// the find
shanselman/WindowsEdgeLight
A lightweight WPF application that adds a customizable glowing edge light effect around your primary monitor
A WPF overlay for Windows that paints a glowing, colour-adjustable border around one or all monitors, mainly as ambient fill light for video calls and streaming. For developers who want a quick on-screen key light without buying a ring light or capture-card lighting rig.
Click-through is done properly via WS_EX_TRANSPARENT/WS_EX_LAYERED rather than faking it with hit-test overrides. DPI handling is explicit - physical pixels get converted to WPF DIPs, which is exactly where most hobby multi-monitor WPF apps fall apart. It ships a real update path (Updatum wired to GitHub Releases) instead of leaving users to check manually, and the single-file publish means no separate .NET install for end users.
WPF rules out AOT and trimming, so the self-contained exe is ~72MB with the full runtime bundled in - 'lightweight' is doing a lot of work in that description. Test coverage is a single file (AppSettingsTests.cs); the parts that are actually hard to get right - DPI math, multi-monitor switching, click-through behavior - have no automated coverage. 'Exclude from screen capture' depends on OS-level capture-exclusion APIs that behave inconsistently across Windows builds and capture tools, so it's not something you can rely on without testing your specific Teams/Zoom/OBS setup. It's Win32-only by design, so there's no realistic path to macOS or Linux if that ever matters to you.