Knitr with gridSVG

Question

Does anybody use gridSVG in Knitr? I found package "gridSVG" provide a device named "gridsvg" and I've written code as follows.

 ```{r message=FALSE, echo=FALSE, warning=FALSE, results='hide', dev='gridsvg', fig.ext='svg'}
analysis.runner.result.plot(result, score.table, info.table) # which produces a gpplot
```

When I click "Knitr HTML", I got:

pandoc.exe: Could not find data file
AnalysisReport_files/figure-html/unnamed-chunk-61.svg pandoc document conversion failed

It seems that the gridsvg didn't produce svg file. I've searched the internet but failed to find any example that uses gridSVG in knitr.

How should I modify the code? (P.S. due to the render quality under windows, I don't want to use the default 'svg' device)

Thanks!

Answer 1

Because gridSVG::gridsvg() is not a standard R graphics device, you cannot use the dev chunk option in knitr. The only way at the moment is to manually save the plots, and use a chunk hook to write the plots to your output (see the knitr graphics manual). Here is an example:

---
title: Save plots using gridSVG and knitr
author: Yihui Xie
output:
  html_document: default
---

Set up a chunk hook for manually saved plots.

```{r setup}
library(knitr)
knit_hooks$set(custom.plot = hook_plot_custom)
```

A single plot.

```{r test-a, fig.keep='none', fig.ext='svg', custom.plot=TRUE}
library(ggplot2)
qplot(speed, dist, data = cars)
gridSVG::grid.export(fig_path('.svg'))
```

Multiple plots.

```{r test-b, fig.keep='none', fig.ext='svg', custom.plot=TRUE, fig.num=2, message=FALSE}
library(ggplot2)
p = qplot(speed, dist, data = cars)
p + geom_smooth()
gridSVG::grid.export(fig_path('svg', number = 1))
p + geom_jitter()
gridSVG::grid.export(fig_path('svg', number = 2))
```

See the source document of this post at
http://stackoverflow.com/q/23852753/559676

See output at http://rpubs.com/yihui/knitr-gridsvg