Glance

All-in-one Quick Look plugin

Glance provides Quick Look previews for files that macOS doesn't support out of the box.

Installation Steps

About

This is a fork of the original Glance plugin. Unfortunately, the owner seems to have discarded the project a while ago, and the app is largely broken on newer macOS systems. The aim of this fork is to revive the project and maintain it for future updates. For now, we have added support for macOS Big Sur and fixed several internal bugs.

Installation

The installation for this plugin is slightly complex, as I am currently unable to register for an Apple Developer account for age reasons. Until then, you will need to code sign the application yourself. The steps are as follows:

  1. Download the .dmg file from GitHub releases page.

  2. Open the file and move Glance.app to the Applications folder (do NOT open it yet).

  3. Install Xcode Command Line Tools with xcode-select --install if you have not previously installed it.

  4. Open a terminal and run the following commands.

    xattr -cr /Applications/Glance.app
echo '<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"><plist version="1.0"><dict><key>com.apple.security.app-sandbox</key><true/><key>com.apple.security.application-groups</key><array><string>group.com.chamburr.glance</string></array><key>com.apple.security.files.user-selected.read-only</key><true/></dict></plist>' > /tmp/Glance.entitlements
codesign -s - -f --deep --entitlements /tmp/Glance.entitlements /Applications/Glance.app
rm /tmp/Glance.entitlements

  5. Launch Glance. Done!

Note: If anyone knows of a better workaround or can supply me with a Developer ID, please let me know. Thanks!

Supported file types

  • Source code (with Chroma syntax highlighting): .cpp, .js, .json, .py, .swift, .yml and many more

  • Markdown (rendered using goldmark): .md, .markdown, .mdown, .mkdn, .mkd, .Rmd

  • Archive: .tar, .tar.gz, .zip

  • Jupyter Notebook (rendered using nbtohtml): .ipynb

  • Tab-separated values (parsed using SwiftCSV): .tab, .tsv

FAQ

There are existing Quick Look apps for some of the supported file types. Why create another one?

  • Glance combines the features of many plugins into one and provides consistent and beautiful previews.
  • Glance is fully compatible with Dark Mode.
  • Some plugins still use the deprecated Quick Look Generator API and might stop working in the future.
  • Glance can easily be extended to support other file types.

Why isn't the app available on macOS 10.14 or older?

The app uses the new Quick Look API that was introduced in 10.15, so it unfortunately won't work with older versions of macOS.

Why are images in my Markdown files not loading?

Glance blocks remote assets. Furthermore, the app only has access to the file that's being previewed. Local image files referenced from Markdown are therefore not loaded.

Why isn't [file type] supported?

Feel free to open an issue or contribute! When opening an issue, please describe what kind of preview you'd expect for your file.

Please note that macOS doesn't allow the handling of some file types (e.g. .plist, .ts and .xml).

You claim to support [file type], but previews aren't showing up.

Please note that Glance skips previews for large files to avoid slowing down your Mac.

It's possible that your file's extension or UTI isn't associated with Glance. You can easily verify this:

  1. Check whether the file extension is matched to the correct class in PreviewVCFactory.swift.
  2. Find your file's UTI by running mdls -name kMDItemContentType /path/to/your/file. Check whether the UTI is listed under QLSupportedContentTypes in Info.plist.
  3. If an association is missing, please feel free to add it and submit a PR.

Contributing

Suggestions and contributions are always welcome! Please discuss larger changes (e.g. adding support for a new file type) via issue before submitting a pull request.

Xcode, Swift and Go need to be installed to build the app locally.

To add previews for a new file extension, please follow these steps:

  1. Create a new class for your file type in this directory. It should implement the Preview protocol. See the other files in the directory for examples.
  2. Match the file extension to your class in PreviewVCFactory.swift.
  3. Find your file's UTI by running mdls -name kMDItemContentType /path/to/your/file. Add it to QLSupportedContentTypes in Info.plist.
  4. Update README.md, SupportedFilesWC.xib, the App Store description and Credits.rtf (if you introduced a new library).

License

This project is licensed under MIT License.

GitHub

https://github.com/chamburr/glance