unknownDevice property

Device? get unknownDevice

The first device in device or canvases that is not in Devices, or null when each of them is.

Refused rather than dropped. A device crosses to the renderer as its id, and the far side looks the id up in the table: an id it does not have resolves to nothing, and one it does resolves to the table's screen, not this one. Either way the picture is taken on something nobody declared, and it looks like a preview rather than like a mistake.

const Device(...) is public, and a size of one's own — store artwork is a fixed number of pixels — is exactly what reaches for it.

Implementation

Device? get unknownDevice {
  for (var candidate in [?device, for (var c in canvases) ...c.devices]) {
    if (!identical(deviceById(candidate.id), candidate)) return candidate;
  }
  return null;
}