tatmapper-app

TatMapper product guide

Product summary

TatMapper is a local-first Android and iOS tool for planning tattoo placement from a still photo. An artist establishes scale with a U.S. quarter, the TatMapper Placement Card perspective-correction backup, another measured round object, or a known-length line; traces placement guides over the photo; places imported artwork; and exports a dimensioned PDF.

The shipping workflow is:

Photo -> Scale -> Trace -> Design -> Export

TatMapper models one physical plane. It does not reconstruct a body, unwrap curvature, or guarantee that a stencil will fit curved skin. The artist must measure the final 100 mm ruler on every physical output.

Artist tutorial

1. On Home, select New placement or Explore the sample.
2. Capture or import a clear still photo. Keep the camera as square to the placement as practical.
3. On Scale, choose a method:
   • Quarter — Recommended: place a U.S. quarter flat in the same plane and align the rim guide.
   • Placement Card — Perspective backup: print/share the free card, place its authoritative square in the same plane, then align the four numbered corners when four-corner rectification is useful.
   • Other coin / round object / known length: enter the real measurement; TatMapper never guesses it.
4. On Trace, add optional placement guides. Use separate strokes and two-finger pan/zoom. These guides remain editor-only and never print.
5. On Design, import PNG, JPEG, or WebP artwork. Position, rotate, and size it. Background removal is optional, local, previewed, and undoable.
6. On Export, choose inches, millimetres, or automatic display; confirm page size and orientation; and explicitly choose No Print Setup or a saved verified setup.
7. If the artwork is too large for one page, select Tile across pages, review the grid, overlap, and origin, then assemble pages using their labels, crosses, trim ticks, and direction arrows.
8. Print at 100% / Actual Size, disable Fit to Page, and measure the final 100 mm ruler before using the stencil.

Functional specification

Area	Behaviour
Storage	Projects, normalized media, settings, and Print Setups stay in app-owned local storage.
Appearance	Persistent System, Light, and Dark selection.
Units	Exact 25.4 mm/in conversion; fractional-inch display for artist-friendly dimensions.
Calibration	Recommended U.S. quarter, four-corner Placement Card backup, supported U.S. coins, custom round object, known length, and migrated legacy references.
Geometry	Canonical normalized or rectified image pixels; reversible viewport transforms; separate trace strokes.
Artwork	Safe still-image ingestion, bounded normalization, placement containment, rotation/scale, and optional nondestructive background preparation.
Export	A4/Letter, portrait/landscape/automatic, single-sheet or tiled full-size PDF, optional X/Y Print Setup correction, mandatory final ruler.
Privacy	No account, cloud, analytics, ads, billing, ATT, or app-owned network transport.
Accessibility	Semantic controls, non-colour cues, large-text layouts, and system appearance support; physical TalkBack/VoiceOver verification remains required.

What an outside critic should test

• Does the first screen make the next action obvious?
• Is the recommended quarter workflow obvious, and can an artist understand when the Placement Card backup is preferable without learning an internal code?
• Do Scale controls collapse into a photo-first positioning view with clear Back, Reset, Use, Adjust, Change, and Continue actions?
• Are transparent design margins ignored by Fit/Center and are out-of-photo warnings helpful without blocking intentional placement?
• Is preview opacity clearly non-destructive, and is output-only stencil mirroring clearly distinguished from the normal placement preview?
• Can the artist recover from camera denial, damaged imports, invalid scale, save failure, and oversized output?
• Are dimensions legible in both inches and millimetres?
• Can the design remain contained and controllable on a phone-sized canvas?
• Is background removal clearly optional, previewed, and reversible?
• Can a multi-page stencil be assembled unambiguously?
• Does the product consistently distinguish editor guides, photo calibration, print correction, and final physical verification?

Evidence boundary

Automated geometry and PDF tests can verify software coordinates. They cannot verify a physical printer, copier, stencil medium, body curvature, camera lens, or artist technique. Store readiness also requires signed artifacts, store acceptance, and device/printer evidence not created by source code alone.