Export R ggplot as windows meta file for powerpoint

I want to make a poster with graphs imported from R, using the ggplot package.

1. I could export the images as png, but they look pixelised on a big file. 
2. I would have liked to import SVG but it's not possible in microsoft powerpoint. 
3. win.metafile() is the solution

Took me a while to figure out that the windows metafile is also a scalable graphic format. It can be used as such:

win.metafile("file name.emf",width=17, height=9) # width and height in inches,
# You can divide by 72 to have the size in pixel
ggplot() + geom_line(data=dtf, aes(...))
dev.off()

Blank the screen in powerpoint to avoid divided attention

When the scientist presents: "Keep what the audience sees in sync with your speech [...] We, human folks, are not very good at doing two things at once when our senses are pulling us in different directions.[...] Blank the screen (B-Key or black slide)."