slider: slider / button control widgets

In TeachingDemos: Demonstrations for Teaching and Learning

slider / button control widgets

Description

slider constructs a Tcl/Tk-widget with sliders and buttons automated calculation and plotting. For example slider allows complete all axes rotation of objects in a plot.

Usage

slider(sl.functions, sl.names, sl.mins, sl.maxs, sl.deltas, sl.defaults,
but.functions, but.names, no, set.no.value, obj.name, obj.value,
reset.function, title) 

Arguments

sl.functions	set of functions or function connected to the slider(s)
sl.names	labels of the sliders
sl.mins	minimum values of the sliders' ranges
sl.maxs	maximum values of the sliders' ranges
sl.deltas	change of step per click
sl.defaults	default values for the sliders
but.functions	function or list of functions that are assigned to the button(s)
but.names	labels of the buttons
no	slider(no=i) requests slider i
set.no.value	slider(set.no.value=c(i,val)) sets slider i to value val
obj.name	slider(obj.name=name) requests the value of variable name from environment slider.env
obj.value	slider(obj.name=name,obj.value=value) assigns value to variable name in environment slider.env
reset.function	function that comprises the commands of the reset.button
title	title of the control window

Details

With slider you can: a. define (multiple) sliders and buttons, b. request or set slider values, and c. request or set variables in the environment slider.env. Slider function management takes place in the environment slider.env. If slider.env is not found it is generated.

Definition: ... of sliders: First of all you have to define sliders, buttons and the attributes of them. Sliders are established by six arguments: sl.functions, sl.names, sl.minima, sl.maxima,sl.deltas, and sl.defaults. The first argument, sl.functions, is either a list of functions or a single function that entails the commands for the sliders. If there are three sliders and slider 2 is moved with the mouse the function stored in sl.functions[[2]] (or in case of one function for all sliders the function sl.functions) is called.

Definition: ... of buttons: Buttons are defined by a vector of labels but.names and a list of functions: but.functions. If button i is pressed the function stored in but.functions[[i]] is called.

Requesting: ... a slider: slider(no=1) returns the actual value of slider 1, slider(no=2) returns the value of slider 2, etc. You are allowed to include expressions of the type slider(no=i) in functions describing the effect of sliders or buttons.

Setting: ... a slider: slider(set.no.value=c(2,333)) sets slider 2 to value 333. slider(set.no.value=c(i,value)) can be included in the functions defining the effects of moving sliders or pushing buttons.

Variables: ... of the environment slider.env: Sometimes information has to be trransferred back and forth between functions defining the effects of sliders and buttons. Imagine for example two sliders: one to control p and another one to control q, but they should satisfy: p+q=1. Consequently, you have to correct the value of the first slider after the second one was moved. To prevent the creation of global variables store them in the environment slider.env. Use slider(obj.name="p.save",obj.value=1-slider(no=2)) to assign value 1-slider(no=2) to the variable p.save . slider(obj.name=p.save) returns the value of variable p.save.

Value

Using slider in definition mode slider returns the value of new created the top level widget. slider(no=i) returns the actual value of slider i. slider(obj.name=name) returns the value of variable name in environment slider.env.

Note

You can move the slider in 3 different ways: You can left click and drag the slider itself, you can left click in the trough to either side of the slider and the slider will move 1 unit in the direction you clicked, or you can right click in the trough and the slider will jump to the location you clicked at.

This function may not stay in this package (consider it semi-depricated), the original of the slider function is in the relax package and can be used from there. In TeachingDemos the tkexamp function is taking the place of slider and gives a possibly more general approach.

