plot incorrectly cropped when setting legend font face

[grlloyd]

When I set the legend font face in a ggplot2 theme to "bold" or "italic" the legend is excluded from the rendered image in the pdf. When using grid plots (e.g. with cowplot package) any plot after the first isn't rendered.

In the example below plots with italic font are rendered incorrectly in the pdf.

---
title: "title"
output: BiocStyle::pdf_document
---

```{r}
library(ggplot2)
library(cowplot)

# iris data
A = iris
```

# solo plot, italic font
```{r solo-plot-italic}
g1 = ggplot(data=A,aes(x=Sepal.Length,y=Sepal.Width,colour=Species)) +
    geom_point() + theme(legend.title = element_text(face='italic'))

plot(g1)
```

# solo plot, plain font
```{r solo-plot-plain}
g2 = g1=ggplot(data=A,aes(x=Sepal.Length,y=Sepal.Width,colour=Species)) +
    geom_point() + theme(legend.title = element_text(face='plain'))

plot(g2)
```

# grid plot, italic font
```{r cowplot-italic}
g1 = ggplot(data=A,aes(x=Sepal.Length,y=Sepal.Width,colour=Species)) +
    geom_point() + theme(legend.title = element_text(face='italic'))

plot_grid(g1,g1,nrow=1)
```

# grid plot, plain font
```{r cowplot-plain}
g2 = ggplot(data=A,aes(x=Sepal.Length,y=Sepal.Width,colour=Species)) +
        geom_point() + theme(legend.title = element_text(face='plain'))

plot_grid(g2,g2,nrow=1)
```

[grlloyd]

Setting knitr::opts_chunk$set(crop = NULL) fixes this. This means that the figures are not being cropped as intended by BiocStyle though.

[lshep]

Also for reference. This conversation on bioc devel: https://stat.ethz.ch/pipermail/bioc-devel/2020-April/016656.html