# Screentone Pattern Maker

> Make dot, line and crosshatch tones with explicit pitch, coverage and print scale. Generate a repeating vector screentone, inspect its nominal ink coverage and lines per inch, and download an SVG or reusable tone recipe. Open it as a Comic Desk study or apply the recipe to an existing panel.

Part of usefulweb.app (https://usefulweb.app/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://fliplinescreentone.usefulweb.app/ (interactive tool at https://fliplinescreentone.usefulweb.app/tool)
- JSON API: POST https://fliplinescreentone.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://fliplinescreentone.usefulweb.app/api/v1/tool)
- OpenAPI: https://fliplinescreentone.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://fliplinescreentone.usefulweb.app/mcp - tool `flipline_screentone`

## Inputs
- pattern (select): Tone pattern
- pitch (integer): Tone pitch (px)
- coverage (integer): Tone coverage (%)
- angle (integer): Tone angle (°)
- dpi (integer): Tone resolution (DPI)
- width (integer): Swatch width (px)
- height (integer): Swatch height (px)
- ink (text): Tone ink (HEX)

## Method
- Pitch is the repeating cell size in source pixels. Nominal lines per inch = DPI / pitch; physical size in mm = pixels / DPI × 25.4. No printer-specific dot gain or color conversion is modelled.
- For dots, radius = pitch × sqrt(coverage / π). Parallel stripe width = pitch × coverage. For perpendicular crosshatch, stripe width = pitch × (1 − sqrt(1 − coverage)), accounting for overlap. Pattern rotation preserves this nominal coverage.
- Coverage is 5–75%, pitch 4–80 px and angle −90° to 90°. SVG keeps vector patterns; the tone recipe imports into Comic Desk with pitch rescaled to preserve lines per inch at the page DPI. Avoid resampling a rasterized tone to reduce moiré.

## Limits
- Nominal geometric coverage, not a measured ink density. Raster resampling and printing can introduce moiré.