momentsAPI = function (...){
  require(tcltk); 
  source('moments.R')

  sc <-10;
  ave <- tclVar(0); 
  sig2 <- tclVar(1*sc); 
  skew <- tclVar(0); 
  kurt <- tclVar(3*sc); 
 
  base <- tktoplevel(); 
  tkwm.title(base,'Pearson type IV Distribution');  
  tt <- tkframe(base, borderwidth=2)
  sliderFrame <- tkframe(tt, borderwidth=2, relief='groove');

  aveFrame <- tkframe(sliderFrame, borderwidth=2);
  aveLabel <- tklabel(aveFrame, text="Expectation: ", width=10);
  aveValueLabel <- tklabel(aveFrame, text="", width=6);

  sig2Frame <- tkframe(sliderFrame, borderwidth=2);
  sig2Label <- tklabel(sig2Frame, text="Variance: ", width=10);
  sig2ValueLabel <- tklabel(sig2Frame, text="", width=6);

  skewFrame <- tkframe(sliderFrame, borderwidth=2);
  skewLabel <- tklabel(skewFrame, text="Skewness: ", width=10);
  skewValueLabel <- tklabel(skewFrame, text="", width=6);

  kurtFrame <- tkframe(sliderFrame, borderwidth=2);
  kurtLabel <- tklabel(kurtFrame, text="Kurtosis : ", width=10);
  kurtValueLabel <- tklabel(kurtFrame, text="", width=6);

  actionPerformed = function(...){
    p <- findparams(as.double(tclvalue(ave))/sc, as.double(tclvalue(sig2))/sc, as.double(tclvalue(skew))/sc, as.double(tclvalue(kurt))/sc);
    plotpearson(p[1], p[2], p[3], p[4]);
    tkconfigure(aveValueLabel, text=as.character(as.double(tclvalue(ave))/sc))
    tkconfigure(sig2ValueLabel, text=as.character(as.double(tclvalue(sig2))/sc))
    tkconfigure(skewValueLabel, text=as.character(as.double(tclvalue(skew))/sc))
    tkconfigure(kurtValueLabel, text=as.character(as.double(tclvalue(kurt))/sc))
  }

  reset = function (...){
    ave <- tclVar(0*sc); 
    sig2 <- tclVar(1*sc); 
    skew <- tclVar(0*sc); 
    kurt <- tclVar(3*sc); 
  }



  aveSlider <- tkscale(aveFrame, from=-3*sc, to=3*sc, length=600, showvalue=F, variable=ave, resolution=1, orient='horizontal', command=actionPerformed)
  tkpack(aveFrame, aveLabel, aveValueLabel, aveSlider, side='left');


  sig2Slider <- tkscale(sig2Frame, from=0.01*sc, to=5*sc, length=600, showvalue=F, variable=sig2, resolution=1, orient='horizontal', command=actionPerformed)
  tkpack(sig2Frame, sig2Label, sig2ValueLabel, sig2Slider, side='left');

  skewSlider <- tkscale(skewFrame, from=-10*sc, to=10*sc, length=600, showvalue=F, variable=skew, resolution=1, orient='horizontal', command=actionPerformed)
  tkpack(skewFrame, skewLabel, skewValueLabel, skewSlider, side='left');

  kurtSlider <- tkscale(kurtFrame, from=0*sc, to=30*sc, length=600, showvalue=F, variable=kurt, resolution=1, orient='horizontal', command=actionPerformed)
  tkpack(kurtFrame, kurtLabel, kurtValueLabel, kurtSlider, side='left');
 
  tkpack(sliderFrame, aveFrame, sig2Frame, skewFrame, kurtFrame, side='top')

  tkpack(tt, sliderFrame,side='top'); 
  tkfocus(aveSlider)
}
momentsAPI();