Save a plot to multiple formats

Saves a ggplot object to disk at a set physical size. Allows specific maximum dimensions with an optional target aspect ratio to fit into specific configurations for publication. e.g. a half page plot or a third of a 2 column page. Allows output in pdf for journal publication or png for inclusion in documents, and makes sure that the outputs are near identical.

Usage

gg_save_as(...)

Arguments

...

Named arguments passed on to .gg_save_as

filename

base of target filename (excluding extension).

plot

a ggplot

size

a standard size see `std_size`

maxWidth

maximum width in inches

maxHeight

maximum height in inches

aspectRatio

defaults to maxWidth/maxHeight

formats

some of svg, png, pdf, Rdata, eps, ...

webfontFinder

a function that takes a plot and returns a properly formatted css specification for webfonts in the plot. This is for internal use and does not need to be changed.

...

Named arguments passed on to svglite::svglite

height,width

Height and width in inches.

bg

Default background color for the plot (defaults to "white").

pointsize

Default point size.

standalone

Produce a standalone svg file? If FALSE, omits xml header and default namespace.

web_fonts

A list containing web fonts to use in the SVG. The fonts will still need to be available locally on the computer running the code, but viewers of the final SVG will not need the font if specified as a web font. Web fonts can either be specified using font_face() or given as a single string in which case they are taken to be URL's for an @import directive to e.g. Google Fonts. For the latter, you can use fonts_as_import() to automatically generate the string, optionally embedding the font data in it. If the passed in string is not in the form of a URL or @import statement then it is considered a font family name and fonts_as_import() will be called to convert it to an import automatically, using the default arguments.

id

A character vector of ids to assign to the generated SVG's. If creating more SVG files than supplied ids the exceeding SVG's will not have an id tag and a warning will be thrown.

fix_text_size

Should the width of strings be fixed so that it doesn't change between svg renderers depending on their font rendering? Defaults to TRUE. If TRUE each string will have the textLength CSS property set to the width calculated by systemfonts and lengthAdjust='spacingAndGlyphs'. Setting this to FALSE can be beneficial for heavy post-processing that may change content or style of strings, but may lead to inconsistencies between strings and graphic elements that depend on the dimensions of the string (e.g. label borders and background).

scaling

A scaling factor to apply to the rendered line width and text size. Useful for getting the right sizing at the dimension that you need.

always_valid

Should the svgfile be a valid svg file while it is being written to? Setting this to TRUE will incur a considerable performance hit (>50% additional rendering time) so this should only be set to TRUE if the file is being parsed while it is still being written to.

file

Identical to filename. Provided for backward compatibility.

system_fonts

Consider using systemfonts::register_font() instead. Named list of font names to be aliased with fonts installed on your system. If unspecified, the R default families sans, serif, mono and symbol are aliased to the family returned by font_info().

user_fonts

Consider using systemfonts::register_font() instead. Named list of fonts to be aliased with font files provided by the user rather than fonts properly installed on the system. The aliases can be fonts from the fontquiver package, strings containing a path to a font file, or a list containing name and file elements with name indicating the font alias in the SVG output and file the path to a font file.

Value

the output is an sensible default object that can be displayed given the context it is called in, for example if knitting an RMarkdown document a link to the png file for embedding, if latex a link to the pdf file.

Details

For maximum cross platform reproducibility we are using the combination of `systemfonts` for font management, `svglite` to render the canonical output `rsvg` to convert that to pdf, and `ragg` to for bitmap formats. In some situations `rsvg` fails in which case we fall back to rendering in a headless chrome instance. This rather complicated pipeline ensures modern webfont support, and editable SVG or PDF.

Examples

try({
.gg_pedantic(fontSize = 6)
p = ggplot2::ggplot(mtcars, ggplot2::aes(mpg, wt, colour=as.factor(cyl))) +
  ggplot2::geom_point()
# p %>% .gg_save_as(filename="~/tmp/plot_example",maxWidth=4,maxHeight=4)
p %>% .gg_save_as(filename=tempfile(),maxWidth=2,maxHeight=1.5)

plot = ggplot2::ggplot(ggplot2::diamonds, ggplot2::aes(x=carat,y=price,color = color))+
  ggplot2::geom_point()+
  ggplot2::annotate("label",x=2,y=10000,label="Hello \u2014 world", family="Kings")+
  ggplot2::labs(tag = "A")+
  ggplot2::xlab("Carat\u2082")+
  ggplot2::ylab("price\u2265")

# plot %>% .gg_save_as(filename="~/tmp/plot_example_2")
res = plot %>% .gg_save_as(filename=tempfile(), formats=c("png","eps"))
as.character(res)
res
})
#> Error in .gg_pedantic(fontSize = 6) : 
#>   could not find function ".gg_pedantic"