User report: "rotating components messes up their connections" — pressing R
on a placed component visibly slid every wire endpoint off its pin tip.
Root cause: the DynamicComponent wrapper has padding:4px + border:2px on
EVERY side, so the inner web-component element sits 6 px in from the
wrapper top-left on BOTH axes. The wire layer assumed an asymmetric
(4, 6) offset, baked into:
* useSimulatorStore.updateWirePositions — store.x + 4, store.y + 6
* useSimulatorStore.recalculateAllWirePositions
— start (startComp.x + 4, startComp.y + 6)
— end (endComp.x + 4, endComp.y + 6)
* pinPositionCalculator.calculatePinPosition — inverse: (componentX - 4, componentY - 6)
Unrotated the 2 px X bias was visible only as a very-slightly-off wire,
which nobody filed. When the user rotated the component, the bias
rotated WITH it — at 90° it became a 2 px Y offset (wires hanging below
the pin), at 180° a 2 px X offset on the other side, at 270° upward. UX
read as "wires disconnected".
Verified the real CSS box via chrome-devtools-mcp against several live
components on velxio.dev (RGB LED + 3 resistors + analog joystick): all
report padding-left/top = 4 px, border-left/top = 2 px, inner offset = 6
on both axes.
Fix: use (+6, +6) at every site, single source of truth in a comment
explaining padding+border arithmetic. Updated the rotation regression
test to match the corrected math (numbers shift by 2 px on every
expectation that referenced the old offset).
Pin position math, pivot derivation and the rotate-N×90° round trip
unchanged — only the offset constant moved.