The 'at a minimum' information requested by the posting guide is missing.
According to their documentation the cairo default fallback resolution is now 300dpi, and when I run your example on Fedora 21 that is what the emitted postscript says it is.
You can easily alter the R code to set it to something different: see http://cairographics.org/manual/cairo-cairo-surface-t.html for the call you would need to add.
However, I would suggest that you generate a bitmap directly and use that, as PostScript does not support semi-transparency.
On 14/07/2015 12:03, Tom Wenseleers wrote:
Dear all, In grDevices R functions cairo_pdf and cairo_ps it is mentioned that when transparency (alpha channels) are used in vector output, it will rasterize the PDF or postscript exported graph at a resolution of 72 dpi : https://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/cairo.html You can see the problem if you try library(ggplot2) cairo_ps(file = "test.eps",onefile = FALSE) qplot(Sepal.Length, Petal.Length, data = iris, color = Species, size = Petal.Width, alpha = I(0.7)) dev.off() as in the output (here zoomed in) the plot symbols are heavily pixelated then, showing it is only using 72 dpi. I was wondering how the fallback resolution could be increased to 600 dpi? In library(RGtk2) there is a command cairoSurfaceSetFallbackResolution, which I think is what is relevant here, but I would not know how to make grDevices use that parameter. Any thoughts? Using postscript() btw also doesn't work, since that doesn't support transparency, and returns the error "semi-transparency is not supported on this device: reported only once per page". I know I can use svg or pdf instead and that this would solve the problem, but problem is the journal (PloS) I would like to submit to only accepts EPS. So is there any solution to increase the quality in EPS, without having to rasterize everything to PNG? best regards, Tom Wenseleers [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
-- Brian D. Ripley, rip...@stats.ox.ac.uk Emeritus Professor of Applied Statistics, University of Oxford 1 South Parks Road, Oxford OX1 3TG, UK ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
