[Rd] png(type='cairo'): point symbols without boarders are not anti-aliased?

[Yihui Xie]

Sorry, typo in the subject: I mean "borders".

Regards,
Yihui
--
Yihui Xie <xieyihui at gmail.com>
Web: http://yihui.name
Department of Statistics, Iowa State University
2215 Snedecor Hall, Ames, IA


On Mon, Oct 21, 2013 at 4:43 PM, Yihui Xie <xie at yihui.name> wrote:
> Hi,
>
> It seems that anti-aliasing in png(type = 'cairo') is not well
> supported for the point symbols without boarders, e.g. pch = 16. The
> Cairo package works well, though. You can compare png() with
> CairoPNG():
>
> png(): http://i.imgur.com/8niB3jX.png
> CairoPNG(): http://i.imgur.com/FZBJOxm.png
>
> f = function(dev, ..., main = '') {
>   dev(...)
>   plot(c(1, 2, 1, 2), c(1, 1, 2, 2), pch=c(16, 19), cex=c(2, 2, 15, 15),
>        xlim=c(0.5, 2.5), ylim=c(0.5, 3), main = deparse(substitute(dev)))
>   dev.off()
> }
> f(grDevices::png, 'png-base.png', type = 'cairo')
> f(Cairo::CairoPNG, 'png-Cairo.png')
>
> If I remove the border for pch=19 (i.e. lwd=0), the point shows rough
> edges as well.
>
> I'm not sure if that is expected, or it is due to my misconfiguration
> somewhere. I installed R via `apt-get install r-base-dev` under Ubuntu
> using the CRAN repository.
>
>> sessionInfo()
> R version 3.0.2 (2013-09-25)
> Platform: x86_64-pc-linux-gnu (64-bit)
>
> locale:
>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
> LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
>  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
> LC_PAPER=en_US.UTF-8       LC_NAME=C
>  [9] LC_ADDRESS=C               LC_TELEPHONE=C
> LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
>
> loaded via a namespace (and not attached):
> [1] Cairo_1.5-2 tools_3.0.2
>
>> capabilities()
>     jpeg      png     tiff    tcltk      X11     aqua http/ftp  sockets
>     TRUE     TRUE     TRUE     TRUE     TRUE    FALSE     TRUE     TRUE
>   libxml     fifo   cledit    iconv      NLS  profmem    cairo
>     TRUE     TRUE     TRUE     TRUE     TRUE     TRUE     TRUE
>
>
> Regards,
> Yihui
> --
> Yihui Xie <xieyihui at gmail.com>
> Web: http://yihui.name
> Department of Statistics, Iowa State University
> 2215 Snedecor Hall, Ames, IA