TrapHouse

Before/after photo comparison with live overlay alignment and blink mode

Source available on GitHub: https://github.com/AlsatianConsulting/TrapHouse

TrapHouse is a before/after photo comparison tool for Android. Take a reference photo, then frame your second shot with the reference overlaid on the live camera feed at adjustable opacity. Once you shoot, compare the two images with a tap or switch on Blink mode to alternate between them automatically.

What it does

- Reference capture — take a photo with the camera or load one from your gallery
- Front/back camera toggle — switch cameras on both the reference capture and alignment screens
- Alignment overlay — the reference image appears ghosted over the live viewfinder at 10–90% opacity so you can match your framing exactly before you shoot
- Tap-to-compare — full-screen display toggles between BEFORE and AFTER on tap
- Blink mode — alternates between the two images every 500 ms to reveal subtle differences at a glance
- Save — both images are written as a matched pair (TrapHouse_Before_… / TrapHouse_After_…) to Pictures/TrapHouse on the device
- Session management — New Comparison Set resets state and clears temporary files with no disk residue

Who uses it

Trade workers, inspectors, landscapers, property managers, stagers, and anyone who needs to document change at a location over time. The alignment overlay means your before and after shots are framed the same way — not just two photos taken in roughly the same direction.

Privacy

No account. No telemetry. No network access. All processing happens on the device. Camera permission is required to capture photos. The Android Photo Picker is used for gallery access on Android 13 and later; on Android 8 and 9, write storage permission is required for gallery saves.

Built by Alsatian Consulting. Source on GitHub: https://github.com/AlsatianConsulting/TrapHouse