gtext: Multiline text edit constructor

In jverzani/gWidgets2: Rewrite of gWidgets API for Simplified GUI Construction

Description

The multiline text widget has its main property the text contained within.

• The svalue will return a string (length-1 character vector) with embedded newlines

• The "change" handler is addHandlerKeystroke

• Use addHandlerSelectionChanged to monitor the selection

generic for toolkit dispatch

insert text into a gtext buffer

insert method for gtext

dispose method for gtext clears buffer

The svalue method for a gtext object returns a) the buffers content; b) the selected text (if drop=TRUE, but not NULL), this can be used to set the selected value, as well; c) the index of the selection if index=TRUE.

Usage

gtext(text = NULL, width = NULL, height = 300, font.attr = NULL,
  wrap = TRUE, handler = NULL, action = NULL, container = NULL, ...,
  toolkit = guiToolkit())

.gtext(toolkit, text = NULL, width = NULL, height = 300,
  font.attr = NULL, wrap = TRUE, handler = NULL, action = NULL,
  container = NULL, ...)

insert(obj, value, where = c("end", "beginning", "at.cursor"),
  font.attr = NULL, do.newline = TRUE, ...)

## S3 method for class 'GText'
insert(obj, value, where = c("end", "beginning", "at.cursor"),
  font.attr = NULL, do.newline = TRUE, ...)

## S3 method for class 'GText'
dispose(obj, ...)

## S3 method for class 'GText'
svalue(obj, index = NULL, drop = NULL, ...)

Arguments

text	initial text
width	width of widget
height	height of widget (when width is specified)
font.attr	font attributes for text buffer. One can also specify font attributes for insertion. The font attributes are specified with a list with named components, with names and values coming from: weight in c("light", "normal", "bold", "heavy") style inc("normal", "oblique", "italic") family in c("sans", "helvetica", "times", "monospace") size in c("xx-small", "x-small", "small", "medium", "large", "x-large", "xx-large") foreground a value in colors() background a value in colors()
wrap	logical do lines wrap
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.
obj	object
value	text to insert
where	position of insertion
do.newline	logical add a newline at end
index	NULL or logical. If TRUE and widget supports it an index, instead of a value will be returned.
drop	NULL or logical. If widget supports it, drop will work as it does in a data frame or perhaps someother means.

Value

called for side effect

Note

with gWidgetstcltk the allocation of size to the widget may be incorrect. It is best to wait until the widget is added before displaying its parent window. See the visible argument for gwindow.

Examples

## Not run: 
w <- gwindow("gtext example", visible=FALSE)
g <- gvbox(cont=w)
t1 <- gtext("initial text", container=g)
t2 <- gtext("monospace", font.attr=list(family="monospace"), container=g)
insert(t2, "new text in bold", font.attr=list(weight="bold"))
visible(w) <- TRUE

## End(Not run)

jverzani/gWidgets2 documentation built on May 20, 2019, 5:17 a.m.