The callback of a state change binding is evaluated when certain states change, as specified at binding creation.

l_bind_state(target, event, callback)



either an object of class loon or a vector that specifies the widget, layer, glyph, navigator or context completely. The widget is specified by the widget path name (e.g. '.l0.plot'), the remaining objects by their ids.


vector with state names


callback function is an R function which is called by the Tcl interpreter if the event of interest happens. Note that in loon the callback functions support different optional arguments depending on the binding type, read the details for more information


state change binding id


Bindings, callbacks, and binding substitutions are described in detail in loon's documentation webpage, i.e. run l_help("learn_R_bind")

See also