Three UX/DI wins in one canvas pass:
1. Edge endpoints now land on the source/target shape's BOUNDARY
rather than the centres. Lines no longer cut through nodes. New
pure helpers boundaryPoint() + edgeEndpoints() do the geometry;
nodeCenter() is still used internally for direction vectors.
2. Connect-mode preview line. Alt+drag now draws a dashed line from
the source node's boundary to the live pointer position so the
user can see where the edge will land before releasing. The original
code marked this 'visual feedback deferred to v2'.
3. Selection state is now owned by the canvas (selectedNodeId /
selectedEdgeId variables), not read from .selected DOM classes.
The controller can ask via api.getSelection(). Fixes the fragile
pattern in flowchart-controller.js where Delete/Backspace read
querySelector('.flowchart-node.selected') — that read is now
redundant and the controller can be cleaned up to use getSelection()
directly.
5 new tests cover: edge starts past source centre, edge ends before
target centre, vertical edges connect top/bottom, label background
auto-sizes for long labels, canvas getSelection() reflects clicks.
Amit Haridas
Amit Haridas
0bb1091c47