R shiny - ggplot/ggforce shape renders highly pixellated, how to anti-alias?

Question

I'm using the package ggforce to make particular shapes for an R shiny ggplot (using geom_ellipse and geom_shape). When I run the app from R itself, it renders the shapes nicely with smooth lines/shapes. However, when I actually run the app on the web, it presents differently, with what look like heavily aliased/pixelated lines.

The circle on the left is the web version, whereas the one on the right is the one that runs from R when I test the app directly.

I am wondering how to get the nice, smoother rendering in the web version, without having to do something like rendering the plot as an image.

Any help would be great!

Answer 1

Try to use cairo within the server function

server <- function(input, output, session){ options(shiny.usecairo=TRUE) ... }

The corresponding package library(Cairo) is required as well.