How strokes, anti-aliasing, and pixel boundaries actually behave in SwiftUI Canvas and Shape rendering. Covers stroke centering, inset-vs-outset, anti-alias-induced flicker on animating strokes, and 1pt vs 0.5pt strokes on retina displays. Use this skill for any app that draws on a grid or canvas — pattern designers, illustration tools, charting, finger-paint, whiteboards, image editors, gauge / dial UIs.
