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Quick Start

This guide gets you from zero to your first repeatable visual check.

1) Install and run Watchlight

Download and install Watchlight from the website.

2) Create a project

In Watchlight, create a new project and save the project JSON file.

A project stores:

  • Project-level settings (executable path, capture defaults)
  • Scene definitions
  • Snapshot and analysis metadata

3) Configure project settings

Set these core values on project settings:

  • Executable: path to your app binary
  • Working directory: folder to run the process from
  • Command line arguments: default args shared by scenes
  • Capture type:
    • Delay (capture after N seconds)
    • StdOut pattern (capture when a regex-like pattern appears)

Tip: Keep project settings generic, then override scene-specific behavior only where needed.

4) Add your first scenes

Create scenes for distinct UI states, for example:

  • Main menu
  • Settings panel
  • Login dialog

For each scene, set only what differs from project defaults:

  • Scene-specific launch arguments
  • Scene-specific capture timing/pattern
  • Scene-specific visual diff threshold when needed

5) Capture and compare

Run snapshot capture for your scene(s), then run analysis.

Watchlight compares the latest snapshot against the baseline/reference and reports diff percentage.

  • If diff is below threshold: pass
  • If diff exceeds threshold: fail

6) Make it repeatable

Use stable test data and deterministic app launch flags.

Good patterns:

  • Start app in a known route/state via args
  • Disable random animations where possible
  • Wait for known readiness output when using stdout capture

Next: move to CLI & Headless for CI automation.

Watchlight Documentation