gslider: Constructors for widgets to select a value from a sequence.

In gWidgets: gWidgets API for Building Toolkit-Independent, Interactive GUIs

Description

The gslider widget and gspinbutton widget allow the user to select a value from a sequence using the mouse. In the slider case, a slider is dragged left or right (or up or down) to change the value. For a spin button a text box with arrows beside allow the user to scroll through the values by clicking the arrows.

Some toolkits only allow integer values for these.

Usage

gslider(from = 0, to = 100, by = 1, length.out=NULL, along.with=NULL, 
value = from[1], horizontal = TRUE, handler = NULL, action = NULL, 
container = NULL, ..., toolkit = guiToolkit())

gspinbutton (from = 0, to = 10, by = 1, length.out=NULL, along.with=NULL, 
value = from, digits = 0, 
    handler = NULL, action = NULL, container = NULL, ..., toolkit = guiToolkit()) 

Arguments

from	Starting point in range. For glider, this may be a vector of values that can be sorted from sort(unique(...)). In this case, to, by, etc. are ignored.
to	Ending point in range
by	Step size between values in the sequence
length.out	In place of by, take number of steps from this
along.with	In place of length.out, take length from this vector
value	The initial value
digits	The number of digits shown
horizontal	Specifies orientation of gslider widget
handler	Called on a change event.
action	Passed to handler
container	Optional container to attach widget to
...	Passed to add method of container
toolkit	Which GUI toolkit to use

Details

Widgets to select from a vector of values. This vector is usually a sequence, as is returned by seq, hence the similar arguments, although the implementation is a bit less general, as length.out and along.with are used to compute by when given.

For gslider any ordered vector may be used if specified to from. Some toolkits only allow integer sequences, see the respective gWidgetsXXX packages for details.

The svalue method returns the selected value. If all values are specified to from, then index argument is respected.

The svalue<- method is used to set the selected value. If all values are specified to from, then index argument is respected.

The [<- method can be used to change the sequence that the value is selected from. It expects a regular sequence, or if all values were originally specified to from a sortable sequence.

The addhandlerchanged handler is called when the widgets' value is changed.

Examples

## Not run: 
  x <- rnorm(100)

  ## our handler
  plotHist <- function(...)
    hist(x, col=gray(svalue(sb)), breaks = svalue(sl))

   

  w <- gwindow("Slider and spinbox example")
  tbl = glayout(container=w)
  tbl[1,1] <- "Slide value to adjust shade"
  tbl[1,2] <- (sb <- gspinbutton(from=0,to=1,by=0.05,value=.5, container=tbl,
    handler=plotHist))
  tbl[2,1] <- "No. breaks"
  tbl[2,2, expand=TRUE] <- (sl <- gslider(from = 1, to= 100, by=1, value = 10,
    container = tbl, handler = plotHist))

## update slider using [<-
  sl[] <- seq(2,50, by=2)


  ## other sequence:
  w <- gwindow("Slider with sequence")
  sl <- gslider(letters, container=w)
  svalue(sl, index=TRUE)
  svalue(sl) <- "m"
  sl[] <- LETTERS ## can be sorted via sort(unique(LETTERS))

## End(Not run)

gWidgets documentation built on April 29, 2020, 9:37 a.m.