Reading Zoom

An Obsidian plugin that adds pinch-to-zoom to notes on touchscreens (Windows, iPad, Android), in reading view and in editing view. It also supports trackpad pinch and Ctrl+scroll.

Features

• Pinch to zoom around your fingers. Moving both fingers pans.
• Reading view has two modes:
  • Reflow (default): text and images grow and rewrap to the pane width, like browser zoom.
  • Magnify: the page grows wider with the zoom and you pan sideways, like a PDF.
• Editing view (Live Preview and Source mode): text and images grow and rewrap. Can be turned off.
• Two-finger tap resets to 100 %.
• Commands: Zoom in, Zoom out, Reset zoom (bind them to hotkeys).
• Per pane: each pane keeps its own zoom, optionally reset when another note opens.
• Shows the zoom percentage while zooming.

Installation

Manual

1. Download main.js, manifest.json and styles.css from the latest release, or build them (see below).
2. Copy them into <vault>/.obsidian/plugins/reading-zoom/.
3. In Obsidian, open Settings → Community plugins, reload the list, and enable Reading Zoom.

From source

npm install
npm run build
npm run install-plugin -- "/path/to/Vault"

npm run dev rebuilds on every change.

Releasing

1. Set the same new version in manifest.json and package.json.
2. Commit, then push a tag that matches the version exactly (no v prefix):

   git tag 1.2.3 && git push origin 1.2.3
   

3. The release workflow builds the plugin, attests main.js, manifest.json and styles.css (build provenance), and creates a draft release. Review it on GitHub and publish it.

How it works

• Text is scaled through Obsidian's --font-preferred-size variable, and the readable line width through --file-line-width.
• Images and videos get a per-element CSS zoom. The plugin never applies CSS zoom to a container, because Obsidian and CodeMirror measure content inside it in unzoomed units, which breaks their lazy rendering.
• Reading view lazy rendering: Obsidian renders only the sections near the viewport and positions them from cached heights. It re-measures them only when the pane width changes. While a note is zoomed, the plugin keeps the whole note attached so scrolling is plain document flow. After each gesture it has Obsidian re-measure the note. Notes longer than 1,500 sections keep lazy rendering, with a wider margin instead.
• Editing view anchors the zoom on a document position and lets CodeMirror scroll it back into place.
• Touch listeners sit on the document in the capture phase, so two-finger gestures don't reach Obsidian's own swipe handlers. Canvas is left alone.

Some of this relies on undocumented Obsidian internals (the reading view renderer). Every such access is guarded: if a future Obsidian version changes it, zoom still works, but you may see sections pop in while scrolling a zoomed note.

License

MIT