* Add the Magnetic Lasso tool
A selection border that snaps to edges as the pointer moves, in the
Lasso (L) flyout after the Polygonal Lasso.
- photocraft-algo `magnetic`: live-wire edge tracing (Mortensen &
Barrett 1995): Sobel strength, non-maximum suppression and gradient
direction link costs, a shortest path inside a corridor of the
detection width around the pointer's path, sub-pixel edge centres.
Pixels are read lazily in 128 px blocks.
- Engine: `EdgeSource` (the active pixel layer, else the composite) and
`select.magneticLasso`: rough points in, a border along the edges out;
`trace: false` selects a given outline, which is how the tool commits.
- UI: click to start, move to trace (button up or down), points fasten
by themselves (Frequency), click fastens, Alt-click straight, Alt-drag
freehand, Backspace/Delete removes points, click the first point,
double-click or Enter closes, Esc cancels, [ ] change the width.
Options bar: Width, Contrast, Frequency, tablet pressure. `ui.inspect`
reports the border in progress.
- The Lasso and Polygonal Lasso now apply the options bar's Feather;
`select.lasso` rejects a feather outside 0..1000.
- Icon adapted from Noun Project's "Magnetic Lasso Tool" by Lil' Seal
(CC BY 3.0, licence file and ATTRIBUTION.md row).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* it: translate the Magnetic Lasso strings (Italian landed after this PR was written)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>
0f16bce0c5