A blurred copy of the overlay's own alpha is drawn in a colour beneath it:
moved by an offset for a shadow, centred for a glow, with a size, a spread
and an opacity. The mask is integer-only so a seed still reproduces it, and
reaches past the canvas so an image lying off it still casts onto it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Lays a single picture from disk over its input: fitted, filled, stretched,
left at its own size or tiled, centred or pinned to the top left corner,
nudged by an offset and mixed in by its opacity.
The file it needs is a new kind of param, Path, so the interface shows a
chooser and the CLI takes a file name, both without knowing an overlay
exists. Projects write it relative to their own folder, as they do a
source, and Image::load can now hand back the alpha channel instead of
flattening it onto white, so a cut-out PNG keeps its cut-out.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
