Show HN: Free tool to mark points and polygon regions
3 days ago
- #image-annotation
- #browser-tool
- #coordinate-marking
- Tack is a browser-based precision tool for marking points and polygon regions on images, designed for use on tablets or desktops due to the need for a larger screen for detailed work.
- It allows users to drop single points, draw open polylines, and create closed polygons, as well as add Bézier curves with handles for smooth anchors, with options to break symmetry and sync controls.
- The tool supports multiple origin points (e.g., top-left, center, custom) and coordinate systems, including pixel or normalized coordinates and Y-axis flipping for screen-space or math-space alignment.
- Key features include JSON/YAML export for code integration, undo/redo functionality, keyboard nudging, and offline capability as a Progressive Web App (PWA), ensuring images and data never leave the user's device.
- Use cases include 2D game development, UI design, ML data labeling, and mapping applications, emphasizing privacy by operating entirely client-side without data uploads or logins.