CalBlend

Merges overlapping Google Calendar events from multiple calendars into a single event with a gradient background. No more unreadable stacked events.

Features

• Event merging — overlapping events become one block with a gradient showing all calendar colors
• Busy event support — "busy" events from shared calendars are merged by position
• Weekend highlighting — customizable colors for weekends in both the main and mini calendar
• Dark mode — adapts borders and weekend colors automatically
• 21 languages — Arabic, Chinese, English, French, German, Hindi, Italian, Japanese, Korean, Dutch, Polish, Portuguese, Romanian, Russian, Spanish, Thai, Turkish, Ukrainian, Vietnamese
• Zero data collection — everything runs locally, no external requests

Install

Desktop App

macOS (Homebrew):

brew install avelino/calblend/calblend@beta

Windows (Scoop):

scoop bucket add calblend https://github.com/avelino/scoop-calblend
scoop install calblend-beta

Windows (Winget):

winget install avelino.CalBlend.Beta

Windows (Chocolatey):

choco install calblend-beta

Linux (AUR):

yay -S calblend-beta-bin

Linux (Snap):

snap install calblend --edge

Linux (Flatpak):

flatpak install run.avelino.calblend

Linux (DEB/RPM) and direct download for all platforms: GitHub Releases

Browser Extension

• Chrome Web Store (coming soon)
• Firefox Add-ons (coming soon)

Development

Requirements: Node.js 22+, pnpm

pnpm install
pnpm dev            # Chrome with hot reload
pnpm dev:firefox    # Firefox with hot reload

Commands

Command	What it does
pnpm dev	Start dev server (Chrome)
pnpm dev:firefox	Start dev server (Firefox)
pnpm build	Production build (Chrome)
pnpm build:firefox	Production build (Firefox)
pnpm zip	Build + zip for Chrome Web Store
pnpm zip:firefox	Build + zip for Firefox Add-ons
pnpm test	Run tests
pnpm test:watch	Run tests in watch mode
pnpm typecheck	TypeScript type check

Contributing

1. Fork the repo
2. Create a branch (git checkout -b my-feature)
3. Make your changes
4. Run pnpm typecheck && pnpm test — both must pass
5. Open a PR

Guidelines

• Tests required — if you change behavior, add or update tests
• TypeScript strict — no any, no ts-ignore
• Keep it simple — this is a small extension, avoid over-engineering
• One concern per module — detection, grouping, merging, and rendering are separate for a reason

Reporting bugs

Open an issue with:

• Browser and version
• What you expected vs what happened
• A screenshot if possible

Architecture

MutationObserver (debounced, filtered to calendar nodes)
  -> restoreAll()           # clean DOM before re-reading
  -> findEvents(container)  # detect events, extract metadata
  -> groupEvents(events)    # group by title, regroup busy by position
  -> applyMerge(groups)     # gradient on kept event, hide duplicates
  -> colorWeekends()        # optional weekend highlighting

The observer disconnects before applying DOM changes and reconnects after, preventing infinite loops. A restoreAll() call before each cycle ensures we always read clean DOM state.

Credits

Originally forked from @limonkufu.

License

MIT