gvis Methods
Print and plot gvis objects
Methods to print and plot gvis
objects
Usage
"print"(x, tag=NULL, file = "", ...)
"plot"(x, tag=NULL,...)
Arguments
- x
-
An object of class
gvis
, or a HTML file in case of plot.gvis. - tag
- Default
NULL
. Name tag of the objects to be extracted from a gvis object. If tag is missing then the values ofgetOption("gvis.print.tag")
,getOption("gvis.plot.tag")
will be used forprint.gvis
andplot.gvis
respectively.A complete list of available tags is given by the command
getOption("gvis.tags")
.The default value of
gvis.print.tag
is"html"
, which meansprint.gvis
will show a complete web page with the visualisation, while the tag"chart"
will present the code for the visualisation chart only. For more information see the details section.The default tag for
plot.gvis.tag
isNULL
, which will result in R opening a browser window, while any tag which is notNULL
will give the same behaviour asprint.gvis
, e.g.tag='chart'
or settingoptions(gvis.plot.tag='chart')
will produce the same output asprint(x, tag='chart')
. This behaviour is particular helpful when googleVis is used in scripts, likeknitr
orR.rsp
. The plot commands can be used initially in an interactive mode and with one change inoptions()
produce the HTML output required for a programmatic run of the script. See the example section below for aknitr
case study.plot.gvis
ignores the argumenttag
itx
is a HTML file name. - file
-
file name. If "" (the
default), output will be printed to the standard output connection,
the console unless redirected by
sink
. - ...
- arguments passed on to
cat
(print.gvis
) orbrowseURL
(plot.gvis
).
Details
An object of class "gvis
" is a list containing at least the
following components (tags):
type
- Google visualisation type, e.g. 'MotionChart'
chartid
html
header
- a character string of a html page header:
...
,
chart
jsHeader
- Opening
tag and reference to Google's JavaScript library.
jsData
- JavaScript function defining the input
data
as a JSON object. jsDrawChart
- JavaScript function combing the data with the visualisation API and user options.
jsDisplayChart
- JavaScript function calling the handler to display the chart.
jsFooter
- End tag
.
jsChart
jsDisplayChart
function.
divChart
container to embed the chart
into the page.
caption
footer
...
, including the used R and googleVis version
and link to Google's Terms of Use.
Value
print.gvis
- None (invisible
NULL
). plot.gvis
- Returns the file name invisibly.
Note
The plot
command does not open a graphics device in the
traditional way. Instead it creates HTML files in a temporary
directory and uses the R HTTP server to display the output
of a googleVis
function locally.
A browser with Flash and Internet connection is required.
The displayed page includes a link (click on the chart id) to a
further page, which shows the code of the chart for the user to copy
and paste into her own page.
References
Please see also the package vignette for the usage of the googleVis package with RApache, brew, knitr and R.rsp.
See Also
See also cat
, browseURL
,
createGoogleGadget
and gvisMerge
for combining charts.
Examples
## Show gvis options
sapply(c("gvis.print.tag", "gvis.plot.tag", "gvis.tags"), getOption)
M <- gvisMotionChart(Fruits, "Fruit", "Year")
str(M)
## The output for a complete web page
M
## Access only the plot,
M$html$chart
## wrap it in cat and it becomes more readable,
cat(unlist(M$html$chart))
## or use the print function.
print(M, tag="chart")
## Extract the data as a JavaScript function.
print(M, tag="jsData")
## Display the visualisation.
## A web browser with Internet connection and Flash is required.
plot(M)
## Combine with another chart, e.g. table
#tbl <- gvisTable(Fruits, options=list(height=220))
#Mtbl <- gvisMerge(M, tbl)
#plot(Mtbl)
