Create a Canvas Binding

Canvas bindings are triggered by a mouse/keyboard gesture over the plot as a whole.

l_bind_canvas(widget, event, callback)

Arguments

widget	widget path as a string or as an object handle
event	event patterns as defined for Tk canvas widget http://www.tcl.tk/man/tcl8.6/TkCmd/bind.htm#M5.
callback	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

Value

canvas binding id

Details

Canvas bindings are used to evaluate callbacks at certain X events on the canvas widget (underlying widget for all of loon's plot widgets). Such X events include re-sizing of the canvas and entering the canvas with the mouse.

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

See also

l_bind_canvas_ids, l_bind_canvas_get, l_bind_canvas_delete, l_bind_canvas_reorder

Examples

# binding for when plot is resized 
p <- l_plot(iris[,1:2], color=iris$Species)

printSize <- function(p) {
    size <- l_size(p)
    cat(paste('Size of widget ', p, ' is: ',
              size[1], 'x', size[2], ' pixels\n', sep=''))
}

l_bind_canvas(p, event='<Configure>', function(W) {printSize(W)})
#> [1] "canvasBinding0"

id <- l_bind_canvas_ids(p)
id
#> [1] "canvasBinding0"

l_bind_canvas_get(p, id)
#> [1] "<Configure>"              "R_call 0x7fadb16833d8 %W"