I've moved this from r-help to r-devel. On 3/23/2006 8:17 PM, Paul Murrell wrote:
>> >> Paul, >> If I read your comments correctly, the problem with manipulating the >> graph history is with saved histories across sessions/versions. Is >> there any reason not to manipulate it *within* a session? I never >> save plots for re-use in R. Re-running code is usually best for me. >> But I would find it handy to fiddle with the display list in a >> session. > > > That is *one* problem with the display list. Messing directly with the > display list *within a session* is *less* dangerous, but R's behaviour > if you do that is "undefined". > > The display list is technically an internal structure for R's internal > use. We can't stop you playing with it, but I do not encourage it and > it is not officially supported. > > There are a number of simple things that you could do to the display > list that should work, but providing proper support for general > manipulations of the display list would require a significant amount of > (re)design of the R graphics code. > > Paul > > p.s. These comments apply to the display list in R's "graphics engine". > The 'grid' package also maintains a display list, and that has been > designed to support more general manipulations. Are we talking about the same thing? I think Peter is only thinking of manipulating the .SavedPlots variable, which is a Windows-only object holding plot history. I imagine the entries in .SavedPlots[[5]] are the things that you are worried about, and I agree people shouldn't play with those, they should be using grid instead with its documented interface. If we do warn people off manipulating .SavedPlots, then I think it should be a higher priority to implement some manipulations ourselves, e.g. "[<-.SavedPlots", to allow entries to be moved around or deleted in the list. Duncan ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
