Higher resolution PDF export?

Hi, I’m exporting a pdf of a plot and am getting really low quality graphics: the lines are choppy, datapoints aren’t actually round, etc. I’m using plotly_IMAGE(x, width = 1000, height = 1000, scale = 1.5, format = "pdf", out_file = filename). Is there a better way to export plotly to pdf?

An example is here: https://drive.google.com/open?id=1K3ZW6bZ1S8VREIufPrRSdoW_4-iYCrW- and as you can see it’s quite low-quality relative to what Plotly produces within the RStudio viewer.

Also, I tried an export to png from the web interface and the quality was much, much higher than from within RStudio (e.g., lines far less pixelated, all elements visible). Is there some way to do this at the command line, ideally with elements as vectors so that there is no pixelation at all?