The 0.2.x canvas auto-recomputed the outputs endpoint's X
position from `max(step.x) + nodeWidth + 120` every build.
Dragging any step rebuilt the layout, the recompute kicked
in, and the outputs panel + every edge entering it
shifted across the screen. Mirror image: the inputs panel
was nailed to a hardcoded (40, 80) but the right side of
the world moved every time the operator touched a node.
Visually catastrophic; Stefan flagged it as the same kind
of "everything moves when I touch one thing" failure that
shelved the jai_client editor.
Structural fix: treat inputs and outputs as first-class
nodes with positions stored in the same layout sidecar as
every step. There is no more auto-recompute path.
Concretely:
- AutoLayout.layout now seeds NodePositions for the
reserved IDs `__inputs__` (column −1) and `__outputs__`
(column max+1) on first open. Existing positions are
never overwritten so subsequent layout passes don't
fight operator-chosen placements.
- FlowCanvas reads inputs/outputs positions from
layout.positions instead of hardcoded `_inputsX` /
`_inputsY` constants and the computed `_outputsX(...)`.
Both functions are deleted; the canvas now has one
single source of truth for ALL node positions, the
sidecar.
- The inputs / outputs endpoints render via a new
`_endpointPositioned` helper that mirrors
`_stepPositioned` — same FlowNode widget, same
drag handler, same `controller.moveStep` path. The
operator can grab the inputs panel and slide it
wherever; the position persists to the sidecar like
every step.
- All port-position helpers (`_outputPortPosition`,
`_inputPortPosition`, the inputs-endpoint port
position) now take a single `FlowLayout` and read
coordinates from there. No more `double outputsX`
parameter threaded through every method.
- Fit-to-content now expands the bounding box using the
endpoints' SIDECAR positions rather than a re-derived
outputs X. Same single source of truth.
Side-benefit: the editor's coordinate model is now strictly
sidecar-driven. No state derivation lives in render code.
This rules out the catastrophic "drag-mid-flight-redoes-
coordinate-transforms" failure mode jai_client hit (where
internal offsets grew during a drag and broke port
positions).
flutter analyze clean, 12/12 tests pass.
Signed-off-by: flemming-it <sf@flemming.it>
flemming-it
c15731fb1b