Reader Margins

中文用户请阅读中文版：README_zh.md

Add page-margin annotation cards to Obsidian's built-in PDF reader: select text, highlight or underline it, and a draggable card with your note appears in the page margin, connected to the mark with a dashed line. Annotations are stored as Markdown notes in your vault (one managed note per PDF), so they sync, search, and reference like any other note.

• Desktop only (isDesktopOnly: true)
• Minimum Obsidian version: 1.12.0
• Current version: 0.1.2

Features

Annotating

• Highlight / underline selected text via the toolbar colors, commands, or right-click menu.
• Margin cards: every annotation gets a card in the left or right margin of its page, showing the quoted source text and your note.
• Connector: a dashed SVG thread links the card to the highlighted text; hovering a card highlights the connector.
• Multiple colors: configurable color set (default yellow/blue/green/red, up to 6), one color per annotation.

Cards

• Hover to select: hovering a card selects it (tinted background + colored border).
• Free drag: drag a card by its grip handle anywhere in the page neighborhood (margins or over the page); the position is persisted per annotation.
• Auto layout: undragged cards push down in reading order; dragged cards are pinned and others route around them.
• Double-click the grip resets to auto layout.
• Click the highlight in the text to flash and locate its card.

Card / popover display

• Card: persistent margin card (default).
• Popover: mark-only; hovering shows the same card near the text with a configurable grace period; click inside to pin, Esc or click outside to close.
• Auto-downgrade: cards that don't fit in a narrow margin fall back to popover automatically.
• Switch a single annotation between forms (card footer button), or convert all annotations in the current PDF from the toolbar.

Editing

• Click card content to edit; save with the button or Cmd/Ctrl+Enter, cancel with Esc.
• "Highlight and annotate" / "Underline and annotate" open the edit box immediately (configurable).
• Card footer (on hover): switch color, highlight/underline, card/popover, copy portable annotation, delete.

Persistence & sync

• Annotations are Markdown: each PDF has one managed note <PDF name>.annotations.md in <PDF folder>/Reader Margins/ by default (configurable; . = same folder as the PDF). The note's frontmatter (reader-margins / reader-margins-pdf) marks ownership; each annotation is one blockquote.
• Survives sessions and syncs with your vault: annotations are plain notes, visible to Obsidian search, graph, and sync; renaming a PDF updates links automatically.
• Optimistic concurrency: when two windows edit the same annotation, the later writer gets a conflict notice and your draft is preserved.
• Save status (saving/failed) is shown in the toolbar; deleting an annotation is undoable.

Annotation index

Open the index view from the toolbar or ribbon: search all annotations by PDF, quote, note, or source note; click to jump to the exact selection in the PDF.

Commands

• Highlight selected text (active color)
• Highlight and annotate selected text
• Underline selected text (active color)
• Underline and annotate selected text
• Save annotation edit box (default Mod+Enter)
• Open Reader Margins annotations

Installation

Install from the Obsidian community plugin directory: Settings → Community plugins → Browse → search for "Reader Margins", then click Install.

Alternatively, build from source:

git clone <repo-url>
cd obsidian-reader-margins
npm install
npm run build        # outputs main.js (+ manifest.json, styles.css)

Copy these files into your vault's plugin folder:

<vault>/.obsidian/plugins/reader-margins/
├── main.js
├── manifest.json
└── styles.css

Then enable it in Obsidian: Settings → Community plugins → disable Restricted mode → enable "Reader Margins".

Development

npm run verify       # all tests + build + diff checks (run before committing)
npm run dev          # esbuild watch
npm test             # run unit / host-contract tests (vitest)
npm run test:watch   # watch mode

Reload with Cmd/Ctrl+P → "Reload app without saving" after rebuilding.

Usage

1. Open a PDF in Obsidian.
2. Select text.
3. Annotate: pick a color and use the highlight/underline buttons in the PDF toolbar, the right-click menu, or the commands palette.
4. The annotation card appears in the margin (or as a popover, per settings); hover to drag, edit, recolor, or delete.
5. Open the index view from the toolbar to browse/search all annotations.

A dismissible hint pill appears when you first open a PDF without annotations.

Settings

Settings → Reader Margins:

• Language: auto (follows Obsidian) / 中文 / English.
• Annotation folder: per-PDF folder for annotation notes (default Reader Margins; . = same folder as the PDF; .. allowed, e.g. ../../test for a shared vault-level folder).
• Auto-open edit box: open the edit box immediately for "annotate" actions.
• Default display mode: card or popover for new annotations.
• Popover grace (ms): how long the popover stays after the pointer leaves the mark (default 180).
• Default color for selection actions.
• Annotation colors: add/rename/change colors (validated #RRGGBB, up to 6; default colors can't be deleted).
• Reset to defaults (with confirmation).

Design

Visual system: Atomic Minimalism — flat, shadowless, 1px borders, tonal layering, 4px/8px radii, Hanken Grotesk. Color is restrained; annotation colors are used for state and identity only, not decoration.

Architecture

Layered and testable: pure logic is isolated from Obsidian/PDF.js host access. Annotations persist in vault Markdown notes; data.json stores settings only (schema v2).

src/
├── main.ts                  # plugin entry: settings, commands, ribbon, rename handling
├── domain/                  # pure domain logic (no DOM/host dependencies)
├── markdown/                # Markdown storage (durable annotation authority)
├── store/                   # settings schema/store, persistence coordinator, repository
├── host/                    # defensive Obsidian/PDF.js private access (fails closed)
├── session/                 # per-view lifecycle: rendering, drag, popover, editing, context menu
├── render/                  # idempotent DOM projection: marks, cards, connectors, layout
├── toolbar/                 # PDF toolbar (colors, highlight/underline, index, convert, status)
├── view/                    # annotation index view
├── settings/                # settings tab
├── i18n/                    # en/zh strings
└── diagnostics/             # diagnostics for DevTools

Key design points:

• Annotations are Markdown: each annotation is a blockquote in a managed note; multi-window conflicts are detected via block uniqueness and revision numbers; deletes are undoable through tombstones.
• Pure logic is testable: domain, layout, rendering, and codecs are pure functions tested with vitest/jsdom; Obsidian private access is confined to host/.
• Stable coordinates: card positions are stored page-local and unscaled (page-css-v2), stable across zoom and scroll.
• Resolvable anchors: annotations store a text locator plus quote; reopening or reflow resolves them against the live text layer; unresolved annotations aren't drawn.
• Reconciled rendering: DOM updates are batched via requestAnimationFrame.

Tests live in src/tests/ (unit + host-contract).

Limitations

• Desktop only.
• Card drag is limited to the page neighborhood (no overlap into other pages; horizontal range spans margin and page).
• Neighbors don't re-layout live while dragging (layout runs on drop).
• Rotated PDFs (non-0°) aren't supported yet.
• Depends on the built-in PDF reader's internal DOM; major Obsidian updates may require adapting host/.
• Anchors are text-layer based (locator + quote); scanned/image-only PDFs without a text layer can't be precisely located.

License

MIT. Free to copy, modify, distribute, and use commercially; keep the copyright notice and this license notice.