Glance Free and Open Source Desktop App CookApps CookApps Marketplace

Overview

Glance is an all-in-one, open-source macOS Quick Look extension bringing instant Spacebar previews for developer file types unsupported out of the box. Powered by Swift, Chroma, and Goldmark, Glance renders syntax-highlighted source code across 100+ languages, richly formatted Markdown, Jupyter notebooks, CSV/TSV tables, and compressed archives directly in Finder.

How It Works

Glance operates through structured, deterministic execution stages:

Native Quick Look Extension Engine: Registers system-wide macOS Quick Look previews triggered instantly when pressing Spacebar on files in Finder.

Chroma Multi-Language Syntax Highlighting: Renders formatted code previews for over 100 programming, config, and markup languages with line numbers.

Goldmark Markdown & Jupyter Previews: Renders tables, code blocks, checklists, Jupyter .ipynb notebooks, and Tab-Separated files interactively.

Archive Content Browsing: Inspects directory trees and file sizes inside .zip, .tar, and .gz archives without extracting to disk.

Glance macOS Quick Look previewing formatted source code

Glance Quick Look syntax highlighting for code and config files

Key Technical Features & Capabilities

100+ Language Syntax Highlighting: Leverages the high-speed Chroma engine to render TypeScript, Rust, Python, Go, YAML, Swift, JSON, and Shell scripts with line numbers.

Goldmark CommonMark & GitHub Flavored Markdown: Previews README docs, tables, checklists, code blocks, and links cleanly in Finder without opening an editor.

Jupyter Notebooks & Archive Inspection: Previews rendered .ipynb cells, .tsv tabular data, and internal directory contents of .zip/.tar archives cleanly.

Modern Quick Look Architecture: Implemented as a native Apple App Extension compliant with modern macOS Sonoma and Sequoia sandboxes.

Architecture & Technology Stack

Primary Languages: Swift, Go (Embedded CGo Chroma/Goldmark rendering library)

Frameworks & APIs: Apple QuickLookUI, AppKit / SwiftUI, Chroma, Goldmark

Build System: Xcode (Glance.xcodeproj)

Supported Platforms: macOS 12+ (Universal Apple Silicon & Intel)

System Requirements

Specification	Minimum Requirement	Recommended Specification
Operating System	macOS 12.0+ (Universal Apple Silicon & Intel)	Latest stable release build
Processor Architecture	4-Core x86_64 or Apple Silicon M1	8-Core Apple Silicon / Core i7+
Memory (RAM)	4 GB Unified Memory	16 GB+ High-Speed RAM
Disk Space	1 GB free SSD storage	5 GB+ free SSD storage

Installation & Setup Guide

macOS Installation

bash

brew install --cask chamburr/tap/glance

Or download Glance-1.6.0.dmg from CookApps, drag Glance.app into /Applications, run xattr -rd com.apple.quarantine /Applications/Glance.app, and launch Glance once to register the Quick Look extension.

Building from Source

bash

git clone https://github.com/chamburr/glance.git
cd glance
open Glance.xcodeproj

How to Use & Workflow

Register Quick Look Extension: Launch Glance.app once after moving it to /Applications.

Verify Extension Status: Confirm GlanceExtension is toggled on in System Settings › Privacy & Security / Login Items & Extensions › Quick Look.

Preview Any File: Click any .rs, .py, .json, .md, or .ipynb file in Finder and press Spacebar.

Troubleshooting & Common Issues

Issue: Spacebar Quick Look still displays generic plain text or empty file icon.

*Cause*: macOS has quarantined the unnotarized extension or requires restarting Quick Look daemon caches.

*Resolution*: Run xattr -rd com.apple.quarantine /Applications/Glance.app, launch Glance once, then run qlmanage -r.

Glance

Overview

How It Works

Key Technical Features & Capabilities

Architecture & Technology Stack

System Requirements

Installation & Setup Guide

macOS Installation

Building from Source

How to Use & Workflow

Troubleshooting & Common Issues

How to Use & Getting Started

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