library("tcltk") doit = function(...) { bin.width = as.numeric(tclvalue(tva)) dd = density(x,bw=bin.width) plot(dd$x,dd$y,ty="l") points(x,rep(0,length(x))) for(xi in x) lines(dd$x,dnorm(dd$x,mean=xi,sd=bin.width)/n,col="red") } n = 2 x = c(-0.1,1.2); tt = tktoplevel() laba <- tklabel(tt,text="bin width=") tva = tclVar(0.9) scla = tkscale(tt, comm=doit, from=0.1, to=2, reso=0.1, orient="horizontal", variable=tva) butt = tkbutton(tt,text="Done!", comm=function() tkdestroy(tt)) tkpack(laba,scla,butt)