Author(s)

Hans Peter Wolf

See Also

tkexamp, sliderv

Examples

# example 1, sliders only
## Not run: 
## This example cannot be run by examples() but should work in an interactive R session
plot.sample.norm<-function(){
 refresh.code<-function(...){
   mu<-slider(no=1); sd<-slider(no=1); n<-slider(no=3)
   x<-rnorm(n,mu,sd)
   plot(x)
 }
 slider(refresh.code,sl.names=c("value of mu","value of sd","n number of observations"),
       sl.mins=c(-10,.01,5),sl.maxs=c(+10,50,100),sl.deltas=c(.01,.01,1),sl.defaults=c(0,1,20))
}
plot.sample.norm()

## End(Not run)

# example 2, sliders and buttons
## Not run: 
## This example cannot be run by examples() but should work in an interactive R session
plot.sample.norm.2<-function(){
 refresh.code<-function(...){
   mu<-slider(no=1); sd<-slider(no=2); n<-slider(no=3)
   type=  slider(obj.name="type")
   x<-rnorm(n,mu,sd)
   plot(seq(x),x,ylim=c(-20,20),type=type)
 }
 slider(refresh.code,sl.names=c("value of mu","value of sd","n number of observations"),
       sl.mins=c(-10,.01,5),sl.maxs=c(10,10,100),sl.deltas=c(.01,.01,1),sl.defaults=c(0,1,20),
       but.functions=list(
              function(...){slider(obj.name="type",obj.value="l");refresh.code()},
              function(...){slider(obj.name="type",obj.value="p");refresh.code()},
              function(...){slider(obj.name="type",obj.value="b");refresh.code()}
       ),
       but.names=c("lines","points","both"))
  slider(obj.name="type",obj.value="l")
}
plot.sample.norm.2()

## End(Not run)

# example 3, dependent sliders
## Not run: 
## This example cannot be run by examples() but should work in an interactive R session
print.of.p.and.q<-function(){
 refresh.code<-function(...){
   p.old<-slider(obj.name="p.old")
   p<-slider(no=1); if(abs(p-p.old)>0.001) {slider(set.no.value=c(2,1-p))}
   q<-slider(no=2); if(abs(q-(1-p))>0.001) {slider(set.no.value=c(1,1-q))}
   slider(obj.name="p.old",obj.value=p)
   cat("p=",p,"q=",1-p,"\n")
 }
 slider(refresh.code,sl.names=c("value of p","value of q"),
       sl.mins=c(0,0),sl.maxs=c(1,1),sl.deltas=c(.01,.01),sl.defaults=c(.2,.8))
 slider(obj.name="p.old",obj.value=slider(no=1))
}
print.of.p.and.q()

## End(Not run)

# example 4, rotating a surface
## Not run: 
## This example cannot be run by examples() but should work in an interactive R session
R.veil.in.the.wind<-function(){
  # Mark Hempelmann / Peter Wolf
  par(bg="blue4", col="white", col.main="white",
      col.sub="white", font.sub=2, fg="white") # set colors and fonts
  samp  <- function(N,D) N*(1/4+D)/(1/4+D*N)
  z<-outer(seq(1, 800, by=10), seq(.0025, 0.2, .0025)^2/1.96^2, samp) # create 3d matrix
  h<-100
  z[10:70,20:25]<-z[10:70,20:25]+h; z[65:70,26:45]<-z[65:70,26:45]+h
  z[64:45,43:48]<-z[64:45,43:48]+h; z[44:39,26:45]<-z[44:39,26:45]+h
  x<-26:59; y<-11:38; zz<-outer(x,y,"+"); zz<-zz*(65<zz)*(zz<73)
  cz<-10+col(zz)[zz>0];rz<-25+row(zz)[zz>0]; z[cbind(cz,rz)]<-z[cbind(cz,rz)]+h
  refresh.code<-function(...){
    theta<-slider(no=1); phi<-slider(no=2)
    persp(x=seq(1,800,by=10),y=seq(.0025,0.2,.0025),z=z,theta=theta,phi=phi,
          scale=T, shade=.9, box=F, ltheta = 45,
          lphi = 45, col="aquamarine", border="NA",ticktype="detailed")
  }
  slider(refresh.code, c("theta", "phi"), c(0, 0),c(360, 360),c(.2, .2),c(85, 270)  )
}
R.veil.in.the.wind()

## End(Not run)

TeachingDemos documentation built on May 29, 2024, 5:59 a.m.