gWidgets2: gslider – R documentation

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gslider

slider widget constructor

Description

A slider widgets allows a selection from a range of numeric values. The widget presents the user with a quick to adjust, but relatively difficult to adjust precisely way to to pick a number.

generic for toolkit dispatch

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())

.gslider(toolkit, from = 0, to = 100, by = 1, value = from,
  horizontal = TRUE, handler = NULL, action = NULL, container = NULL,
  ...)

Arguments

`from`	If a number of length one then a starting point, in which case to, by are passed to `seq`. Otherwise a sequence of values for which sort(unique(from)) will order
`to`	ending point when from is starting point
`by`	step size if not specified by `from`
`length.out`	in place of by
`along.with`	in place of length.out
`value`	initial value
`horizontal`	Logical. Is separator drawn horizontally?
`handler`	A handler assigned to the default change signal. Handlers are called when some event triggers a widget to emit a signal. For each widget some default signal is assumed, and handlers may be assigned to that through `addHandlerChanged` or at construction time. Handlers are functions whose first argument, `h` in the documentation, is a list with atleast two components `obj`, referring to the object emitting the signal and `action`, which passes in user-specified data to parameterize the function call. Handlers may also be added via `addHandlerXXX` methods for the widgets, where `XXX` indicates the signal, with a default signal mapped to `addHandlerChanged` (cf. `addHandler` for a listing). These methods pass back a handler ID that can be used with `blockHandler` and `unblockHandler` to suppress temporarily the calling of the handler.
`action`	User supplied data passed to the handler when it is called
`container`	A parent container. When a widget is created it can be incorporated into the widget heirarchy by passing in a parent container at construction time. (For some toolkits this is not optional, e.g. gWidgets2tcltk or gWidgets2WWW2.)
`...`	These values are passed to the `add` method of the parent container. Examples of values are `expand`, `fill`, and `anchor`, although they're not always supported by a given widget. For more details see add. Occasionally the variable arguments feature has been used to sneak in hidden arguments to toolkit implementations. For example, when using a widget as a menubar object one can specify a parent argument to pass in parent information, similar to how the argument is used with gaction and the dialogs.
`toolkit`	Each widget constructor is passed in the toolkit it will use. This is typically done using the default, which will lookup the toolkit through `guiToolkit`.

Examples

if(interactive()) {
  ## a range widget uses either a slider or a linked spinbutton to select a value
  w <- gwindow("Range widget", visible=FALSE)
  g <- ggroup(cont=w, horizontal=TRUE)
  sl <- gslider(from=0, to=100, by=1, value=0, cont=g, expand=TRUE, fill="both")
  sp <- gspinbutton(from=0, to=100, by=1, value=0, cont=g)

  ## Two ways to do this:
  ##  addHandlerChanged(sl, function(...) svalue(sp) <- svalue(sl))
  ##  addHandlerChanged(sp, function(...) svalue(sl) <- svalue(sp))

  f <- function(h, ...) svalue(h$action) <- svalue(h$obj)
  addHandlerChanged(sl, f, action=sp)
  addHandlerChanged(sp, f, action=sl)
  
  visible(w) <- TRUE
}

gWidgets2

Rewrite of gWidgets API for Simplified GUI Construction

v1.0-8

GPL (>= 3)

Authors

John Verzani

Initial release