Display a {googleVis} graphic in R Markdown

googleVis_test.Rmd

---
title: "googleVis test"
author: "Matt Dray"
date: "23/04/2019"
output: html_document
---

Set up example dataframe from [the {googleVis} examples](https://cran.r-project.org/web/packages/googleVis/vignettes/googleVis_examples.html) CRAN vignette.

```{r}
df <- data.frame(
  country = c("US", "GB", "BR"), 
  val1 = c(10, 13, 14), 
  val2 = c(23, 12, 32)
)
```

Call library and set options as in the [Markdown example with knitr and googleVis](https://cran.r-project.org/web/packages/googleVis/vignettes/Using_googleVis_with_knitr.html) CRAN vignette.

```{r}
library(googleVis)
op <- options(gvis.plot.tag = 'chart')
```

Create and plot. Make sure you set `results='asis'` in the chunk settings so the JavaScript for your plot is read and compiled as an image.

```{r results='asis'}
Line <- gvisLineChart(df, options = list(title = "Var by country"))
plot(Line)
```