linemitre threshold

[teunbrand]

Hi Thomas and team,

I just noticed that the ragg png and cairo png devices handle linemitre thresholds somewhat differently. This causes the cairo device to bevel the linejoins in the graphic below, whereas ragg does not. I'm no expert on the subject, but I had expected to see bevelled linejoins at linemitre = 1 (the lower limit that {grid} accepts).

Thanks for reading!

library(grid)

grob <- polylineGrob(
  x = seq(0.1, 0.9, length.out = 4),
  y = rep(c(0.1, 0.9), length.out = 4),
  gp = gpar(
    linemitre = 1, lwd = 20,
    linejoin = "mitre"
  )
)

tmp1 <- tempfile(fileext = ".png")
png(tmp1, type = "cairo")
grid.newpage() 
grid.draw(grob)
dev.off()
#> png 
#>   2
knitr::include_graphics(tmp1)

tmp2 <- tempfile(fileext = ".png")
ragg::agg_png(tmp2)
grid.newpage()
grid.draw(grob)
dev.off()
#> png 
#>   2
knitr::include_graphics(tmp2)

^{Created on 2022-10-24 by the reprex package (v2.0.1)}

[thomasp85]

Thanks for noticing - this is a regression due to some refactoring of the rendering code

[teunbrand]

Great, thanks Thomas!