Wrap plot instructions for DrawingML plotting in Powerpoint

A simple wrapper to mark the plot instructions as Vector Graphics instructions. It produces an object of class 'dml' with a corresponding method ph_with.

The function enables usage of any R plot with argument code and with ggplot objects with argument ggobj.

Note: the output is a vector graphic, not a native Microsoft Office chart. The underlying data is not embedded in the document.

Usage

dml(
  code,
  ggobj = NULL,
  bg = "white",
  fonts = list(),
  pointsize = 12,
  editable = TRUE,
  ...
)

Arguments

code

plotting instructions

ggobj

ggplot object to print. argument code will be ignored if this argument is supplied.

bg, fonts, pointsize, editable

Parameters stored and later passed to dml_pptx by ph_with.dml.

...

unused arguments

background color

When dealing with a ggplot object, the bg parameter sets the device background but the ggplot theme's plot.background will typically draw over it. To control the background appearance, set it in the theme instead:

theme(
  panel.background = element_rect(fill = "#EFEFEF"),
  plot.background = element_rect(fill = "wheat"))

Limitations

The DrawingML format does not support the following R graphics features:

• Patterns and gradients: grid patterns (GridPattern), linear and radial gradients used as fill are not translated into DrawingML. ggplot2 will emit a warning when these are used.

• Rich text (ggtext/gridtext): packages such as ggtext render HTML/Markdown into composite grid grobs. The rvg device can only capture low-level primitives (text strings, lines, polygons), so the rich formatting (inline images, coloured spans, HTML markup) is lost. Use standard ggplot2 text functions or apply formatting after export in PowerPoint.

• Plotmath expressions: R's graphics engine decomposes expression() into individual text primitives before the device sees them. Compound expressions (e.g. expression("a" * "b"), superscripts, subscripts) are rendered as separate text boxes, causing vertical misalignment.

• Clipping paths, masks, compositing and transformations: these R >= 4.1 features have no DrawingML equivalent and are silently ignored.

See also

ph_with.dml

Examples

anyplot <- dml(code = barplot(1:5, col = 2:6), bg = "wheat")

library(officer)
doc <- read_pptx()
doc <- add_slide(doc, "Title and Content", "Office Theme")
doc <- ph_with(doc, anyplot, location = ph_location_fullsize())
fileout <- tempfile(fileext = ".pptx")
# fileout <- "vg.pptx"
print(doc, target = fileout)