Easy PDF Highlight

Select text in a PDF, click a color. That's the whole workflow.

• The passage is listed in a note next to the PDF, grouped by color and sorted by page.
• The passage is shown highlighted on the PDF.
• The two are linked both ways: the note entry opens the PDF at the exact passage; clicking a highlight in the PDF opens its entry in the note.
• The PDF file is never modified. The note is the record; the colors are drawn from it.

Use

1. Open a PDF and select some text. A small palette appears at the end of the selection.
2. Click a color. Done — the highlight is drawn, and an entry is added to <pdf name>_highlights.md in the same folder (created the first time).
3. Click a highlight in the PDF for a menu: open its entry in the note, change its color, delete it.

Deleting an entry's line in the note removes the highlight from the PDF. Indented lines you write under an entry are your notes on it; they stay attached when the note is re-sorted.

Each color is also a command (Highlight selection: Yellow, …), so you can bind hotkeys.

What an entry looks like

## Yellow
- "Highlights are most useful when they can be found" [[article.pdf#page=1&selection=2,0,2,50|p.1]] (page:: 1) (type:: yellow) %%hl:0.117,0.359,0.61,0.021%% ^h1-k3jf
    my own note about this passage

• The link is a standard PDF link: it opens the PDF at that page and flashes the passage, even with this plugin disabled.
• (page:: …) and (type:: …) are Dataview inline fields, so highlights can be queried across the vault (FLATTEN file.lists AS L WHERE L.type = "yellow"). Dataview is not required.
• %%hl:…%% is where the highlight sits on the page (one rectangle per text line, as fractions of the page). It is a comment, hidden in reading view. Don't edit it by hand.
• ^h1-k3jf is a block id: cite one exact highlight from any note with ![[article_highlights#^h1-k3jf]].

Settings

Each color has a fixed type id (shown under its label) which is what entries store, so renaming a label never disconnects existing highlights — the headings in the note simply follow on the next change. Removing a color keeps its highlights: they are drawn in grey and grouped last.

Install

Until it is in the community directory:

• BRAT: add maxdokukin/easy-pdf-highlight as a beta plugin.
• Manual: download main.js, manifest.json and styles.css from the latest release into <vault>/.obsidian/plugins/easy-pdf-highlight/, then enable it under Settings → Community plugins.

Good to know

• Highlights are visible inside Obsidian only. Nothing is written into the PDF, so other PDF readers show a clean file. In exchange the PDF stays byte-identical to its source and can't be corrupted.
• Highlights are positioned by page number and location on the page. Replacing a PDF with a different edition of the document will misplace them.
• A selection that runs past the end of a page is clamped to that page.
• Desktop only for now: the palette is opened by a mouse selection.
• It relies on the PDF viewer's page and text-layer elements (.page, .textLayer). Positions come from the browser's own selection geometry rather than PDF.js internals, which has kept it stable, but a large change to the built-in viewer could require an update.

Development

Plain JavaScript, no build step: main.js is the source and the release artifact.

• npm test — unit tests for parsing, grouping/sorting, word snapping, settings logic.
• test/e2e/ — end-to-end test that drives a real, isolated Obsidian instance with real mouse input over the DevTools protocol. See test/e2e/README.md.
• Release: bump version in manifest.json and package.json, add it to versions.json, push a tag equal to the version (no v prefix). The workflow tests and publishes the three files.
• Listing in the in-app plugin browser: ./register.sh checks everything the directory's automated review looks at and opens the submission page. See SUBMISSION.md.

License

MIT