Fix PDF text misplacement/loss caused by mid-paragraph page breaks

[Copilot]

Long markdown documents (e.g. demos.md) converted to PDFs with content missing or drawn in the wrong position — text would visually derail as soon as a paragraph wrapped across a page boundary, even though the same document previewed correctly in-app.

Root cause

• drawRuns word-wraps text using a local cursor y1, calling ensureSpace(lineHeight) to trigger a page break when needed.
• ensureSpace correctly reset the module-level y to margin on a new page, but y1 — the coordinate actually passed to doc.text(...) — was never updated, so subsequent words kept drawing at the stale, now off-page y1.

Fix

• Replaced the boolean-returning ensureSpace(h) check inside the wrapping loop with ensureSpaceAt(yPos, h), which returns the correct y-coordinate to draw at (margin after a page break, unchanged otherwise) while still keeping the outer y in sync.
• drawRuns now does y1 = ensureSpaceAt(y1, lineHeight) before each doc.text(...) call, so the wrapping cursor and page-break state can never diverge.

// before
if (ensureSpace(lineHeight)) { y1 = y; }
doc.text(w, x, y1);

// after
y1 = ensureSpaceAt(y1, lineHeight);
doc.text(w, x, y1);

No changes to parsing, block layout, or other renderers — this only corrects cursor tracking during inline word-wrapping across page boundaries.

• Fixes PDF is incorrectly formatted #3

[Copilot]

Pull request overview

Fixes a jsPDF rendering bug where inline word-wrapping across a page boundary could cause text to be drawn at a stale Y coordinate, leading to missing/mispositioned content in long Markdown-to-PDF conversions.

Changes:

• Updated ensureSpace to return a boolean when it performs a page break.
• Added ensureSpaceAt(yPos, h) to page-break based on an explicit in-progress Y position used during wrapping.
• Updated drawRuns to keep its wrapping cursor (y1) aligned with page breaks and to sync the outer y cursor after rendering.

Suppressed comments (1)

index.html:757

• drawRuns now mutates the outer y as a side effect (y = y1 + lineHeight) even though every call site already assigns y = drawRuns(...). Keeping drawRuns side-effect free makes it easier to reason about cursor state and reduces the risk of future ordering bugs.

      y = y1 + lineHeight;
      return y;

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.