On Tue, 21 Feb 2006, Hin-Tak Leung wrote: > Prof Brian Ripley wrote: >> On Mon, 20 Feb 2006, Prof Brian Ripley wrote: >> >>> On Mon, 20 Feb 2006, Paul Murrell wrote: > <snipped> >>>>> >> x11() >>>>> >> plot(rnorm(10)) >>>>> >> dev.print(png) > <snipped> >>> I don't think there is a way to do that unambiguously (there is no >>> standard way to do the conversion), and in any case dev.print() was passed >>> a function, not the name of a function, and so does not in general know >>> how it behaves (and your 'png' need not be R's png()). > > There is a "standard" way of querying the X display directly about > the size each pixel supposedly represents - well, an X display can > be configured wrongly, etc, but you get what you ask for... > > $ xdpyinfo |grep 'resolution' > resolution: 75x75 dots per inch > > (this 75x75 seems to be a default value as I did not set it anywhere, > but I believe it is configurable)
Yes, but this is png, not X11. The resolution of your X11 screen is unrelated to a .png file you might produce. > I am not sure about png files, but tiff files also have internal data > claiming x pixels corresponds to y inches. (and I am fairly sure jpeg > does *not* have this feature). Reading the help page for the R devices will enlighten you. (Really, you should do so before posting as we do ask.) An assumption of 72ppi is quite common, but so are 180 and 300. The png/jpeg devices now tell careless users that small width/height values are probably a mistake. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
