[R] PNG resolution

[Matthew Walker]

Hi,

For those who are interested in the solution to this problem, I modified 
the cairoDevice driver (version 2.10) so that it is now 
resolution-aware.  The owner of the package will probably include my 
changes in his next release, but if in the meantime you would like to 
use the modified version, please email me.

Cheers,

Matthew Walker

Joshua Wiley wrote:
> Hello Matthew,
>  
> I do not have a direct answer to your problem, but you could try 
> saving it as an EPS and then rasterizing it using a graphics program 
> (e.g., GIMP) to whatever resolution you wanted.
>  
> Best luck finding a real solution.
>  
>  
> Joshua
>
>
>  
> On Tue, Jan 26, 2010 at 9:05 AM, Matthew Walker 
> <matthew.walker.1 at ulaval.ca <mailto:matthew.walker.1 at ulaval.ca>> wrote:
>
>     Hi,
>
>     I expect that if I change only the resolution of an image,
>     although the image would have more pixels, if viewed in the same
>     physical size, the elements in the image would have the same
>     physical size but with more detail.  However, when I use the "res"
>     parameter of png() this is not what I see.  Would someone show me
>     how I can just "increase the resolution" without changing the
>     physical sizes of elements in my plot?
>
>     Maybe an example would help?  Below are three images.  I expect
>     that if I print them out, let's say scaled to fit the page, then
>     items such as the words "Title Text" would appear the same size.
>      Instead (for the last two) it appears that the same number of
>     pixels are being used, thus the text size appears smaller.
>
>     What should I do to just increase the resolution?
>
>     png("72dpi.png", width=6+2/3, height=6+2/3, units="in", res=72)
>     plot(0,0, main="Title Text")
>     dev.off()
>
>     png("300dpi.png", width=6+2/3, height=6+2/3, units="in", res=300)
>     plot(0,0, main="Title Text")
>     dev.off()
>
>     png("600dpi.png", width=6+2/3, height=6+2/3, units="in", res=600)
>     plot(0,0, main="Title Text")
>     dev.off()
>
>     Thanks in advance,
>
>     Matthew Walker
>
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>
>
> -- 
> Joshua Wiley
> Senior in Psychology
> University of California, Riverside
> http://www.joshuawiley.com/