Support 'Positron Graphics Device'

[HulacSt]

When attempting to specify font in Positron, I get the following error:

Error : thematic doesn't (yet) support the 'Positron Graphics Device' graphics device.

Example

library(ggplot2)
library(thematic)
thematic::thematic_on(bg = '#191919',
                      fg = '#da831a',
                      accent = '#1A71DA',
                      font = 'Helvetica')

mtcars |> 
  ggplot(aes(x = disp, y = mpg)) +
  geom_point()

Error : thematic doesn't (yet) support the 'Positron Graphics Device' graphics device.

Session info

R version 4.3.1 (2023-06-16)
Platform: aarch64-apple-darwin20 (64-bit)
Running under: macOS Sonoma 14.1.1

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib 
LAPACK: /Library/Frameworks/R.framework/Versions/4.3-arm64/Resources/lib/libRlapack.dylib;  LAPACK version 3.11.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

time zone: America/Denver
tzcode source: internal

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] thematic_0.1.5 ggplot2_3.4.4 

loaded via a namespace (and not attached):
 [1] vctrs_0.6.4       cli_3.6.1         knitr_1.43        rlang_1.1.1       xfun_0.39         renv_1.0.0        generics_0.1.3    textshaping_0.3.6 labeling_0.4.3   
[10] glue_1.6.2        colorspace_2.1-0  ragg_1.2.5        scales_1.2.1      fansi_1.0.5       grid_4.3.1        munsell_0.5.0     tibble_3.2.1      yaml_2.3.7       
[19] lifecycle_1.0.3   compiler_4.3.1    dplyr_1.1.3       pkgconfig_2.0.3   rstudioapi_0.15.0 farver_2.1.1      lattice_0.21-8    systemfonts_1.0.4 R6_2.5.1         
[28] tidyselect_1.2.0  utf8_1.2.4        pillar_1.9.0      magrittr_2.0.3    tools_4.3.1       withr_2.5.2       gtable_0.3.4