The window's underlying ID (see the id property on hs.window objects).
OptionalkeepTransparency: booleanWhether to preserve the window's alpha channel. If false (the default), transparent regions are filled with an opaque black background.
Resolves with the captured image, or rejects if no window with that ID can be found, or the capture fails.
Capture the current on-screen contents of the window with the given ID. Requires Screen Recording permission.