The graphic engine in R only supports 8bit colours. This is for the most part fine, as 8bit gives all the fidelity needed for most graphing needs. However, this may become a limitation if you need to plot thousands of very translucent shapes on top of each other. 8bit only afford a minimum of 1/255 alpha, which may end up accumulating to fully opaque at some point. This device allows you to create a 16bit device that modifies the alpha level of all incomming colours by a fixed multiplier, thus allowing for much more translucent colours. The device will only modify transparent colour, so if you pass in an opaque colour it will be left unchanged.
agg_supertransparent(filename = "Rplot%03d.png", width = 480,
height = 480, units = "px", pointsize = 12, background = "white",
res = 72, alpha_mod = 1)The name of the file. Follows the same semantics as the file naming in [grDevices::png()], meaning that you can provide a [sprintf()] compliant string format to name multiple plots (such as the default value)
The dimensions of the device
The dimensions of the device
The unit `width` and `height` is measured in, in either pixels (`'px'`), inches (`'in'`), millimeters (`'mm'`), or centimeter (`'cm'`).
The default pointsize of the device in pt
The background colour of the device
The resolution of the device. This setting will govern how device dimensions given in inches, centimeters, or millimeters will be converted to pixels. Further, it will be used to scale text sizes and linewidths
A numeric between 0 and 1 that will be multiplied to the alpha channel of all transparent colours