On Jan 12, 2010, at 8:50 , Kasper Daniel Hansen wrote:
Steffen Neuman has provided the following reproducible example for (subtype in c("cairo", "Xlib", "quartz")) { png(filename=paste("test",subtype,"plot%003d.png", sep="_"), width = 640, height = 480, type=subtype) for (i in c(1,2,3)) { plot(0,0, type="n", main=i, xlim=c(-1 + 0.1*i, +1 + 0.1*i), ylim=c(-1 + 0.1*i, +1 + 0.1*i), xlab="xlab",ylab="ylab") points(0.1*i, 0.1*i , col=i) Sys.sleep(1) } dev.off() }which shows that there is a clear problem with png(type = "quartz"). I am even ready to mention the dreaded "b"-word :)
It's clearly a bug in multi-page bitmap output. Thanks, it is fixed now.
As an aside I find the difference between cairo and Xlib a bit strange: in the cairo device you can clearly see a difference between the box around the plot and where the x-axis / y-axis has been plotted. This might be a rendering issue, but personally I find it less aesthetically pleasing.
It depends a lot on your pixel size - in general it is not very pleasing when you use line widths that are narrower than the pixels of your bitmap output (Xlib just ignores it and always uses at least a pixel regardless since it does not support subpixel rendering). Therefore you may want to adjust the resolution (dpi) and/or pixel size for your output. Alternatively you can disable anti-aliasing but the output is even more horrible (as the Xlib rendering shows). Quartz does pixel-snapping for rectangles so if your line width is close to a pixel it works well.
Cheers, Simon _______________________________________________ R-SIG-Mac mailing list R-SIG-Mac@stat.math.ethz.ch https://stat.ethz.ch/mailman/listinfo/r-sig-mac
