PDF Viewer & Editor

About

View and edit PDFs like in Acrobat or Preview. This extension also allows annotating in LaTeX maths and supports Copilot integration for explanations/summaries. Super useful for analyzing research papers or working with documents in general.

Tip

See example.pdf for a guided tour. Any saved edits open in Acrobat, Preview and browsers

Features

🖍️ Annotate	Highlight, underline, comment, reply and resolve
✍️ Rich text	Bold, italic, code and $\LaTeX$ in comments and text boxes
🎨 Draw	Pen, shapes, arrows, images, and text boxes in six fonts
🖊️ Fill & sign	Forms, signatures and ✓ ✗ marks
✨ Copilot	Explain or summarize a passage with Copilot; @pdf in Copilot Chat
📄 Pages	Rotate, reorder, insert, print; undo everything

Note

The PDF's own text and images cannot be edited

Examples

Comments beside the page	Tool customization dropdown

Shortcuts

Key	Action
Ctrl/Cmd+S · Ctrl/Cmd+P	Save · print
Ctrl/Cmd+Z · Ctrl/Cmd+Shift+Z	Undo · redo (in a text field: the typing)
Del · Esc	Delete the selection · close, cancel or deselect
S · H	Select · Hand (pan)
Ctrl/Cmd+B · I · U	Bold · italic · underline while writing
Ctrl/Cmd+Enter	Post a comment or reply

Settings

Setting	Default	Description
pdf-editor.authorName	OS user name	Author of new comments and annotations
pdf-editor.presetColors	5 colors	Name=#RRGGBB presets shared by every tool
pdf-editor.defaultZoomValue	auto	Zoom when opening a PDF
pdf-editor.sidebarViewOnLoad	0	Side panel when opening a PDF
pdf-editor.printCommand	default PDF app	Command that prints the file path given to it, e.g. lpr
pdf-editor.copilot.model	a Copilot model	Model for Ask Copilot, as picked with PDF: Choose Copilot Model...

Tip

Ask Copilot and @pdf call VS Code's language models - GitHub Copilot's (Claude, GPT, Gemini, etc)

Development Notes

Install the latest version of Node.js LTS and the dependent packages (note all packages install locally into node_modules/ so no virtual environment is needed):

make setup

Windows: install Node.js LTS from nodejs.org manually, then use make install (requires Git Bash or WSL).

npm run test                          # run tests + generate coverage report
npm run package                       # compile → out/ and build .vsix (what gets published)
npx semantic-release --dry-run        # preview next release version and notes

Tip

You can run make clean to clean up compiled/generated files.

Open extension.ts and press F5 (fn + F5 if on Mac) to launch VS Code Extension Development Window with the extension loaded.

How it works?

Concern	Owner
Pages, text selection, links, forms, find, thumbnails	pdf.js, the unmodified release (resources/pdf.js)
Reading and writing annotations	the extension host, with pdf-lib (src/pdf/)
Drawing and editing annotations	the viewer layer (resources/viewer/)
Undo/redo, dirty state, save, hot exit	VS Code's custom-editor edit stack (src/editor/)
Ask Copilot, @pdf	VS Code's Language Model and Chat APIs (src/copilot/)

The host reads the annotations it manages into a JSON model and gives pdf.js the file without them, so nothing is drawn twice; one codec per kind (src/pdf/kinds.ts) writes standard PDF keys and appearance streams, so every reader shows the same thing. Saving merges the model back and leaves untouched annotations byte-identical. All saved types are standard PDF annotations, from Highlight to FreeText (maths drawn as vector outlines) to image Stamps.

src/              # extension host: commands, host <-> viewer messages
  editor/         # custom editor, save, undo
  pdf/            # annotation codecs, read, write
  copilot/        # @pdf chat participant
resources/viewer/ # the webview UI
scripts/          # downloads, example.pdf, media
test/             # unit and e2e tests

License

This extension is under MIT license. Note that pdf.js (Apache-2.0) and MathJax (Apache-2.0) are bundled unmodified, as are the Roboto, Lora and Comic Neue fonts (SIL Open Font License; each license is in resources/fonts).