## Example of using googleVis with knitr and markdown
## Not run:
# ## Simple knitr/markdown file with googleVis
# knitrRmd <-"
# # Markdown example with knitr and googleVis
# ===========================================
# This is a little Markdown example file.
# Set the googleVis options first.
# In this case change the behaviour of plot.gvis
# ```{r setOptions, message=FALSE}
# library(googleVis)
# op <- options(gvis.plot.tag='chart')
# ```
# The following plot statements will automatically return the HTML
# required for the 'knitted' output.
#
# ## Combo chart
# ```{r ComboExample, results='asis', tidy=FALSE}
# ## Add the mean
# CityPopularity$Mean=mean(CityPopularity$Popularity)
# CC <- gvisComboChart(CityPopularity, xvar='City',
# yvar=c('Mean', 'Popularity'),
# options=list(seriesType='bars',
# width=450, height=300,
# title='City Popularity',
# series='{0: {type:\"line\"}}'))
# plot(CC)
# ```
# Example of gvisComboChart with R code shown above.
#
# ## Place two charts next to each other
# ```{r gvisMergeExample, results='asis', echo=FALSE}
# Geo <- gvisGeoChart(Exports, locationvar='Country', colorvar='Profit',
# options=list(height=300, width=350))
# Tbl <- gvisTable(Exports, options=list(height=300, width=200))
# plot(gvisMerge(Geo, Tbl, horizontal=TRUE))
# ``````
# Example of a gvisGeoChart with gvisTable and R code hidden.
#
# ## Motion Chart
# ```{r MotionChartExample, results='asis', tidy=FALSE}
# M <- gvisMotionChart(Fruits, 'Fruit', 'Year',
# options=list(width=400, height=350))
# plot(M)
# ```
# Please note that the Motion Chart is only displayed when hosted on a
# web server, or is placed in a directory which has been added to the
# trusted sources in the [security settings of Macromedia]
# (http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager04.html).
# See the googleVis package vignette for more details.
#
# ```{r resetOptions}
# ## Set options back to original options
# options(op)
# ```
# "
#
# ## Write the content of knitrRmd into a Rmd-file, knit it and convert it
# ## into a html output. Finally show the file with the R-help http
# ## server, this will ensure that also the motion chart is visible.
#
# library(knitr)
# library(markdown)
#
# wd <- getwd()
# setwd(tempdir())
# fn=tempfile()
# fn.Rmd <- paste(fn, ".Rmd", sep="")
# fn.md <- paste(fn, ".md", sep="")
# fn.html <- paste(fn, "-out.html", sep="")
# ## Write R Markdown into a file
# cat(knitrRmd, file=fn.Rmd)
# render_markdown()
# knit(fn.Rmd, fn.md)
# knit2html(fn.md)
#
# ## Open output in browser
# ## Use plot.gvis which will use the R-help http server
# ## The URL will start with http://127.0.0.1...
# ## The HTML file will be copied into a temporary directory
# plot.gvis(fn.html)
# ## Compare to browseURL, its URL will start with file://... the motion
# ## chart is unlikely to be displayed because of Flash security
# ## settings. See the googleVis vignette for more details.
# browseURL(fn.html)
# setwd(wd)
# ## End(Not run)
## Not run:
# ## Updating the data of an existing googleVis web page
#
# ## Suppose you have an existing web page in which you embedded a
# ## motion chart with the id "mtnc".
# ## Now you have a new set of data, but you would like to avoid
# ## touching the html file again.
# ## The idea is to write the data and JavaScript functions into separate
# ## files and to refer to these in the html page.
#
# ## In this example we call the chart id "mtnc"
# ## To display the example we use the R HTTP server again, and
# ## write the files into a temp directory
#
# myChartID <- "mtnc"
# ## baseURL should reflect your web address, e.g. http://myHomePage.com
# baseURL <- sprintf("http://127.0.0.1:%s/custom/googleVis", tools:::httpdPort)
# wwwdir <- tempdir() ## the www repository on your computer
#
#
# ## Create a motion chart
# M=gvisMotionChart(Fruits, "Fruit", "Year", chartid=myChartID)
#
# ## Here is our plot again
# plot(M)
#
# ## Write the data and functions into separate files:
# cat(M$html$chart['jsData'], file=file.path(wwwdir, "gvisData.js"))
# cat(M$html$chart[c('jsDrawChart', 'jsDisplayChart', 'jsChart')],
# file=file.path(wwwdir, "gvisFunctions.js"))
#
#
# ## Create a html page with reference to the above
# ## JavaScript files
#
# html <- sprintf('
# <html>
# <head>
# <script type="text/javascript" src="http://www.google.com/jsapi">
# </script>
# <script type="text/javascript" src="%s/gvisFunctions.js"></script>
# <script type="text/javascript" src="%s/gvisData.js"></script>
# <script type="text/javascript">
# displayChart%s()
# </script>
# </head>
# <body>
# <div id="%s" style="width: 600px; height: 500px;"></div>
# </body>
# </html>
# ', baseURL, baseURL, myChartID, myChartID)
#
# ## Write html scaffold into a file
# cat(html, file=file.path(wwwdir, paste("Chart", myChartID, ".html", sep="")))
#
# ## Display the result via
# URL <- paste(baseURL,"/Chart", myChartID, ".html", sep="")
# browseURL(URL)
#
# ## Update the data, say the data should have shown North and South
# ## instead of East and West as a location
# FruitsUpdate <- Fruits
# levels(FruitsUpdate$Location)=c("North", "South")
#
# Mupdate=gvisMotionChart(FruitsUpdate, "Fruit", "Year", chartid=myChartID)
#
# ## Only update the file gvisData.js:
# cat(Mupdate$html$chart['jsData'], file=file.path(wwwdir, "gvisData.js"))
#
# ## Redisplay the chart with the updated data
# browseURL(URL)
#
# ## End(Not run)