On Fri, 14 Mar 2008, Deepayan Sarkar wrote: > On 3/13/08, Ben Bolker <[EMAIL PROTECTED]> wrote: >> >> Can someone point me to a justification for the design >> decisions, which seem to be similar in lattice and >> ggplot2, of > > Disclaimer: I don't have strong personal preferences, I just went with > what Trellis had. That said, > >> (1) gray backgrounds and > > lattice's default background is now white, and this was partly because > many people seemed to dislike the grey background. My personal feeling > is that it looked good on a screen or when using a beamer, but not so > good when printed. ggplot's background is lighter, so this probably > does not apply.
My memory is that Trellis had different schemes for different devices, so the background was white for plots intended for a printer. Also, the default scheme for postscript() was 'black and white', and few people had colour printers. Viewing conditions do matter here. I remember that in 1992 Trellis' grey looked horribly dark and muddy on Bill Venables' Sun monitor, something we were able to alleviate by adjusting it. But there is dissent about the gamma to be used on viewing screens and how dark a particular mid grey appears do depends on the gamma. [Most use ca 2.2, Macs have always been different at 1.8, and I believe the SGI systems used at Bell Labs at the time Trellis was developed were different again. Beamers (computer projectors) are often way off in their colour accuracy.] >> (2) filled points? >> [I seem to remember seeing somewhere the opposite recommendation >> for points, i.e. that open points make it much easier to >> see if there are overlapping values -- and this would >> be a reason that pch=1 gives an open circle ...] > > lattice does have open circles by default, except in ungrouped dot > plots, where there is no possibility of overlapping. There are choices between 'open' and 'closed', and I find using translucent fills makes overlap easier to detect. As from R 2.7.0 most graphics devices are capable of handling semi-transparent colours (at least on an opaque background, which is what is needed here). -- 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
