This function returns the name of the PNG file that it generates. In
essence, it calls png(), then func(), then dev.off().
So func must be a function that will generate a plot when used this
way.
plotPNG(func, filename = tempfile(fileext = ".png"), width = 400,
height = 400, res = 72, ...)A function that generates a plot.
The name of the output file. Defaults to a temp file with
extension .png.
Width in pixels.
Height in pixels.
Resolution in pixels per inch. This value is passed to
png. Note that this affects the resolution of PNG rendering in
R; it won't change the actual ppi of the browser.
Arguments to be passed through to png.
These can be used to set the width, height, background color, etc.
For output, it will try to use the following devices, in this order:
quartz (via png), then CairoPNG,
and finally png. This is in order of quality of
output. Notably, plain png output on Linux and Windows may not
antialias some point shapes, resulting in poor quality output.
In some cases, Cairo() provides output that looks worse than
png(). To disable Cairo output for an app, use
options(shiny.usecairo=FALSE).