simplepanel: Simple Point-and-Click Interface Panels

Description

These functions enable the user to create a simple, robust, point-and-click interface to any R code.

Usage

simplepanel(title, B, boxes, clicks,
      redraws=NULL, exit = NULL, env)
   grow.simplepanel(P, side = c("right", "left", "top", "bottom"),
      len = NULL, new.clicks, new.redraws=NULL, ..., aspect)

Value

An object of class "simplepanel".

Arguments

title: Character string giving the title of the interface panel.
B: Bounding box of the panel coordinates. A rectangular window (object of class "owin")
boxes: A list of rectangular windows (objects of class "owin") specifying the placement of the buttons and other interactive components of the panel.
clicks: A list of R functions, of the same length as boxes, specifying the operations to be performed when each button is clicked. Entries can also be NULL indicating that no action should occur. See Details.
redraws: Optional list of R functions, of the same length as boxes, specifying how to redraw each button. Entries can also be NULL indicating a simple default. See Details.
exit: An R function specifying actions to be taken when the interactive panel terminates.
env: An environment that will be passed as an argument to all the functions in clicks, redraws and exit.
P: An existing interaction panel (object of class "simplepanel").
side: Character string identifying which side of the panel P should be grown to accommodate the new buttons.
len: Optional. Thickness of the new panel area that should be grown to accommodate the new buttons. A single number in the same units as the coordinate system of P.
new.clicks: List of R functions defining the operations to be performed when each of the new buttons is clicked.
new.redraws: Optional. List of R functions, of the same length as new.clicks, defining how to redraw each of the new buttons.
...: Arguments passed to layout.boxes to determine the layout of the new buttons.
aspect: Optional. Aspect ratio (height/width) of the new buttons.

Author

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Rolf Turner r.turner@auckland.ac.nz and Ege Rubak rubak@math.aau.dk.

Details

These functions enable the user to create a simple, robust, point-and-click interface to any R code.

The functions simplepanel and grow.simplepanel create an object of class "simplepanel". Such an object defines the graphics to be displayed and the actions to be performed when the user interacts with the panel.

The panel is activated by calling run.simplepanel.

The function simplepanel creates a panel object from basic data. The function grow.simplepanel modifies an existing panel object P by growing an additional row or column of buttons.

For simplepanel,

The spatial layout of the panel is determined by the rectangles B and boxes.
The argument clicks must be a list of functions specifying the action to be taken when each button is clicked (or NULL to indicate that no action should be taken). The list entries should have names (but there are sensible defaults). Each function should be of the form function(env, xy) where env is an environment that may contain shared data, and xy gives the coordinates of the mouse click, in the format list(x, y). The function returns TRUE if the panel should continue running, and FALSE if the panel should terminate.
The argument redraws, if given, must be a list of functions specifying the action to be taken when each button is to be redrawn. Each function should be of the form function(button, name, env) where button is a rectangle specifying the location of the button in the current coordinate system; name is a character string giving the name of the button; and env is the environment that may contain shared data. The function returns TRUE if the panel should continue running, and FALSE if the panel should terminate. If redraws is not given (or if one of the entries in redraws is NULL), the default action is to draw a pink rectangle showing the button position, draw the name of the button in the middle of this rectangle, and return TRUE.
The argument exit, if given, must be a function specifying the action to be taken when the panel terminates. (Termination occurs when one of the clicks functions returns FALSE). The exit function should be of the form function(env) where env is the environment that may contain shared data. Its return value will be used as the return value of run.simplepanel.
The argument env should be an R environment. The panel buttons will have access to this environment, and will be able to read and write data in it. This mechanism is used to exchange data between the panel and other R code.

For grow.simplepanel,

the spatial layout of the new boxes is determined by the arguments side, len, aspect and by the additional ... arguments passed to layout.boxes.
the argument new.clicks should have the same format as clicks. It implicitly specifies the number of new buttons to be added, and the actions to be performed when they are clicked.
the optional argument new.redraws, if given, should have the same format as redraws. It specifies the actions to be performed when the new buttons are clicked.

Examples

Run this code

  # make boxes (alternatively use layout.boxes())
  Bminus <- square(1)
  Bvalue <- shift(Bminus, c(1.2, 0))
  Bplus <- shift(Bvalue, c(1.2, 0))
  Bdone <- shift(Bplus, c(1.2, 0))
  myboxes <- list(Bminus, Bvalue, Bplus, Bdone)
  myB <- do.call(boundingbox,myboxes)

  # make environment containing an integer count
  myenv <- new.env()
  assign("answer", 0, envir=myenv)

  # what to do when finished: return the count.
  myexit <- function(e) { return(get("answer", envir=e)) }

  # button clicks
  # decrement the count
  Cminus <- function(e, xy) {
    ans <- get("answer", envir=e)
    assign("answer", ans - 1, envir=e)
    return(TRUE)
  }
  # display the count (clicking does nothing)
  Cvalue <- function(...) { TRUE }
  # increment the count
  Cplus <- function(e, xy) {
    ans <- get("answer", envir=e)
    assign("answer", ans + 1, envir=e)
    return(TRUE)
  }
  # 'Clear' button
  Cclear <- function(e, xy) {
    assign("answer", 0, envir=e)
    return(TRUE)
  }
  # quit button
  Cdone <- function(e, xy) { return(FALSE) }

  myclicks <- list("-"=Cminus,
                   value=Cvalue,
                   "+"=Cplus,
                   done=Cdone)

  # redraw the button that displays the current value of the count
  Rvalue <- function(button, nam, e) {
     plot(button, add=TRUE)
     ans <- get("answer", envir=e)
     text(centroid.owin(button), labels=ans)
     return(TRUE)
  }

  # make the panel
  P <- simplepanel("Counter",
                   B=myB, boxes=myboxes,
                   clicks=myclicks,
                   redraws = list(NULL, Rvalue, NULL, NULL),
                   exit=myexit, env=myenv)
  # print it
  P
  # show what it looks like
  redraw.simplepanel(P)

  # ( type run.simplepanel(P) to run the panel interactively )

  # add another button to right
  Pplus <- grow.simplepanel(P, "right", new.clicks=list(clear=Cclear))

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