forOrigin method
storage with its translation set for origin (world − origin, the
frame paintWorldOverlay paints in). Call update first.
Implementation
Float64List forOrigin(Vector2 origin) {
final p = _p;
if (p == null) {
throw StateError('GhostMatrix.forOrigin before update');
}
_writeTranslation(storage, p, origin);
return storage;
}