2026-03-15 Session Log

lingua-rag

PDF cross-page drag highlights, note page accuracy, pin annotation removal, TTS word-highlight sync investigation

What I Did

• Fixed cross-page drag highlight not rendering — When scrolled so page 2 is partially visible and you drag-select text there, the blue selection overlay didn’t appear. Root cause: the render condition checked n === pageNumber (the active page from scroll position), so highlights only drew on the current page. Added a selectionPage state that tracks which page the selection actually occurred on, and passed the correct page number to ensureTextContent(forPage?) so it loads the right page’s text data for rect computation.

• Fixed notes/vocab saving with wrong page number — When selecting text on a non-active page (e.g., page 2 while viewing page 1), notes and vocabulary were saved with the wrong page. Added a page field to the SelectionPopup interface so the popup carries the actual selected page. Updated note panel, vocab panel, and highlight-index calculation to use popup.page instead of the scroll-based pageNumber.

• Prevented popup from appearing on empty area drag — Dragging in blank space (no text) still triggered the selection popup. This happened because caretRangeFromPoint always returns the nearest text node even when clicking empty areas. Added an e.target !== textLayer guard — if the click target is the text layer container itself (not a child <span>), it’s treated as empty space and the drag is ignored.

• Removed pin/sticky annotation system (~280 lines) — The old pin-based annotation system (📌 icons on PDF pages with sticky-note-style editing popovers) was fully superseded by the highlight notes system. Pins were being created at x_pct: 0, y_pct: 0, causing stray 📌 icons in the top-left corner. Removed: STICKY_COLORS constant, 6 state variables (isStickyMode, pendingSticky, editingSticky, stickyText, stickyColor, draggingPin), 2 refs (pinDragRef, pinWasDraggedRef), the pin-drag useEffect, sticky mode click handler on page containers, and all pin/sticky rendering JSX. Kept the annotation API functions since the highlight note system still uses them.

• Reverted compound word merging for pronunciation — Implemented adjacent-word merging to handle STT splitting compound words like “ChatGPT” → “chat” + “gpt”. The approach was to concatenate 1-2 adjacent unmatched STT words and compare against the expected word. Reverted per user request — needs further design consideration.

• Diagnosed TTS word-highlight sync issue with numbers — When TTS reads “Microsoft 365”, the highlight chip jumps past “365” too quickly. Root cause: the timer-based highlighting estimates duration by character count (w.length). “365” gets weight 3 (3 chars), but TTS pronounces it as “three hundred sixty-five” (~1-1.5 seconds). The 210ms allocation (3 × 70ms) is far too short. Investigated SpeechSynthesisUtterance.onboundary as a solution — it provides exact word timing from the speech engine. However, Chrome’s Google network voices (localService: false) don’t fire boundary events because audio is streamed from Google servers without word-level metadata. Local voices do support it.

Key Decisions

• Pin annotations removed entirely — Highlight-based notes replaced this feature completely. The pin system had a side effect where annotations created via the note panel got x_pct: 0, y_pct: 0, placing unwanted pins at the top-left corner.
• popup.page pattern — Embedding the page number in the popup state decouples selection context from scroll position. This is more reliable than relying on pageNumber which updates asynchronously based on scroll events.

Next

• Improve TTS word highlighting — prefer local voices + onboundary events, with timer-based fallback for network voices (hybrid approach)
• Resolve compound word STT splitting (e.g., “ChatGPT” → “chat” + “gpt”) — revisit adjacent word merging design
• Test full guest→login flow with 2+ PDFs
• Commit all session changes