# Layer Transform & Bounds Planner

> Calculate a layer transform, rotated corners and canvas bounds. Enter canvas and layer dimensions, center position, rotation and flips. Get the affine matrix for normalized layer coordinates plus exact corner and bounding-box coordinates.

Part of usefulweb.site (https://usefulweb.site/). 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://luminalayertransform.usefulweb.site/ (interactive tool at https://luminalayertransform.usefulweb.site/tool)
- JSON API: POST https://luminalayertransform.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://luminalayertransform.usefulweb.site/api/v1/tool)
- OpenAPI: https://luminalayertransform.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://luminalayertransform.usefulweb.site/mcp - tool `lumina_layer_transform`

## Inputs
- canvasWidth (integer): Canvas width (px)
- canvasHeight (integer): Canvas height (px)
- width (integer): Layer width (px)
- height (integer): Layer height (px)
- x (number): Layer center X (px)
- y (number): Layer center Y (px)
- rotation (number): Rotation (degrees)
- flipX (boolean): Flip horizontally
- flipY (boolean): Flip vertically

## Method
- For layer-local coordinates u/v from 0 to 1, canvas x = a*u + c*v + e and y = b*u + d*v + f.
- The layer rotates around its center. Flips apply in local space before rotation. Coordinates outside the canvas are retained.
- The same affine transform is used by Design Layers for selection, dragging and mask coordinates.