gWidgets (version 0.0-27)

gedit: Constructors for widgets to handle text input

Description

The gedit widget is used to enter single lines of text. The gtext widget creates a text buffer for handling multiple lines of text.

Usage

gedit(text = "", width = 25, coerce.with = NULL, handler = NULL, action = NULL, container = NULL, ..., toolkit = guiToolkit())
gtext (text = NULL, width = NULL, height = 300, font.attr = NULL, 
    wrap = TRUE, handler = NULL, action = NULL, container = NULL, 
    ..., toolkit = guiToolkit())

Arguments

text

Initial text in widget

width

Width of widget. For gedit, this means the number of characters. For gtext the pixel widget

height

Height of gtext widget in pixels

font.attr

Optional specification of font attributes

wrap

For gtext, are long lines wrapped?

coerce.with

For gedit, when the value is retrieved this function is applied to the result. (The stored value is always a character, this can be used to make it numerc, to quote it, ...

handler

Handler called when text is changed. For gedit, this means the enter key is pressed.

action

Passed to handler

container

Optional container to attach widget to

...

Passed to add method of container

toolkit

Which GUI toolkit to use

Details

The gedit widget has the following methods:

The svalue method retrieves the value. If a function is given to the argument coerce.with it is applied before the value is returned. This can be used to coerce the text value (always of class character) to a numeric, or to a date, or to be quoted, ...

The svalue<- method is used to set the value.

The "[" and "[<-" methods refer to the widgets "type-ahead" values. A familiar usage is when a url is typed into a web browser, matches appear from a users history that could possibly complete the typed url.

The gtext widget has the following methods.

The svalue method returns the text held in the buffer. If drop=TRUE, then only the text in the buffer selected by the mouse is returned.

The svalue<- method replaces the text in the buffer with the new text.

New text is added with the add method. The basic usage is add(obj,text) where "text" could be a single line or a vector of text, or a gwidget (although some, like gedit, are kind of flaky). Extra arguments include do.newline a logical indicating if a new line after the last line should be added (default is TRUE); font.attr to specify any font attributes; where indicating where to add the text (either end or beginning).

The font can be changed. The font.attr argument to the constructon and to add specifies fonts using a namedcharacter vector. For instance c(style="normal", weights="bold",sizes="medium"). The command obj[['tags']] will produce a list containing all the available attributes.

The font<- method is used to change the font of the currently selected text. It too takes a named character vector specifying the font attributes.

The dispose method clears the text in the buffer.

The addHandlerKeystroke method for geditand gtext is called for each keystroke. In gtext or RGtk2 the component key of the h argument contains the keystroke.

Examples

gedit("type here", container=gwindow())
	
	## change handler
	obj <- gedit(container=gwindow())
	addhandlerchanged(obj, handler=function(h,...) 
	  cat("You typed", svalue(h$obj),"\n"))

	 ## coerce to numeric
	 obj <- gedit("7", container=gwindow(), coerce.with=as.numeric)
	 svalue(obj)

        ## gtext example
        obj <- gtext("First line", container=gwindow())
        add(obj,"second line", font.attr=c(family="monospace"))
        add(obj,"third line", font.attr=c(foreground.colors="red"))