PDF Ink

Draw and type directly on top of PDFs inside Obsidian.

What This Plugin Is For

PDF Ink is for people who want to stay inside Obsidian while reading PDFs.

Instead of bouncing between Obsidian and another PDF app, you can:

• draw freehand notes directly on the PDF page
• click anywhere to add text boxes
• drag text boxes with a handle
• change text size from the PDF toolbar
• switch quickly between red, white, and black
• keep Chinese text in 宋体 / SimSun and English text in Times New Roman
• export an annotated PDF copy
• reopen the PDF later and keep working from the same annotations

If your pain point is "I want to mark up a PDF in Obsidian itself, not in another app", this plugin is built for exactly that.

What It Does

• Adds an inline PDF toolbar to Obsidian's native PDF viewer
• Supports three tools:
  • Pen
  • Text
  • Erase
• Supports:
  • freehand drawing
  • text boxes
  • draggable text boxes
  • text size control
  • color control
  • red / white / black quick color presets
  • undo
  • clear current page
  • export annotated PDF
• Saves annotations per PDF file + page
• Keeps annotations persistent after reopening the vault

How It Works

PDF Ink adds a persistent overlay on top of Obsidian's built-in PDF viewer.

That means:

• you draw and type directly in Obsidian
• the original PDF file is not modified yet
• annotations are currently stored as plugin data inside the vault

This is intentional for the current version because it keeps the workflow fast and native inside Obsidian.

Toolbar

When a PDF is open, PDF Ink adds these controls to the PDF toolbar:

• Ink: turn annotation mode on or off
• Pen: draw freehand strokes
• Text: click anywhere on the page to create a text box
• Erase: remove the nearest annotation
• Undo: remove the last annotation on the current page
• Clear: clear all annotations on the current page
• Export: generate an annotated PDF copy
• Color: used for new pen strokes and new text boxes
• Width: pen width
• Text Size: font size for text boxes

Text Defaults

Text boxes use this default font stack:

Times New Roman, SimSun, Songti SC, 宋体, serif

In practice this means:

• English text prefers Times New Roman
• Chinese text prefers 宋体 / SimSun

Installation

From Obsidian Community Plugins

After the community-plugin review is approved:

1. Open Settings -> Community plugins
2. Click Browse
3. Search for PDF Ink
4. Install and enable it

Manual Install

1. Download manifest.json, main.js, and styles.css from the latest GitHub release
2. Create a folder named pdf-ink under:
   • Windows: .obsidian/plugins/pdf-ink
   • macOS: .obsidian/plugins/pdf-ink
   • Linux: .obsidian/plugins/pdf-ink
3. Put the three files into that folder
4. Reload Obsidian
5. Enable PDF Ink in Settings -> Community plugins

Usage

1. Open a PDF in Obsidian
2. Click Ink
3. Choose a tool:
   • Pen to draw
   • Text to add editable text boxes
   • Erase to remove the nearest item
4. Use Undo or Clear when needed

Drag Text Boxes

1. Click Ink
2. Click Text
3. Use the small handle on the left side of a text box
4. Drag it to the place you want

Export

1. Open a PDF with annotations
2. Click Export
3. The plugin creates a new file next to the original PDF:
   • your-file.annotated.pdf

If that filename already exists, the plugin creates:

• your-file.annotated-2.pdf
• your-file.annotated-3.pdf

Add Text

1. Open a PDF
2. Click Ink
3. Click Text
4. Adjust Text Size if needed
5. Click anywhere on the PDF page
6. Start typing

Draw

1. Open a PDF
2. Click Ink
3. Click Pen
4. Adjust Color and Width
5. Draw directly on the page

Current Limitations

• Annotations are not embedded into the original PDF file yet
• Erase removes the nearest whole annotation object, not pixel-by-pixel fragments
• Export currently renders the PDF pages with annotations into a new annotated copy
• The first export may need network access once to load the PDF export library

Roadmap

• export annotations back into PDF
• text box moving and resizing
• highlight tool
• better mobile touch ergonomics
• more annotation controls

Compatibility

• Minimum Obsidian version: 1.5.0
• Works best with Obsidian's desktop PDF viewer

Why Another PDF Plugin?

There are already strong PDF plugins in the Obsidian ecosystem, but this plugin is focused on a specific use case:

direct pen + direct text boxes on top of the native PDF viewer

The goal is simple:

stay in Obsidian, open a PDF, and annotate immediately.

License

MIT

Author

lyx