[R] Problems with graphical devices, e.g., png(), pdf(): blurry graphical output

Y-H Chen myaverageorange at gmail.com
Wed Dec 17 21:43:11 CET 2008

On Wed, Dec 17, 2008 at 3:06 AM, Martyn Plummer <plummer at iarc.fr> wrote:
> The artefacts that you see are a normal result of using bitmap graphics
> devices.  I have tried to explain these below:

Thanks very much for your explanations, MP; they were quite informative!!

I recognize that others may feel differently, but to me, the "default"
PNG being produced by my system -- e.g.,
http://www.piccdrop.com/images/1229495327.png -- is not ideal for
presentation on the web. E.g., the image mentioned in the last
sentence is blurry at 100% in every web browser and image viewer I've
tried (even when I turn off aliasing in Eye of Gnome, as MP suggests).

Given my feelings about the blurriness, my question is: how can I
produce a non-blurry image via png()? I recognize that I can do so via
png('plot.png',type='Xlib') but, I am wondering if there are solutions
that don't involve Xlib.

I guess my second question (if anybody has patience for it) is: what
is the philosophy behind the current behavior? I was able to find some
of that here:


... but I am wondering if somebody could elaborate on this philosophy
in relationship to R and statistical graphics, or point me to some
links that do so. The link above does suggest that sharp single-pixel
lines are possible via Cairo. So: are sharp single-pixel lines
possible via Cairo in R, and if so how (this of course the question
I've asked above)? And if not, why?

(Just to be clear: I'm not saying the current implementation is
necessarily "bad." At present, I'm just trying to understand more
about why it is the way it is.)

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