Hi, Thanks for pointing this out. I do have the book, unfortunately I left it abroad this year. I would think that such brief mention in ?gpar could be useful (because that's where one first looks for gpar() defaults --- which are not listed).
Best regards, baptiste On 6 August 2010 00:54, Paul Murrell <p.murr...@auckland.ac.nz> wrote: > Hi > > The help page for "Working with Viewports" (e.g., pushViewport()) has a > brief mention when talking about the ROOT viewport ... > > "The viewport tree always has a single root viewport (created by the system) > which corresponds to the entire device (and default graphical parameter > settings)." > > ... which is a reasonable place for it because this is a feature of the gpar > of the ROOT viewport, not of gpars in general. That mention might be a bit > hard to find, but a very similar statement is also made in the Section on > Viewports in the R Graphics book. That in turn might be hard to find if you > don't have the book, but that chapter is also available online > (http://www.stat.auckland.ac.nz/~paul/RGraphics/chapter5.pdf) > > It might be worth adding something more explicit about this sort of gotcha > ... > > "Some devices have different default graphics parameter settings, so it is > not safe to assume that the ROOT viewport will be identical on different > devices." > > ... ? > > Paul > > On 5/08/2010 8:14 a.m., baptiste auguie wrote: >> >> Dear list, >> >> I'm puzzled by the graphical output in the following example, >> >> library(grid) >> >> foo<- function(){ >> grid.rect(gp=gpar(fill="black")) >> print(get.gpar()$fill) >> grid.rect(width=0.2,height=0.2) >> } >> >> png("test.png", bg = "transparent") >> foo() >> dev.off() >> >> png("test1.png", bg = "white") >> foo() >> dev.off() >> >> >> It seems that the default value of gpar()$fill is set according to the >> device background. I couldn't find this documented in ?gpar or in >> ?png, and it caused a rather puzzling bug in my code (the pdf() output >> was OK, whilst the png output (default bg to white) was seemingly >> empty because covered by a white rectangle.) >> >> Best regards, >> >> baptiste >> >> ______________________________________________ >> R-devel@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-devel > > -- > Dr Paul Murrell > Department of Statistics > The University of Auckland > Private Bag 92019 > Auckland > New Zealand > 64 9 3737599 x85392 > p...@stat.auckland.ac.nz > http://www.stat.auckland.ac.nz/~paul/ > -- ____________________ Dr. Baptiste Auguié Departamento de Química Física, Universidade de Vigo, Campus Universitario, 36310, Vigo, Spain tel: +34 9868 18617 http://webs.uvigo.es/coloides ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
