README.md

In jverzani/gWidgetsWWW2: Toolkit implementation of the gWidgets API for use with web pages

Port of gWidgets to the web

This package implements the gWidgets API for web programming. Deployment is through Rook, best suited for local use or limited internet usage. For wider deployment, there is gWidgetsWWW2.rapache which runs under Jeffrey Horner's rapache module for the apache webserver.

Primarily, the package turns the gWidgets commands into JavaScript commands. The ExtJS javascript libraries (www.sencha.com) are used for this, as they provide an excellent programming environment for JavaScript. Of course, the R user need not know any JavaScript, or even any web technologies -- not even HTML. Basically, most simple gWidgets scripts will just work.

If installed from github or r-forge, the extjs files will be included. If in the future the package will be available on CRAN, likely the commmand download_extjs will have to be issued to download the extjs files (67Mb) and install them within the package directory.

Example

To use gWidgetsWWW2 locally, one writes scripts to be executed by Rook. The basic "Hello World" app with a window, container, button and callback is created in a script hello.R and contains:

w <- gwindow("Hello world example")
g <- ggroup(cont=w, width=300, height=300)
b <- gbutton("click me", cont=g, handler=function(h,...) {
  galert("Hello World", parent=w)
})

This script is turned into a web page through the load_app function:

require(gWidgetsWWW2)
load_app("hello.R", app_name="hello")

The app is then mapped to the url

http://127.0.0.1:PORT/custom/hello/indexgw.rhtml

The "PORT" will be that for R's internal help server. The port argument can pass in a value if that has not yet been started, with a default of 9000.

The "hello" in the url matches that given by the app_name argument.

Read on for notes on deployment beyond the local computer.

Installation

You can install the package from RForge:

install.packages("gWidgetsWWW2", 
                 repos = c("http://r-forge.r-project.org", getOption("repos")))

Alternatively you can install from github, if the devtools package of H. Wickham is installed:

library(devtools)
install_github("jverzani/gWidgetsWWW2")

Otherwise, a) install git, b) clone the project c) use +R CMD INSTALL+, or some such to install from a local set of files.

Graphics

There is no interactive graphic device, though one can use several non-interactive graphics devices, in particular: png, through the gimage widget; and RSVGTipsDevice, through the gsvg widget. The basic use for each is similar.

jverzani/gWidgetsWWW2 documentation built on Feb. 9, 2020, 5:18 p.m.