });
-    expect(staffPlacement("D7")).toEqual({ index: 20, accidental: null });
+    expect(staffPlacement("D7")).toEqual({ index: 13, accidental: null });
+    expect(ledgerIndexes(-2)).toEqual([-2]);
     expect(ledgerIndexes(5)).toEqual([]);
-    expect(ledgerIndexes(9)).toEqual([]);
+    expect(ledgerIndexes(12)).toEqual([10, 12]);
-    expect(ledgerIndexes(10)).toEqual([10]);
+    expect(ledgerIndexes(13)).toEqual([10, 12]);
-    expect(ledgerIndexes(20)).toEqual([10, 12, 14, 16, 18, 20]);
+    expect(stemDown(-2)).toBe(false);
     expect(stemDown(5)).toBe(true);
   });