# make boxes (alternatively use layout.boxes())
Bminus <- square(1)
Bvalue <- shift(Bminus, c(1.2, 0))
Bplus <- shift(Bvalue, c(1.2, 0))
Bdone <- shift(Bplus, c(1.2, 0))
myboxes <- list(Bminus, Bvalue, Bplus, Bdone)
myB <- do.call(boundingbox,myboxes)
# make environment containing an integer count
myenv <- new.env()
assign("answer", 0, envir=myenv)
# what to do when finished: return the count.
myexit <- function(e) { return(get("answer", envir=e)) }
# button clicks
# decrement the count
Cminus <- function(e, xy) {
ans <- get("answer", envir=e)
assign("answer", ans - 1, envir=e)
return(TRUE)
}
# display the count (clicking does nothing)
Cvalue <- function(...) { TRUE }
# increment the count
Cplus <- function(e, xy) {
ans <- get("answer", envir=e)
assign("answer", ans + 1, envir=e)
return(TRUE)
}
# 'Clear' button
Cclear <- function(e, xy) {
assign("answer", 0, envir=e)
return(TRUE)
}
# quit button
Cdone <- function(e, xy) { return(FALSE) }
myclicks <- list("-"=Cminus,
value=Cvalue,
"+"=Cplus,
done=Cdone)
# redraw the button that displays the current value of the count
Rvalue <- function(button, nam, e) {
plot(button, add=TRUE)
ans <- get("answer", envir=e)
text(centroid.owin(button), labels=ans)
return(TRUE)
}
# make the panel
P <- simplepanel("Counter",
B=myB, boxes=myboxes,
clicks=myclicks,
redraws = list(NULL, Rvalue, NULL, NULL),
exit=myexit, env=myenv)
P
# ( type run.simplepanel(P) to run the panel interactively )
# add another button to right
Pplus <- grow.simplepanel(P, "right", new.clicks=list(clear=Cclear))
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