Polygon masks and better borders

[bobnik]

Layer mask and better borders (via boundary tracing and polygon machines)

Features

Mask effect: layer shape option

Lets you use one layer as the mask for another. Works with any shape, including self-intersecting patterns like Fractal Spirograph or text.

Control	Description
Mask shape: layer	Use another layer's shape as the mask
Source layer	Dropdown to select which layer defines the mask boundary
Boundary type	Auto (recommended), or manual: expand, concave, footprint, convex

Fine tuning effect: enhanced border

Provides several improved border options.

Control	Description
Border Type	Auto, expand, concave, footprint, or convex
Pad (%)	Expand/contract border relative to shape
Draw border only	Skip the pattern, output only the border path

Implementation

1. Polygon machines

New machine types that clip patterns to arbitrary polygon boundaries:

• PolygonMachine - Clips vertices inside a polygon boundary
• PolygonInvertedMachine - Clips vertices outside a polygon boundary

2. Boundary tracing

Methods for extracting outer boundaries from complex shapes. When drawing a boundary, it auto-detects the optimal algorithm based on shape characteristics.

Algorithm	Use Case
expand	Simple closed shapes (Star, Heart, Polygon)
footprint	Complex shapes (Text, Fractals, Mazes)
fillPattern	Disconnected cells (Voronoi, Tessellation)
concave	Uniform edge offset
convex	Convex hull

Use cases

Add a layer mask

1. Create Layer 1 with a Star shape
2. Create Layer 2 with a Spirograph pattern
3. Add Mask effect to Layer 2
4. Set mask shape to "layer"
5. Select Layer 1 (Star) as source
6. Spirograph is now clipped to the star shape

Add a border

1. Create a layer
2. Add Fine Tuning effect
3. Check "Add border"
4. Select a border type.