Every drawing tool now asks one snapper (guides::DrawSnap) for the points it
places: the Pen's and Curvature tool's anchors, the Pencil's ends, the shape
tools' start and dragged corner or radius (Rectangle, Rounded Rectangle,
Ellipse, Polygon, Star, Line Segment, Arc, Spiral, the grids), the Type tool's
click and frame and a new artboard's corners. Points land on other objects'
anchors, centres and paths ("anchor", "center", "path") or line up with their
anchors, edges and centres ("align"); hovering shows it before the press, the
Pen's guides end its rubber band, and the Pen lands on the path being drawn
too. Shift keeps a point to its 45-degree step (from Constrain Angle) or a
box's diagonal and slides it along that way into line with a target.
Preferences > Smart Guides > Construction Guides and Angles now act: a drawn
point near a guide through the point it leaves from lands on it.
Before, the Pen snapped only its press and showed nothing, and the shape tools
re-gathered targets on every drag step from the document showing their own
preview, so the dragged corner stuck to where the last step left it.
Performance: targets are gathered once per document state (keyed on the
document's uid and revision, now in ToolContext), from the art in the window,
and sorted, so the anchors, centres and lines near the pointer are found by
bisection. Leaving objects out of the targets no longer looks up each node's
ancestry (quadratic in the document's size): one pruned walk does it, which
also speeds up the Selection tool's moves and resizes.
The direction handles' HandleSnap (#494) is now a DrawSnap holding its own
targets (Targets::for_handle) for the drag: one cache, one lookup.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
4eac7b505f