FAQ

About the tool

What is tack. for?

Marking points and polygon regions on images, then exporting the coordinates as data your code can use. Common applications: 2D game collision shapes and hotspots, ML object-detection annotations, sprite anchor points, image-map regions for documentation, ROI markup for image processing.

Is it free?

Yes. tack. is free to use. No account, no signup, no usage limits.

Is it open source?

Not currently.

Who builds it?

tack. is built by Smoking Media under the Provaz B.V. umbrella. It originated as an internal tool for an 8.bitretro.games adventure game and was made public after we realised others might want it too.

Privacy and data

Are my images uploaded?

No. tack. runs entirely in your browser. The image, the points you draw, and the data you export never leave your device.

Are my exported coordinates uploaded?

No. Export happens locally. Copy puts the data on your clipboard; Download writes a file. Neither touches a server.

What analytics do you collect?

Anonymous, cookie-less page views only — enough to know whether the site is reaching people. We don’t track individual users, sessions, or anything you do inside the app. See the privacy statement for the formal version.

Do I need an account?

No. There are no accounts.

Browsers and devices

Which browsers are supported?

Any modern Chromium-based browser (Chrome, Edge, Brave, Arc, Opera), Firefox, and Safari. tack. uses standard web APIs — no engine-specific tricks — so anything within roughly the last two years should work.

Does it work on a phone?

Not well, by design. Marking pixel-precise points and pulling bezier handles is a tablet-or-desktop task. The mobile site shows a notice explaining this. iPad with a stylus works very well.

Can I install it as an app?

Yes — tack. is a Progressive Web App. Once installed it runs in its own window and works offline.

Does offline mode have any limitations?

None for the core editing experience. Loading and exporting all happen locally either way. The only thing that won’t work offline is checking for an updated version of the app itself.

Drawing and editing

How do I make a perfect circle?

Press E for the Ellipse tool, then hold Shift while dragging.

How do I make a perfect square?

Press R for the Rectangle tool, then hold Shift while dragging.

How do I draw from the center instead of the corner?

Hold Alt while dragging with the Rectangle or Ellipse tool. Combine with Shift for a square or circle drawn from center.

How do I close a polygon?

Press C, or use the Close button in the toolbar. The shape needs at least two anchors.

How do I move a whole shape?

Hold Shift and drag any anchor of the shape.

How do I delete a single anchor without deleting the whole shape?

Alt+click the anchor, or select it and press Del.

What’s the difference between corner and smooth anchors?

Corner anchors produce sharp angles; smooth anchors produce curves via bezier handles. Switch between them by double-clicking an anchor or selecting it and pressing S. See the manual for the longer explanation.

Is there a limit to how many shapes I can draw?

No hard limit. Performance starts to degrade past several hundred complex bezier shapes on a single image.

My shapes disappeared after loading a new image. Why?

Loading a new image resets the canvas. Export your data before swapping images. To re-use shapes across images, load the JSON back in after loading the new image.

Output and integration

What output formats does tack. support?

JSON, YAML, and HTML image map. See Exporting for examples of each.

Which format should I use?

• JSON — most game engines, ML pipelines, web apps. Default choice.
• YAML — when your project’s config or data is already YAML (Defold, Rails, some static site generators).
• HTML image map — when you need clickable regions in a plain HTML page.

Can I import existing JSON to keep editing it?

Yes. Use Load Data and select your JSON or YAML file. Load the matching image first so the coordinates align. See Round-trip editing.

Can I import an HTML image map?

Not currently. Image map is a one-way export.

How do I use the JSON in my game engine?

Load the JSON file at runtime (or import it at build time) and iterate over shapes and their anchors. The exact API depends on your engine. Per-engine tutorials are on the way; in the meantime the JSON structure is documented in the manual.

Why do my coordinates look wrong in my engine?

Almost always one of three things:

1. Y-axis direction. Your engine expects Y-up but you exported Y-down (or vice versa). Flip the toggle and re-export.
2. Origin. You expected (0, 0) at the center but exported with TL origin. Switch the origin and re-export.
3. Resolution mismatch. You traced on a 4K image but the engine renders at 1080p. Switch to 0–1 normalized output and the coordinates will scale automatically.

Can I use tack.’s output commercially?

Yes. The data you create with tack. is yours. There is no licensing claim on coordinates you produce.

Roadmap and contributing

Will you add [feature X]?

Maybe. Email feedback or feature requests to the address in the credits. We prioritise features that come up repeatedly and that align with tack. as a precision data tool — not as a general image editor.

How do I report a bug?

Same channel as feature requests. Include the browser, OS, and a screenshot or short screen recording if the bug is visual.

Will tack. ever require payment?

There are currently no plans for paid features. tack. is free today and we have no roadmap item to change that.