library(ggsvg)
library(ggplot2)

# the svg that I need to use 
svg_url <- "https://raw.githubusercontent.com/luisDVA/luisdva.github.io/master/assets/images/Cat-green.svg"
cat_svg <- paste(readLines(svg_url), collapse = "\n")
# toy data
dat <-
  expand.grid(y=1:2,x=seq_len(2))
dat$qual <- letters[1:4]  
dat  

# works and uses default colors
ggplot(dat)+
  geom_point_svg(aes(x, y,css(selector = "path:nth-child(1)", fill = qual)), svg = cat_svg) +
  scale_svg_default()
  
# all colors are unchanged
ggplot(dat)+
  geom_point_svg(aes(x, y,css(selector = "path:nth-child(1)", fill = qual)), svg = cat_svg) +
  scale_svg_fill_viridis_d(aesthetics="fill")
                     
# colors unchanged
ggplot(dat)+
  geom_point_svg(aes(x, y,css(selector = "path:nth-child(1)", fill = qual)), svg = cat_svg) +
  scale_svg_fill_viridis_d("path:nth-child(1)")